[top]
000
FXUS66 KPQR 082238
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
238 PM PST SUN NOV 8 2009
.SYNOPSIS...SHOWERS WILL DECREASE THIS EVENING. THEN A RATHER STRONG
PACIFIC COLD FRONT WILL MOVE THROUGH THE FORECAST AREA MONDAY INTO
MONDAY EVENING WITH MORE RAIN...MOUNTAIN SNOW...AND BRISK WINDS.
ADDITIONAL SYSTEMS ARE EXPECTED MID WEEK AND BY NEXT WEEKEND.
&&
.SHORT TERM...SHOWERS CONTINUE THIS AFTERNOON BUT LOOKING MORE
OROGRAPHIC AND MAINLY CONFINED TO THE NW HALF OF THE AREA. SHOWERS
SHOULD CONTINUE TO TAPER OFF THIS EVENING AS THE FLOW ALOFT BACKS
AHEAD OF THE THIS SYSTEM...AND WILL CANCEL THE CASCADE WINTER WEATHER
ADVISORY FOR SNOW.
THIS NEXT FRONT WILL APPROACH LATE TONIGHT AND LIKELY MOVE ONSHORE
MON MORNING...THEN E OF THE AREA BY LATE MON AFTERNOON. THERE IS A
BIT OF A DOUBLE JET STRUCTURE IN THE GFS...WITH ONE WEAK JET POINTED
TOWARD NORTHERN CA....WHILE THE OTHER SEGMENT IS POINTED TO VANCOUVER
ISLAND MON MORNING. THIS WEAK SPLIT MAY SERVE TO HOLD S-SE COASTAL
WINDS BELOW HIGH WIND LEVELS AT THE HEADLANDS EARLY MON. THE SNOW
LEVEL WILL RISE ABOVE THE PASSES LATER TONIGHT AND ON MON... THEN
FALL BACK TO NEAR THE PASSES LATE MON AFTERNOON THROUGH TUE. IT IS
POSSIBLE THE HIGHER CASCADES OR THE SKI RESORTS COULD GET CLOSE TO
ADVISORY TOTALS...BUT PROBABLY NOT AT THE PASSES. SHOWERS WILL SPREAD
IN BEHIND THE FRONT MON NIGHT AND TUE BUT DO NOT LOOK AS WIDESPREAD
OR INTENSE AS THIS WEEKEND.
MODELS SHOW ANOTHER FRONT AHEAD OF AN ELONGATING UPPER TROUGH PUSHING
INTO THE REGION ON WED...FOR ADDITIONAL VALLEY RAIN AND MOUNTAIN
SNOW. RW
.LONG TERM...MODELS GENERALLY SHOWING AN UPPER TROUGH DROPPING SE OF
THE REGION THU...BRINGING SHOWERY WEATHER WITH SNOW LEVELS BETWEEN
3000 AND 4000 FT. EXTENDED MODELS ARE STILL SHOWING A POTENTIAL BREAK
IN THE WEATHER FROM LATE THU INTO AT LEAST FRI MORNING AS A WEAK
UPPER RIDGE MOVES THROUGH. MODEL CONSENSUS SHOWS ANOTHER PAC SYSTEM
MOVING IN FOR THE WEEKEND...BUT 12Z ECMWF HAS SHIFTED AWAY FROM THIS
SOLUTION SHOWING A BIT MORE RIDGING...WHICH WOULD HOLD THE STORM
TRACK A LITTLE TO THE N IF IT VERIFIES. RW
&&
.AVIATION...AREAS OF MVFR CONTINUE NEAR THE PORTLAND METRO AREA...
OTHERWISE MAINLY VFR CONDITIONS THROUGH THIS EVENING EXCEPT
OCCASIONAL MVFR IN SHOWERS AND ISOLATED THUNDERSTORMS. SMALL HAIL IS
ALSO POSSIBLE WITH THE HEAVIER SHOWERS. SHOWERS DECREASE AFTER
SUNSET...WITH MAINLY VFR CONDITIONS OVERNIGHT. STRONG FRONT
APPROACHES EARLY MON MORNING...CAUSING S WINDS TO INCREASE
ESPECIALLY ALONG THE COAST. CONDITIONS WILL DETERIORATE QUICKLY TO
MVFR/LOCAL IFR IN PERIODS OF RAIN ALONG THE COAST...WITH AREAS OF
MVFR DEVELOPING INLAND AS WELL.
KPDX AND APPROACHES...AREAS OF MVFR ARE LINGERING AROUND THE
PORTLAND METRO AREA THIS AFTERNOON...BUT THESE CIGS SHOULD LIFT
BREAK UP OR LIFT TO VFR BY 00Z. SCATTERED SHOWERS AND A SLIGHT
CHANCE OF A THUNDERSTORM CONTINUES THROUGH EARLY THIS EVENING...BUT
THE SHOWER THREAT IS EXPECTED TO DECREASE QUICKLY AFTER SUNSET.
MAINLY VFR CONDITIONS OVERNIGHT...FOLLOWED BY INCREASING S-SE WINDS
AND AREAS OF MVFR IN RAIN DEVELOPING MON MORNING. WEAGLE
&&
.MARINE...COASTAL BUOYS REPORTING 13-16 FT SEAS THIS AFTERNOON.
SEAS WILL GRADUALLY SUBSIDE TO 10-12 FT BY TUE MORNING. ANOTHER GOOD
CHANCE FOR GALES TONIGHT AND MONDAY AS ANOTHER STRONG FRONT
MOVES ACROSS THE COASTAL WATERS. LONG RANGE MODELS ARE SUGGESTING
THIS UNSETTLED WEATHER PATTERN WILL CONTINUE WELL INTO THE UPCOMING
WEEK. WEAGLE
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
WA/OR...GALE WARNING FOR CAPE SHOALWATER TO FLORENCE OUT 60 NM
THIS EVENING THROUGH MONDAY AFTERNOON.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR THROUGH
MONDAY AFTERNOON.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
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000
FXUS66 KOTX 082224
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
224 PM PST SUN NOV 8 2009
.SYNOPSIS...
THE ACTIVE WEATHER PATTERN WILL CONTINUE OVER THE INLAND NORTHWEST
THROUGH THE MIDDLE OF THE WEEK. LINGERING VALLEY RAIN AND
MOUNTAIN SNOW SHOWERS WILL CONTINUE INTO THIS EVENING...THEN A
BREAK IN THE PRECIPITATION IS EXPECTED MONDAY...BEFORE ANOTHER
MOIST STORM SYSTEM ARRIVES LATE IN THE DAY. MORE PACIFIC STORM
SYSTEMS ARE EXPECTED EVERY 24 TO 36 HOURS THROUGH THE NEW WORK
WEEK.
&&
.DISCUSSION...
TONIGHT AND MONDAY...A WEAK WARM FRONT IS PASSING THROUGH THE
FORECAST AREA FROM SOUTH TO NORTH THIS AFTERNOON...WITH MOST OF
THE PRECIPITATION FROM THIS LIFTING MECHANISM FALLING OVER THE
EASTERN HALF OF THE AREA WHERE THE MOIST ISENTROPIC ASCENT IS
AUGMENTED BY UPSLOPE FLOW ABOVE THE RISING TERRAIN OF THE EASTERN
BASIN AND PANHANDLE HIGH TERRAIN. THIS IS A SLOW MOVING FRONT WITH
REGIONAL RADAR AND SATELLITE SUGGESTING MORE MOISTURE UPSTREAM
WHICH WILL ENHANCE OVER THE EASTERN THIRD OF THE FORECAST AREA
INTO THIS EVENING. THE WARM FRONT WILL GRADUALLY LIFT OUT OF THE
FORECAST AREA TO THE NORTHEAST OVERNIGHT TONIGHT...ALLOWING
PRECIPITATION TO TAPER OFF LATER THIS EVENING...TO ONLY LINGERING
MOUNTAIN SNOW SHOWERS BY MIDNIGHT OR SO. HOWEVER...THE RECENT
PRECIPITATION WILL SET THE STAGE FOR A VERY MOIST AIR MASS BY DAWN
WITH THE PROSPECT FOR SIGNIFICANT FOG AND STRATUS FIELDS OVER THE
REGION AND CHOKING THE VALLEYS FOR THE MONDAY MORNING COMMUTE PERIOD.
FORTUNATELY THE MOIST AIR MASS AND EXPECTED RESIDUAL CLOUD COVER
WILL HELP KEEP MOST POPULATED LOCATIONS AT LEAST SLIGHTLY ABOVE
FREEZING OVERNIGHT.
FOR MONDAY THE GFS AND NAM MODELS ARE IN REASONABLE AGREEMENT AND
PLAUSIBLE AGAINST SATELLITE EXTRAPOLATION IN ESTABLISHING A SHORT
WAVE RIDGE OVER THE REGION AHEAD OF THE NEXT FRONTAL SYSTEM
VISIBLE OFF THE COAST NEAR 130W. THIS COLD FRONT WILL MOVE INTO
THE WESTERN ZONES DURING THE DAY MONDAY BRINGING MORE LIGHT
MOUNTAIN SNOW AND VALLEY RAIN TO THE CASCADES BY AFTERNOON...AND
SPREADING OUT OVER THE BASIN LATE IN THE DAY. SOUTHWEST FLOW AHEAD
OF THIS FRONT WILL ALLOW MONDAY`S HIGH TEMPERATURES TO ACHIEVE
SLIGHTLY HIGHER MAXIMUM TEMPS TOMORROW THAN TODAY. /FUGAZZI
MONDAY NIGHT THROUGH WEDNESDAY NIGHT...THE REGION WILL BE AFFECTED
BY TWO WEATHER SYSTEMS WITH A BRIEF BREAK ON TUESDAY. THE FIRST
SYSTEM WILL SPREAD WARM FRONTAL PRECIPITATION ACROSS THE FORECAST
AREA MONDAY NIGHT. MOIST ISENTROPIC UPGLIDE WILL BE ENHANCED BY
SYNOPTIC ASCENT FROM THE NOSE OF A 100KT JET DIRECTED SOUTHWEST TO
NORTHEAST ACROSS THE FORECAST AREA. THE MOST FAVORABLE AREA FOR
PRECIPITATION WILL SHIFT FROM THE WESTERN ZONES TO THE NORTHEAST
ZONES OVERNIGHT. WARM AIR ADVECTION WILL KEEP SNOW LEVELS ABOVE 4000
FT THROUGHOUT THE BULK OF THE PRECIPITATION. VALLEYS SHOULD SEE ALL
RAIN FOR THIS EVENT. COLD AIR ADVECTION ON TUESDAY WILL SHUT OFF
PRECIP ACROSS THE BASIN WITH MAINLY OROGRAPHIC SHOWERS LINGERING
OVER THE FAVORED TERRAIN. A SECOND STRONGER FRONTAL SYSTEM WILL
START TO AFFECT THE INLAND NORTHWEST BY TUESDAY NIGHT. STRONG
ISENTROPIC UPGLIDE WILL SPREAD OVERRUNNING PRECIPITATION FROM THE
CASCADES AND NORTHERN MOUNTAINS OVERNIGHT TUESDAY...REACHING THE
REMAINDER OF THE FORECAST AREA ON WEDNESDAY. UPPER JET DYNAMICS WILL
ONCE AGAIN ENHANCE SYNOPTIC LIFT WITH THE NORTHEAST ZONES AGAIN
FAVORABLY LOCATED IN THE LEFT FRONT QUAD. ONCE THE COLD FRONT SWEEPS
THROUGH WEDNESDAY NIGHT...SNOW LEVELS WILL DROP TO 2000-2500 FT.
THERE IS THE POTENTIAL FOR SNOWFALL ACCUMULATION IN THE NORTHEAST
VALLEYS. THIS SYSTEM WILL BE MONITORED CLOSELY FOR POSSIBLE WINTER
HIGHLIGHTS. TEMPERATURES WILL TREND NEAR SEASONAL NORMALS. /KELCH
THURSDAY THROUGH SUNDAY...VERY DYNAMIC PERIOD WITH JET STREAM
REMAINING IN CLOSE PROXIMITY AND GENERALLY TO THE SOUTH OF THE
FORECAST AREA MOST OF THE TIME DURING THIS FORECAST INTERVAL...MEANING
SENSIBLE WEATHER WILL BE HEAVILY INFLUENCED BY SHORTWAVE ACTIVITY
RUNNING NEAR THE JET THROUGH THIS TIME INTERVAL. SHORTWAVE/LOW
PRESSURE SYSTEM CONTAINING QUITE THE CONDITIONALLY UNSTABLE
AIR MASS TO BE EXPECTED ON THE NORTH SIDE OF THE JET KEEPS
THURSDAY/THURSDAY NIGHT SOMEWHAT UNSETTLED ALONG ITS WAY OF OF
EXIT...PRIMARILY THE IDAHO PANHANDLE BUT WRAP AROUND MOISTURE AND
FORCING COULD KEEP SHOWER ACTIVITY UP ALONG WASHINGTON NORTHEAST
MOUNTAINS AND OVER TO THE EAST SLOPES OF THE NORTHERN CASCADES.
SHORTWAVE RIDGING ENTERING IN THE WAKE OF THE EARLIER MENTIONED
EXITING WEATHER SYSTEM ALLOWS WARMING AND IMPROVING TREND FRIDAY
INTO PART OF FRIDAY NIGHT PERHAPS UNTIL MOISTURE PLUME/SUBTROPICAL
MOISTURE TAP ALIGNED AHEAD OF INCOMING COLD FRONT/LOW PRESSURE
SYSTEM ALLOWS STABLE STRATIFORM OVERRUNNING RAIN/SNOWFALL TO SWEEP
FROM WEST TO EAST SATURDAY NIGHT INTO SUNDAY. THE LOW LEVEL FLOW
AHEAD OF THIS INCOMING WET FRONTAL ZONE HAS ENOUGH LOW LEVEL
SOUTH/SOUTHEAST FLOW TO WORK AGAINST ANY LOWER LEVEL COLD AIR THAT
THE FRONT IS EXPECTED TO OVERRUN AND WILL LIKELY RESULT IN NOISY
SNOW LEVELS THAT RISE OVER MOST LOCATIONS FROM WENATCHEE TO COEUR
D` ALENE AND POINTS SOUTH TO PERHAPS GO WITH SNOW CHANGING TO ALL
RAIN WORDING THERE...BUT UP NORTH COLD AIR IS MORE STUBBORN TO
MODIFY VIA THIS SOUTH/SOUTHEAST FLOW AND WILL BE HARDER TO PIN
DOWN A HOMOGENEOUS SNOW LEVEL. LATER SUNDAY AS MORE OF EASTERN
WASHINGTON AND NORTHERN IDAHO IS BEHIND THE COLD FRONT A
TRANSITION TO INSTABILITY SHOWERS OF LESSER INTENSITY AND COVERAGE
COUPLED WITH A DROP IN SNOW LEVEL IS EXPECTED. FORECAST
TEMPERATURE WISE THE EXPECTATION IS THAT WITH SHORTWAVE RIDGING
AND LACK OF SENSIBLE WEATHER WILL ALLOW WARMING FOR FRIDAY...WITH
THE EARLIER DISCUSSED WARM AIR ADVECTION AHEAD OF THE WEEKEND
WEATHER SYSTEM TO SHOW ADDITIONAL WARMING SATURDAY OVER ALL BUT
PERHAPS THE NORTHERN THIRD OF THE FORECAST AREA DUE TO THE EARLIER
DISCUSSED STUBBORNNESS OF COOLER AIR MASSES TO MODIFY IN THIS
MANNER GIVEN THEIR LOCATION. /PELATTI
&&
.AVIATION...
A WEAK WARM FRONT WILL MOVE THROUGH THE REGION FROM SOUTH TO NORTH
TODAY BRINGING MAINLY MVFR CEILINGS IN LIGHT RAIN TO MOST TAF
LOCATIONS. MOUNTAINS RINGING THE COLUMBIA BASIN WILL SUFFER
WIDESPREAD OBSCURATIONS IN CLOUDS AND SNOW THROUGH TODAY. MILD
IMPROVEMENT IS EXPECTED OVERNIGHT TONIGHT WITH AN END TO
WIDESPREAD PRECIPITATION...BUT A MOIST LOW LEVEL AIR MASS WITH
LIGHT WINDS WILL PROMOTE FIELDS OF MVFR AND LOCAL IFR STRATUS
CEILINGS OVERNIGHT AND INTO MONDAY MORNING AT THE KGEG VCNTY TAF
SITES AND KEAT.
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 33 45 36 46 32 43 / 50 20 50 30 10 50
COEUR D`ALENE 33 45 34 45 32 43 / 60 10 60 40 20 60
PULLMAN 31 52 35 48 33 46 / 30 10 40 20 10 50
LEWISTON 35 53 40 52 38 50 / 10 10 20 20 10 40
COLVILLE 35 48 33 46 30 44 / 50 20 60 30 20 60
SANDPOINT 34 44 34 42 32 40 / 70 20 60 50 20 60
KELLOGG 34 40 34 41 33 39 / 60 10 50 70 30 60
MOSES LAKE 30 48 33 50 31 47 / 10 30 70 0 10 30
WENATCHEE 36 46 35 47 34 45 / 10 50 80 10 10 40
OMAK 34 48 30 46 25 44 / 20 50 90 0 20 40
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...NONE.
WA...NONE.
&&
$$
000
FXUS66 KOTX 081738
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
938 AM PST SUN NOV 8 2009
.SYNOPSIS...
THE ACTIVE WEATHER PATTERN WILL CONTINUE TODAY OVER THE PACIFIC
NORTHWEST THROUGH THE MIDDLE OF THE WEEK. VALLEY RAIN AND HIGH
MOUNTAIN SNOW IS EXPECTED THIS AFTERNOON OVER MUCH OF EASTERN
WASHINGTON AND NORTHERN IDAHO. A BREAK IN THE PRECIPITATION IS
EXPECTED MONDAY...BEFORE ANOTHER MOIST STORM SYSTEM ARRIVES LATE
IN THE DAY. MID WEEK ALSO PROMISES TO BE WET IN THE VALLEYS AND
SNOWY IN THE MOUNTAINS.
&&
.DISCUSSION...
REST OF TODAY...SATELLITE INDICATES A CONTINUING PROGRESSIVE AND
UNSETTLED WEATHER REGIME OVER THE REGION. A SEEMINGLY ENDLESS
SERIES OF FRONTAL COMPLEXES AND WAVES CONTINUES TO MENACE THE
REGION. A WEAK COLD FRONT PASSED LAST NIGHT...AND NOW A WEAK WARM
FRONT IS SETTING UP OVER THE FORECAST AREA WITH SATELLITE AND
REGIONAL RADAR BEGINNING TO FILL WITH LIGHT RETURNS OVER THE
COLUMBIA BASIN. THIS TREND WILL CONTINUE THROUGH THE REST OF THE
MORNING AND INTO THE AFTERNOON RESULTING IN A BROAD AREA OF LIGHT
VALLEY RAIN AND LIGHT MOUNTAIN SNOW AS THIS WARM FRONT SLOWLY
MOVES NORTH AND EAST OUT OF THE REGION. AMOUNTS WILL BE LIGHT WITH
THIS RELATIVELY WEAK SYSTEM. INHERITED FORECAST ALREADY REFLECTS THIS
EXPECTATION...BUT FORECAST WILL BE UPDATED TO REFINE POPS AND
TRENDS. /FUGAZZI
&&
.AVIATION...
A WEAK WARM FRONT WILL MOVE THROUGH THE REGION FROM SOUTH TO NORTH
TODAY BRINGING MAINLY MVFR CEILINGS IN LIGHT RAIN TO MOST TAF
LOCATIONS. MOUNTAINS RINGING THE COLUMBIA BASIN WILL SUFFER
WIDESPREAD OBSCURATIONS IN CLOUDS AND SNOW THROUGH TODAY. MILD
IMPROVEMENT IS EXPECTED OVERNIGHT TONIGHT WITH AN END TO
WIDESPREAD PRECIPITATION...BUT A MOIST LOW LEVEL AIR MASS WITH
LIGHT WINDS WILL PROMOTE FIELDS OF MVFR AND LOCAL IFR STRATUS
CEILINGS OVERNIGHT AND INTO MONDAY MORNING AT THE KGEG VCNTY TAF
SITES AND KEAT.
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 43 33 49 37 47 33 / 70 20 0 80 30 10
COEUR D`ALENE 44 33 49 35 46 32 / 70 20 0 80 40 20
PULLMAN 47 33 54 38 49 34 / 40 10 0 70 20 10
LEWISTON 53 37 57 43 54 40 / 10 10 0 40 20 10
COLVILLE 45 35 48 35 48 32 / 70 40 10 80 30 20
SANDPOINT 43 35 46 34 43 31 / 70 50 0 80 50 20
KELLOGG 40 32 47 34 41 33 / 80 30 0 70 80 30
MOSES LAKE 48 33 48 35 52 30 / 60 10 20 80 0 10
WENATCHEE 43 35 43 38 50 34 / 50 10 30 70 0 10
OMAK 44 33 44 33 48 28 / 60 30 40 90 0 20
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...NONE.
WA...NONE.
&&
$$
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000
FXUS66 KSEW 081732
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
930 AM PST SUN NOV 8 2009
.SYNOPSIS...A MOIST AND UNSTABLE AIR MASS WILL CONTINUE TO SUPPORT
SHOWERY WEATHER TODAY. A COLD FRONT WILL SPREAD RAIN AND WIND TO THE
COAST LATE TONIGHT AND INLAND ON MONDAY. A LARGE UPPER LEVEL TROUGH
WILL BRING SHOWERS TO THE AREA TUESDAY THROUGH THURSDAY AS IT
CROSSES THE REGION. ANOTHER FRONTAL SYSTEM WILL REACH THE AREA
FRIDAY OR SATURDAY.
&&
.SHORT TERM...A MOIST AND UNSTABLE AIR MASS IS STILL IN PLACE OVER
WRN WA THIS MORNING...THOUGH THE INSTABILITY ON THIS MORNINGS 12Z
KUIL SOUNDING WAS WEAKER THAN WHAT WAS SHOWN ON THE PREVIOUS TWO
MORNINGS. IN ADDITION...PRESSURE GRADIENTS HAVE BEEN TRENDING LESS
SOUTHERLY AND LESS ONSHORE DURING THE PAST 12-18 HOURS. IN
FACT...THE 16Z UIL-BLI GRADIENT WAS -2.3 MB...SO LOW-LEVEL FLOW IS
ACTUALLY NOW TRENDING OFFSHORE. THESE FACTORS WILL MEAN A MUCH LESS
VIGOROUS FIELD OF SHOWERS TODAY WITH NO MORE THUNDER EXPECTED.
LOOKS LIKE THE SHORTWAVE ABOUT TO CROSS 150W WILL AMPLIFY THE
LONGWAVE TROUGH OVER THE ERN PAC...TURNING OUR FLOW ALOFT MORE
SOUTHERLY TODAY AND THIS EVENING. AS THE SHORTWAVE EXITS THE BASE OF
THE LONGWAVE TROUGH THIS AFTERNOON...IT WILL ENERGIZE THE BAROCLINIC
BOUNDARY DRAPED OUT ALONG 40N WITH CYCLOGENESIS TAKING PLACE. BOTH
THE 12Z NAM AND GFS AGREE THAT BY 12Z MON...A DEEPENING 996 MB LOW
WILL REACH THE CENTRAL VANCOUVER ISLAND COAST AS IT TRACKS N-NE. AS
THE LOW PASSES BY...WINDY CONDITIONS WILL DEVELOP...MOST NOTABLY FOR
THE COAST AND THE NORTH INTERIOR. AT ITS PEAK AROUND 12Z MON...THE
GFS SHOWS 850 MB WINDS REACHING 70 KT ALONG THE NORTH COAST. THE NAM
SHOWS 925 MB WINDS REACHING 55-65 KT ALONG THE NORTH COAST AND NORTH
INTERIOR AROUND 12-15Z. THE NAM-BASED MARINE MOS GUIDANCE BRINGS
SUSTAINED WIND SPEEDS OF 41-45 KT AT TATOOSH ISLAND DURING THIS
TIME. BEST IDEA AT THIS TIME IS THAT WIND SPEEDS WILL FALL JUST SHY
OF WARNING CRITERIA...BUT SUFFICE IT TO SAY THAT IT WILL BE A WINDY
LATE NIGHT AND MONDAY MORNING FOR MANY. WIND ADVISORIES WILL LIKELY
BE ISSUED FOR THE NORTH INTERIOR AND WESTERN STRAIT WITH THE
AFTERNOON FORECAST PACKAGE.
TRAILING THE DEEPENING LOW CENTER WILL BE A COLD FRONT...WHICH WILL
CROSS WRN WA DURING THE DAY ON MON. IT WILL BE ACCOMPANIED BY RAIN
AND FOLLOWED BY A DECREASE IN WIND. A SHORTWAVE RIDING UP IN SW FLOW
ALOFT WILL KEEP THE RAIN GOING ON MON NIGHT. SNOW LEVELS SHOULD
GENERALLY RUN NEAR 3500 FEET ON MON NIGHT FOLLOWING THE COLD FRONT.
THE UPPER PATTERN WILL AGAIN AMPLIFY ON TUE. THIS TIME...THE WRN
U.S. UPPER RIDGE WILL TRY NUDGING INTO WRN WA...SUPPORTING ON TUE
NIGHT THE BEST CHANCE FOR SOME DRY WEATHER THROUGH MID-WEEK. THE ERN
PAC TROUGH WILL THEN START TO MARCH EAST...PUSHING YET ANOTHER COLD
FRONT THROUGH WRN WA ON WED WITH ANOTHER ROUND OF RAIN.
AN UPPER TROUGH AXIS SHOULD BE NEARBY LATER ON WED AND WED NIGHT.
THE ACCOMPANYING COLD AIR ALOFT AND INSTABILITY SHOULD SUPPORT
SHOWERY WEATHER THROUGH AT LEAST WED NIGHT...POSSIBLY INTO THU.
HANER
.LONG TERM...FROM PREVIOUS DISCUSSION...GFS AND ECMWF AGREE ON
BRINGING AN UPPER LEVEL TROUGH AXIS ACROSS THE AREA WEDNESDAY
NIGHT...WITH A MORE ORGANIZED BAND OF SHOWERS OR RAIN MOVING OVER
THE AREA JUST AHEAD OF THE TROUGH AXIS ON WEDNESDAY. SHOWERS LIKELY
FORECAST WORKS FINE FOR NOW. SNOW LEVELS SHOULD DROP DOWN BELOW PASS
LEVELS WEDNESDAY NIGHT...BUT SHOWER ACTIVITY SHOULD BE DECREASING AT
THAT POINT. GFS/ECMWF SOLUTIONS DIVERGE SIGNIFICANTLY AFTER
THURSDAY...SO THE FRIDAY/SATURDAY SYSTEM REMAINS IN DOUBT. WILL
LEAVE THE FORECASTS AS IS FOR NOW SINCE CONFIDENCE IN THE MODELS IS
LOW. KAM
&&
.HYDROLOGY...NO SIGNIFICANT FLOODING IS EXPECTED IN WESTERN
WASHINGTON DURING THE NEXT WEEK. THIS INCLUDES THE GREEN RIVER.
NO SIGNIFICANT FRONTAL SYSTEMS ARE EXPECTED THIS WEEK. MONDAYS FRONT
WILL BRING SOME BRIEF MODERATE RAIN...WITH SNOW LEVELS AROUND 4500
OR 5000 FEET. THE PRECIPITATION BAND THAT IS FORECAST TO FORM AHEAD
OF THE UPPER LEVEL TROUGH ON WEDNESDAY MAY BRING SOME BRIEF MODERATE
SHOWERS TO THE AREA...BUT SNOW LEVELS WILL BE DOWN TO 3000 TO 3500
FEET. MODELS ARE HAVING TROUBLE IN THE LONG TERM WITH THE FRIDAY OR
SATURDAY FRONTAL SYSTEM...BUT SO FAR ALL THE SOLUTIONS INDICATE A
PROGRESSIVE SYSTEM THAT ONLY BRINGS A RELATIVELY SHORT PERIOD OF
MODERATE TO HEAVY PRECIPITATION. IN THE EXTENDED WAY OUT
PERIOD...THE GFS HEMISPHERIC 5-WAVE CHARTS SHOW A MEAN LONG WAVE
TROUGH OUT NEAR 150W OR SO WHICH WOULD MAINTAIN THE CURRENT
PROGRESSIVE PATTERN OF WEATHER SYSTEMS CROSSING THE AREA...BUT NOT
LINGERING TO PRODUCE LENGTHY PERIODS OF RAIN. KAM
&&
.AVIATION...BASIC PATTERN HAS CHANGED LITTLE...WEST-SOUTHWEST FLOW
ALOFT WITH A DEVELOPING LOW PRESSURE CENTER OFFSHORE. AIR MASS IS
MOIST AND SLIGHTLY UNSTABLE. SCATTERED SHOWERS WILL CONTINUE. THIS
MORNING THE SHOWERS SEEM TO BE CONCENTRATED IN SOUTHERN AREAS.
CEILINGS AGAIN RANGE FROM NO CEILING TO MVFR IN OR NEAR SHOWERS.
AFTER 00Z HIGH AND MID LEVEL CLOUDS WILL INCREASE AS NEXT SYSTEM
BEGINS TO AFFECT THE AREA.
KSEA...PARAGRAPH ABOVE APPLIES. SOUTH WIND 5-10 KT WITH HIGHER GUSTS
IN SHOWERS. WIND WILL TURN SOUTHEAST AND INCREASE TO 10-15 KT AFTER
03Z. CHB
&&
.MARINE...NO REASON TO DOUBT MODELS WHICH SPIN UP A DEEP LOW
SOUTHWEST OF WASHINGTON AND BRING IT NORTHEAST THEN NORTH ALONG THE
COAST LATE TONIGHT. THIS WILL BRING GALES TO MOST WATERS AND HAVE
CONVERTED THE REMAINING GALE WATCHES TO WARNINGS. WIND IS
SURPRISINGLY STRONG THIS MORNING SO HAVE SIMPLIFIED MATTERS BY
HAVING THE GALE WARNED ZONES HAVE SMALL CRAFT ADVISORIES UNTIL THE
GALE WARNING GOES INTO EFFECT TONIGHT. MODELS HAVE BACKED OFF A BIT
ON THE PEAK STRENGTH OF THE SYSTEM...NO 50 KT SURFACE WINDS AROUND
TATOOSH. WILL INSPECT THE 12Z MM5-GFS CLOSELY.
ANOTHER IMPULSE MOVES THROUGH THE FLOW MONDAY NIGHT...WITH ANOTHER
FRONT WEDNESDAY. PATTERN IS QUITE PROGRESSIVE AND TIMING DETAILS
LIKELY TO CHANGE. AFTER WEDNESDAY SPLIT FLOW APPEARS TO DEVELOP
WHICH KEEPS WASHINGTON FAIRLY DRY. CHB
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...GALE WARNING COAST...ENTRANCES...ADMIRALTY INLET...CAMANO
ISLAND TO POINT ROBERTS TONIGHT AND MONDAY.
SMALL CRAFT ADVISORY SAME ZONES TODAY.
$$
WWW.WEATHER.GOV/SEATTLE
FOR AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION...PLEASE SEE
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML.
000
FXUS66 KPQR 081657
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
857 AM PST SUN NOV 8 2009
.SYNOPSIS...ONE MORE DAY OF COOL SHOWERY WEATHER IS IN STORE FOR
SOUTHWEST WASHINGTON AND NORTHWEST OREGON TODAY...WITH A THREAT OF
SOME THUNDERSTORMS AS WELL. THE SHOWERS WILL DECREASE THIS EVENING.
THEN A RATHER STRONG PACIFIC COLD FRONT WILL MOVE THROUGH THE
FORECAST AREA MONDAY INTO MONDAY EVENING WITH MORE RAIN...MOUNTAIN
SNOW...AND BRISK WINDS. ADDITIONAL SYSTEMS ARE EXPECTED MID WEEK AND
LATE IN THE WEEK.
&&
.SHORT TERM...SHOWERS CONTINUE TO SPREAD ONSHORE THIS MORNING AND
WILL LIKELY CONTINUE MUCH OF TODAY AS RADAR AND MODELS SHOW
ADDITIONAL MOISTURE SHIFTING INLAND. THERE LOOKS TO BE SOME TENDENCY
FOR THE SHOWERS TO BEGIN TAPERING OFF DURING THE AFTERNOON. ONLY ONE
LIGHTNING STRIKE OFF OF NORTH BEND HAS BEEN DETECTED SINCE 15Z BUT
THE COLD TOPPED CLOUDS OFFSHORE SHOW THAT THE THREAT SHOWN IN MODELS
REMAINS TODAY. HEAVY SHOWERS ON RADAR MOVING INTO THE N OREGON
CASCADES SUPPORTS THE WINTER WEATHER ADVISORY FOR SNOW IN THE S WA/N
OREGON CASCADES TODAY. THE MODELS ARE IN PRETTY GOOD AGREEMENT ON THE
AXIS OF THE MAIN PRECIPITATION BEING FROM THE MIDDLE OF THE COAST UP
THROUGH THE S WA/N OREGON CASCADES.
THE SHOWERS DECREASE RAPIDLY LATE TODAY AND TONIGHT...THEN THE NEXT
FRONT APPROACHES. IT MOVES THROUGH MON AND EARLY MON NIGHT WITH MORE
RAIN...SNOW UP IN THE CASCADES...AND BRISK WINDS. THE COAST MAY GET
CLOSE TO HIGH WIND BUT FOR NOW WILL STAY JUST BELOW...AND ANALYZE
FURTHER FOR THE AFTERNOON PACKAGE. THE SNOW LEVEL WILL RISE ABOVE THE
PASSES LATER TONIGHT AND ON MON...THEN FALL BACK TO NEAR THE PASSES
MON NIGHT AND TUE. IT IS POSSIBLE THE HIGHER CASCADES OR THE SKI
RESORTS COULD GET CLOSE TO ADVISORY TOTALS...BUT PROBABLY NOT AT THE
PASSES. SHOWERS WILL SPREAD IN BEHIND THE FRONT MON NIGHT AND TUE BUT
DO NOT LOOK AS WIDESPREAD OR INTENSE AS THIS WEEKEND. RW/TOLLESON
.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...
MODELS IN FAIRLY GOOD AGREEMENT SHOWING A COOL UPPER TROUGH DROPPING
SE THROUGH THE REGION WED AND THU. THIS SHOULD BRING SHOWERY WEATHER
WITH SNOW LEVELS BETWEEN 3000 AND 4000 FT. EXTENDED MODELS ARE STILL
SHOWING A POTENTIAL BREAK IN THE WEATHER FROM LATE THU INTO AT LEAST
FRI MORNING AS A WEAK UPPER RIDGE MOVES THROUGH. ANOTHER PAC SYSTEM
LOOKS LIKELY FRI NIGHT AND SAT. RW
&&
.AVIATION...GENERALLY VFR EXCEPT OCCASIONAL MVFR CONDITIONS IN
SHOWERS OVER THE FORECAST AREA THIS MORNING...MVFR MAINLY IN THE
NORTH VALLEY. ISOLATED THUNDERSTORMS WITH SMALL HAIL POSSIBLE AGAIN
TODAY. SHOWERS DECREASE AFTER SUNSET...WITH MAINLY VFR CONDITIONS
OVERNIGHT.
KPDX AND APPROACHES...AREAS OF MVFR THIS MORNING...BECOMING
GENERALLY VFR BY MIDDAY. SHOWERS MAY BRIEFLY LOWER CIGS/VSBYS TO
MVFR THROUGH THIS EVENING. SOME SHOWERS MAY BE HEAVY WITH THE
POSSIBILITY OF SMALL HAIL AND LIGHTNING AGAIN TODAY. COVERAGE OF
SHOWERS SHOULD DECREASE AFTER SUNSET...WITH MAINLY VFR CONDITIONS
OVERNIGHT. WEAGLE
&&
.MARINE...COASTAL BUOYS REPORTING 14-17 FT SEAS THIS MORNING...BELOW
OUR HIGH SURF ADVISORY CRITERIA. A SLOW DOWNWARD TREND IN SEAS WILL
CONTINUE THROUGH TONIGHT...SO DECIDED TO CANCEL HIGH SURF ADVISORY.
SEAS SHOULD DROP TO 10-12 FT BY TUE MORNING. ANOTHER GOOD CHANCE FOR
GALES TONIGHT AND MONDAY AS ANOTHER STRONG FRONT MOVES ACROSS THE
COASTAL WATERS. LONG RANGE MODELS ARE SUGGESTING THIS UNSETTLED
WEATHER PATTERN WILL CONTINUE WELL INTO THE UPCOMING WEEK.
WEAGLE/WOLFE
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
WA/OR...GALE WARNING FOR CAPE SHOALWATER TO FLORENCE OUT 60
NM THIS EVENING THROUGH MONDAY AFTERNOON.
SMALL CRAFT ADVISORY FOR WINDS CAPE SHOALWATER TO
FLORENCE OUT 60 NM THROUGH THIS AFTERNOON.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS CAPE SHOALWATER
TO FLORENCE OUT 60 NM THIS AFTERNOON.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR THROUGH
MONDAY AFTERNOON.
WINTER WEATHER ADVISORY FOR SNOW IN THE SOUTH WASHINGTON
AND NORTH OREGON CASCADES TODAY.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
000
FXUS66 KOTX 081216
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
415 AM PST SUN NOV 8 2009
.SYNOPSIS...
THE ACTIVE WEATHER PATTERN WILL CONTINUE TODAY OVER THE PACIFIC
NORTHWEST THROUGH THE MIDDLE OF THE WEEK. VALLEY RAIN AND HIGH
MOUNTAIN SNOW IS EXPECTED THIS AFTERNOON OVER MUCH OF EASTERN
WASHINGTON AND NORTHERN IDAHO. A BREAK IN THE PRECIPITATION IS
EXPECTED MONDAY...BEFORE ANOTHER MOIST STORM SYSTEM ARRIVES LATE
IN THE DAY. MID WEEK ALSO PROMISES TO BE WET IN THE VALLEYS AND
SNOWY IN THE MOUNTAINS.
&&
.DISCUSSION...
TODAY AND TONIGHT...THE EARLY MORNING WATER VAPOR LOOP SHOWS ZONAL
FLOW CONTINUING INTO THE PACIFIC NORTHWEST. THE UPPER LOW THAT HAS
BEEN OVER THE GULF OF ALASKA THE LAST TWO DAYS IS MORE DIFFUSE
THAN 24 HOURS AGO...AND THE FLOW OVER THE EASTERN PACIFIC IS
CLUTTERED WITH LITTLE SHORTWAVES. IT IS TOUGH TO PICK OUT THESE
FAST MOVING WAVES ON SATELLITE...AND THE MODELS HAVE STRUGGLED TO
RESOLVE THEM DURING THE LAST COUPLE OF DAYS. A VORTICITY MAX
NEARING THE MOUTH OF THE COLUMBIA RIVER (AS OF 10Z) WILL BE THE
MAIN PLAYER FOR THE WEATHER OVER EASTERN WASHINGTON AND NORTHERN
IDAHO TODAY. BOTH THE 00Z NAM AND 00Z GFS GRABBED ONTO THIS
VORTICITY AND GENERATED A GENEROUS BAND OF PRECIPITATION ACROSS
THE COLUMBIA BASIN THROUGH THE NORTHERN IDAHO PANHANDLE. LIFT
AHEAD OF THIS VORTICITY CENTER SHOULD BE ENHANCED BY MOIST
ISENTROPIC ASCENT IN THE 295-300K LAYER COUPLED WITH ELEVATED
THETA-E LAPSE RATES APPROACHING 0C. THE BEST PRECIPITATION BAND
SHOULD OCCUR FROM 18Z-03Z ALONG THE BEST THERMAL GRADIENT NEAR
700MB. SINCE THE WESTERLY FLOW IN THE 850-700MB LAYER HAS BEEN
WEAKENING OROGRAPHIC SNOWS OVER THE PANHANDLE HAVE BEEN
DECREASING...SO THE WINTER STORM WARNINGS FOR THE MOUNTAINS WILL
BE TAKEN DOWN EARLY THIS MORNING. THE WEAKENING WESTERLY FLOW IN
THE MID LEVELS WILL ALSO HELP TO MINIMIZE THE RAIN SHADOW OVER THE
BASIN TODAY. THE RAIN AMOUNTS GENERATED BY THE MODELS OF .10-.25
INCHES FROM THE MOSES LAKE AREA THROUGH DEER PARK WILL HAVE A GOOD
CHANCE OF VERIFYING. ELEVATIONS ABOVE 3500 FEET IN THIS SWATH OF
PRECIPITATION STAND A GOOD CHANCE OF RECEIVING 1-4 INCHES OF SNOW
THIS AFTERNOON/EVENING INCLUDING THE MT. SPOKANE AREA THROUGH THE
HIGH ELEVATIONS OF KOOTENAI AND BONNER COUNTIES.
STRATUS DEVELOPMENT THIS EVENING LOOKS LIKELY IN THE MOSES
LAKE...WENATCHEE...AND OMAK AREAS. WEAK SOUTHEASTERLY BOUNDARY
LAYER FLOW...MID LEVEL WARMING...AND THE LIKELIHOOD OF WET GROUND
DUE TO PRECIPITATION SUGGESTS FOG OR STRATUS. THE SPOKANE AREA AND
THE VALLEYS NORTH AND EAST OF THE METRO MAY ALSO BE PLAGUED BY
STRATUS OVERNIGHT. /GKOCH
MONDAY THROUGH WEDNESDAY...THE LARGE SCALE FLOW PATTERN CONTINUES
TO EXHIBIT SIMILAR PATTERNS TO THOSE EXHIBITED BY THE MODELS
DURING THIS PORTION OF THE FORECAST FOR THE LAST SEVERAL DAYS. IN
GENERAL...A RIDGE POPPING UP OVER CENTRAL MONTANA AND A DEEPENING
LONG WAVE TROUGH OFF THE PACIFIC COAST OF NORTH AMERICA LEAVE THE
FORECAST AREA IN THE TRANSITION ZONE BETWEEN THE TWO REGIMES EARLY
IN THE WEEK. THE RESULT IS BROAD SOUTHWESTERLY FLOW ALOFT WITH A
STRONG WEST-TO-EAST SURFACE PRESSURE GRADIENT BECOMING
INCREASINGLY ESTABLISHED ACROSS THE AREA ON MONDAY. THIS SETUP
GRADUALLY MIGRATES EASTWARD BY MONDAY NIGHT AND TUESDAY...BRINGING
A RATHER IMPRESSIVE SHORT WAVE ACROSS THE AREA WITH A VERY STRONG
COLD FRONT. DOWNSLOPE DRYING BEHIND THE FRONT QUICKLY ENVELOPES
THE AREA BY MID-WEEK...BEFORE LARGE CHANGES AGAIN OCCUR LATER IN
THE WEEK.
THE PRESSURE GRADIENT SETUP ON MONDAY PER THE MODEL CONSENSUS
SHOULD ALLOW FAIRLY IMPRESSIVE EASTERLY SURFACE FLOW TO
CONCENTRATE DOWNSLOPE DRYING FROM THE LEWISTON AREA...THROUGH THE
PALOUSE AND INTO THE SPOKANE/CDA AREA ON MONDAY. WITH MEAGER LAYER
RH VALUES ABOVE THE BOUNDARY LAYER...CLEAR TO PARTLY CLOUDY SKIES
SHOULD BE THE RULE THROUGH AT LEAST THE FIRST HALF OF THE DAY
ACROSS FAR EASTERN WA AND PORTIONS OF THE ID PANHANDLE. THE LONE
EXCEPTION WILL BE ALONG THE CANADIAN BORDER WHERE A NORTHWARD
ADVANCING WARM FRONT WILL LIKELY STILL BE STRADDLING THE BORDER
THROUGH 18Z OR SO ON MONDAY. WHILE A BIT OF PRECIP ALONG THIS
FRONT IS POSSIBLE MONDAY MORNING...UNIMPRESSIVE ISENTROPIC OMEGAS
AROUND 295K AND FAIRLY HIGH CONDENSATION PRESSURE DEFICITS PER THE
GFS SEEM TO INDICATE THAT CHANCE IS FAIRLY SMALL. HOWEVER...BY
MONDAY AFTERNOON AND MONDAY NIGHT...WITH THE OFF SHORE SHORT WAVE
ADVANCING TOWARD THE COAST...LAYER RH VALUES WILL INCREASE RAPIDLY
FROM WEST TO EAST. AS THEY DO...DEEP LAYER ISENTROPIC LIFT WILL DO
LIKEWISE. MIXING RATIOS APPROACHING 4 G/KG AND STRONG SOUTHWEST TO
NORTHEAST MOISTURE TRANSPORT ON THE 295K SURFACE WILL INCREASE THE
CHANCES OF PRECIPITATION PROGRESSIVELY INTO MONDAY EVENING. WITH
THE FLOW BECOMING INCREASINGLY SOUTHERLY FROM EASTERLY...SNOW
LEVELS WILL ALSO BEGIN TO RISE. BY MONDAY AFTERNOON...850 MB
TEMPERATURES ACROSS THE ENTIRE AREA AWAY FROM THE EAST SLOPES OF
THE CASCADES WILL BE IN THE 2 TO 7C RANGE...WITH WET BULB ZERO
HEIGHTS GENERALLY IN THE VICINITY OF 4500 TO 5500 FEET. AS A
RESULT...SNOW LEVELS SHOULD BE HIGH ENOUGH EVEN WITH IMPRESSIVE
LIFT AND FAIRLY IMPRESSIVE QPF TO PRECLUDE WINTER STORM HIGHLIGHTS
FOR THE MOUNTAINS.
THE SYSTEM FROM MONDAY NIGHT SHIFTS EASTWARD QUICKLY BY
TUESDAY NIGHT...WITH WESTERLY FLOW INCREASING AND COLD ADVECTION
AT ALL LAYERS TAKING HOLD. TEMPERATURES AT 850 MB FALL OFF TOWARD
THE 0 TO -2C RANGE BY WEDNESDAY MORNING...WITH WBZ HEIGHTS
DROPPING TO AROUND 3500 FEET.
WEDNESDAY NIGHT THROUGH THE EXTENDED FORECAST...WITH COLD
ADVECTION THE MAIN PLAYER BY WEDNESDAY NIGHT ACROSS THE
AREA...ANOTHER DEEPER SYSTEM IS SET TO TAKE SHAPE OFF SHORE. THE
00Z MODEL GUIDANCE HAS REALLY COME INTO MUCH BETTER AGREEMENT ON
CLOSING OFF A DEEP MID-LEVEL SYSTEM AROUND 535 DAM ACROSS WESTERN
WASHINGTON AND SHIP IT SOUTHEASTWARD FROM THAT POINT WEDNESDAY
NIGHT. IMPRESSIVE Q-VECTOR CONVERGENCE AND IMPRESSIVE DIFFERENTIAL
PVA SET THE STAGE FOR A DECENT BATCH OF PRECIPITATION AHEAD OF
THIS SYSTEM. HOWEVER...DEPENDING ON THE DEPTH AND TRACK OF ANY LOW
LEVEL FEATURE ASSOCIATED WITH IT...THE BOUNDARY LAYER THERMAL
PROFILE IS LIKELY TO BE STARKLY DIFFERENT ACROSS THE FORECAST AREA.
AT THE MOMENT...THE MODELS ARE FAVORING A MUCH COLDER BOUNDARY
LAYER BY THURSDAY NIGHT AND INTO THE NEXT WEEKEND SUCH THAT SNOW
IN ASSOCIATION WITH THIS SYSTEM SEEMS LIKELY BY THURSDAY NIGHT
ACROSS MOST VALLEY LOCATIONS. HOWEVER...THIS WILL LIKELY CONTINUE
TO EVOLVE AS THE WEEK GOES ON...SO STAY TUNED. /FRIES
&&
.AVIATION...
A BAND OF PRECIPITATION IS EXPECTED TO DEVELOP OVER THE COLUMBIA
BASIN AROUND 17Z AND SPREAD EAST THROUGH SPOKANE AND INTO THE
NORTHERN IDAHO PANHANDLE BY 22Z. RAIN WILL BRING CEILINGS DOWN TO
IFR OR MVFR AT KEAT...KGEG...KSFF...AND KCOE. CEILINGS PROBABLY
WON`T IMPROVE MUCH AS THE RAIN ENDS FROM WEST TO EAST BETWEEN
20Z-02Z. WEAK LOW LEVEL WINDS AND INCREASINGLY LOW LEVEL STABILITY
WILL PROVIDE FAVORABLE CONDITIONS FOR THE DEVELOPMENT OF STRATUS AT
THE AIRPORTS MENTIONED ABOVE. LOW CEILINGS WILL LIKELY LINGER
THROUGH MOST OF THE NIGHT...ESPECIALLY AROUND WENATCHEE. /GKOCH
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 43 33 49 37 47 33 / 60 20 0 80 30 20
COEUR D`ALENE 44 33 49 35 46 32 / 60 20 0 80 40 20
PULLMAN 47 33 54 38 49 34 / 30 10 0 70 20 20
LEWISTON 53 37 57 43 54 40 / 10 10 0 40 20 10
COLVILLE 45 35 48 35 48 32 / 70 40 10 80 30 20
SANDPOINT 43 35 46 34 43 31 / 60 50 0 80 50 30
KELLOGG 40 32 47 34 41 33 / 50 30 0 70 80 30
MOSES LAKE 48 33 48 35 52 30 / 60 10 20 80 0 10
WENATCHEE 43 35 43 38 50 34 / 50 10 30 70 0 10
OMAK 44 33 44 33 48 28 / 60 30 40 90 0 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...NONE.
WA...NONE.
&&
$$
000
FXUS66 KSEW 081142
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
342 AM PST SUN NOV 8 2009
.SYNOPSIS...A SMALL WEAK UPPER LEVEL TROUGH WILL BRING SHOWERS TO
WESTERN WASHINGTON THIS MORNING...WITH A CHANCE OF SHOWERS
CONTINUING THIS AFTERNOON IN THE UNSTABLE AIR MASS. A COLD FRONT
WILL SPREAD RAIN AND WIND TO THE COAST LATE TONIGHT AND INLAND ON
MONDAY. A LARGE UPPER LEVEL TROUGH WILL BRING SHOWERS TO THE AREA
TUESDAY THROUGH THURSDAY AS IT CROSSES THE REGION. ANOTHER FRONTAL
SYSTEM WILL REACH THE AREA FRIDAY OR SATURDAY.
&&
.SHORT TERM...THE BROAD UPPER LEVEL TROUGH AND UNSTABLE AIR MASS
CONTINUE OVER THE AREA TODAY. IR SATELLITE IMAGERY SHOWS A WEAK
SHORTWAVE TROUGH EMBEDDED IN THE FLOW JUST OFFSHORE THAT SHOULD
INCREASE THE SHOWER ACTIVITY THIS MORNING. SHOULD SEE SHOWERS
DECREASE BY THIS AFTERNOON BEHIND THE SHORTWAVE...BUT WILL HAVE TO
MAINTAIN A CHANCE OF SHOWERS DUE TO CONTINUING AIR MASS INSTABILITY.
NAM BUFR SOUNDINGS LACK THE DEEPER INSTABILITY OF THE PAST FEW DAYS
SO WILL LEAVE THUNDERSTORMS OUT OF THE FORECAST. WITH UPSLOPE FLOW
OVER THE MOUNTAINS WEAKENING AND SHOWERS DECREASING THIS
AFTERNOON...WILL LET THE WINTER WEATHER ADVISORY FOR THE CASCADES
EXPIRE.
BOTH GFS/ECMWF ARE STICKING WITH THEIR SOLUTION TO FORM A SOMEWHAT
VIGOROUS COLD FRONT OUT OF THE WAVE CROSSING 140W THIS MORNING. THE
WAVE IS QUITE WEAK LOOKING AT THIS POINT...SO THERE WILL HAVE TO BE
SOME RAPID DEVELOPMENT THROUGH THIS EVENING FOR THE SYSTEM CATCH UP
WITH THE MODELS SOLUTION. FURTHERMORE...LAST NIGHTS MODELS HAD SHOWN
A WARM FRONT CROSSING W WA THIS EVENING...WHICH THE LATEST MODELS
NOW TAKE UP OVER VANCOUVER ISLAND. DESPITE LINGERING DOUBTS WILL
STICK WITH THE MODEL SOLUTION FOR A LITTLE LONGER AND BRING RAIN TO
THE COAST LATE TONIGHT...THEN SPREAD IT INLAND MONDAY. WILL COUNT ON
ENOUGH GRADIENT DEVELOPING TO PRODUCE WINDY CONDITIONS COAST AND ONE
NOTCH BELOW INLAND.
ANOTHER ROUND OF SHOWERY WEATHER SHOULD RESUME MONDAY NIGHT AND
TUESDAY AS A COOLER MORE UNSTABLE AIR MASS MOVES INLAND AHEAD OF A
LARGE UPPER LEVEL TROUGH. SHOULD HAVE ANOTHER SERIES OF WEAK
SHORTWAVE TROUGHS ROUNDING THE MAIN TROUGH...EACH BRINGING A MORE
ORGANIZED BATCH OF SHOWERS TO W WA. MODEL SOLUTIONS SEEM TO BE IN
FLUX WITH THESE DETAILS.
UPSLOPE FLOW OVER THE CASCADES NEVER GETS PARTICULARLY STRONG FOR
VERY LONG THROUGH TUESDAY...AND THE NAM NEVER SHOWS THE 12 HOUR SNOW
ACCUMULATION GETTING ABOVE 6 INCHES...EXCEPT FOR THE VOLCANOES. WILL
HAVE WATCH FOR ANYTHING REACHING WINTER WEATHER ADVISORY
CRITERIA...BUT ONE MAY NOT BE NEEDED OVER THE NEXT FEW DAYS. LOOKS
LIKE SNOW LEVELS WILL GET DOWN TO 3500-4000 FEET AT THE LOWEST. KAM
.LONG TERM...GFS AND ECMWF AGREE ON BRINGING AN UPPER LEVEL TROUGH
AXIS ACROSS THE AREA WEDNESDAY NIGHT...WITH A MORE ORGANIZED BAND OF
SHOWERS OR RAIN MOVING OVER THE AREA JUST AHEAD OF THE TROUGH AXIS
ON WEDNESDAY. SHOWERS LIKELY FORECAST WORKS FINE FOR NOW. SNOW
LEVELS SHOULD DROP DOWN BELOW PASS LEVELS WEDNESDAY NIGHT...BUT
SHOWER ACTIVITY SHOULD BE DECREASING AT THAT POINT. GFS/ECMWF
SOLUTIONS DIVERGE SIGNIFICANTLY AFTER THURSDAY...SO THE
FRIDAY/SATURDAY SYSTEM REMAINS IN DOUBT. WILL LEAVE THE FORECASTS AS
IS FOR NOW SINCE CONFIDENCE IN THE MODELS IS LOW. KAM
&&
.HYDROLOGY...NO SIGNIFICANT FLOODING IS EXPECTED IN WESTERN
WASHINGTON DURING THE NEXT WEEK. THIS INCLUDES THE GREEN RIVER.
NO SIGNIFICANT FRONTAL SYSTEMS ARE EXPECTED THIS WEEK. MONDAYS FRONT
WILL BRING SOME BRIEF MODERATE RAIN...WITH SNOW LEVELS AROUND 4500
OR 5000 FEET. THE PRECIPITATION BAND THAT IS FORECAST TO FORM AHEAD
OF THE UPPER LEVEL TROUGH ON WEDNESDAY MAY BRING SOME BRIEF MODERATE
SHOWERS TO THE AREA...BUT SNOW LEVELS WILL BE DOWN TO 3000 TO 3500
FEET. MODELS ARE HAVING TROUBLE IN THE LONG TERM WITH THE FRIDAY OR
SATURDAY FRONTAL SYSTEM...BUT SO FAR ALL THE SOLUTIONS INDICATE A
PROGRESSIVE SYSTEM THAT ONLY BRINGS A RELATIVELY SHORT PERIOD OF
MODERATE TO HEAVY PRECIPITATION. IN THE EXTENDED WAY OUT
PERIOD...THE GFS HEMISPHERIC 5-WAVE CHARTS SHOW A MEAN LONG WAVE
TROUGH OUT NEAR 150W OR SO WHICH WOULD MAINTAIN THE CURRENT
PROGRESSIVE PATTERN OF WEATHER SYSTEMS CROSSING THE AREA...BUT NOT
LINGERING TO PRODUCE LENGTHY PERIODS OF RAIN. KAM
&&
.AVIATION...A WEAKER IMPULSE OF SHOWERS WAS MOVING INTO WRN WA EARLY
THIS MORNING...PLENTY OF CLOUDS ON SATELLITE IMAGE BUT JUST
SCATTERED SHOWERS ON RADAR AT 3AM. I THINK THAT BY THE MIDDLE OF THE
AFTERNOON SOME OF THE LOWER TO MID LEVEL CLOUDS WILL BE DRYING UP
SOMEWHAT. I DO NOT SEE ON SATELLITE IMAGERY A WARM ADVECTION DECK OF
MID LEVEL CLOUDS OFFSHORE...IN FACT THE NEXT SYSTEM NEARING 135W AND
THE SECONDARY FRONTAL WAVE NEAR 145W DO NOT LOOK LIKE THEY HAVE A
GREAT DEAL OF MOISTURE GETTING INTO THEM. SO I THINK IT IS A GOOD
BET THAT IT WILL BE DRY LATER TODAY THROUGH TONIGHT WITH IMPROVING
CONDITIONS AS OFFSHORE FLOW SETS UP AHEAD OF THE NEXT FRONT. THEN
AROUND DAYBREAK ON MONDAY CIGS AND VSBY COMES DOWN FAST WITH RAIN
SPREADING INLAND. 19
KSEA...NOT PLANNING AND BIG CHANGES TO THE TAF...SCATTERED SHOWERS
TODAY...INCREASING SE OR ELY FLOW TONIGHT AND DRIER...AND THERE
MIGHT BE ENUF CROSS CASCADE GRADIENT MONDAY MORNING FOR SOME
EASTERLY WIND FOR A FEW HOURS. THE RAIN AGAIN DVLPG MON MORNING WITH
ANOTHER VIGOROUS FRONTAL SYS. 19
&&
.MARINE...I HAVE MADE NO SGFNT CHANGES TO THE FCSTS...SO THE GALE
WATCH FOR THE COASTAL WATERS AND WEST ENTRANCE BECOMES A GALE
WARNING FOR TONIGHT. A SMALL CRAFT FOR HAZARDOUS SEAS IS UP FOR
TODAY FOR THE COAST AND WEST ENTRANCE TO THE STRAIT...COASTAL SEAS
STILL 18FT EARLY THIS MORNING. THIS NEXT FNTL SYS LOOKS TO BE QUITE
STRONG AND A FULL GALE UP AND DOWN THE COAST IS LIKELY BETWEEN
MIDNIGHT TONIGHT TIL ARND 10 AM MONDAY WITH THE FROPA. A GOOD CHANCE
OF GALES ACROSS ALL THE NRN INLAND WATERS AS WELL...BUT LEFT THAT A
GALE WATCH FOR NOW. THE LATEST NAM SHOWS A 994MB LOW OVER NRN VRISL
ARND DAYBREAK MON WITH THE FRONT OVER THE COASTAL WATERS AND
925MB/2500FT WINDS UP TO 60KT. THE 4KM WRFGFS HAD A GOOD PART OF THE
COASTAL WATERS GETTING UP TO 45KT LATE MONDAY NIGHT...SO THERE IS A
CHANCE OF REACHING STORM FORCE 50KT IN A FEW SPOTS BY DAWN MON. 19
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS COASTAL
WATERS AND WEST ENTRANCE TO THE STRAIT OF JUAN DE FUCA TODAY. GALE
WARNING COASTAL WATERS AND WEST ENTRANCE TONIGHT. SMALL CRAFT
ADVISORY PUGET SOUND AND HOOD CANAL TIL 9AM. SMALL CRAFT ADVISORY
FOR ROUGH GRAYS HARBOR BAR. GALE WATCH FOR THE EAST ENTRANCE TO THE
STRAIT AND NORTHERN WATERS FOR TONIGHT AND MON MORNING.
$$
WWW.WEATHER.GOV/SEATTLE
FOR AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION...PLEASE SEE
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML.
000
FXUS66 KPQR 081059
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
257 AM PST SUN NOV 8 2009
.SYNOPSIS...ONE MORE DAY OF COOL SHOWERY WEATHER IS IN STORE FOR
SOUTHWEST WASHINGTON AND NORTHWEST OREGON TODAY...WITH POSSIBLE
THUNDERSTORMS NEAR THE COAST. THE SHOWERS WILL DECREASE THIS EVENING.
THEN A RATHER STRONG PACIFIC COLD FRONT WILL MOVE THROUGH THE
FORECAST AREA MONDAY INTO MONDAY EVENING WITH MORE RAIN... MOUNTAIN
SNOW...AND BRISK WINDS. ADDITIONAL SYSTEMS ARE EXPECTED MID WEEK AND
LATE IN THE WEEK.
&&
.SHORT TERM...SHOWERS CONTINUE TO SPREAD ONSHORE EARLY THIS MORNING
AND WILL LIKELY CONTINUE MUCH OF TODAY AS A COUPLE OF UPPER LEVEL
SHORT WAVES MOVE THROUGH. WE STILL ARE SEEING LIGHTNING OFF THE
COAST AND ALONG THE COAST INTO THE COAST RANGE EARLY THIS MORNING...
AND EXPECT THIS TO CONTINUE TODAY. SOME OF THE STORMS CONTINUE TO
HAVE SOME MORE ORGANIZED STRUCTURE...AND SUSPECT THIS WILL CONTINUE
AT LEAST THROUGH THE MORNING. WITH WHAT THE MODELS ARE FORECASTING
FOR QPF...WILL REISSUE THE WINTER WEATHER ADVISORY FOR SNOW IN THE
SOUTH WASHINGTON AND NORTH OREGON CASCADES FOR TODAY...BUT NOT THE
LANE COUNTY CASCADES. THE MODELS ARE IN PRETTY GOOD AGREEMENT ON THE
AXIS OF THE MAIN PRECIPITATION BEING FROM THE MIDDLE OF THE COAST UP
THROUGH THE SOUTH WASHINGTON AND NORTH OREGON CASCADES.
THE SHOWERS DECREASE RAPIDLY LATE TODAY AND TONIGHT...THEN THE NEXT
FRONT APPROACHES. IT MOVES THROUGH MONDAY AND EARLY MONDAY NIGHT WITH
MORE RAIN...SNOW UP IN THE CASCADES...AND BRISK WINDS. THE COAST MAY
GET CLOSE TO HIGH WIND BUT FOR NOW WILL STAY JUST BELOW. THE SNOW
LEVEL WILL RISE ABOVE THE PASSES LATER TONIGHT AND ON MONDAY...THEN
FALL BACK TO NEAR THE PASSES MONDAY NIGHT AND TUESDAY. IT IS POSSIBLE
THE HIGHER CASCADES OR THE SKI RESORTS COULD GET CLOSE TO ADVISORY
TOTALS...BUT PROBABLY NOT AT THE PASSES. SHOWERS WILL SPREAD IN
BEHIND THE FRONT MONDAY NIGHT AND TUESDAY BUT PROBABLY NOT AS
WIDESPREAD AND INTENSE AS THIS WEEKEND. TOLLESON
.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...
MODELS IN FAIRLY GOOD AGREEMENT SHOWING A COOL UPPER TROUGH DROPPING
SE THROUGH THE REGION WED AND THU. THIS SHOULD BRING SHOWERY WEATHER
WITH SNOW LEVELS BETWEEN 3000 AND 4000 FT. EXTENDED MODELS ARE STILL
SHOWING A POTENTIAL BREAK IN THE WEATHER FROM LATE THU INTO AT LEAST
FRI MORNING AS A WEAK UPPER RIDGE MOVES THROUGH. ANOTHER PAC SYSTEM
LOOKS LIKELY FRI NIGHT AND SAT. RW
&&
.AVIATION...GENERALLY VFR EXCEPT OCCASIONAL MVFR CONDITIONS IN
SHOWERS OVER THE FORECAST AREA THIS MORNING...MVFR MAINLY IN THE
NORTH VALLEY. THUNDERSTORM ACTIVITY WILL CONTINUE ALONG THE COAST
THROUGH THE DAY THOUGH PROBABLY NOT INLAND. SHOWERS WILL CONTINUE TO
MOVE ONSHORE TODAY. SMALL HAIL IS POSSIBLE WITH ANY OF THE HEAVIER
SHOWERS.
KPDX AND APPROACHES...VFR WITH LOCAL MVFR CONDITIONS AND BRIEF SMALL
HAIL POSSIBLE IN THE HEAVIER SHOWERS. A LOT OF SHOWERS TODAY
POSSIBLY BRINGING MORE WIDESPREAD MVFR. GOOD THREAT FOR MVFR BETWEEN
11-15Z. WOLFE
&&
.MARINE...COASTAL BUOYS CONTINUE TO REPORT 19-22 FT SEAS. A SLOW
DOWNWARD TREND IN SEAS WILL CONTINUE TODAY THOUGH WILL MAINTAIN THE
HIGH SURF ADVISORY THROUGH THIS AFTERNOON. SEAS SHOULD DROP TO 12 FT
BY TUE MORNING. ANOTHER GOOD CHANCE FOR GALES TONIGHT AND MONDAY AS
ANOTHER STRONG FRONT MOVES ACROSS THE COASTAL WATERS. LONG RANGE
MODELS ARE SUGGESTING THIS UNSETTLED WEATHER PATTERN WILL CONTINUE
WELL INTO THE UPCOMING WEEK.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
WA/OR...GALE WARNING FOR CAPE SHOALWATER TO FLORENCE OUT 60
NM THIS EVENING THROUGH MONDAY AFTERNOON.
SMALL CRAFT ADVISORY FOR WINDS CAPE SHOALWATER TO
FLORENCE OUT 60 NM THROUGH THIS AFTERNOON.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS CAPE SHOALWATER
TO FLORENCE OUT 60 NM THIS AFTERNOON.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR THROUGH
MONDAY AFTERNOON.
HIGH SURF ADVISORY SOUTH WASHINGTON...NORTH AND CENTRAL
OREGON COAST THROUGH THIS AFTERNOON.
WINTER WEATHER ADVISORY FOR SNOW IN THE SOUTH WASHINGTON
AND NORTH OREGON CASCADES TODAY.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
000
FXUS66 KOTX 081039
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
239 AM PST SUN NOV 8 2009
.SYNOPSIS...
THE ACTIVE WEATHER PATTERN WILL CONTINUE TODAY OVER THE PACIFIC
NORTHWEST THROUGH THE MIDDLE OF THE WEEK. VALLEY RAIN AND HIGH
MOUNTAIN SNOW IS EXPECTED THIS AFTERNOON OVER MUCH OF EASTERN
WASHINGTON AND NORTHERN IDAHO. A BREAK IN THE PRECIPITATION IS
EXPECTED MONDAY...BEFORE ANOTHER MOIST STORM SYSTEM ARRIVES LATE
IN THE DAY. MID WEEK ALSO PROMISES TO BE WET IN THE VALLEYS AND
SNOWY IN THE MOUNTAINS.
&&
.DISCUSSION...
TODAY AND TONIGHT...THE EARLY MORNING WATER VAPOR LOOP SHOWS ZONAL
FLOW CONTINUING INTO THE PACIFIC NORTHWEST. THE UPPER LOW THAT HAS
BEEN OVER THE GULF OF ALASKA THE LAST TWO DAYS IS MORE DIFFUSE
THAN 24 HOURS AGO...AND THE FLOW OVER THE EASTERN PACIFIC IS
CLUTTERED WITH LITTLE SHORTWAVES. IT IS TOUGH TO PICK OUT THESE
FAST MOVING WAVES ON SATELLITE...AND THE MODELS HAVE STRUGGLED TO
RESOLVE THEM DURING THE LAST COUPLE OF DAYS. A VORTICITY MAX
NEARING THE MOUTH OF THE COLUMBIA RIVER (AS OF 10Z) WILL BE THE
MAIN PLAYER FOR THE WEATHER OVER EASTERN WASHINGTON AND NORTHERN
IDAHO TODAY. BOTH THE 00Z NAM AND 00Z GFS GRABBED ONTO THIS
VORTICITY AND GENERATED A GENEROUS BAND OF PRECIPITATION ACROSS
THE COLUMBIA BASIN THROUGH THE NORTHERN IDAHO PANHANDLE. LIFT
AHEAD OF THIS VORTICITY CENTER SHOULD BE ENHANCED BY MOIST
ISENTROPIC ASCENT IN THE 295-300K LAYER COUPLED WITH ELEVATED
THETA-E LAPSE RATES APPROACHING 0C. THE BEST PRECIPITATION BAND
SHOULD OCCUR FROM 18Z-03Z ALONG THE BEST THERMAL GRADIENT NEAR
700MB. SINCE THE WESTERLY FLOW IN THE 850-700MB LAYER HAS BEEN
WEAKENING OROGRAPHIC SNOWS OVER THE PANHANDLE HAVE BEEN
DECREASING...SO THE WINTER STORM WARNINGS FOR THE MOUNTAINS WILL
BE TAKEN DOWN EARLY THIS MORNING. THE WEAKENING WESTERLY FLOW IN
THE MID LEVELS WILL ALSO HELP TO MINIMIZE THE RAIN SHADOW OVER THE
BASIN TODAY. THE RAIN AMOUNTS GENERATED BY THE MODELS OF .10-.25
INCHES FROM THE MOSES LAKE AREA THROUGH DEER PARK WILL HAVE A GOOD
CHANCE OF VERIFYING. ELEVATIONS ABOVE 3500 FEET IN THIS SWATH OF
PRECIPITATION STAND A GOOD CHANCE OF RECEIVING 1-4 INCHES OF SNOW
THIS AFTERNOON/EVENING INCLUDING THE MT. SPOKANE AREA THROUGH THE
HIGH ELEVATIONS OF KOOTENAI AND BONNER COUNTIES.
STRATUS DEVELOPMENT THIS EVENING LOOKS LIKELY IN THE MOSES
LAKE...WENATCHEE...AND OMAK AREAS. WEAK SOUTHEASTERLY BOUNDARY
LAYER FLOW...MID LEVEL WARMING...AND THE LIKELIHOOD OF WET GROUND
DUE TO PRECIPITATION SUGGESTS FOG OR STRATUS. THE SPOKANE AREA AND
THE VALLEYS NORTH AND EAST OF THE METRO MAY ALSO BE PLAGUED BY
STRATUS OVERNIGHT. /GKOCH
MONDAY THROUGH WEDNESDAY...THE LARGE SCALE FLOW PATTERN CONTINUES
TO EXHIBIT SIMILAR PATTERNS TO THOSE EXHIBITED BY THE MODELS
DURING THIS PORTION OF THE FORECAST FOR THE LAST SEVERAL DAYS. IN
GENERAL...A RIDGE POPPING UP OVER CENTRAL MONTANA AND A DEEPENING
LONG WAVE TROUGH OFF THE PACIFIC COAST OF NORTH AMERICA LEAVE THE
FORECAST AREA IN THE TRANSITION ZONE BETWEEN THE TWO REGIMES EARLY
IN THE WEEK. THE RESULT IS BROAD SOUTHWESTERLY FLOW ALOFT WITH A
STRONG WEST-TO-EAST SURFACE PRESSURE GRADIENT BECOMING
INCREASINGLY ESTABLISHED ACROSS THE AREA ON MONDAY. THIS SETUP
GRADUALLY MIGRATES EASTWARD BY MONDAY NIGHT AND TUESDAY...BRINGING
A RATHER IMPRESSIVE SHORT WAVE ACROSS THE AREA WITH A VERY STRONG
COLD FRONT. DOWNSLOPE DRYING BEHIND THE FRONT QUICKLY ENVELOPES
THE AREA BY MID-WEEK...BEFORE LARGE CHANGES AGAIN OCCUR LATER IN
THE WEEK.
THE PRESSURE GRADIENT SETUP ON MONDAY PER THE MODEL CONSENSUS
SHOULD ALLOW FAIRLY IMPRESSIVE EASTERLY SURFACE FLOW TO
CONCENTRATE DOWNSLOPE DRYING FROM THE LEWISTON AREA...THROUGH THE
PALOUSE AND INTO THE SPOKANE/CDA AREA ON MONDAY. WITH MEAGER LAYER
RH VALUES ABOVE THE BOUNDARY LAYER...CLEAR TO PARTLY CLOUDY SKIES
SHOULD BE THE RULE THROUGH AT LEAST THE FIRST HALF OF THE DAY
ACROSS FAR EASTERN WA AND PORTIONS OF THE ID PANHANDLE. THE LONE
EXCEPTION WILL BE ALONG THE CANADIAN BORDER WHERE A NORTHWARD
ADVANCING WARM FRONT WILL LIKELY STILL BE STRADDLING THE BORDER
THROUGH 18Z OR SO ON MONDAY. WHILE A BIT OF PRECIP ALONG THIS
FRONT IS POSSIBLE MONDAY MORNING...UNIMPRESSIVE ISENTROPIC OMEGAS
AROUND 295K AND FAIRLY HIGH CONDENSATION PRESSURE DEFICITS PER THE
GFS SEEM TO INDICATE THAT CHANCE IS FAIRLY SMALL. HOWEVER...BY
MONDAY AFTERNOON AND MONDAY NIGHT...WITH THE OFF SHORE SHORT WAVE
ADVANCING TOWARD THE COAST...LAYER RH VALUES WILL INCREASE RAPIDLY
FROM WEST TO EAST. AS THEY DO...DEEP LAYER ISENTROPIC LIFT WILL DO
LIKEWISE. MIXING RATIOS APPROACHING 4 G/KG AND STRONG SOUTHWEST TO
NORTHEAST MOISTURE TRANSPORT ON THE 295K SURFACE WILL INCREASE THE
CHANCES OF PRECIPITATION PROGRESSIVELY INTO MONDAY EVENING. WITH
THE FLOW BECOMING INCREASINGLY SOUTHERLY FROM EASTERLY...SNOW
LEVELS WILL ALSO BEGIN TO RISE. BY MONDAY AFTERNOON...850 MB
TEMPERATURES ACROSS THE ENTIRE AREA AWAY FROM THE EAST SLOPES OF
THE CASCADES WILL BE IN THE 2 TO 7C RANGE...WITH WET BULB ZERO
HEIGHTS GENERALLY IN THE VICINITY OF 4500 TO 5500 FEET. AS A
RESULT...SNOW LEVELS SHOULD BE HIGH ENOUGH EVEN WITH IMPRESSIVE
LIFT AND FAIRLY IMPRESSIVE QPF TO PRECLUDE WINTER STORM HIGHLIGHTS
FOR THE MOUNTAINS.
THE SYSTEM FROM MONDAY NIGHT SHIFTS EASTWARD QUICKLY BY
TUESDAY NIGHT...WITH WESTERLY FLOW INCREASING AND COLD ADVECTION
AT ALL LAYERS TAKING HOLD. TEMPERATURES AT 850 MB FALL OFF TOWARD
THE 0 TO -2C RANGE BY WEDNESDAY MORNING...WITH WBZ HEIGHTS
DROPPING TO AROUND 3500 FEET.
WEDNESDAY NIGHT THROUGH THE EXTENDED FORECAST...WITH COLD
ADVECTION THE MAIN PLAYER BY WEDNESDAY NIGHT ACROSS THE
AREA...ANOTHER DEEPER SYSTEM IS SET TO TAKE SHAPE OFF SHORE. THE
00Z MODEL GUIDANCE HAS REALLY COME INTO MUCH BETTER AGREEMENT ON
CLOSING OFF A DEEP MID-LEVEL SYSTEM AROUND 535 DAM ACROSS WESTERN
WASHINGTON AND SHIP IT SOUTHEASTWARD FROM THAT POINT WEDNESDAY
NIGHT. IMPRESSIVE Q-VECTOR CONVERGENCE AND IMPRESSIVE DIFFERENTIAL
PVA SET THE STAGE FOR A DECENT BATCH OF PRECIPITATION AHEAD OF
THIS SYSTEM. HOWEVER...DEPENDING ON THE DEPTH AND TRACK OF ANY LOW
LEVEL FEATURE ASSOCIATED WITH IT...THE BOUNDARY LAYER THERMAL
PROFILE IS LIKELY TO BE STARKLY DIFFERENT ACROSS THE FORECAST AREA.
AT THE MOMENT...THE MODELS ARE FAVORING A MUCH COLDER BOUNDARY
LAYER BY THURSDAY NIGHT AND INTO THE NEXT WEEKEND SUCH THAT SNOW
IN ASSOCIATION WITH THIS SYSTEM SEEMS LIKELY BY THURSDAY NIGHT
ACROSS MOST VALLEY LOCATIONS. HOWEVER...THIS WILL LIKELY CONTINUE
TO EVOLVE AS THE WEEK GOES ON...SO STAY TUNED. /FRIES
&&
.AVIATION...
A COLD FRONT WILL CONTINUE TO PASS EAST THROUGH THE IDAHO PANHANDLE
AND SOUTHEAST WASHINGTON OVERNIGHT SATURDAY...WITH RAIN AND
MOUNTAIN SNOW SHOWERS RETREATING TO THE PANHANDLE. VFR/LCL MVFR CIGS
ARE EXPECTED IN SHOWERS...WITH MTN OBSCURATIONS. THE SSW FLOW WILL
BRING THE THREAT FOR MVFR/LCL IFR STRATUS AROUND KGEG-KCOE-KPUW
TAF SITES. A WARM FRONT LIFTS IN SUNDAY...RENEWING THE RISK
FOR PRECIPITATION THROUGHOUT THE REGION..BUT WITH THE BEST CHANCES
LAYING OVER THE WEST AND NORTHERN TAF SITES. VFR WITH LCL MVFR CIGS
EXPECTED. /JCOTE
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 43 33 49 37 47 33 / 60 20 0 80 30 20
COEUR D`ALENE 44 33 49 35 46 32 / 60 20 0 80 40 20
PULLMAN 47 33 54 38 49 34 / 30 10 0 70 20 20
LEWISTON 53 37 57 43 54 40 / 10 10 0 40 20 10
COLVILLE 45 35 48 35 48 32 / 70 40 10 80 30 20
SANDPOINT 43 35 46 34 43 31 / 60 50 0 80 50 30
KELLOGG 40 32 47 34 41 33 / 50 30 0 70 80 30
MOSES LAKE 48 33 48 35 52 30 / 60 10 20 80 0 10
WENATCHEE 43 35 43 38 50 34 / 50 10 30 70 0 10
OMAK 44 33 44 33 48 28 / 60 30 40 90 0 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...NONE.
WA...NONE.
&&
$$
000
FXUS66 KOTX 080617
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
1017 PM PST SAT NOV 7 2009
.SYNOPSIS...
ANOTHER PACIFIC FRONTAL SYSTEM WILL BRING VALLEY RAIN AND POSSIBLY
HEAVY MOUNTAIN SNOW TO THE REGION TONIGHT. A TRAIN OF MODERATELY
STRONG STORMS AND FRONTS WILL CONTINUE TO PASS THROUGH THE REGION
THROUGH MOST OF NEXT WEEK. IN GENERAL THESE STORMS WILL PRODUCE
MOUNTAIN SNOW...WHILE IN THE VALLEYS DAYTIME STORMS WILL FEATURE
RAIN...AND OVERNIGHT STORMS BY THE MIDDLE OF NEXT WEEK WILL ALLOW
SOME LIGHT SNOW TO REACH DOWN TO VALLEY FLOORS.
&&
.DISCUSSION...
REST OF TONIGHT...THE COLD FRONT THAT WAS PUSHING ACROSS THE
CASCADES IS RAPIDLY MOVING EAST...STRETCHING FROM NEAR NORTHEAST
WAS TO CENTRAL OREGON. THE MAIN AREA OF PRECIPITATION AROUND 06 UTC
WAS SPREADING FROM THE PALOUSE AND EASTERN SPOKANE COUNTY INTO THE
IDAHO PANHANDLE. THIS AREA AND THE CASCADE CREST IS WHERE THE MAIN
PRECIPITATION THREAT WILL CONTINUE TO RETREAT TO OVERNIGHT. A LACK
OF SIGNIFICANT RADAR RETURNS AND WARMING CLOUD TOPS OVER THE
NORTHEAST WASHINGTON MOUNTAINS HAS PROMPTED THE CANCELLATION OF
THE WINTER STORM WARNING IN WAZ037 ABOVE 3500 FEET. THE WINTER
STORM WARNING CONTINUE OVER IDZ001 AND IZ004. WEBCAMS AROUND
LOOKOUT PASS SHOW A FAIR AMOUNT OF SNOW ON THE ROADS.
UPDATES MADE TO FINE-TUNE POPS AND CLOUD COVER FOR THE OVERNIGHT
...WITH SOME CLEARING DEVELOPING IN THE LEE OF THE CASCADES NOW.
OTHER TWEAKS MADE TO WINDS...WHICH CONTINUE TO LOOK MARGINALLY
BREEZY THROGH MUCH OF THE OVERNIGHT...AND OVERNIGHT LOWS WHICH
ARE EXPECTED TO COME IN SIMILAR TO LAST NIGHT`S LOW...SAVE FOR
OVER THE PANHANDLE AND SOUTHEAST ZONES WHERE MORE CLOUD COVER
SHOULD HELP TEMPS STAY A BIT WARMER THAN LAST NIGHT. /JCOTE
&&
.AVIATION...
A COLD FRONT WILL CONTINUE TO PASS EAST THROUGH THE IDAHO PANHANDLE
AND SOUTHEAST WASHINGTON OVERNIGHT SATURDAY...WITH RAIN AND
MOUNTAIN SNOW SHOWERS RETREATING TO THE PANHANDLE. VFR/LCL MVFR CIGS
ARE EXPECTED IN SHOWERS...WITH MTN OBSCURATIONS. THE SSW FLOW WILL
BRING THE THREAT FOR MVFR/LCL IFR STRATUS AROUND KGEG-KCOE-KPUW
TAF SITES. A WARM FRONT LIFTS IN SUNDAY...RENEWING THE RISK
FOR PRECIPITATION THROUGHOUT THE REGION..BUT WITH THE BEST CHANCES
LAYING OVER THE WEST AND NORTHERN TAF SITES. VFR WITH LCL MVFR CIGS
EXPECTED. /JCOTE
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 34 42 33 47 37 45 / 30 60 20 0 80 30
COEUR D`ALENE 35 43 32 47 36 45 / 60 60 20 0 80 40
PULLMAN 35 47 34 53 38 48 / 90 30 10 0 70 20
LEWISTON 38 52 37 55 43 55 / 50 20 10 0 40 20
COLVILLE 33 45 38 46 35 46 / 30 60 20 10 80 30
SANDPOINT 35 43 35 43 35 42 / 90 50 20 0 80 50
KELLOGG 33 41 30 45 36 40 / 100 80 20 0 70 80
MOSES LAKE 32 48 34 48 35 50 / 20 50 10 20 80 0
WENATCHEE 35 45 37 43 38 48 / 10 50 10 30 70 0
OMAK 31 45 37 44 34 46 / 10 60 20 40 90 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...WINTER STORM WARNING UNTIL 4 AM PST SUNDAY ABOVE 3500 FEET FOR
NORTHERN PANHANDLE.
WINTER STORM WARNING UNTIL 6 AM PST SUNDAY ABOVE 4000 FEET FOR
CENTRAL PANHANDLE MOUNTAINS.
WA...NONE.
&&
$$
000
FXUS66 KSEW 080511
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
907 PM PST SAT NOV 7 2009
.SYNOPSIS...MOIST ONSHORE FLOW AND A COOL AND UNSTABLE AIRMASS OVER
THE REGION WILL KEEP SHOWERS OVER WESTERN WASHINGTON INTO SUNDAY. A
WEAK WARM FRONT WILL BRUSH THE AREA SUNDAY NIGHT FOLLOWED BY A
TRAILING COLD FRONT MONDAY. A WEAKER FRONT AND A COOL UPPER LEVEL
TROUGH WILL BRING RAIN THEN SHOWERS TUESDAY AND WEDNESDAY FOLLOWED
BY DRIER WEATHER THURSDAY AND THURSDAY NIGHT. ANOTHER PACIFIC
FRONTAL SYSTEM WILL MOVE INTO THE AREA FRIDAY AND SATURDAY.
&&
.SHORT TERM...CLOUD COVER TODAY MAY HAVE PREVENTED JUST ENOUGH
DIURNAL HEATING TO KEEP MORE WIDESPREAD THUNDERSTORM ACTIVITY AT BAY
DESPITE THE OVERALL UNSTABLE CONDITIONS. HOWEVER...COOL AND UNSTABLE
PATTERN REMAINS IN PLACE AND WILL CONTINUE TO SUPPORT BANDS OF
SHOWERS AND POSSIBLY ISOLATED THUNDERSTORMS TONIGHT. LIGHTNING
ACTIVITY TAPERED OFF QUICKLY AFTER SUNDOWN...WITH A FEW LINGERING
LIGHTNING STRIKES OVER PACIFIC COUNTY AND ALONG THE OREGON COAST.
SHOWERS WILL LIKELY PICK UP AGAIN AFTER MIDNIGHT AS A WEAK UPPER
LEVEL WAVE JUST INSIDE OF 130W MOVES OVER HEAD. SNOW LEVELS WILL
REMAIN AROUND 3000 TO 3500 FEET OVERNIGHT...WITH ADVISORY LEVEL
SNOWFALL CONTINUING OVER THE CASCADES INTO SUNDAY MORNING.
THE EASTERN PACIFIC UPPER TROUGH WILL BEGIN TO DEEPEN SUNDAY ALONG
140W AS THE FIRST OF A SERIES OF EMBEDDED SHORTWAVE TROUGHS SLIDE
INTO THE REGION SOUTH OF 50 N. HEIGHTS WILL RISE SOMEWHAT SUNDAY
EVENING OVER WESTERN WASHINGTON AS A WEAK WARM FRONT BRUSHES THE
AREA FROM THE SOUTHWEST. THE WARM FRONT WILL BRING A CHANCE OF RAIN
MOSTLY TO THE COAST...OLYMPICS AND NORTH CASCADES...WITH THE
INTERIOR AND CENTRAL CASCADES REMAINING RELATIVELY DRY. A TRAILING
COLD FRONT WILL MOVE INTO WESTERN WASHINGTON MONDAY...BRINGING
VIGOROUS S-SE WINDS MONDAY MORNING IN ADVANCE OF THE FRONT AND A FEW
HOURS OF HEAVY RAIN AS THE FRONT PASSES. MODELS CONTINUE TO SUPPORT
THE IDEA OF THE FRONT MOVING THROUGH QUICKLY...KEEPING THE HEAVIEST
RAINFALL OVER A SHORT PERIOD AND NOT FOCUSED OVER A PARTICULAR
LOCATION. COLD AIR ALOFT WILL MOVE INTO THE REGION TUESDAY WITH THE
UPPER LEVEL TROUGH FOR A TYPICAL POSTFRONTAL PATTERN. COOK
.LONG TERM...MEDIUM RANGE MODELS REMAIN IN GOOD AGREEMENT FOR THE
EXTENDED...BRINGING A WEAK COLD FRONT TO THE AREA TUESDAY NIGHT AND
A COOL AND UNSTABLE AIR MASS WEDNESDAY AS THE UPPER LEVEL TROUGH
MOVES IN FROM THE NORTHWEST. THE PATTERN REMAINS VERY PROGRESSIVE
WITH ANOTHER DEEP UPPER LEVEL TROUGH SETTING UP OVER THE NORTHEAST
PACIFIC THURSDAY...WHICH IN TURN BRINGS A BIT OF RIDGING AND DRIER
WEATHER TO THE PACIFIC NORTHWEST THURSDAY AFTERNOON AND EVENING.
TRUE TO FORM THE NEXT IN THE SERIES OF FRONTS SHOULD BEGIN TO MOVE
THROUGH THE REGION AGAIN FRIDAY...BRINGING ANOTHER ROUND OF
RELATIVELY SHORT LIVED HEAVY RAIN WITH THE FRONT FOLLOWED BY
POST-FRONTAL SHOWERS FOR SATURDAY. COOK
&&
.HYDROLOGY...NO SIGNIFICANT FLOODING IS EXPECTED IN WESTERN
WASHINGTON DURING THE NEXT WEEK. THIS INCLUDES THE GREEN RIVER.
THE COMING WEEK WILL BE CHARACTERIZED BY SEVERAL FRONTAL SYSTEMS
MOVING INTO WESTERN WASHINGTON. THE FIRST WILL ARRIVE
MONDAY...FOLLOWED BY A SECOND WEAKER FRONT TUESDAY NIGHT...AND THEN
FRIDAY OR FRIDAY NIGHT. EACH WILL BE ACCOMPANIED BY A PERIOD OF
HEAVY RAINFALL WITH THE FRONT ITSELF FOLLOWED BY COOL AND SHOWERY
WEATHER IN THE POST FRONTAL ENVIRONMENT. RAINFALL ACCUMULATIONS WILL
ULTIMATELY BE LIMITED BY THE PROGRESSIVE MOVEMENT OF FRONTS. SNOW
LEVELS ARE EXPECTED TO REMAIN AROUND 3500 FEET THROUGH WEDNESDAY...
LOWERING TO NEAR 2000 BY THURSDAY. CONDITIONS ARE NOT FAVORABLE FOR
RIVER FLOODING. AGAIN...THE RISK OF MAINSTEM RIVER FLOODING DURING
THE NEXT WEEK IS VERY LOW.
&&
.AVIATION...SCATTERED SHOWERS CONTINUE. THERE IS COLD AIR ALOFT OFF
VANCOUVER ISLAND AND THE SHOWERS THERE AREA ESPECIALLY NUMEROUS AND
CONVECTIVE LOOKING...WHILE THE AREA FURTHER SOUTH STRAIGHT WEST OF
ASTORIA FOR INSTANCE LOOKS LIKE IT HAS BECOME A NOTCH MORE STABLE AS
SOME WARM ADVECTION BEGINS. THE NAM 850MB WINDS AND TEMPS SHOW
THIS...TEMPS ALOFT WARM A COUPLE DEGREES C OVERNIGHT...BUT THAT DOES
NOT SEEM TO SUPPRESS THE SHOWERS AT ALL AND THE NAM12 ACTUALLY HAS
THE SHOWERS INCREASING AROUND DAYBREAK SUN...PROBABLY FROM THE
IMPULSE JUST NOW ARRIVING 130W. THE WARM ADVECTION DOES BEGIN IN
EARNEST LATER SUNDAY HOWEVER...AND THAT WILL MARK THE END OF THE
SCT-BKN LOWER CIGS AND SKIES WILL TRANSITION TO A MID LEVEL
OVERRUNNING OVERCAST LATE IN THE AFTERNOON. RAIN WITH THE NEXT
FRONTAL SYSTEM ARRIVES MON MORNING...BEFORE DAYBREAK ON THE COAST
AND PERHAPS HOLDING OFF TIL 18Z FOR THE INTERIOR. 19
KSEA...HARD TO CHASE SHOWER ACTIVITY IN THE TAF SO PROBABLY WONT DO
A LOT OF THAT UNLESS THE RADAR SHOWS ESPECIALLY WET SHOWERS MOVING
TOWARD SEATTLE...I PROBABLY WILL FOLLOW THE NAM IDEA OF BRINGING
ANOTHER BATCH OF SHOWERS THRU WRN WA AROUND DAYBREAK...DRYING UP IN
THE AFTERNOON...AND THEN A MID LEVEL OVERCAST LOWERING LATER IN THE
DAY AHEAD OF THE NEXT FNTL SYS...SO THE 06Z TAF WILL CHANGE A BIT
FROM THE CURRENT FCST. 19
&&
.MARINE...STILL GUSTY NEAR SHOWER BANDS...SHERINGHAM HAD A WIND OF
30024G32KT AT 7PM AS SHOWERS WENT BY...AND SOUTHERLIES 20-25KT
PERSIST IN PUGET SOUND...BUT WINDS FOR NOW HAVE DIED DOWN MANY OTHER
AREAS. WESTERLY SWELL IS STILL FAIRLY IMPRESSIVE...ARND 18FT
TONIGHT...BUT THE NEXT 24HRS WILL MARK A RELATIVE LULL IN THE
WEATHER. THE LATEST UW MM5NAM BRINGS SSE GALES BACK TO THE COASTAL
WATERS SUNDAY EVENING...AND TO THE NORTHERN INLAND WATERS AND EAST
PART OF THE STRAIT BY 5AM MON. THAT MIGHT BE A TAD SLOWER THAN THE
FCST BUT A LOT DEPENDS ON WHETHER THERE IS ONE FRONTAL WAVE AND LOW
PRES SYS OR TWO...THE MODELS HAVE BEEN LEANING TOWARD TWO WITH THE
FIRST INTO THE CHARLOTTES LATE SUN AFTERNOON AS A SECOND LOW FORMS
ON THE FRONT JUST OUTSIDE OF 130W SUNDAY EVENING. THIS SECOND LOW IS
THE ONE THAT REALLY TIGHTENS UP THE GRADIENT AND WILL DEVELOP THE
GALES SUNDAY NIGHT/MON MORNING. THE NAM DEEPENS IT TO 992MB AT TAKES
IT INTO NRN VRISL JUST BEFORE DAYBREAK MON...THE GFS IS NOT AS DEEP
BUT STILL GIVES A SOLID SSE GALE TO THE COASTAL WATERS DVLPG SUN
EVENING...AND TO THE NORTHERN WATERS FROM MIDNIGHT THRU DAYBREAK
MON. 19
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...WINTER WEATHER ADVISORY FOR THE OLYMPIC AND CASCADE MOUNTAINS.
PZ...SMALL CRAFT ADVISORY ALL WATERS.
SMALL CRAFT ADVISORY FOR ROUGH GRAYS HARBOR BAR.
$$
WWW.WEATHER.GOV/SEATTLE
FOR AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION...PLEASE SEE
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML.
000
FXUS66 KPQR 080424
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
825 PM PST SAT NOV 7 2009
.SYNOPSIS...A COOL SHOWERY AIR MASS WILL CONTINUE TO SPREAD INTO THE
PACIFIC NORTHWEST TONIGHT. THE SHOWERS ARE EXPECTED TO TAPER OFF
SOME ON SUNDAY IN THE SOUTH...WHILE A WARM FRONT SHOULD MOVE THROUGH
THE NORTHERN AREAS FOR ADDITIONAL RAIN. A RATHER STRONG COLD FRONT
WILL MOVE THROUGH MONDAY AFTERNOON AND EVENING WITH MORE
RAIN...MOUNTAIN SNOW AND BRISK WINDS.
&&
.SHORT TERM...THE WIDESPREAD HEAVIER PRECIPITATION HAS MOVED OFF
WITH THE OCCLUDED FRONT THIS EVENING. SATELLITE AND RADAR SHOW
SCATTERED SHOWERS CONTINUING BEHIND THE FRONT. SNOWFALL TOTALS AT
CASCADE SNOTEL SITES AND AVALANCHE CENTER SITES SUGGEST TOTALS
AROUND 6 INCHES THIS AFTERNOON AND EVENING. AS THE HEAVIER AMOUNTS
ARE LIKELY PAST WITH THE FRONT AND THE H8 FLOW WEAKENS SLIGHTLY AND
BACKS SOME...WILL LET THE ADVISORY FOR SNOW EXPIRE AT 10 PM.
REMAINDER OF SHORT TERM DISCUSSION UNCHANGED...
THE UPPER FLOW BEGINS TO SLOWLY BUCKLE SUN AND MON AS THE NEXT
FRONTAL SYSTEM DEVELOPS OFF THE COAST. THE MODELS SAY SOME SORT OF
WARM ADVECTION PRECIP MAY WILL SPREAD ACROSS THE NW HALF OF OUR AREA
SUN...WITH LOCAL MODERATE RAINFALL AMOUNTS AROUND ONE HALF INCH
INDICATED IN THE GFS AND NAM. THIS COULD REQUIRE ANOTHER WINTER
WEATHER ADVISORY IN THE S WA CASCADES SUN. CONDITIONS APPEAR TO DRY
OUT SUN NIGHT INTO MON MORNING IN THE SLIGHTLY WARMER SECTOR...THEN
THE ASSOCIATED STRONG COLD FRONT WILL MOVE IN MON AFTERNOON AND MOVE
E MON NIGHT. THIS FRONT SHOULD PRODUCE GUSTY WINDS ALONG THE COASTAL
STRIP...AND BREEZY CONDITIONS INLAND. SNOW LEVELS LIFT SOME AHEAD OF
THIS FRONT...SO WE WILL HAVE TO SEE IF THEY LOWER SOON ENOUGH TO GET
ENOUGH SNOW FOR ANOTHER WINTER WEATHER ADVISORY IN THE CASCADES.
RIGHT NOW IT IS LOOKING RATHER IFFY.
GFS SHOWS DRYING AGAIN ON TUE AHEAD OF THE NEXT SYSTEM...ALTHOUGH THE
ECMWF HAS FASTER TIMING WITH A MINIMAL PERIOD OF DRY WEATHER.
RW
.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...
MODELS IN FAIRLY GOOD AGREEMENT SHOWING A COOL UPPER TROUGH DROPPING
SE THROUGH THE REGION WED AND THU. THIS SHOULD BRING SHOWERY WEATHER
WITH SNOW LEVELS BETWEEN 3000 AND 4000 FT. EXTENDED MODELS ARE STILL
SHOWING A POTENTIAL BREAK IN THE WEATHER FROM LATE THU INTO AT LEAST
FRI MORNING AS A WEAK UPPER RIDGE MOVES THROUGH. ANOTHER PAC SYSTEM
LOOKS LIKELY FRI NIGHT AND SAT. RW
&&
.AVIATION...VFR/ OCCASIONAL MVFR CONDITIONS IN SHOWERS AND ISOLATED
THUNDERSTORSMS OVER THE FORECAST AREA THIS EVENING. THUNDERSTORMA
ACTIVITY WILL DIMINISH OVER THE INTERIOR PORTIONS THIS EVENING...BUT
CONTINUE ALONG THE COAST THROUGH THE NIGHT. SHOWERS WILL GRADUALLY
DECREASE AS THE NIGHT GOES ON. YET ANOTHER AREA OF SHOWERS IS
EXPECTED TO MOVE ONSHORE EARLY SUNDAY MORNING. SMALL HAIL IS
POSSIBLE WITH ANY OF THE HEAVIER SHOWERS.
KPDX AND APPROACHES...VFR/ LOCAL MVFR CONDITIONS IN SHOWERS. BRIEF
SMALL HAIL IS POSSIBLE WITH THE HEAVIER SHOWERS. SHOWERS TAPER OFF
OVERNIGHT...BUT AREAS OF MVFR CIGS MAY LINGER THROUGH THE NIGHT.
MORE RAIN EXPECTED SUN MORNING...POSSIBLY BRINGING MORE WIDESPREAD
MVFR.
&&
.MARINE...COASTAL BUOYS CONTINUE TO REPORT 19-22 FT SEAS. A SLOW
DOWNWARD TREND IN SEAS WILL CONTINUE THROUGH SUNDAY...WILL CONTINUE
THE HIGH SURF ADVISORY. ANOTHER GOOD CHANCE FOR GALES ANTICIPATED
EARLY MONDAY AS ANOTHER STRONG FRONT MOVES ACROSS THE COASTAL
WATERS. LONG RANGE MODELS ARE SUGGESTING THIS UNSETTLED WEATHER
PATTERN WILL CONTINUE WELL INTO THE UPCOMING WEEK.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
WA/OR...SMALL CRAFT ADVISORY FOR WINDS CAPE SHOALWATER TO FLORENCE
OUT 60 NM THROUGH SUNDAY AFTERNOON.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS CAPE SHOALWATER TO
FLORENCE OUT 60 NM THROUGH MONDAY AFTERNOON.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR THROUGH
SUNDAY NIGHT.
HIGH SURF ADVISORY SOUTH WASHINGTON...NORTH AND CENTRAL
OREGON COAST THROUGH SUNDAY AFTERNOON.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
000
FXUS66 KSEW 072352
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
350 PM PST SAT NOV 7 2009
.SYNOPSIS...COOL...MOIST AND UNSTABLE ONSHORE FLOW WILL CONTINUE TO
SUPPORT SHOWERS AND A FEW THUNDERSTORMS INTO SUNDAY. A WEAK WARM
FRONT WILL LIFT ACROSS THE AREA SUNDAY NIGHT...FOLLOWED BY A COLD
FRONT ON MONDAY. A WEAKER COLD FRONT SHOULD CROSS THE AREA TUESDAY
AND TUESDAY NIGHT...FOLLOWED BY SHOWERS FROM AN UPPER LEVEL TROUGH
ON WEDNESDAY AND WEDNESDAY NIGHT. A WEAK UPPER LEVEL RIDGE ON
THURSDAY SHOULD LOWER THE CHANCE OF RAIN...BUT ANOTHER FRONTAL
SYSTEM WILL PROBABLY REACH THE AREA FRIDAY OR SATURDAY.
&&
.SHORT TERM...AS HAS BEEN THE CASE FOR NEARLY 48 HOURS NOW...COOL
MOIST AND UNSTABLE AIR CONTINUES OVER WRN WA WITH ONSHORE FLOW. THIS
CONTINUES TO SUPPORT BANDS OF SHOWERS AND A FEW THUNDERSTORMS ALONG
WITH SNOW LEVELS AROUND 3000 TO 3500 FEET. THIS PATTERN WILL
CONTINUE THROUGH SUNDAY MORNING BUT SHOULD START TO FINALLY
TRANSITION OUT ON SUNDAY AFTERNOON.
AS FOR MOUNTAIN SNOW...THE WAVE FROM EARLIER TODAY WAS EXPECTED TO
BE THE BIGGEST PRECIP PRODUCER...YET MTN SNOWFALL AMTS GENERALLY
FELL SHY OF WARNING CRITERIA. SO BASED ON THE HISTORY OF THE PAST 24
HOURS AND A GRADUAL RAMP-DOWN OF THE SHOWERY PATTERN ON SUN
AFTN...OPTED TO REPLACE THE WINTER STORM WARNING WITH AN ADVISORY
FOR THE CASCADES. WILL ONLY RUN THAT THROUGH TONIGHT.
ON SUNDAY EVENING...THE BROAD UPPER TROUGH OVER THE ERN PAC WILL
AMPLIFY A BIT...BACKING OUR UPPER FLOW TO A MORE SOUTHERLY
DIRECTION. THIS WILL HELP A WEAK WARM FRONT LIFT NORTH ACROSS WRN WA
ON SUN NIGHT. RAIN IS POSSIBLE...PARTICULARLY FOR THE COAST AND
OLYMPIC MTNS...BUT SUN NIGHT AND MON MORNING SHOULD ACTUALLY BE A
RELATIVELY DRY TIME FOR THE INTERIOR AND CENTRAL CASCADES.
AS THE ERN PAC UPPER TROUGH SCOOTS EAST ON MONDAY...A COLD FRONT
WILL MOVE ACROSS WRN WA ON MON. SHOULD GET WINDY FROM THE S-SE ON
MON MORNING IN ADVANCE OF THE FRONT. SHOULD GET A FEW HOURS OF HEAVY
RAIN AS THE FRONT PASSES...BUT THE FRONT WILL BE MOVING
STEADILY...SO HEAVIEST RAIN SHOULD ONLY LAST A FEW HOURS. COLDER AIR
ALOFT WILL FOLLOW WITH A POST-FRONTAL SHOWERY PATTERN ON TUE.
HANER
.LONG TERM...THE GFS AND ECMWF ARE ACTUALLY IN DECENT AGREEMENT
DURING THE EXTENDED FORECAST PERIOD. BOTH POINT TO ANOTHER
QUICK-MOVING COLD FRONT CROSSING WRN WA ON TUE NIGHT WITH A COOL AND
UNSTABLE UPPER TROUGH SETTLING IN ON WED. WITHIN THE UNSTABLE AIR
MASS...A WEAKENING OR DISSIPATING SURFACE LOW WILL DROP DOWN THE
VANCOUVER ISLAND COAST...ENHANCING ONSHORE FLOW OVER WRN WA WITH
NUMEROUS SHOWERS EXPECTED. THE COOL UPPER TROUGH FINALLY EXITS ON
THU WITH AN OPPORTUNITY FOR DRIER WEATHER ON THU AFTN AND THU NIGHT.
THE NEXT IN THE SERIES OF FRONTS SHOULD REACH WRN WA ON FRI OR FRI
NIGHT. ONCE AGAIN...A QUICK SHOT OF HEAVY RAINS SHOULD ACCOMPANY THE
FRONT WITH POST-FRONTAL SHOWERS TO FOLLOW ON SAT. IN TYPICAL FASHION
FOR NOVEMBER...THE FORECAST CHALLENGE IS PICKING OUT A TIME PERIOD
TO HIGHLIGHT DRY WEATHER.
&&
.HYDROLOGY...NO SIGNIFICANT FLOODING IS EXPECTED IN WESTERN
WASHINGTON DURING THE NEXT WEEK. THIS INCLUDES THE GREEN RIVER.
THE COMING WEEK WILL BE CHARACTERIZED BY THREE COLD FRONTS. THEY
SHOULD ARRIVE ON MONDAY...TUESDAY NIGHT...AND THEN FRIDAY OR FRIDAY
NIGHT. EACH WILL BE ACCOMPANIED BY A PERIOD OF HEAVY RAINFALL
RATES...BUT THE QUICK MOVEMENT OF THESE FRONTS WILL LIMIT THE
DURATION OF THE HEAVIEST RAIN. IN BETWEEN THE COLD FRONTS...COOL AND
SHOWERY WEATHER IS EXPECTED WITH SOME MOUNTAIN SNOW ABOVE 3000 FEET.
ALL OF THESE FACTORS ARE NOT FAVORABLE FOR RIVER FLOODING. AGAIN...
THE RISK OF MAINSTEM RIVER FLOODING DURING THE NEXT WEEK IS VERY
LOW. HANER
&&
.AVIATION...A STRONG UPPER LEVEL LOW CONTINUES TO SPIN OFF OF THE
ALASKA PANHANDLE WITH WEST-SOUTHWEST FLOW ALOFT ACROSS THE PACIFIC
NORTHWEST. IR SATELLITE SHOWS AN EXTENSIVE CUMULUS FIELD OVER THE
OCEAN DRIFTING INLAND. A BAND OF SHOWERS ASSOCIATED WITH A SURFACE
TROUGH IS MOVING INTO THE PUGET SOUND AREA THIS AFTERNOON. AFTER IT
PASSES...SOME NIGHT TIME STABILIZATION WILL OCCUR...THOUGH SHOWERS
WILL CONTINUE OFF AND ON INTO SUNDAY. SCATTERED THUNDERSTORMS ARE
POSSIBLE LATE THIS AFTERNOON AND EARLY THIS EVENING ALONG WITH SMALL
HAIL. CEILINGS WILL RANGE FROM NO CEILING TO MVFR IN SHOWERS...
INCLUDING MVFR VISIBILITY. WITH ALL THE MOISTURE AROUND...CEILINGS
COULD BE FAIRLY LOW SUNDAY MORNING IF THE AIR MASS STABILIZES.
KSEA...SEE ABOVE...NO REASON TO THINK KSEA WILL BE DIFFERENT. WIND
WILL BE GUSTY SOUTHWEST 10-20 KT WITH GUSTS TO 30 KT. WINDS EASE
TONIGHT...BECOMING SOUTHEAST 5-10 KT BY MORNING. CHB
&&
.MARINE...STRONG SOUTHWEST FLOW WILL CONTINUE THIS EVENING...WITH
WINDS DIMINISHING AFTER MIDNIGHT. HAVE SMALL CRAFT ADVISORIES ALL
WATERS ENDING AT MIDNIGHT. THERE SHOULD BE SIX HOURS OR SO OF WIND
THAT IS SUB-ADVISORY STRENGTH...THOUGH THIS MIGHT NOT HAPPEN IN A
FEW ZONES. WESTERLIES IN THE STRAIT SHOULD GET GOING THIS EVENING
AFTER THE LATEST IN A SERIES OF SHOWER BANDS MOVES BY...AND A
SURFACE TROUGH ALSO PASSES.
NEXT SYSTEM IS DUE SUNDAY NIGHT THOUGH ITS EFFECTS WILL BEGIN TO BE
FELT EARLIER. GALE FORCE WINDS EXPECTED IN MANY ZONES DURING THE
PERIOD 06Z-18Z MONDAY AND HAVE HOISTED A GALE WATCH. THE MM5-GFS HAD
A BRIEF PERIOD OF STORM FORCE WINDS TOWARD THE END OF THAT PERIOD
OFF THE COAST. HAVE KEPT THE FORECAST HIGH-END GALE BUT THIS BEARS
WATCHING.
MEANWHILE...THE SWELL TRAIN ON THE COAST HAS BEEN DIMINISHING AND
THE SWELLS ARE LIKELY TO DROP BELOW 20 FEET SHORTLY. WILL ALLOW THE
HIGH SURF WARNING TO EXPIRE AT 4 PM. CHB
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...WINTER WEATHER ADVISORY FOR THE OLYMPIC AND CASCADE MOUNTAINS.
PZ...SMALL CRAFT ADVISORY ALL WATERS.
SMALL CRAFT ADVISORY FOR ROUGH GRAYS HARBOR BAR.
$$
WWW.WEATHER.GOV/SEATTLE
FOR AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION...PLEASE SEE
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML.
000
FXUS66 KOTX 072332
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
330 PM PST SAT NOV 7 2009
.SYNOPSIS...
ANOTHER PACIFIC FRONTAL SYSTEM WILL BRING VALLEY RAIN AND POSSIBLY
HEAVY MOUNTAIN SNOW TO THE REGION TONIGHT. A TRAIN OF MODERATELY
STRONG STORMS AND FRONTS WILL CONTINUE TO PASS THROUGH THE REGION
THROUGH MOST OF NEXT WEEK. IN GENERAL THESE STORMS WILL PRODUCE
MOUNTAIN SNOW...WHILE IN THE VALLEYS DAYTIME STORMS WILL FEATURE
RAIN...AND OVERNIGHT STORMS BY THE MIDDLE OF NEXT WEEK WILL ALLOW
SOME LIGHT SNOW TO REACH DOWN TO VALLEY FLOORS.
&&
.DISCUSSION...
...MORE ACTIVE WEATHER IN STORE FOR THE INLAND NORTHWEST WITH
WINTER STORM HIGHLIGHTS REMAINING FOR THE NORTHEAST WASHINGTON AND
PANHANDLE MOUNTAINS THROUGH TONIGHT...
TONIGHT...THE INLAND NORTHWEST IS UNDER A BROAD TROUGH ALOFT AND A
SWIFT JET DIVING SOUTH OF THE REGION. A SERIES OF SHORTWAVES HAVE
BEEN WHIPPING THROUGH THE REGION ALONG THIS JET STREAM. THE
ATMOSPHERE HAS BEEN AND CONTINUES TO BE UNSTABLE...LEADING TO
INCREASED SHOWER DEVELOPMENT AS EACH WAVE PASSES. THE MODELS HAVE
BEEN STRUGGLING WITH THE TIMING OF THESE FEATURES...AND BELIEVE
SATELLITE AND RADAR ARE THE BEST TOOLS FOR THE NEAR TERM WEATHER.
CURRENTLY...A POTENT SHORTWAVE IS HAMMERING THE WEST SIDE OF
WASHINGTON WITH A BAND OF HEAVY RAINFALL...AND HEAVY SNOW FOR THE
CASCADES. THIS WAVE WILL PUSH ACROSS THE CASCADES AND INTO THE
IDAHO PANHANDLE OVERNIGHT...DRAGGING THE BAND OF SHOWERS WITH IT.
ANTICIPATE SOME DOWN SLOPE CONDITIONS...BUT THE SHOWERS WILL BECOME
MORE WIDESPREAD OVER THE EXTREME EASTERN WASHINGTON AND THE
PANHANDLE. BREEZY SOUTHWEST SURFACE FLOW ACROSS THE REGION WILL
SLACKEN AS THE SHOWERS INCREASE AND IR SATELLITE COOLING OF THE CLOUD
TOPS. ANTICIPATE THE MAIN BAND OF SHOWERS MOVING THROUGH EASTERN
WASHINGTON EARLY THIS EVENING...AND LINGERING IN THE PANHANDLE
OVERNIGHT WITH SNOW LEVELS 3500-4K FT. THIS WILL BE THE SECOND
ROUND OF SNOW FOR THE MOUNTAINS AS DEFINED IN THE CURRENT WINTER
STORM WARNINGS.
SUNDAY...THE WAVE EXITS THE PANHANDLE EARLY SUNDAY MORNING AND
OROGRAPHIC SHOWERS WILL LINGER THROUGH MIDDAY. MEANWHILE
UPSTREAM...SHORTWAVE RIDGING WILL DEVELOP AS A SURFACE LOW NEARS
VANCOUVER ISLAND. THIS WILL SEND A WARM FRONT ACROSS WASHINGTON
AND REACHING EAST OF THE CASCADES SUNDAY AFTERNOON. ISENTROPIC
LIFTS INCREASES DURING THE DAY AS THE ATMOSPHERE STABILIZES....WARMS
ALOFT AND MOISTURE INCREASES. ANTICIPATING THICKENING CLOUDS DURING
THE DAY AND LIGHT RAIN AND MOUNTAIN SNOW DEVELOPING FROM MIDDAY
ONWARD FOR THE NORTHWEST AND NORTHERN TIER ZONES. DESPITE THE
WARMING ALOFT AND SLOWLY RISING SNOW LEVELS...SURFACE TEMPERATURES WILL
BE SUBJECTED TO WET BULB COOLING FROM THE RAINFALL AND COOLER
TEMPERATURES THAN TODAY ARE ANTICIPATED. /RFOX.
SUNDAY NIGHT THROUGH TUESDAY...THE NAM/GFS/EC AND UK MODELS ALL
INDICATE A CONTINUING PROGRESSIVE FLOW PATTERN FEATURING MODERATE
STRENGTH AND RATHER FAST MOVING FRONTAL SYSTEMS...PUNCTUATED BY
SHORT DRY BREAKS BETWEEN STORMS. TIMING THESE WAVES AND BREAKS IS
THE MAIN CHALLENGE. THUS WHILE CONFIDENCE IS HIGH FOR AN ACTIVE
AND UNSETTLED AUTUMN WEATHER PATTERN...CONFIDENCE IS LESS FOR
NAILING DOWN THE TIMING OF THE INCOMING SYSTEMS. THE IMMINENT
FORECAST PACKAGE REFLECTS THE LATEST CONSENSUS TIMING OF A NUMBER
OF COMMONLY USED MODELS...WHICH ARE AT LEAST PLAUSIBLE WHEN
COMPARED TO SATELLITE EXTRAPOLATION. THE FAST AND PROGRESSIVE
NATURE OF THE INCOMING FLOW PATTERN SUGGESTS A POSSIBILITY THAT
TIMING OF THESE WAVES AND FRONTS MAY PROVE TO BE 6 TO 12 HOURS TOO
FAST OR SLOW AS SUBSEQUENT RUNS REFINE THE FLOW FIELD.
SUNDAY EVENING WILL BRING A DRYING TREND TO THE REGION AS THE
AFOREMENTIONED WARM FRONT MOVES OUT OF THE REGION ALLOWING WEAK
HIGH PRESSURE TO TAKE OVER. THIS BREAK WILL BE SHORT LIVED AS
ANOTHER WAVE PLOWS INTO THE REGION SPREADING THICKENING CLOUDS
OVER THE FORECAST AREA MONDAY...WITH A MOIST FRONTAL PASSAGE
MONDAY NIGHT ACROSS THE REGION. SNOW LEVELS WILL STILL BE HIGH
ENOUGH TO KEEP SNOW OUT OF THE VALLEYS WITH THIS FRONT...BUT THERE
IS HIGH CONFIDENCE THAT MOST LOCATIONS WILL EXPERIENCE A FEW
TENTHS OF PRECIPITATION WITH THIS WAVE. ON TUESDAY ANOTHER SHORT
WAVE RIDGE WILL ALLOW BRIEF DRYING BEFORE YET ANOTHER DISTURBANCE
ENCROACHES N THE REGION. /FUGAZZI
TUESDAY NIGHT THROUGH SATURDAY...THE REGION WILL REMAIN IN A COOL
AND UNSETTLED WEATHER PATTERN THROUGH THURSDAY AS A PACIFIC FRONTAL
SYSTEM AND COLD UPPER LOW WILL TRACK THROUGH THE INLAND NORTHWEST.
TUESDAY NIGHT ONE SYSTEM WILL BE EXITING TO OUR EAST WHILE THE NEXT
ONE APPROACHES FROM THE WEST. THE GREATEST THREAT FOR SHOWERS WILL
BE OVER THE HIGHER ELEVATIONS. ON WEDNESDAY A COLD FRONTAL PASSAGE
WILL KEEP SHOWERS ACROSS THE FORECAST AREA. THE HIGHEST POPS WILL BE
ACROSS THE EASTERN MOUNTAINS WHERE UPSLOPE FLOW WILL COMBINE WITH
WRAP AROUND MOISTURE AND A TROWEL FEATURE EVIDENT IN 700MB THETA E
CONTOURS. THIS THETA E RIDGE POKES INTO THE NORTHERN PANHANDLE AND
NE MTS OF WA. THERE IS THE POTENTIAL FOR SIGNIFICANT SNOWFALL IN THE
HIGHER ELEVATIONS ACROSS THE NORTHEAST ZONES WEDNESDAY NIGHT. SNOW
LEVELS DROP TO AROUND 2000-2500 FT BEHIND THE COLD FRONT. SCATTERED
SHOWERS WILL CONTINUE ON THURSDAY AS THE UPPER TROUGH AND -35C COLD
POOL AT 500MB TRACK OVERHEAD. SHOWERS WILL DIMINISH THURSDAY NIGHT AS
MID LEVEL RIDGING COMMENCES. MEDIUM RANGE MODELS ARE IN BETTER
AGREEMENT ON A COOL BUT DRY DAY FRIDAY. ANOTHER WET SYSTEM WILL
AFFECT THE REGION FOR THE WEEKEND. TEMPERATURES WILL TREND NEAR OR
SLIGHTLY BELOW SEASONAL NORMALS. /KELCH
&&
.AVIATION...
A MOIST COLD FRONT WILL PASS THROUGH THE REGION THIS EVEING.
WIDESPREAD MOUNTAIN OBSCURATIONS IN CLOUDS AND SNOW WILL OCCUR
THROUGH TONIGHT AND SUNDAY MORNING. OVER THE BASIN AND AT THE TAF
SITES WIDESPREAD RAIN SHOWERS WILL PROMOTE MAINLY LOW VFR CEILINGS
WITH OCCASIONAL MVFR CEILINGS POSSIBLE AT ALL TAF SITES EXCEPT KLWS.
THE COLD FRONT WILL PASS KEAT EARLY THIS EVENING...KGEG AROUND 06Z
AND KLWS BY 12Z. WEAK HIGH PRESSURE WILL BECOME ESTABLISHED OVER THE
IDAHO PANHANDLE SUNDAY...BUT ANOTHER DISTURBANCE WILL BRING SHOWERS
TO THE CASCADES AND KMWH AND KEAT TAF SITES AFTER 21Z SUNDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 34 42 33 47 37 45 / 80 60 20 0 60 30
COEUR D`ALENE 35 43 32 47 36 45 / 80 50 20 0 70 40
PULLMAN 35 47 34 53 38 48 / 70 40 10 0 60 20
LEWISTON 40 52 37 55 43 55 / 50 20 10 0 30 20
COLVILLE 34 45 38 46 35 46 / 90 60 20 10 80 40
SANDPOINT 36 43 35 43 35 42 / 90 50 20 0 70 40
KELLOGG 33 41 30 45 36 40 / 100 80 20 10 60 50
MOSES LAKE 34 48 34 48 35 50 / 60 50 10 10 60 10
WENATCHEE 36 45 37 43 38 48 / 30 50 10 20 60 10
OMAK 31 45 37 44 34 46 / 70 60 20 20 80 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...WINTER STORM WARNING UNTIL 4 AM PST SUNDAY ABOVE 3500 FEET FOR
NORTHERN PANHANDLE.
WINTER STORM WARNING UNTIL 6 AM PST SUNDAY ABOVE 4000 FEET FOR
CENTRAL PANHANDLE MOUNTAINS.
WA...WINTER STORM WARNING UNTIL 4 AM PST SUNDAY ABOVE 3500 FEET FOR
NORTHEAST MOUNTAINS.
&&
$$
000
FXUS66 KPQR 072248
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
248 PM PST SAT NOV 7 2009
.SYNOPSIS...A COOL SHOWERY AIR MASS WILL CONTINUE TO SPREAD INTO THE
PACIFIC NORTHWEST EARLY TONIGHT. THE AIR MASS WILL ALSO CONTINUE TO
BE RATHER UNSTABLE FOR A THREAT OF THUNDERSTORMS NEAR THE COAST. THE
SHOWERS ARE EXPECTED TO TAPER OFF ON SUNDAY IN THE SOUTH...WHILE A
WARM FRONT SHOULD MOVE THROUGH THE NORTHERN AREAS FOR ADDITIONAL
RAIN. A RATHER STRONG COLD FRONT WILL MOVE THROUGH MONDAY AFTERNOON
AND EVENING WITH MORE RAIN...MOUNTAIN SNOW AND BRISK WINDS.
&&
.SHORT TERM...A COOL UNSTABLE WESTERLY FLOW ALOFT WILL CONTINUE TO
MOVE INTO THE REGION THROUGH THIS EVENING...WITH EMBEDDED CONVECTION
FOR TSTMS NEAR THE COAST. LOCAL HEAVY RAIN INLAND AREAS SHOULD PUSH
INTO THE CASCADES THIS EVENING...AND THE URBAN AND SMALL STREAM FLOOD
ADVISORY IN THE N WILL LIKELY END. THE WINTER WEATHER ADVISORY FOR
THE CASCADES CONTINUES TO LOOK GOOD THROUGH THE 10 PM TERMINATION
TIME AS THE SLUG OF PRECIP MOVES THROUGH. SNOW LEVELS WILL BE MAINLY
AROUND 3500 TONIGHT.
THE UPPER FLOW BEGINS TO SLOWLY BUCKLE SUN AND MON AS THE NEXT
FRONTAL SYSTEM DEVELOPS OFF THE COAST. THE MODELS SAY SOME SORT
OF WARM ADVECTION PRECIP MAY WILL SPREAD ACROSS THE NW HALF OF OUR
AREA SUN...WITH LOCAL MODERATE RAINFALL AMOUNTS AROUND ONE HALF INCH
INDICATED IN THE GFS AND NAM. THIS COULD REQUIRE ANOTHER WINTER
WEATHER ADVISORY IN THE S WA CASCADES SUN. CONDITIONS APPEAR TO DRY
OUT SUN NIGHT INTO MON MORNING IN THE SLIGHTLY WARMER SECTOR...THEN
THE ASSOCIATED STRONG COLD FRONT WILL MOVE IN MON AFTERNOON AND MOVE
E MON NIGHT. THIS FRONT SHOULD PRODUCE GUSTY WINDS ALONG THE COASTAL
STRIP...AND BREEZY CONDITIONS INLAND. SNOW LEVELS LIFT SOME AHEAD OF
THIS FRONT...SO WE WILL HAVE TO SEE IF THEY LOWER SOON ENOUGH TO GET
ENOUGH SNOW FOR ANOTHER WINTER WEATHER ADVISORY IN THE CASCADES.
RIGHT NOW IT IS LOOKING RATHER IFFY.
GFS SHOWS DRYING AGAIN ON TUE AHEAD OF THE NEXT SYSTEM...ALTHOUGH THE
ECMWF HAS FASTER TIMING WITH A MINIMAL PERIOD OF DRY WEATHER.
RW
.LONG TERM...MODELS IN FAIRLY GOOD AGREEMENT SHOWING A COOL UPPER
TROUGH DROPPING SE THROUGH THE REGION WED AND THU. THIS SHOULD BRING
SHOWERY WEATHER WITH SNOW LEVELS BETWEEN 3000 AND 4000 FT. EXTENDED
MODELS ARE STILL SHOWING A POTENTIAL BREAK IN THE WEATHER FROM LATE
THU INTO AT LEAST FRI MORNING AS A WEAK UPPER RIDGE MOVES THROUGH.
ANOTHER PAC SYSTEM LOOKS LIKELY FRI NIGHT AND SAT. RW
&&
.AVIATION...TWO ORGANIZED BANDS OF HEAVY SHOWERS AND ISOLATED
THUNDERSTORMS ARE MOVING THROUGH THE AREA THIS AFTERNOON. THE FIRST
LINE IS CREATING FAIRLY WIDESPREAD MVFR CIGS/VSBYS ACROSS THE
NORTHERN HALF OF THE WILLAMETTE VALLEY...WITH LOCAL IFR EMBEDDED IN
THE HEAVIER AREAS OF RAIN. A SECOND LINE OF STORMS...CURRENTLY
WEAKER THAN THE FIRST...IS MOVING ONSHORE NEAR ASTORIA. THIS LINE
WILL LIKELY SPREAD MORE SHOWERS ONSHORE THROUGH THE EVENING...BUT
OVERALL ACTIVITY IS EXPECTED TO GRADUALLY DECREASE AS THE NIGHT GOES
ON. YET ANOTHER AREA OF SHOWERS IS EXPECTED TO MOVE ONSHORE EARLY
SUNDAY MORNING. SMALL HAIL IS POSSIBLE WITH ANY OF THE HEAVIER
SHOWERS. OUTSIDE OF SHOWERS...MAINLY VFR CONDITIONS ARE EXPECTED
THROUGH SUN MORNING.
KPDX AND APPROACHES...MAINLY VFR...BRIEF MVFR CIGS/VSBYS AND GUSTY
WINDS UP TO 35 KT POSSIBLE IN SHOWERS/ISOLATED THUNDERSTORMS THROUGH
THIS EVENING. BRIEF SMALL HAIL IS ALSO POSSIBLE WITH THE HEAVIER
CELLS. SHOWERS TAPER OFF OVERNIGHT...BUT AREAS OF MVFR CIGS MAY
LINGER THROUGH THE NIGHT. MORE RAIN EXPECTED SUN MORNING...POSSIBLY
BRINGING MORE WIDESPREAD MVFR.WEAGLE
&&
.MARINE...COASTAL BUOYS CONTINUE TO REPORT 20-22 FT SEAS...SLIGHTLY
DOWN FROM THE EARLIER PEAK AROUND 23-27 FT. SLOW DOWNWARD TREND IN
SEAS WILL CONTINUE THROUGH TONIGHT AND SUNDAY...THEREFORE WILL
REPLACE THE HIGH SURF WARNING WITH AN ADVISORY. ONE MORE ORGANIZED
ROUND OF SHOWERS MAY BRING SOME LIGHTNING AND GUSTS APPROACHING GALE
FORCE...BUT MOST OF THE GALES ARE DONE FOR NOW...PUSHED SOUTH OF
FLORENCE ALONG WITH THE COLD FRONT. ANOTHER GOOD CHANCE FOR GALES
WITH A STRONGER FRONT ANTICIPATED EARLY MONDAY AS ANOTHER STRONG
FRONT MOVES ACROSS THE COASTAL WATERS...AND LONG RANGE MODELS ARE
SUGGESTING THIS UNSETTLED WEATHER PATTERN WILL CONTINUE WELL INTO
THE UPCOMING WEEK. WEAGLE
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
WA/OR...SMALL CRAFT ADVISORY FOR WINDS CAPE SHOALWATER TO FLORENCE
OUT 60 NM THROUGH SUNDAY AFTERNOON.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS CAPE SHOALWATER TO
FLORENCE OUT 60 NM THROUGH MONDAY AFTERNOON.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR THROUGH
SUNDAY NIGHT.
HIGH SURF ADVISORY SOUTH WASHINGTON...NORTH AND CENTRAL
OREGON COAST THROUGH SUNDAY AFTERNOON.
WINTER WEATHER ADVISORY FOR SNOW FOR THE SOUTH
WASHINGTON AND THE NORTH AND CENTRAL OREGON CASCADES
CONTINUES THROUGH 10 PM TONIGHT.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
000
FXUS66 KOTX 072227
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
227 PM PST SAT NOV 7 2009
.SYNOPSIS...
ANOTHER PACIFIC FRONTAL SYSTEM WILL BRING VALLEY RAIN AND POSSIBLY
HEAVY MOUNTAIN SNOW TO THE REGION TONIGHT. A TRAIN OF MODERATELY
STRONG STORMS AND FRONTS WILL CONTINUE TO PASS THROUGH THE REGION
THROUGH MOST OF NEXT WEEK. IN GENERAL THESE STORMS WILL PRODUCE
MOUNTAIN SNOW...WHILE IN THE VALLEYS DAYTIME STORMS WILL FEATURE
RAIN...AND OVERNIGHT STORMS BY THE MIDDLE OF NEXT WEEK WILL ALLOW
SOME LIGHT SNOW TO REACH DOWN TO VALLEY FLOORS.
&&
.DISCUSSION...
...MORE ACTIVE WEATHER IN STORE FOR THE INLAND NORTHWEST WITH
WINTER STORM HIGHLIGHTS REMAINING FOR THE NORTHEAST WASHINGTON AND
PANHANDLE MOUNTAINS THROUGH TONIGHT...
TONIGHT...THE INLAND NORTHWEST IS UNDER A BROAD TROUGH ALOFT AND A
SWIFT JET DIVING SOUTH OF THE REGION. A SERIES OF SHORTWAVES HAVE
BEEN WHIPPING THROUGH THE REGION ALONG THIS JET STREAM. THE
ATMOSPHERE HAS BEEN AND CONTINUES TO BE UNSTABLE...LEADING TO
INCREASED SHOWER DEVELOPMENT AS EACH WAVE PASSES. THE MODELS HAVE
BEEN STRUGGLING WITH THE TIMING OF THESE FEATURES...AND BELIEVE
SATELLITE AND RADAR ARE THE BEST TOOLS FOR THE NEAR TERM WEATHER.
CURRENTLY...A POTENT SHORTWAVE IS HAMMERING THE WEST SIDE OF
WASHINGTON WITH A BAND OF HEAVY RAINFALL...AND HEAVY SNOW FOR THE
CASCADES. THIS WAVE WILL PUSH ACROSS THE CASCADES AND INTO THE
IDAHO PANHANDLE OVERNIGHT...DRAGGING THE BAND OF SHOWERS WITH IT.
ANTICIPATE SOME DOWN SLOPE CONDITIONS...BUT THE SHOWERS WILL BECOME
MORE WIDESPREAD OVER THE EXTREME EASTERN WASHINGTON AND THE
PANHANDLE. BREEZY SOUTHWEST SURFACE FLOW ACROSS THE REGION WILL
SLACKEN AS THE SHOWERS INCREASE AND IR SATELLITE COOLING OF THE CLOUD
TOPS. ANTICIPATE THE MAIN BAND OF SHOWERS MOVING THROUGH EASTERN
WASHINGTON EARLY THIS EVENING...AND LINGERING IN THE PANHANDLE
OVERNIGHT WITH SNOW LEVELS 3500-4K FT. THIS WILL BE THE SECOND
ROUND OF SNOW FOR THE MOUNTAINS AS DEFINED IN THE CURRENT WINTER
STORM WARNINGS.
SUNDAY...THE WAVE EXITS THE PANHANDLE EARLY SUNDAY MORNING AND
OROGRAPHIC SHOWERS WILL LINGER THROUGH MIDDAY. MEANWHILE
UPSTREAM...SHORTWAVE RIDGING WILL DEVELOP AS A SURFACE LOW NEARS
VANCOUVER ISLAND. THIS WILL SEND A WARM FRONT ACROSS WASHINGTON
AND REACHING EAST OF THE CASCADES SUNDAY AFTERNOON. ISENTROPIC
LIFTS INCREASES DURING THE DAY AS THE ATMOSPHERE STABILIZES....WARMS
ALOFT AND MOISTURE INCREASES. ANTICIPATING THICKENING CLOUDS DURING
THE DAY AND LIGHT RAIN AND MOUNTAIN SNOW DEVELOPING FROM MIDDAY
ONWARD FOR THE NORTHWEST AND NORTHERN TIER ZONES. DESPITE THE
WARMING ALOFT AND SLOWLY RISING SNOW LEVELS...SURFACE TEMPERATURES WILL
BE SUBJECTED TO WET BULB COOLING FROM THE RAINFALL AND COOLER
TEMPERATURES THAN TODAY ARE ANTICIPATED. /RFOX.
SUNDAY NIGHT THROUGH TUESDAY...THE NAM/GFS/EC AND UK MODELS ALL
INDICATE A CONTINUING PROGRESSIVE FLOW PATTERN FEATURING MODERATE
STRENGTH AND RATHER FAST MOVING FRONTAL SYSTEMS...PUNCTUATED BY
SHORT DRY BREAKS BETWEEN STORMS. TIMING THESE WAVES AND BREAKS IS
THE MAIN CHALLENGE. THUS WHILE CONFIDENCE IS HIGH FOR AN ACTIVE
AND UNSETTLED AUTUMN WEATHER PATTERN...CONFIDENCE IS LESS FOR
NAILING DOWN THE TIMING OF THE INCOMING SYSTEMS. THE IMMINENT
FORECAST PACKAGE REFLECTS THE LATEST CONSENSUS TIMING OF A NUMBER
OF COMMONLY USED MODELS...WHICH ARE AT LEAST PLAUSIBLE WHEN
COMPARED TO SATELLITE EXTRAPOLATION. THE FAST AND PROGRESSIVE
NATURE OF THE INCOMING FLOW PATTERN SUGGESTS A POSSIBILITY THAT
TIMING OF THESE WAVES AND FRONTS MAY PROVE TO BE 6 TO 12 HOURS TOO
FAST OR SLOW AS SUBSEQUENT RUNS REFINE THE FLOW FIELD.
SUNDAY EVENING WILL BRING A DRYING TREND TO THE REGION AS THE
AFOREMENTIONED WARM FRONT MOVES OUT OF THE REGION ALLOWING WEAK
HIGH PRESSURE TO TAKE OVER. THIS BREAK WILL BE SHORT LIVED AS
ANOTHER WAVE PLOWS INTO THE REGION SPREADING THICKENING CLOUDS
OVER THE FORECAST AREA MONDAY...WITH A MOIST FRONTAL PASSAGE
MONDAY NIGHT ACROSS THE REGION. SNOW LEVELS WILL STILL BE HIGH
ENOUGH TO KEEP SNOW OUT OF THE VALLEYS WITH THIS FRONT...BUT THERE
IS HIGH CONFIDENCE THAT MOST LOCATIONS WILL EXPERIENCE A FEW
TENTHS OF PRECIPITATION WITH THIS WAVE. ON TUESDAY ANOTHER SHORT
WAVE RIDGE WILL ALLOW BRIEF DRYING BEFORE YET ANOTHER DISTURBANCE
ENCROACHES N THE REGION. /FUGAZZI
TUESDAY NIGHT THROUGH SATURDAY...THE REGION WILL REMAIN IN A COOL
AND UNSETTLED WEATHER PATTERN THROUGH THURSDAY AS A PACIFIC FRONTAL
SYSTEM AND COLD UPPER LOW WILL TRACK THROUGH THE INLAND NORTHWEST.
TUESDAY NIGHT ONE SYSTEM WILL BE EXITING TO OUR EAST WHILE THE NEXT
ONE APPROACHES FROM THE WEST. THE GREATEST THREAT FOR SHOWERS WILL
BE OVER THE HIGHER ELEVATIONS. ON WEDNESDAY A COLD FRONTAL PASSAGE
WILL KEEP SHOWERS ACROSS THE FORECAST AREA. THE HIGHEST POPS WILL BE
ACROSS THE EASTERN MOUNTAINS WHERE UPSLOPE FLOW WILL COMBINE WITH
WRAP AROUND MOISTURE AND A TROWEL FEATURE EVIDENT IN 700MB THETA E
CONTOURS. THIS THETA E RIDGE POKES INTO THE NORTHERN PANHANDLE AND
NE MTS OF WA. THERE IS THE POTENTIAL FOR SIGNIFICANT SNOWFALL IN THE
HIGHER ELEVATIONS ACROSS THE NORTHEAST ZONES WEDNESDAY NIGHT. SNOW
LEVELS DROP TO AROUND 2000-2500 FT BEHIND THE COLD FRONT. SCATTERED
SHOWERS WILL CONTINUE ON THURSDAY AS THE UPPER TROUGH AND -35C COLD
POOL AT 500MB TRACK OVERHEAD. SHOWERS WILL DIMINISH THURSDAY NIGHT AS
MID LEVEL RIDGING COMMENCES. MEDIUM RANGE MODELS ARE IN BETTER
AGREEMENT ON A COOL BUT DRY DAY FRIDAY. ANOTHER WET SYSTEM WILL
AFFECT THE REGION FOR THE WEEKEND. TEMPERATURES WILL TREND NEAR OR
SLIGHTLY BELOW SEASONAL NORMALS. /KELCH
&&
.AVIATION...
MOST OF THE TAF SITES ARE IN BETWEEN SYSTEMS ATTM WITH LINGERING
MVFR STRATUS AT KCOE. BREEZY SOUTHWEST WINDS WILL STRETCH FROM
KPSC TO KGEG FOR MUCH OF THE DAY...BUT ANTICIPATE LOCAL GUSTY
WINDS ACROSS MANY OF THE TAF SITES BETWEEN 21Z-02Z. ANOTHER
SHORTWAVE WILL MOVE FROM WESTERN WASHINGTON...ACROSS THE FORECAST
AREA THIS AFTERNOON AND USHER IN ANOTHER BAND OF SHOWERS. THESE
SHOWERS WILL MARCH FROM THE LEE OF THE CASCADES AND OKANOGAN
VALLEY BY 20Z...ACROSS THE BASIN TO THE KGEG-KCOE AND KPUW AREA
AFTER 23Z. ANTICIPATE LOCAL MVFR CIGS AND MOUNTAIN OBSCURATIONS
WITH THE SHOWERS AND SNOW LEVELS 3K-3500 FT. ANOTHER ROUND OF RAIN
WILL PUSH UP SOUTH BY MIDDAY SUNDAY WITH AN INCOMING WARM FRONT.
/RFOX.
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 34 42 33 47 37 45 / 80 60 20 0 60 30
COEUR D`ALENE 35 43 32 47 36 45 / 80 50 20 0 70 40
PULLMAN 35 47 34 53 38 48 / 70 40 10 0 60 20
LEWISTON 40 52 37 55 43 55 / 50 20 10 0 30 20
COLVILLE 34 45 38 46 35 46 / 90 60 20 10 80 40
SANDPOINT 36 43 35 43 35 42 / 90 50 20 0 70 40
KELLOGG 33 41 30 45 36 40 / 100 80 20 10 60 50
MOSES LAKE 34 48 34 48 35 50 / 60 50 10 10 60 10
WENATCHEE 36 45 37 43 38 48 / 30 50 10 20 60 10
OMAK 31 45 37 44 34 46 / 70 60 20 20 80 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...WINTER STORM WARNING UNTIL 4 AM PST SUNDAY ABOVE 3500 FEET FOR
NORTHERN PANHANDLE.
WINTER STORM WARNING UNTIL 6 AM PST SUNDAY ABOVE 4000 FEET FOR
CENTRAL PANHANDLE MOUNTAINS.
WA...WINTER STORM WARNING UNTIL 4 AM PST SUNDAY ABOVE 3500 FEET FOR
NORTHEAST MOUNTAINS.
&&
$$
000
FXUS66 KSEW 071811 CCA
AFDSEW
AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE SEATTLE WA
935 AM PST SAT NOV 7 2009
CORRECTED WATCH/WARNING/ADVISORY SEGMENT NEAR BOTTOM.
.SYNOPSIS...A BROAD UPPER LEVEL TROUGH WITH COOL MOIST UNSTABLE AIR
WILL CONTINUE TO DIRECT SHOWERS...THUNDERSTORMS AND BREEZY WEATHER
INTO WESTERN WASHINGTON THROUGH SUNDAY MORNING. A WARM FRONT WILL
MOVE THROUGH THE AREA SUNDAY NIGHT...FOLLOWED BY A COLD FRONT ON
MONDAY. A WEAKER COLD FRONT SHOULD CROSS THE AREA TUESDAY FOLLOWED
BY SHOWERS FROM AN UPPER LEVEL TROUGH ON WEDNESDAY. A WEAK UPPER
LEVEL RIDGE ON THURSDAY SHOULD LOWER THE CHANCE OF RAIN...BUT
ANOTHER FRONTAL SYSTEM WILL PROBABLY REACH THE AREA FRIDAY OR
SATURDAY.
&&
.SHORT TERM...A BROAD UPPER TROUGH WILL CONTINUE OVER THE ERN PAC
INTO THE MIDDLE OF NEXT WEEK. THIS TYPICALLY SPELLS ACTIVE AND
UNSETTLED WEATHER FOR THE PAC NW.
FOR TODAY...SATELLITE IMAGERY STILL SHOWS A LOT OF COLD CONVECTIVE
CLOUD TOPS FOR A LONG DISTANCE UPSTREAM OFF THE COAST...ALLOWING THE
COLD AND CONVECTIVE PATTERN TO CONTINUE THROUGH TONIGHT AND INTO
SUNDAY MORNING. VERY COLD AIR ALOFT (500 MB TEMPS AT OR BELOW -30C)
CONTINUES TO SUPPORT AN UNSTABLE ATMOSPHERE ALONG WITH SHOWERS AND
SCATTERED THUNDERSTORMS. WITH SNOW LEVELS AROUND 3000 FEET...THIS
WILL EQUATE TO BURSTS OF HEAVY SNOW IN THE MOUNTAINS...WHERE A
WINTER STORM WARNING IS IN EFFECT. COLD AIR ALOFT WILL CONTRIBUTE TO
GENEROUS SNOW RATIOS...AGAIN SUPPORTING THE NOTION OF HEAVY SNOW IN
THE MTNS. LOOKS LIKE A SHORTWAVE IS CURRENTLY SPREADING ACROSS WRN
WA...ENHANCING LIFT AND CONVECTION. UNLIKE EARLY YESTERDAY AFTERNOON
WHEN THERE WERE SEVERAL DISCRETE CELLS ON RADAR...SOME WITH
ROTATION...PRECIP ON RADAR RIGHT NOW LOOKS A LITTLE MORE SPREAD OUT
WITHOUT SO MANY DISCRETE CELLS. COLD AIR ALOFT AND DEPTH OF THE
CONVECTION WILL CONTINUE TO SUPPORT PROLIFIC AMOUNTS OF SMALL HAIL
IN THUNDERSTORMS.
LOOKS LIKE A SHORTWAVE DROPPING INTO THE BACK SIDE OF THE ERN PAC
TROUGH WILL AMPLIFY THE LONGWAVE PATTERN A BIT LATER SUNDAY. THIS
WILL TURN THE FLOW ALOFT MORE SOUTHERLY ON SUNDAY NIGHT. AT
FIRST...A WEAK WARM FRONT WILL LIFT ACROSS THE AREA ON SUNDAY NIGHT.
CONSIDERING THE CURRENT ATMOSPHERIC INSTABILITY...THE ADDED
STABILITY MAY ACTUALLY DO MORE TO INHIBIT PRECIP THAN WILL BE ADDED
BY ISENTROPIC LIFT. STILL...LOWERING OF POPS OVER THE INTERIOR INTO
THE CHANCE CATEGORY LATE SUN NIGHT IS APPROPRATE. A COLD FRONT WILL
THEN MOVE INLAND LATER ON MONDAY AND EAST OF THE CASCADES ON MON
NIGHT...BRINGING ANOTHER ROUND OF MODERATE TO HEAVY RAIN FOR SEVERAL
HOURS. HANER
.LONG TERM...FROM PREVIOUS DISCUSSION...GFS AND ECMWF REMAIN IN GOOD
AGREEMENT REGARDING THE OVERALL PATTERN THROUGH THE END OF NEXT
WEEK...BUT AFTER WEDNESDAY BEGIN DIVERGING ON TIMING...WITH THE GFS
FASTER. THE OVERALL PATTERN REMAINS PROGRESSIVE AS THE PARADE
CONTINUES. MODELS HAVE GOOD AGREEMENT WITH ANOTHER COLD FRONT
TUESDAY...FOLLOWED BY AN UPPER LEVEL TROUGH WEDNESDAY. MINOR BREAK
THURSDAY WITH A RIDGE BRIEFLY OVERHEAD...BUT THE GFS KEEPS SOME
LIGHT PRECIP IN THE AREA. ANOTHER FRONTAL SYSTEM ARRIVES EITHER
FRIDAY OR FRIDAY NIGHT. KAM
&&
.HYDROLOGY...NO SIGNIFICANT FLOODING IS EXPECTED IN WESTERN
WASHINGTON DURING THE NEXT WEEK. THIS INCLUDES THE GREEN RIVER.
FOR THIS WEEKEND...SNOW LEVELS OF 2500 TO 3000 FEET WILL ELIMINATE
THE POTENTIAL FOR EXCESSIVE RUNOFF OVER MOUNTAIN HEADWATERS. SNOW
LEVELS WILL RISE TO NEAR 5000 FEET IN ADVANCE OF A WET COLD FRONT ON
MONDAY...BUT THE FRONT WILL BE MOVING QUICKLY...LIMITING THE
DURATION OF HEAVY RAINFALL. LIMITED DURATION TENDS TO REDUCE THE
RISK OF EXCESSIVE RUNOFF. MORE PRECIPITATION IS EXPECTED ON TUESDAY
AND WEDNESDAY...BUT SNOW LEVELS WILL AGAIN BE BACK DOWN NEAR 3000
FEET. DRY WEATHER IS POSSIBLE ON THURSDAY AND FRIDAY BEFORE ANOTHER
WET BUT FAST-MOVING COLD FRONT ARRIVES EARLY NEXT WEEKEND.
AGAIN...THE RISK OF MAINSTEM RIVER FLOODING DURING THE NEXT WEEK IS
VERY LOW. HANER
&&
.AVIATION...UNSETTLED WEATHER WILL CONTINUE ACROSS WESTERN
WASHINGTON TODAY. A STRONG UPPER LEVEL LOW CONTINUES TO SPIN OFF OF
THE ALASKA PANHANDLE WITH CYCLONIC FLOW ALOFT ACROSS THE PACIFIC
NORTHWEST. IR SATELLITE SHOWS AN EXTENSIVE CUMULUS FIELD OVER THE
OCEAN DRIFTING INLAND. A BAND OF SHOWERS IS MOVING THROUGH THE PUGET
SOUND AREA THIS MORNING. AN UPTICK IN ACTIVITY IS ANTICIPATED THIS
AFTERNOON AS A SURFACE TROUGH MOVES INLAND. SCATTERED THUNDERSTORMS
WILL BE POSSIBLE ALONG WITH SMALL HAIL...SOME LIGHTNING ALREADY
ALONG THE COAST. SHOWERS WILL DECREASE TONIGHT. CEILINGS WILL RANGE
FROM NO CEILING TO MVFR IN SHOWERS...INCLUDING MVFR VISIBILITY.
KSEA...SEE ABOVE...NO REASON TO THINK KSEA WILL BE DIFFERENT. GUSTY
SOUTH WINDS 10-20 KT WITH GUSTS TO 30 KT...BECOMING MORE SOUTHWEST
IN THE AFTERNOON. WINDS EASE TONIGHT. CHB
&&
.MARINE...GALE WARNING POSTED FOR COAST AS MARGINAL GALE SEEMS
LIKELY. SMALL CRAFT ADVISORY SOUTHWEST WINDS WILL CONTINUE THE REST
OF TODAY AND INTO THE EVENING AND HAVE EXTENDED THE END TIME OF THE
ADVISORIES UNTIL MIDNIGHT TONIGHT. THERE WILL BE SOMETHING OF A
LULL...INLAND AT LEAST...ON SUNDAY AS WASHINGTON IS BETWEEN SYSTEMS.
NEXT SYSTEM SUNDAY NIGHT AND MONDAY LOOKS LIKE A STRONG GALE ON THE
COAST AND AT THE WEST ENTRANCE...POSSIBLY PUSHING STORM FORCE WINDS.
GALES MOST OTHER WATERS INDICATED AS WELL. FRONT PASSES MONDAY
AFTERNOON FOR A BURST OF WESTERLIES DOWN THE STRAIT. PATTERN OF LOW
PRES OFFSHORE WITH SE WINDS QUICKLY RESUMES AS ONE SYSTEM AFTER
ANOTHER MOVES TOWARD WASHINGTON.
MEANWHILE...LARGE WESTERLY SWELLS UP TO 25 FT CONTINUE ACROSS THE
COASTAL WATERS TODAY...WILL CONTINUE THE HIGH SURF WARNING FOR THE
BEACHES. SWELLS WILL GRADUALLY DECAY TO 20 FT ON SUN. CHB
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...WINTER STORM WARNING FOR THE CENTRAL AND NORTH CASCAES UNTIL
4 AM PST SUNDAY.
WINTER WEATHER ADVISORY FOR THE OLYMPICS UNTIL 10 PM PST
TONIGHT.
HIGH SURF WARNING FOR THE COAST THROUGH 4 PM TODAY.
PZ...GALE WARNING COAST.
SMALL CRAFT ADVISORY ALL OTHER WATERS.
SMALL CRAFT ADVISORY FOR ROUGH GRAYS HARBOR BAR.
$$
WWW.WEATHER.GOV/SEATTLE
FOR AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION...PLEASE SEE
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML.
000
FXUS66 KOTX 071809
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
1009 AM PST SAT NOV 7 2009
.SYNOPSIS...
HEAVY SNOW IS EXPECTED OVER THE HIGH ELEVATIONS OF THE INLAND
NORTHWEST THIS AFTERNOON AND OVERNIGHT. THE MOUNTAINS OF
NORTHEAST WASHINGTON...NORTHERN IDAHO...AND PORTIONS OF THE
CASCADES CAN EXPECT SIGNIFICANT ACCUMULATIONS BY SUNDAY MORNING.
MONDAY WILL BE A RELATIVELY DRY DAY FOR THE INLAND NORTHWEST...BUT
ANOTHER STORM SYSTEM WILL BRING RAIN AND HIGH ELEVATION SNOW TO
THE REGION MONDAY NIGHT INTO TUESDAY.
&&
.DISCUSSION...
UPDATED THE FORECAST TO ADD SOME TIMING. THE FORECAST AREA WILL BE
UNDER SIEGE BY SEVERAL FAST MOVING IMPULSES DURING THE NEXT 24
HOURS. EACH WILL BRING A ROUND OF SHOWERS ACROSS THE REGION. THE
OTX SOUNDING SHOWS UNSTABLE CONDITIONS THROUGH OUT MUCH OF THE
ATMOSPHERE. ONE IMPULSE IS EXITING THE IDAHO PANHANDLE THIS
MORNING...WHILE SATELLITE SHOWS ANOTHER WAVE MOVING THROUGH
WESTERN WASHINGTON...PACKED WITH BANDS OF HEAVY PCPN AND
LIGHTNING. ANTICIPATE THE CASCADES CREST TO GET HIT BY HEAVY
SNOW...AND SHOWERS TO INCREASE THIS AFTERNOON ACROSS EASTERN
WASHINGTON AND THROUGH THE EVENING IN THE IDAHO PANHANDLE THE MODELS MAY
BE LAGGING BEHIND WITH THE TIMING OF THESE FEATURES...SO WILL RELY
HEAVILY ON RADAR AND SATELLITE FOR THE NEAR TERM FORECAST. APPEARS
TO BE A WEAKER IMPULSE ANTICIPATED BY SUNDAY MORNING. SO WILL
CONTINUE THE MOUNTAIN SNOW HIGHLIGHTS FOR THE REST OF THE DAY AND
NIGHT TIME HOURS. /RFOX.
&&
.AVIATION...
MOST OF THE TAF SITES ARE IN BETWEEN SYSTEMS ATTM WITH LINGERING
MVFR STRATUS AT KCOE. BREEZY SOUTHWEST WINDS WILL STRETCH FROM
KPSC TO KGEG FOR MUCH OF THE DAY...BUT ANTICIPATE LOCAL GUSTY
WINDS ACROSS MANY OF THE TAF SITES BETWEEN 21Z-02Z. ANOTHER
SHORTWAVE WILL MOVE FROM WESTERN WASHINGTON...ACROSS THE FORECAST
AREA THIS AFTERNOON AND USHER IN ANOTHER BAND OF SHOWERS. THESE
SHOWERS WILL MARCH FROM THE LEE OF THE CASCADES AND OKANOGAN
VALLEY BY 20Z...ACROSS THE BASIN TO THE KGEG-KCOE AND KPUW AREA
AFTER 23Z. ANTICIPATE LOCAL MVFR CIGS AND MOUNTAIN OBSCURATIONS
WITH THE SHOWERS AND SNOW LEVELS 3K-3500 FT. ANOTHER ROUND OF RAIN
WILL PUSH UP SOUTH BY MIDDAY SUNDAY WITH AN INCOMING WARM FRONT.
/RFOX.
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 46 34 43 32 46 35 / 30 80 20 10 0 60
COEUR D`ALENE 45 34 43 32 47 34 / 40 80 30 10 0 50
PULLMAN 47 35 48 30 53 36 / 60 70 20 0 0 40
LEWISTON 55 38 53 36 55 41 / 30 40 20 0 0 30
COLVILLE 46 34 46 32 46 32 / 50 90 20 10 10 80
SANDPOINT 42 35 41 32 43 33 / 90 90 40 10 0 60
KELLOGG 40 33 38 31 43 33 / 90 100 60 10 0 50
MOSES LAKE 52 34 50 32 50 33 / 20 70 10 10 20 60
WENATCHEE 48 35 48 35 47 36 / 10 30 0 10 30 50
OMAK 49 33 46 34 46 29 / 30 70 10 10 20 60
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...WINTER STORM WARNING UNTIL 4 AM PST SUNDAY ABOVE 3500 FEET FOR
NORTHERN PANHANDLE.
WINTER STORM WARNING UNTIL 4 AM PST SUNDAY ABOVE 4000 FEET FOR
CENTRAL PANHANDLE MOUNTAINS.
WA...WINTER STORM WARNING UNTIL 4 AM PST SUNDAY ABOVE 3500 FEET FOR
NORTHEAST MOUNTAINS.
&&
$$
000
FXUS66 KSEW 071735
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
935 AM PST SAT NOV 7 2009
.SYNOPSIS...A BROAD UPPER LEVEL TROUGH WITH COOL MOIST UNSTABLE AIR
WILL CONTINUE TO DIRECT SHOWERS...THUNDERSTORMS AND BREEZY WEATHER
INTO WESTERN WASHINGTON THROUGH SUNDAY MORNING. A WARM FRONT WILL
MOVE THROUGH THE AREA SUNDAY NIGHT...FOLLOWED BY A COLD FRONT ON
MONDAY. A WEAKER COLD FRONT SHOULD CROSS THE AREA TUESDAY FOLLOWED
BY SHOWERS FROM AN UPPER LEVEL TROUGH ON WEDNESDAY. A WEAK UPPER
LEVEL RIDGE ON THURSDAY SHOULD LOWER THE CHANCE OF RAIN...BUT
ANOTHER FRONTAL SYSTEM WILL PROBABLY REACH THE AREA FRIDAY OR
SATURDAY.
&&
.SHORT TERM...A BROAD UPPER TROUGH WILL CONTINUE OVER THE ERN PAC
INTO THE MIDDLE OF NEXT WEEK. THIS TYPICALLY SPELLS ACTIVE AND
UNSETTLED WEATHER FOR THE PAC NW.
FOR TODAY...SATELLITE IMAGERY STILL SHOWS A LOT OF COLD CONVECTIVE
CLOUD TOPS FOR A LONG DISTANCE UPSTREAM OFF THE COAST...ALLOWING THE
COLD AND CONVECTIVE PATTERN TO CONTINUE THROUGH TONIGHT AND INTO
SUNDAY MORNING. VERY COLD AIR ALOFT (500 MB TEMPS AT OR BELOW -30C)
CONTINUES TO SUPPORT AN UNSTABLE ATMOSPHERE ALONG WITH SHOWERS AND
SCATTERED THUNDERSTORMS. WITH SNOW LEVELS AROUND 3000 FEET...THIS
WILL EQUATE TO BURSTS OF HEAVY SNOW IN THE MOUNTAINS...WHERE A
WINTER STORM WARNING IS IN EFFECT. COLD AIR ALOFT WILL CONTRIBUTE TO
GENEROUS SNOW RATIOS...AGAIN SUPPORTING THE NOTION OF HEAVY SNOW IN
THE MTNS. LOOKS LIKE A SHORTWAVE IS CURRENTLY SPREADING ACROSS WRN
WA...ENHANCING LIFT AND CONVECTION. UNLIKE EARLY YESTERDAY AFTERNOON
WHEN THERE WERE SEVERAL DISCRETE CELLS ON RADAR...SOME WITH
ROTATION...PRECIP ON RADAR RIGHT NOW LOOKS A LITTLE MORE SPREAD OUT
WITHOUT SO MANY DISCRETE CELLS. COLD AIR ALOFT AND DEPTH OF THE
CONVECTION WILL CONTINUE TO SUPPORT PROLIFIC AMOUNTS OF SMALL HAIL
IN THUNDERSTORMS.
LOOKS LIKE A SHORTWAVE DROPPING INTO THE BACK SIDE OF THE ERN PAC
TROUGH WILL AMPLIFY THE LONGWAVE PATTERN A BIT LATER SUNDAY. THIS
WILL TURN THE FLOW ALOFT MORE SOUTHERLY ON SUNDAY NIGHT. AT
FIRST...A WEAK WARM FRONT WILL LIFT ACROSS THE AREA ON SUNDAY NIGHT.
CONSIDERING THE CURRENT ATMOSPHERIC INSTABILITY...THE ADDED
STABILITY MAY ACTUALLY DO MORE TO INHIBIT PRECIP THAN WILL BE ADDED
BY ISENTROPIC LIFT. STILL...LOWERING OF POPS OVER THE INTERIOR INTO
THE CHANCE CATEGORY LATE SUN NIGHT IS APPROPRATE. A COLD FRONT WILL
THEN MOVE INLAND LATER ON MONDAY AND EAST OF THE CASCADES ON MON
NIGHT...BRINGING ANOTHER ROUND OF MODERATE TO HEAVY RAIN FOR SEVERAL
HOURS. HANER
.LONG TERM...FROM PREVIOUS DISCUSSION...GFS AND ECMWF REMAIN IN GOOD
AGREEMENT REGARDING THE OVERALL PATTERN THROUGH THE END OF NEXT
WEEK...BUT AFTER WEDNESDAY BEGIN DIVERGING ON TIMING...WITH THE GFS
FASTER. THE OVERALL PATTERN REMAINS PROGRESSIVE AS THE PARADE
CONTINUES. MODELS HAVE GOOD AGREEMENT WITH ANOTHER COLD FRONT
TUESDAY...FOLLOWED BY AN UPPER LEVEL TROUGH WEDNESDAY. MINOR BREAK
THURSDAY WITH A RIDGE BRIEFLY OVERHEAD...BUT THE GFS KEEPS SOME
LIGHT PRECIP IN THE AREA. ANOTHER FRONTAL SYSTEM ARRIVES EITHER
FRIDAY OR FRIDAY NIGHT. KAM
&&
.HYDROLOGY...NO SIGNIFICANT FLOODING IS EXPECTED IN WESTERN
WASHINGTON DURING THE NEXT WEEK. THIS INCLUDES THE GREEN RIVER.
FOR THIS WEEKEND...SNOW LEVELS OF 2500 TO 3000 FEET WILL ELIMINATE
THE POTENTIAL FOR EXCESSIVE RUNOFF OVER MOUNTAIN HEADWATERS. SNOW
LEVELS WILL RISE TO NEAR 5000 FEET IN ADVANCE OF A WET COLD FRONT ON
MONDAY...BUT THE FRONT WILL BE MOVING QUICKLY...LIMITING THE
DURATION OF HEAVY RAINFALL. LIMITED DURATION TENDS TO REDUCE THE
RISK OF EXCESSIVE RUNOFF. MORE PRECIPITATION IS EXPECTED ON TUESDAY
AND WEDNESDAY...BUT SNOW LEVELS WILL AGAIN BE BACK DOWN NEAR 3000
FEET. DRY WEATHER IS POSSIBLE ON THURSDAY AND FRIDAY BEFORE ANOTHER
WET BUT FAST-MOVING COLD FRONT ARRIVES EARLY NEXT WEEKEND.
AGAIN...THE RISK OF MAINSTEM RIVER FLOODING DURING THE NEXT WEEK IS
VERY LOW. HANER
&&
.AVIATION...UNSETTLED WEATHER WILL CONTINUE ACROSS WESTERN
WASHINGTON TODAY. A STRONG UPPER LEVEL LOW CONTINUES TO SPIN OFF OF
THE ALASKA PANHANDLE WITH CYCLONIC FLOW ALOFT ACROSS THE PACIFIC
NORTHWEST. IR SATELLITE SHOWS AN EXTENSIVE CUMULUS FIELD OVER THE
OCEAN DRIFTING INLAND. A BAND OF SHOWERS IS MOVING THROUGH THE PUGET
SOUND AREA THIS MORNING. AN UPTICK IN ACTIVITY IS ANTICIPATED THIS
AFTERNOON AS A SURFACE TROUGH MOVES INLAND. SCATTERED THUNDERSTORMS
WILL BE POSSIBLE ALONG WITH SMALL HAIL...SOME LIGHTNING ALREADY
ALONG THE COAST. SHOWERS WILL DECREASE TONIGHT. CEILINGS WILL RANGE
FROM NO CEILING TO MVFR IN SHOWERS...INCLUDING MVFR VISIBILITY.
KSEA...SEE ABOVE...NO REASON TO THINK KSEA WILL BE DIFFERENT. GUSTY
SOUTH WINDS 10-20 KT WITH GUSTS TO 30 KT...BECOMING MORE SOUTHWEST
IN THE AFTERNOON. WINDS EASE TONIGHT. CHB
&&
.MARINE...GALE WARNING POSTED FOR COAST AS MARGINAL GALE SEEMS
LIKELY. SMALL CRAFT ADVISORY SOUTHWEST WINDS WILL CONTINUE THE REST
OF TODAY AND INTO THE EVENING AND HAVE EXTENDED THE END TIME OF THE
ADVISORIES UNTIL MIDNIGHT TONIGHT. THERE WILL BE SOMETHING OF A
LULL...INLAND AT LEAST...ON SUNDAY AS WASHINGTON IS BETWEEN SYSTEMS.
NEXT SYSTEM SUNDAY NIGHT AND MONDAY LOOKS LIKE A STRONG GALE ON THE
COAST AND AT THE WEST ENTRANCE...POSSIBLY PUSHING STORM FORCE WINDS.
GALES MOST OTHER WATERS INDICATED AS WELL. FRONT PASSES MONDAY
AFTERNOON FOR A BURST OF WESTERLIES DOWN THE STRAIT. PATTERN OF LOW
PRES OFFSHORE WITH SE WINDS QUICKLY RESUMES AS ONE SYSTEM AFTER
ANOTHER MOVES TOWARD WASHINGTON.
MEANWHILE...LARGE WESTERLY SWELLS UP TO 25 FT CONTINUE ACROSS THE
COASTAL WATERS TODAY...WILL CONTINUE THE HIGH SURF WARNING FOR THE
BEACHES. SWELLS WILL GRADUALLY DECAY TO 20 FT ON SUN. CHB
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...WINTER WEATHER ADVISORY MOUNTAINS THROUGH FRIDAY EVENING.
WINTER STORM WATCH MOUNTAINS FRIDAY EVENING THROUGH SATURDAY
EVENING.
HIGH SURF WARNING FOR THE COAST THROUGH 4 PM SATURDAY.
PZ...GALE WARNING COAST.
SMALL CRAFT ADVISORY ALL OTHER WATERS.
SMALL CRAFT ADVISORY FOR ROUGH GRAYS HARBOR BAR.
$$
WWW.WEATHER.GOV/SEATTLE
FOR AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION...PLEASE SEE
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML.
000
FXUS66 KPQR 071659
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
859 AM PST SAT NOV 7 2009
.SYNOPSIS...A COOL SHOWERY AIR MASS WILL CONTINUE TO SPREAD INTO THE
PACIFIC NORTHWEST THROUGH EARLY TONIGHT. THE AIR MASS WILL ALSO
CONTINUE TO BE RATHER UNSTABLE FOR A THREAT OF THUNDERSTORMS
ESPECIALLY NEAR THE COAST. THE SHOWERS ARE EXPECTED TO TAPER OFF ON
SUNDAY IN THE SOUTH...WHILE A WEAK SYSTEM MAY BRUSH THE NORTHERN
AREAS. A RATHER STRONG COLD FRONT WILL MOVE THROUGH MONDAY AFTERNOON
AND EVENING WITH MORE RAIN...MOUNTAIN SNOW AND BRISK WINDS.
&&
.SHORT TERM...A COOL UNSTABLE WESTERLY FLOW ALOFT WILL CONTINUE TO
MOVE INTO THE REGION TODAY THROUGH THIS EVENING...WITH EMBEDDED
DISTURBANCES ENHANCING THE SHOWERS AT TIMES. THE LEADING PORTION OF
ONE SUCH BAND IS CURRENTLY MOVING ONTO THE COAST WITH TSTMS SHOWING
ON LIGHTNING DETECTORS...RADAR AND THE ASTORIA METAR. SHEAR PROFILES
LOOK SIMILAR TO OVERNIGHT...NOT A LOT OF DIRECTIONAL SHEAR BUT GOOD
SPEED SHEAR...AND THUS THE TSTMS NEAR THE COAST TODAY COULD AGAIN BE
ON THE STRONGER SIDE. THIS DISTURBANCE TRAILS OFF TO THE SW AND DOES
NOT APPEAR TO CLEAR OUR FORECAST AREA UNTIL SOME TIME THIS
EVENING...AFTER WHICH THE SHOWERS SHOULD EASE. AS A RESULT...THE
WINTER WEATHER ADVISORY FOR THE CASCADES CONTINUES TO LOOK GOOD
THROUGH THE 10 PM TERMINATION TIME. SNOW LEVELS WILL BE AROUND 3000
TO 3500 FEET TODAY AND TONIGHT.
THE UPPER FLOW BEGINS TO BUCKLE AND BACK SUN AND MON AS THE
NEXT FRONTAL SYSTEM DEVELOPS OFF THE COAST. THE MODELS SAY SOME SORT
OF WARM ADVECTION PRECIPITATION MAY AFFECT AT LEAST THE NW PART OF
OUR AREA SUN...ALTHOUGH THE GFS MAINTAINS AN UNSTABLE AIR MASS NEAR
THE COAST. THIS ACTIVITY THEN LIFTS N SUN NIGHT FOR DRYING. THE
ASSOCIATED STRONG COLD FRONT WILL MOVE IN MON AFTERNOON AND MOVE E
MON NIGHT. THIS FRONT SHOULD PRODUCE GALES AGAIN ALONG THE COAST WITH
GUSTY WINDS ALONG THE COASTAL STRIP...AND BREEZY CONDITIONS INLAND.
SNOW LEVELS LIFT SOME AHEAD OF THIS FRONT...SO WE WILL HAVE TO SEE IF
THEY LOWER SOON ENOUGH TO GET ENOUGH SNOW FOR ANOTHER WINTER WEATHER
ADVISORY IN THE CASCADES. RIGHT NOW IT IS LOOKING RATHER IFFY.
RW/TOLLESON
.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...SNOW LEVELS
WILL START FALLING AGAIN MONDAY NIGHT AS THE NEXT STRONG FRONTAL
SYSTEM MOVES ACROSS THE CASCADES AND THE COOL UPPER LEVEL TROUGH
MOVES IN BEHIND IT. SHOWERY WEATHER WITH SNOW LEVELS BETWEEN 3000
AND 4000 FT WILL PERSIST THROUGH WEDNESDAY MORNING. EXTENDED MODELS
ARE CURRENTLY SHOWING THE UPPER LEVEL TROUGH WEAKENING OUT ON
WEDNESDAY TO BE REPLACE BY A RIDGE ON THURSDAY AND FRIDAY. IF THIS
TREND HOLDS TRUE DRIER WEATHER IS POSSIBLE FOR A COUPLE OF DAYS.
RUTHFORD.
&&
.AVIATION...MOSTLY VFR TODAY EXCEPT LOCAL MVFR/IFR CIGS/VSBYS AND
SMALL HAIL POSSIBLE IN SHOWERS AND THUNDERSTORMS AS WEAK FRONT MOVES
THROUGH. THIS FRONT IS ALREADY MOVING ONSHORE AT KAST AND WILL MOVE
SE ACROSS THE AREA THROUGH THE DAY. SOME GUSTY WINDS OF UP TO 35 KT
ARE POSSIBLE IN SOME OF THE STRONGER CELLS.
KPDX AND APPROACHES...MAINLY VFR...BRIEF MVFR CIGS/VSBYS AND GUSTY
WINDS UP TO 35 KT POSSIBLE IN SHOWERS/ISOLATED THROUGH THIS EVENING.
STRONGEST CELLS ARE LIKELY TO MOVE THROUGH THE PDX AREA BETWEEN 18Z
AND 00Z...AS COLD FRONT PRESENTLY NEAR KAST MOVES SLOWLY MOVES SE
ACROSS THE DISTRICT. BRIEF SMALL HAIL IS ALSO POSSIBLE WITH THE
HEAVIER CELLS.WEAGLE
&&
.MARINE...MAIN CONCERN TODAY WILL BE THE VERY LARGE SEAS AND GUSTY
WINDS ASSOCIATED WITH SQUALLY WEATHER TODAY ACROSS THE COASTAL
WATERS. SEAS OF 23-27 FT WILL IMPACT THE COASTAL WATERS THROUGH THIS
AFTERNOON...THEN VERY GRADUALLY SUBSIDE TONIGHT THROUGH EARLY NEXT
WEEK. A COLD FRONT THIS AFTERNOON SHOULD BRING BRIEF GALES TODAY.
ANOTHER GOOD CHANCE FOR GALES WITH A STRONGER FRONT ANTICIPATED LATE
SUN NIGHT/MON.WEAGLE
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
WA/OR...GALE WARNING FROM CAPE SHOALWATER TO FLORENCE OUT 60 NM
TODAY.
HIGH SURF WARNING SOUTH WASHINGTON...NORTH AND CENTRAL
OREGON COAST TODAY.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR IN
EFFECT THROUGH SUNDAY.
WINTER WEATHER ADVISORY FOR SNOW FOR THE SOUTH
WASHINGTON AND THE NORTH AND CENTRAL OREGON CASCADES
CONTINUES THROUGH 10 PM TONIGHT.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
000
FXUS66 KOTX 071631
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
831 AM PST SAT NOV 7 2009
.SYNOPSIS...
HEAVY SNOW IS EXPECTED OVER THE HIGH ELEVATIONS OF THE INLAND
NORTHWEST THIS AFTERNOON AND OVERNIGHT. THE MOUNTAINS OF
NORTHEAST WASHINGTON...NORTHERN IDAHO...AND PORTIONS OF THE
CASCADES CAN EXPECT SIGNIFICANT ACCUMULATIONS BY SUNDAY MORNING.
MONDAY WILL BE A RELATIVELY DRY DAY FOR THE INLAND NORTHWEST...BUT
ANOTHER STORM SYSTEM WILL BRING RAIN AND HIGH ELEVATION SNOW TO
THE REGION MONDAY NIGHT INTO TUESDAY.
&&
.DISCUSSION...
UPDATED THE FORECAST TO ADD SOME TIMING. THE FORECAST AREA WILL BE
UNDER SIEGE BY SEVERAL FAST MOVING IMPULSES DURING THE NEXT 24
HOURS. EACH WILL BRING A ROUND OF SHOWERS ACROSS THE REGION. THE
OTX SOUNDING SHOWS UNSTABLE CONDITIONS THROUGH OUT MUCH OF THE
ATMOSPHERE. ONE IMPULSE IS EXITING THE IDAHO PANHANDLE THIS
MORNING...WHILE SATELLITE SHOWS ANOTHER WAVE MOVING THROUGH
WESTERN WASHINGTON...PACKED WITH BANDS OF HEAVY PCPN AND
LIGHTNING. ANTICIPATE THE CASCADES CREST TO GET HIT BY HEAVY
SNOW...AND SHOWERS TO INCREASE THIS AFTERNOON ACROSS EASTERN
WASHINGTON AND THROUGH THE EVENING IN THE IDAHO PANHANDLE THE MODELS MAY
BE LAGGING BEHIND WITH THE TIMING OF THESE FEATURES...SO WILL RELY
HEAVILY ON RADAR AND SATELLITE FOR THE NEAR TERM FORECAST. APPEARS
TO BE A WEAKER IMPULSE ANTICIPATED BY SUNDAY MORNING. SO WILL
CONTINUE THE MOUNTAIN SNOW HIGHLIGHTS FOR THE REST OF THE DAY AND
NIGHT TIME HOURS. /RFOX.
&&
.AVIATION...
A PAIR OF FAST MOVING STORM SYSTEMS WILL MOVE THROUGH WASHINGTON
TODAY AND TONIGHT. LOOK FOR PRECIPITATION TO BEGIN IN THE
SPOKANE...PULLMAN...AND LEWISTON AREAS AROUND 15Z AND CONTINUE
THROUGH 18-19Z. TEMPORARY MVFR CEILINGS ARE POSSIBLE FOR A COUPLE OF
HOURS AT KGEG...KCOE...KSFF...AND KPUW BEFORE PRECIPITATION QUICKLY
CLEARS THESE AIRPORTS. THE SECOND ROUND OF PRECIPITATION WILL SPREAD
ACROSS EASTERN WASHINGTON SHORTLY AFTER 00Z. LOOK FOR POSSIBLE MVFR
CEILINGS AGAIN AT THE SAME TERMINALS BETWEEN 04Z AND 08Z. /GKOCH
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 46 34 43 32 46 35 / 30 80 20 10 0 60
COEUR D`ALENE 45 34 43 32 47 34 / 40 80 30 10 0 50
PULLMAN 47 35 48 30 53 36 / 60 70 20 0 0 40
LEWISTON 55 38 53 36 55 41 / 30 40 20 0 0 30
COLVILLE 46 34 46 32 46 32 / 50 90 20 10 10 80
SANDPOINT 42 35 41 32 43 33 / 90 90 40 10 0 60
KELLOGG 40 33 38 31 43 33 / 90 100 60 10 0 50
MOSES LAKE 52 34 50 32 50 33 / 20 70 10 10 20 60
WENATCHEE 48 35 48 35 47 36 / 10 30 0 10 30 50
OMAK 49 33 46 34 46 29 / 30 70 10 10 20 60
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...WINTER STORM WARNING UNTIL 4 AM PST SUNDAY ABOVE 3500 FEET FOR
NORTHERN PANHANDLE.
WINTER STORM WARNING UNTIL 4 AM PST SUNDAY ABOVE 4000 FEET FOR
CENTRAL PANHANDLE MOUNTAINS.
WA...WINTER STORM WARNING UNTIL 4 AM PST SUNDAY ABOVE 3500 FEET FOR
NORTHEAST MOUNTAINS.
&&
$$
000
FXUS66 KOTX 071502
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
702 AM PST SAT NOV 7 2009
.SYNOPSIS...
HEAVY SNOW IS EXPECTED OVER THE HIGH ELEVATIONS OF THE INLAND
NORTHWEST TODAY AND TONIGHT. THE MOUNTAINS OF NORTHEAST
WASHINGTON...NORTHERN IDAHO...AND PORTIONS OF THE CASCADES CAN
EXPECT BIG ACCUMULATIONS BY SUNDAY MORNING. MONDAY WILL BE A
RELATIVELY DRY DAY FOR THE INLAND NORTHWEST...BUT ANOTHER STORM
SYSTEM WILL BRING RAIN AND HIGH ELEVATION SNOW TO THE REGION
MONDAY NIGHT INTO TUESDAY.
&&
.DISCUSSION...
A FORECAST UPDATE HAS BEEN ISSUED TO LOWER PRECIPITATION CHANCES
THIS MORNING OVER A GOOD CHUNK OF EASTERN WASHINGTON. IT APPEARS
THAT THIS MORNING`S SHORTWAVE HAS COME THROUGH FASTER AND WEAKER
THAN THE 00Z AND 06Z MODELS SUGGESTED. 14Z INFRARED SATELLITE
SHOWS COOLING CLOUD TOPS APPROACHING THE OLYMPIC PENINSULA...BUT
THE OMEGA WITH THIS WAVE PROBABLY WON`T IMPACT THE SPOKANE
FORECAST AREA UNTIL AFTERNOON. SURFACE PRESSURE RISES INTO THE
COLUMBIA BASIN SUGGEST THAT PRECIPITATION CHANCES WILL BE LOW IN
THE MOSES LAKE AREA AND POSSIBLY AS FAR EAST SPOKANE THIS MORNING.
A WEAKER AND FASTER WAVE THIS MORNING COULD POTENTIALLY CUT INTO
THE SNOWFALL TOTALS FOR THE MOUNTAINS OF IDAHO AND NORTHEAST
WASHINGTON. WE WERE COUNTING ON A SOLID 3-6 INCHES THIS MORNING IN
THE HIGH ELEVATIONS TO REACH WINTER STORM WARNING CRITERIA. SNOW
TOTALS MAY NEED TO BE ADJUSTED DOWNWARD. /GKOCH
&&
.AVIATION...
A PAIR OF FAST MOVING STORM SYSTEMS WILL MOVE THROUGH WASHINGTON
TODAY AND TONIGHT. LOOK FOR PRECIPITATION TO BEGIN IN THE
SPOKANE...PULLMAN...AND LEWISTON AREAS AROUND 15Z AND CONTINUE
THROUGH 18-19Z. TEMPORARY MVFR CEILINGS ARE POSSIBLE FOR A COUPLE OF
HOURS AT KGEG...KCOE...KSFF...AND KPUW BEFORE PRECIPITATION QUICKLY
CLEARS THESE AIRPORTS. THE SECOND ROUND OF PRECIPITATION WILL SPREAD
ACROSS EASTERN WASHINGTON SHORTLY AFTER 00Z. LOOK FOR POSSIBLE MVFR
CEILINGS AGAIN AT THE SAME TERMINALS BETWEEN 04Z AND 08Z. /GKOCH
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 45 34 43 32 46 35 / 30 80 20 10 0 60
COEUR D`ALENE 45 34 43 32 47 34 / 40 80 30 10 0 50
PULLMAN 47 35 48 30 53 36 / 60 70 20 0 0 40
LEWISTON 54 38 53 36 55 41 / 30 40 20 0 0 30
COLVILLE 45 34 46 32 46 32 / 50 90 20 10 10 80
SANDPOINT 42 35 41 32 43 33 / 90 90 40 10 0 60
KELLOGG 40 33 38 31 43 33 / 90 100 60 10 0 50
MOSES LAKE 52 34 50 32 50 33 / 10 70 10 10 20 60
WENATCHEE 50 35 48 35 47 36 / 10 30 0 10 30 50
OMAK 48 33 46 34 46 29 / 20 70 10 10 20 60
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...WINTER STORM WARNING UNTIL 4 AM PST SUNDAY ABOVE 3500 FEET FOR
NORTHERN PANHANDLE.
WINTER STORM WARNING UNTIL 4 AM PST SUNDAY ABOVE 4000 FEET FOR
CENTRAL PANHANDLE MOUNTAINS.
WA...WINTER STORM WARNING UNTIL 4 AM PST SUNDAY ABOVE 3500 FEET FOR
NORTHEAST MOUNTAINS.
&&
$$
000
FXUS66 KOTX 071248
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
445 AM PST SAT NOV 7 2009
.SYNOPSIS...
HEAVY SNOW IS EXPECTED OVER THE HIGH ELEVATIONS OF THE INLAND
NORTHWEST TODAY AND TONIGHT. THE MOUNTAINS OF NORTHEAST
WASHINGTON...NORTHERN IDAHO...AND PORTIONS OF THE CASCADES CAN
EXPECT BIG ACCUMULATIONS BY SUNDAY MORNING. MONDAY WILL BE A
RELATIVELY DRY DAY FOR THE INLAND NORTHWEST...BUT ANOTHER STORM
SYSTEM WILL BRING RAIN AND HIGH ELEVATION SNOW TO THE REGION
MONDAY NIGHT INTO TUESDAY.
&&
.DISCUSSION...
....HEAVY HIGH ELEVATION SNOWS TODAY AND TONIGHT...
TODAY AND TONIGHT...AN UPPER LEVEL LOW ANCHORED OVER THE GULF OF
ALASKA WILL REMAIN NEARLY STATIONARY FOR THE NEXT 24-48
HOURS...AND THE FAST ZONAL FLOW INTO THE PACIFIC NORTHWEST WILL
CONTINUE TO PROVIDE UNSETTLED WEATHER TO REGION. A PAIR OF
VIGOROUS SHORTWAVES WILL MOVE THROUGH THE FAST FLOW TODAY AND
TONIGHT. WATER VAPOR IMAGERY AS OF 10Z SHOWS THE FIRST WAVE ON THE
WASHINGTON COAST...AND THIS WAVE WILL BRING A ROUND OF
PRECIPITATION TO THE SPOKANE FORECAST AREA THIS MORNING THROUGH
EARLY THIS AFTERNOON. THE SECOND WAVE IS ABOUT 500 MILES DUE SOUTH
OF THE ALASKA COAST...AND THIS WAVE WILL BRING ANOTHER ROUND OF
PRECIPITATION TONIGHT. NEITHER OF THESE SHORTWAVES HAS A
PARTICULARLY IMPRESSIVE MOISTURE TAP. THE AMSU SATELLITE DERIVED
PRODUCT DEPICTS TWO-THIRDS OF AN INCH PRECIPITABLE WATER WITH EACH
SHORTWAVE. EVEN WITH THE LIMITED MOISTURE...SIGNIFICANT
PRECIPITATION WILL LIKELY ACCOMPANY THE PASSAGE OF BOTH WAVES.
DEEP LAYER INSTABILITY AND GOOD OROGRAPHICS WILL COMPENSATE FOR
THE LIMITED MOISTURE. THE MODELS ARE IN GOOD AGREEMENT THAT EACH
WAVE WILL PRODUCE A BAND OF PRECIPITATION BETWEEN .25 AND .33
INCHES OVER THE MOUNTAINS OF THE PANHANDLE AND NORTHEAST
WASHINGTON. GIVEN THE FAVORABLE WEST-SOUTHWEST WIND INTO THE
MOUNTAINS...SOME OF THE SOUTHWEST FACING SLOPES COULD RECEIVE
UPWARDS OF A HALF INCH OF LIQUID EQUIVALENT WITH EACH WAVE. WITH
THE HIGHLY CONVECTIVE NATURE OF THE PRECIPITATION...ELEVATIONS
ABOVE 4000 FEET CAN EXPECT SNOW RATIOS OF BETWEEN 12 TO 1 AND 15
TO 1. SNOW TOTALS OF 6 TO 12 INCHES SEEM PLAUSIBLE BY SUNDAY
MORNING FOR THE MOUNTAINS AROUND SANDPOINT...CHEWELAH...AND
KELLOGG. THE WINTER STORM WATCH FOR THESE AREAS HAS BEEN UPGRADED
TO A WINTER STORM WARNING FOR ELEVATIONS ABOVE 4000 FEET IN THE
CENTRAL PANHANDLE...AND ABOVE 3500 FEET FOR THE MOUNTAINS NEAR THE
CANADIAN BORDER. ACCUMULATIONS OF 10-18 INCHES ARE LIKELY FOR THE
CASCADE CREST...WITH LESSER AMOUNTS WEST OF THE CREST DUE TO THE
CONSIDERABLE WESTERLY DOWN-SLOPE WIND.
LOCALLY BREEZY WINDS WILL OCCUR THIS AFTERNOON BEHIND THE FIRST
SHORTWAVE. WINDS WILL NOT BE AS STRONG AS YESTERDAY...BUT WITH
850MB WINDS IN AROUND 30KTS AND FAVORABLE LAPSE RATES FOR LOW
LEVEL MIXING...GUSTY CONDITIONS WILL BE EXPERIENCED AGAIN OVER THE
PALOUSE...WEST PLAINS...AND SPOKANE AREA. /GKOCH
SUNDAY THROUGH TUESDAY...THE MODELS BEGIN THIS PERIOD OF THE
FORECAST WITH A FAIR SPREAD IN QPF VALUES ACROSS THE FORECAST AREA
ON SUNDAY MORNING...HOWEVER WITH A TREND TOWARD MUCH IMPROVED
CONDITIONS BY SUNDAY AFTERNOON WELL ESTABLISHED. THE NAM HAS
CONSISTENTLY BEEN SLOWER THAN THE GFS/CANADIAN WITH THE
PROGRESSION OF SATURDAY NIGHT`S SYSTEM TO THE EAST OF THE
AREA...AND TONIGHT`S 00Z AND 06Z RUNS WERE NO EXCEPTION. AS A
RESULT...THE FORECAST TRENDS A BIT CLOSER TOWARD THE GFS/CANADIAN
CONSENSUS AND NEGLECTS THE RATHER IMPRESSIVE QPF GENERATED BY THE
NAM OVER THE SOUTHEASTERN PORTION OF THE AREA ON SUNDAY MORNING.
BY 12Z SUNDAY...THE GFS IS TRACKING THE MAIN VORT WELL INTO
NORTHWESTERN MONTANA...WHILE THE NAM TRAILS IT A BIT FATHER WEST.
THE MAIN DIFFERENCES IN THE MODELS CENTER AROUND STRONG QPF
GENERATED BY THE NAM ALONG THE COLD FRONT AS IT SAGS SOUTHWARD
INTO THE SOUTHEASTERN PORTION OF THE AREA. HARNESSING OF
INSTABILITY AND COUPLING IT WITH VERY IMPRESSIVE DIFFERENTIAL PVA
TO GENERATE STRONG OMEGAS OVER A VERY NARROW REGION ALONG THE
FRONT YIELD QPF VALUES AROUND 0.60 INCHES FROM THE BLUES ACROSS
THE PALOUSE ON SUNDAY MORNING. HOWEVER...GIVEN THE LARGE SALE
WESTERLY TO SOUTHWESTERLY FLOW...THIS SCENARIO SEEMS RATHER
UNLIKELY TO MATERIALIZE...GIVEN THE PROPENSITY OF THE LARGE SCALE
FLOW TO ADVECT ANY PARTICULAR VORT MAX EAST RATHER THAN ALLOW IT
TO SAG DUE SOUTH ALONG THE FRONT. IN ADDITION...WITH RIDGING
POPPING UP IMMEDIATELY TO THE WEST OF THE MAIN VORT LOBE...IT
SEEMS INCREASINGLY UNLIKELY THAT ANY ADDITIONAL INCOMING VORT MAY
RUN DOWN THE FRONT...EFFECTIVELY RE-ACTIVATING LIFT ALONG THE
FRONTAL BAND. AS A RESULT...THE FORECAST FEATURES MUCH LIGHTER
DIMINISHING UP-SLOPE SHOWERS RATHER THAN ORGANIZED FRONTAL
RAIN/SNOW THROUGH SUNDAY.
AFTER FORCING ALONG THE COLD FRONT SHIFTS EASTWARD SUNDAY
AFTERNOON AND EVENING...THE GFS STARTS TO SHIFT THE THERMAL
GRADIENT A BIT FARTHER FARTHER NORTH...WITH INCOMING LARGE SCALE
SOUTHERLY FLOW INCREASING THE NORTHWARD TRANSLATION OF THE FRONT
OVERNIGHT SUNDAY NIGHT AS A WARM FRONTAL PUSH. SOME ISENTROPIC
LIFT IS NOTED ALONG THE FRONT AS IT SHIFTS NORTHWARD SUNDAY
NIGHT...HOWEVER CONDENSATION PRESSURE DEFICITS IN THE 290K AREA
GENERALLY STAY NEAR OR ABOVE 30 MB OVER EASTERN WASHINGTON...WITH
THE ONLY AREA OF REDUCED CONDENSATION PRESSURE DEFICITS NEAR THE
CASCADES. AS A RESULT...PRECIP CHANCES HAVE BEEN RELEGATED TO THE
CASCADES...WITH THE REST OF THE AREA DRY ALONG AND BEHIND THE WARM
FRONT SUNDAY NIGHT INTO MONDAY.
BETTER MODEL AGREEMENT EXISTS IN CLEARING BEHIND THE WARM FRONT
FOR SUNDAY NIGHT AND MONDAY. ADDITIONALLY...THE 00Z GFS AND 06Z
NAM HAVE COME INTO MUCH CLOSER AGREEMENT FOR TRACKING THE TRAILING
COLD FRONT INTO THE AREA ON MONDAY NIGHT WITH A 120 KT JET STREAK
LEFT ENTRANCE REGION COMING ON SHORE AND DEEP LAYER PVA SPREADING
STRATIFORM RAINS INTO THE AREA MONDAY NIGHT. LAYER TEMPERATURES
AFTER THE WARM FRONTAL PASSAGE SURGE ABOVE FREEZING WELL UP INTO
THE ATMOSPHERE...AND WET BULB ZERO HEIGHTS REACH NEARLY 6000 FEET
OVER MANY AREAS. AS A RESULT...MANY LOCATIONS THAT WILL HAVE SEEN
SNOW THIS WEEKEND ARE LIKELY TO SEE RAIN WITH THE NEXT SYSTEM ON
MONDAY NIGHT AND TUESDAY. /FRIES
&&
.AVIATION...
A PAIR OF FAST MOVING STORM SYSTEMS WILL MOVE THROUGH WASHINGTON
TODAY AND TONIGHT. LOOK FOR PRECIPITATION TO BEGIN IN THE
SPOKANE...PULLMAN...AND LEWISTON AREAS AROUND 15Z AND CONTINUE
THROUGH 18-19Z. TEMPORARY MVFR CEILINGS ARE POSSIBLE FOR A COUPLE OF
HOURS AT KGEG...KCOE...KSFF...AND KPUW BEFORE PRECIPITATION QUICKLY
CLEARS THESE AIRPORTS. THE SECOND ROUND OF PRECIPITATION WILL SPREAD
ACROSS EASTERN WASHINGTON SHORTLY AFTER 00Z. LOOK FOR POSSIBLE MVFR
CEILINGS AGAIN AT THE SAME TERMINALS BETWEEN 04Z AND 08Z. /GKOCH
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 45 34 43 32 46 35 / 90 80 20 10 0 50
COEUR D`ALENE 45 34 43 32 47 34 / 90 80 20 10 0 40
PULLMAN 47 35 48 30 53 36 / 70 70 20 0 0 40
LEWISTON 54 38 53 36 55 41 / 40 40 20 0 0 30
COLVILLE 45 34 46 32 46 32 / 70 90 20 10 0 60
SANDPOINT 42 35 41 32 43 33 / 100 90 40 10 0 50
KELLOGG 40 33 38 31 43 33 / 90 100 50 10 0 60
MOSES LAKE 52 34 50 32 50 33 / 20 70 10 10 10 30
WENATCHEE 50 35 48 35 47 36 / 10 30 0 10 10 50
OMAK 48 33 46 34 46 29 / 20 70 10 10 10 60
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...WINTER STORM WARNING FROM 7 AM THIS MORNING TO 4 AM PST SUNDAY
ABOVE 3500 FEET FOR NORTHERN PANHANDLE.
WINTER STORM WARNING FROM 7 AM THIS MORNING TO 4 AM PST SUNDAY
ABOVE 4000 FEET FOR CENTRAL PANHANDLE MOUNTAINS.
WA...WINTER STORM WARNING FROM 7 AM THIS MORNING TO 4 AM PST SUNDAY
ABOVE 3500 FEET FOR NORTHEAST MOUNTAINS.
&&
$$
000
FXUS66 KSEW 071121
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
320 AM PST SAT NOV 7 2009
.SYNOPSIS...A BROAD UPPER LEVEL TROUGH WITH COOL MOIST UNSTABLE AIR
WILL CONTINUE TO DIRECT SHOWERS AND BREEZY WEATHER INTO WESTERN
WASHINGTON THROUGH SATURDAY NIGHT. A WARM FRONT WILL MOVE THROUGH
THE AREA SUNDAY AFTERNOON AND EVENING...FOLLOWED BY A COLD FRONT ON
MONDAY. A WEAKER COLD FRONT SHOULD CROSS THE AREA TUESDAY FOLLOWED
BY SHOWERS FROM AN UPPER LEVEL TROUGH ON WEDNESDAY. A WEAK UPPER
LEVEL RIDGE ON THURSDAY SHOULD LOWER THE CHANCE OF RAIN...BUT
ANOTHER FRONTAL SYSTEM WILL PROBABLY REACH THE AREA FRIDAY OR
SATURDAY.
&&
.SHORT TERM...THE LARGE SCALE HEMISPHERIC 5-WAVE PATTERN LOOKS
PRETTY STABLE OVER THE NEXT WEEK AND A HALF...SO WESTERN WASHINGTON
WILL REMAIN IN A WET PATTERN WITH A BROAD STRONG LONG WAVE TROUGH
OFFSHORE MOST OF THE TIME.
GFS AND ECMWF ARE IN GOOD AGREEMENT THROUGH MID NEXT WEEK
MAINTAINING A LONGWAVE TROUGH OFFSHORE...WITH A PARADE SHORTWAVE
TROUGHS PROPAGATING THROUGH THE LONGWAVE TROUGH AND CROSSING WESTERN
WA. THE LEADING EDGE OF THE NEXT SIGNIFICANT SHORTWAVE FEATURE TO
ARRIVE WAS JUST APPROACHING 130W AT 08Z AND SHOULD CROSS WESTERN WA
LATE THIS MORNING THROUGH AFTERNOON. EXPECT THE AIR MASS TO REMAIN
UNSTABLE WITH MORE SHOWERS AND THUNDERSTORMS. CAPE COULD BE
BETTER...BUT WHAT STANDS OUT WITH THIS WAVE IS THE LOW LEVEL SPEED
SHEAR UP THROUGH 5000 FEET...FROM ABOUT SSW 15 KT JUST ABOVE THE
SURFACE TO SW 30 KT AT 2500 FEET AND SW 45 KT AT 5000 FEET. HELICITY
GETS ABOVE 200 E AND SE OF PUGET SOUND WHICH SUGGESTS THAT
INDIVIDUAL THUNDERSTORMS MAY BE MORE LIKELY TO DEVELOP ROTATION.
OTHERWISE...850 MB FLOW WILL REMAIN AROUND SW 40 KT WITH LOTS
MOISTURE AVAILABLE...SO EXPECT SNOW SHOWERS TO CONTINUE PILING UP
THE SNOW OVER THE CASCADES. THE UPSLOPE FLOW FINALLY DECREASES AFTER
12Z SUNDAY...SO WILL KEEP THE WINTER STORM WARNING FOR THE CASCADES
GOING UNTIL THEN. 850 MB TEMPS HOVER AROUND -1C...SO EXPECT THE SNOW
LEVEL TO REMAIN AROUND 3500 FEET...BUT BRIEFLY LOWER IN HEAVIER
SHOWERS.
BOTH GFS/ECMWF BRING A STRONGER SOMEWHAT LARGER SHORTWAVE TROUGH SE
ACROSS THE BERING SEA SATURDAY...THAT EVENTUALLY MATURES INTO A
FRONTAL SYSTEM OFF THE PACIFIC NW COAST ON SUNDAY. A SMALL WARM
FRONT MOVES ACROSS W WA LATE SUNDAY AFTERNOON FOLLOWED BY A STRONGER
COLD FRONT ON MONDAY. THIS SYSTEM APPEARS TO PACK PRETTY STANDARD
STUFF...BREEZY SE WINDS WITH THE WARM FRONT...THEN WINDY THE COLD
FRONT. COULD END UP WITH ANOTHER WIND ADVISORY FOR THE N INTERIOR
WITH THE COLD FRONT. WILL ADDRESS PRECIP AMOUNTS AND SNOW LEVELS IN
THE HYDRO SECTION BELOW. KAM
.LONG TERM...GFS AND ECMWF REMAIN IN GOOD AGREEMENT REGARDING THE
OVERALL PATTERN THROUGH THE END OF NEXT WEEK...BUT AFTER WEDNESDAY
BEGIN DIVERGING ON TIMING...WITH THE GFS FASTER. THE OVERALL PATTERN
REMAINS PROGRESSIVE AS THE PARADE CONTINUES. MODELS HAVE GOOD
AGREEMENT WITH ANOTHER COLD FRONT TUESDAY...FOLLOWED BY AN UPPER
LEVEL TROUGH WEDNESDAY. MINOR BREAK THURSDAY WITH A RIDGE BRIEFLY
OVERHEAD...BUT THE GFS KEEPS SOME LIGHT PRECIP IN THE AREA. ANOTHER
FRONTAL SYSTEM ARRIVES EITHER FRIDAY OR FRIDAY NIGHT. KAM
&&
.HYDROLOGY...IT IS UNLIKELY THAT RIVER FLOODING WILL BE A PROBLEM
OVER THEN NEXT WEEK. THE PATTERN REMAINS TOO PROGRESSIVE WITH
SYSTEMS ONLY AFFECTING W WA FOR A BRIEF TIME EACH. SNOW LEVELS DOWN
TO 3500 FEET WILL LIMIT RUNOFF PROBLEMS DURING THE HEAVIER PRECIP
PERIOD THROUGH SUNDAY MORNING. 850 MB WINDS SSW 40 KT WILL PRODUCE
GOOD UPSLOPE FLOW WITH SUNDAYS WARM FRONT...BUT THE SHORT PRECIP
PERIOD WILL PROBABLY ONLY PRODUCE 1-2 INCHES OVER THE MOUNTAINS EVEN
WITH SNOW LEVELS AROUND 5000 FEET. AFTER A SHORT BREAK BETWEEN
SYSTEMS MONDAYS COLD FRONT PACKS ANOTHER SHORT PERIOD OF HEAVY
RAIN...850 MB WINDS SSW 40-50KT...SNOW LEVELS STILL AROUND 5000 FEET
AND ANOTHER 1-2 INCHES OF RAIN. TUESDAYS COLD FRONT IS MUCH WEAKER.
THE FRONTAL SYSTEM AROUND FRIDAY OR SATURDAY ALSO APPEARS TO BE THE
STANDARD PROGRESSIVE TYPE. IN THE 8-10 DAY PERIOD BEYOND THE REACHES
OF ANY REAL FORECAST SKILL...OUR CURRENT PROGRESSIVE PATTERN APPEARS
TO CONTINUE. KAM
&&
.AVIATION...UNSETTLED WEATHER WILL CONTINUE ACROSS WESTERN
WASHINGTON TODAY. A STRONG UPPER LEVEL LOW CONTINUES TO SPIN OFF
THE AK PANHANDLE WITH CYCLONIC FLOW ALOFT ACROSS THE PAC NW. IR
SATELLITE SHOWS AN EXTENSIVE CU FIELD OVER THE OCEAN DRIFTING
INLAND. THROUGH THE MORNING...SHOWERS WILL BE OFF-AND-ON...THEN AN
UPTICK IN ACTIVITY ANTICIPATED THIS AFTERNOON AS A SURFACE TROUGH
MOVES INLAND. MODELS SHOW STRONG VERTICAL SHEAR PROFILE WITH A FEW
HUNDRED CAPE OVER THE REGION...ISOLD-SCT THUNDERSTORMS WILL BE
POSSIBLE ALONG WITH SMALL HAIL. SHOWERS WILL DECREASE IN COVERAGE
TONIGHT. 33
KSEA...OFF-AND-ON SHOWERS EXPECTED THROUGH THE MORNING...THEN AN
INCREASE IN ACTIVITY THIS AFTERNOON AS THE NEXT WAVE MOVE THROUGH.
AIR MASS REMAINS UNSTABLE WITH ISOLD-SCT THUNDERSTORMS DEVELOPING
ONCE AGAIN. BRIEF HEAVY DOWNPOURS WILL REDUCE VIS AND/OR CIGS INTO
THE MVFR RANGE. WILL CONTINUE TO SEE GUSTY SLY WINDS THIS
AFTERNOON...THEN WINDS EASING THIS EVENING. SHOWERS WILL DECREASE IN
COVERAGE TONIGHT. 33
&&
.MARINE...STRONG SOUTHWEST TO WEST FLOW WILL CONTINUE ACROSS WESTERN
WA TODAY...WITH POSSIBLE GALES OVER THE COASTAL WATERS LATE
MORNING/AFTERNOON AS SFC TROUGH PASSES THROUGH. WINDS ACROSS ALL
WATERS EXPECTED TO EASE TONIGHT. THE NEXT COLD FRONT WILL ARRIVE ON
MON AND MAY SEE SLY GALES ACROSS THE COAST/ENTRANCES JDF/N INLAND
WATERS JUST AHEAD OF THIS SYSTEM SUN NIGHT INTO EARLY MON. ANOTHER
FRONT IS SLATED FOR TUE.
MEANWHILE...LARGE WESTERLY SWELLS OVER 25 FT CONTINUE ACROSS THE
COASTAL WATERS TODAY...WILL CONTINUE THE HIGH SURF WARNING FOR THE
BEACHES. SWELLS WILL GRADUALLY DECAY TO 20 FT ON SUN. 33
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...WINTER STORM WARNING FOR THE CASCADES THROUGH SATURDAY
NIGHT.
WEATHER ADVISORY FOR THE OLYMPIC MOUNTAINS THROUGH SATURDAY
EVENING FOR THE OLYMPIC MOUNTAINS.
HIGH SURF WARNING FOR THE COAST THROUGH 4 PM SATURDAY.
PZ...SMALL CRAFT ADVISORY ALL WATERS.
SMALL CRAFT ADVISORY FOR ROUGH GRAYS HARBOR BAR.
$$
WWW.WEATHER.GOV/SEATTLE
FOR AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION...PLEASE SEE
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML.
000
FXUS66 KPQR 071059 CCA
AFDPQR
AREA FORECAST DISCUSSION...CORRECTION
NATIONAL WEATHER SERVICE PORTLAND OR
230 AM PST SAT NOV 7 2009
CORRECTED ADVISORY SECTION
.SYNOPSIS...A COOL SHOWERY AIR MASS WILL CONTINUE TO SPREAD INTO THE
PACIFIC NORTHWEST TODAY AND EARLY TONIGHT AS A COUPLE OF SHORT WAVES
MOVE THROUGH IN A WESTERLY FLOW ALOFT. THIS WILL PRODUCE VALLEY RAIN
SHOWERS AND MOUNTAIN SNOW SHOWERS. THE AIR MASS WILL ALSO CONTINUE TO
BE A BIT UNSTABLE ESPECIALLY NEAR THE COAST. THE UPPER FLOW WILL
BUCKLE AS A FRONTAL SYSTEM DEVELOPS OFF THE COAST SUNDAY...BRUSHING
THE AREA WITH A WEAK WARM FRONT. THE ASSOCIATED RATHER STRONG COLD
FRONT WILL MOVE THROUGH MONDAY AND EARLY MONDAY EVENING WITH MORE
RAIN...MOUNTAIN SNOW AND BRISK WINDS.
&&
.SHORT TERM...A WESTERLY FLOW ALOFT IN THE WAKE OF THE COLD FRONT
THAT MOVED THROUGH SOUTHWEST WASHINGTON AND NORTHWEST OREGON THURSDAY
NIGHT WILL CONTINUE TODAY AND INTO EARLY TONIGHT. ONE SHORT WAVE IN
THIS FLOW CAME THROUGH OVERNIGHT WITH SOME PRETTY GOOD RAIN
SHOWERS...AND A FEW THUNDERSTORMS NEAR THE COAST. ONE STRONG STORM
CAME THROUGH THE NORTH LINCOLN CITY AND ROADS END AREA AROUND 930 PM
AND APPARENTLY DID SOME DAMAGE. THIS SHORT WAVE WILL MOVE MOSTLY EAST
OF OUR AREA BY SUNRISE.
A SECOND SHORT WAVE IS JUST NOW CROSSING 130W AND WILL REACH THE
COAST THIS MORNING AND PUSH INLAND IN THE LATE MORNING AND AFTERNOON.
THIS SHORT WAVE WILL PRODUCE A GOOD BAND OF SHOWERS AGAIN. IT SHOULD
ALSO BE A BIT UNSTABLE WITH THIS BAND...ESPECIALLY AT THE COAST BUT
POSSIBLY INLAND AGAIN AS WELL. SHEAR PROFILES LOOK SIMILAR TO
OVERNIGHT...NOT A LOT OF DIRECTIONAL SHEAR BUT GOOD SPEED SHEAR...AND
THUS THE THUNDERSTORMS NEAR THE COAST TODAY COULD AGAIN BE ON THE
STRONGER SIDE. THIS SHORT WAVE DOES NOT APPEAR TO CLEAR OUR FORECAST
AREA UNTIL SOME TIME TONIGHT...AFTER WHICH THE SHOWERS SHOULD EASE.
AS A RESULT...THE WINTER WEATHER ADVISORY FOR THE CASCADES CONTINUES
TO LOOK GOOD INTO TONIGHT AS WELL. SNOW LEVELS WILL BE AROUND 3000 TO
3500 FEET TODAY AND TONIGHT.
WINDS WILL BE A BIT BREEZY AT TIMES WITH THIS SHORT WAVE TODAY...
ESPECIALLY AT THE COAST. IN ADDITION...WINDS WILL BE GUSTY AT TIMES
WITH THE SHOWERS.
THE UPPER FLOW BEGINS TO BUCKLE AND BACK SUNDAY AND MONDAY AS THE
NEXT FRONTAL SYSTEM DEVELOPS OFF THE COAST. THE MODELS SAY SOME SORT
OF WARM ADVECTION PRECIPITATION MAY AFFECT PART OF OUR AREA
SUNDAY...THEN LIFT NORTH SUNDAY NIGHT. THE ASSOCIATED STRONG COLD
FRONT WILL MOVE IN MONDAY AND MOVE EAST MONDAY NIGHT. THIS FRONT
SHOULD PRODUCE GALES AGAIN ALONG THE COAST WITH GUSTY WINDS ALONG THE
COASTAL STRIP...AND BREEZY CONDITIONS INLAND. SNOW LEVELS LIFT SOME
AHEAD OF THIS FRONT...SO WE WILL HAVE TO SEE IF THEY LOWER SOON
ENOUGH TO GET ENOUGH SNOW FOR ANOTHER WINTER WEATHER ADVISORY IN THE
CASCADES. RIGHT NOW IT IS LOOKING RATHER IFFY. TOLLESON
.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...SNOW LEVELS
WILL START FALLING AGAIN MONDAY NIGHT AS THE NEXT STRONG FRONTAL
SYSTEM MOVES ACROSS THE CASCADES AND THE COOL UPPER LEVEL TROUGH
MOVES IN BEHIND IT. SHOWERY WEATHER WITH SNOW LEVELS BETWEEN 3000
AND 4000 FT WILL PERSIST THROUGH WEDNESDAY MORNING. EXTENDED MODELS
ARE CURRENTLY SHOWING THE UPPER LEVEL TROUGH WEAKENING OUT ON
WEDNESDAY TO BE REPLACE BY A RIDGE ON THURSDAY AND FRIDAY. IF THIS
TREND HOLDS TRUE DRIER WEATHER IS POSSIBLE FOR A COUPLE OF DAYS.
RUTHFORD.
&&
.AVIATION...MOSTLY VFR TODAY EXCEPT...LOCAL MVFR CIGS/VSBYS AND
SMALL HAIL POSSIBLE IN AFTERNOON SHOWERS AND THUNDERSTORMS AS WEAK
FRONT MOVES THROUGH. THESE SHOWERS/ISOLATED TSTMS SHOULD MOVE SE
ACROSS THE WILLAMETTE VALLEY BETWEEN 20Z-07Z.
KPDX AND APPROACHES...MAINLY VFR...BRIEF MVFR CIGS/VSBYS POSSIBLE IN
SHOWERS/ISOLATED TSTMS THIS AFTERNOON AND EVENING.
&&
.MARINE...MAIN CONCERN TODAY WILL BE THE VERY LARGE SEAS AND HIGH
WINDS. SEAS OF 23-27 FT WILL IMPACT THE COASTAL WATERS THROUGH THIS
AFTERNOON...THEN VERY GRADUALLY SUBSIDE TONIGHT THROUGH EARLY NEXT
WEEK. A COLD FRONT THIS AFTERNOON SHOULD BRING BRIEF GALES TODAY.
ANOTHER GOOD CHANCE FOR GALES WITH A STRONGER FRONT ANTICIPATED SUN
NIGHT/MON.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
WA/OR...GALE WARNING FROM CAPE SHOALWATER TO FLORENCE TODAY.
HIGH SURF WARNING SOUTH WASHINGTON...NORTH AND CENTRAL
OREGON COAST TODAY.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR IN
EFFECT THROUGH SUNDAY.
WINTER WEATHER ADVISORY FOR SNOW FOR THE SOUTH
WASHINGTON AND THE NORTH AND CENTRAL OREGON CASCADES
CONTINUES THROUGH 10 PM TONIGHT.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
000
FXUS66 KOTX 071043
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
243 AM PST SAT NOV 7 2009
.SYNOPSIS...
HEAVY SNOW IS EXPECTED OVER THE HIGH ELEVATIONS OF THE INLAND
NORTHWEST TODAY AND TONIGHT. THE MOUNTAINS OF NORTHEAST
WASHINGTON...NORTHERN IDAHO...AND PORTIONS OF THE CASCADES CAN
EXPECT BIG ACCUMULATIONS BY SUNDAY MORNING. MONDAY WILL BE A
RELATIVELY DRY DAY FOR THE INLAND NORTHWEST...BUT ANOTHER STORM
SYSTEM WILL BRING RAIN AND HIGH ELEVATION SNOW TO THE REGION
MONDAY NIGHT INTO TUESDAY.
&&
.DISCUSSION...
....HEAVY HIGH ELEVATION SNOWS TODAY AND TONIGHT...
TODAY AND TONIGHT...AN UPPER LEVEL LOW ANCHORED OVER THE GULF OF
ALASKA WILL REMAIN NEARLY STATIONARY FOR THE NEXT 24-48
HOURS...AND THE FAST ZONAL FLOW INTO THE PACIFIC NORTHWEST WILL
CONTINUE TO PROVIDE UNSETTLED WEATHER TO REGION. A PAIR OF
VIGOROUS SHORTWAVES WILL MOVE THROUGH THE FAST FLOW TODAY AND
TONIGHT. WATER VAPOR IMAGERY AS OF 10Z SHOWS THE FIRST WAVE ON THE
WASHINGTON COAST...AND THIS WAVE WILL BRING A ROUND OF
PRECIPITATION TO THE SPOKANE FORECAST AREA THIS MORNING THROUGH
EARLY THIS AFTERNOON. THE SECOND WAVE IS ABOUT 500 MILES DUE SOUTH
OF THE ALASKA COAST...AND THIS WAVE WILL BRING ANOTHER ROUND OF
PRECIPITATION TONIGHT. NEITHER OF THESE SHORTWAVES HAS A
PARTICULARLY IMPRESSIVE MOISTURE TAP. THE AMSU SATELLITE DERIVED
PRODUCT DEPICTS TWO-THIRDS OF AN INCH PRECIPITABLE WATER WITH EACH
SHORTWAVE. EVEN WITH THE LIMITED MOISTURE...SIGNIFICANT
PRECIPITATION WILL LIKELY ACCOMPANY THE PASSAGE OF BOTH WAVES.
DEEP LAYER INSTABILITY AND GOOD OROGRAPHICS WILL COMPENSATE FOR
THE LIMITED MOISTURE. THE MODELS ARE IN GOOD AGREEMENT THAT EACH
WAVE WILL PRODUCE A BAND OF PRECIPITATION BETWEEN .25 AND .33
INCHES OVER THE MOUNTAINS OF THE PANHANDLE AND NORTHEAST
WASHINGTON. GIVEN THE FAVORABLE WEST-SOUTHWEST WIND INTO THE
MOUNTAINS...SOME OF THE SOUTHWEST FACING SLOPES COULD RECEIVE
UPWARDS OF A HALF INCH OF LIQUID EQUIVALENT WITH EACH WAVE. WITH
THE HIGHLY CONVECTIVE NATURE OF THE PRECIPITATION...ELEVATIONS
ABOVE 4000 FEET CAN EXPECT SNOW RATIOS OF BETWEEN 12 TO 1 AND 15
TO 1. SNOW TOTALS OF 8 TO 12 INCHES SEEM PLAUSIBLE BY SUNDAY
MORNING FOR THE MOUNTAINS AROUND SANDPOINT...CHEWELAH...AND
KELLOGG. THE WINTER STORM WATCH FOR THESE AREAS HAS BEEN UPGRADED
TO A WINTER STORM WARNING FOR ELEVATIONS ABOVE 4000 FEET IN THE
CENTRAL PANHANDLE...AND ABOVE 3500 FEET FOR THE MOUNTAINS NEAR THE
CANADIAN BORDER. ACCUMULATIONS OF 10-20 INCHES ARE LIKELY FOR THE
CASCADE CREST...WITH LESSER AMOUNTS WEST OF THE CREST DUE TO THE
CONSIDERABLE WESTERLY DOWN-SLOPE WIND.
LOCALLY BREEZY WINDS WILL OCCUR THIS AFTERNOON BEHIND THE FIRST
SHORTWAVE. WINDS WILL NOT BE AS STRONG AS YESTERDAY...BUT WITH
850MB WINDS IN AROUND 30KTS AND FAVORABLE LAPSE RATES FOR LOW
LEVEL MIXING...GUSTY CONDITIONS WILL BE EXPERIENCED AGAIN OVER THE
PALOUSE...WEST PLAINS...AND SPOKANE AREA. /GKOCH
SUNDAY THROUGH TUESDAY...THE MODELS BEGIN THIS PERIOD OF THE
FORECAST WITH A FAIR SPREAD IN QPF VALUES ACROSS THE FORECAST AREA
ON SUNDAY MORNING...HOWEVER WITH A TREND TOWARD MUCH IMPROVED
CONDITIONS BY SUNDAY AFTERNOON WELL ESTABLISHED. THE NAM HAS
CONSISTENTLY BEEN SLOWER THAN THE GFS/CANADIAN WITH THE
PROGRESSION OF SATURDAY NIGHT`S SYSTEM TO THE EAST OF THE
AREA...AND TONIGHT`S 00Z AND 06Z RUNS WERE NO EXCEPTION. AS A
RESULT...THE FORECAST TRENDS A BIT CLOSER TOWARD THE GFS/CANADIAN
CONSENSUS AND NEGLECTS THE RATHER IMPRESSIVE QPF GENERATED BY THE
NAM OVER THE SOUTHEASTERN PORTION OF THE AREA ON SUNDAY MORNING.
BY 12Z SUNDAY...THE GFS IS TRACKING THE MAIN VORT WELL INTO
NORTHWESTERN MONTANA...WHILE THE NAM TRAILS IT A BIT FATHER WEST.
THE MAIN DIFFERENCES IN THE MODELS CENTER AROUND STRONG QPF
GENERATED BY THE NAM ALONG THE COLD FRONT AS IT SAGS SOUTHWARD
INTO THE SOUTHEASTERN PORTION OF THE AREA. HARNESSING OF
INSTABILITY AND COUPLING IT WITH VERY IMPRESSIVE DIFFERENTIAL PVA
TO GENERATE STRONG OMEGAS OVER A VERY NARROW REGION ALONG THE
FRONT YIELD QPF VALUES AROUND 0.60 INCHES FROM THE BLUES ACROSS
THE PALOUSE ON SUNDAY MORNING. HOWEVER...GIVEN THE LARGE SALE
WESTERLY TO SOUTHWESTERLY FLOW...THIS SCENARIO SEEMS RATHER
UNLIKELY TO MATERIALIZE...GIVEN THE PROPENSITY OF THE LARGE SCALE
FLOW TO ADVECT ANY PARTICULAR VORT MAX EAST RATHER THAN ALLOW IT
TO SAG DUE SOUTH ALONG THE FRONT. IN ADDITION...WITH RIDGING
POPPING UP IMMEDIATELY TO THE WEST OF THE MAIN VORT LOBE...IT
SEEMS INCREASINGLY UNLIKELY THAT ANY ADDITIONAL INCOMING VORT MAY
RUN DOWN THE FRONT...EFFECTIVELY RE-ACTIVATING LIFT ALONG THE
FRONTAL BAND. AS A RESULT...THE FORECAST FEATURES MUCH LIGHTER
DIMINISHING UP-SLOPE SHOWERS RATHER THAN ORGANIZED FRONTAL
RAIN/SNOW THROUGH SUNDAY.
AFTER FORCING ALONG THE COLD FRONT SHIFTS EASTWARD SUNDAY
AFTERNOON AND EVENING...THE GFS STARTS TO SHIFT THE THERMAL
GRADIENT A BIT FARTHER FARTHER NORTH...WITH INCOMING LARGE SCALE
SOUTHERLY FLOW INCREASING THE NORTHWARD TRANSLATION OF THE FRONT
OVERNIGHT SUNDAY NIGHT AS A WARM FRONTAL PUSH. SOME ISENTROPIC
LIFT IS NOTED ALONG THE FRONT AS IT SHIFTS NORTHWARD SUNDAY
NIGHT...HOWEVER CONDENSATION PRESSURE DEFICITS IN THE 290K AREA
GENERALLY STAY NEAR OR ABOVE 30 MB OVER EASTERN WASHINGTON...WITH
THE ONLY AREA OF REDUCED CONDENSATION PRESSURE DEFICITS NEAR THE
CASCADES. AS A RESULT...PRECIP CHANCES HAVE BEEN RELEGATED TO THE
CASCADES...WITH THE REST OF THE AREA DRY ALONG AND BEHIND THE WARM
FRONT SUNDAY NIGHT INTO MONDAY.
BETTER MODEL AGREEMENT EXISTS IN CLEARING BEHIND THE WARM FRONT
FOR SUNDAY NIGHT AND MONDAY. ADDITIONALLY...THE 00Z GFS AND 06Z
NAM HAVE COME INTO MUCH CLOSER AGREEMENT FOR TRACKING THE TRAILING
COLD FRONT INTO THE AREA ON MONDAY NIGHT WITH A 120 KT JET STREAK
LEFT ENTRANCE REGION COMING ON SHORE AND DEEP LAYER PVA SPREADING
STRATIFORM RAINS INTO THE AREA MONDAY NIGHT. LAYER TEMPERATURES
AFTER THE WARM FRONTAL PASSAGE SURGE ABOVE FREEZING WELL UP INTO
THE ATMOSPHERE...AND WET BULB ZERO HEIGHTS REACH NEARLY 6000 FEET
OVER MANY AREAS. AS A RESULT...MANY LOCATIONS THAT WILL HAVE SEEN
SNOW THIS WEEKEND ARE LIKELY TO SEE RAIN WITH THE NEXT SYSTEM ON
MONDAY NIGHT AND TUESDAY. /FRIES
&&
.AVIATION...
PREDOMINANT VFR CONDITIONS AT TAF SITES WITH LCL MVFR/IFR CIGS
POSSIBLE OVERNIGHT/EARLY SATURDAY AROUND KGEG-KCOE IN THE SW FLOW
AND IN SHOWERS. ISOLATED SHOWERS AROUND THE MOUNTAINS FRIDAY NIGHT WILL
BECOME MORE NUMEROUS OVERNIGHT INTO SATURDAY AS THE NEXT SYSTEM
SLIDES THROUGH. THE SHOWERS WILL BECOME LESS NUMEROUS PAST MIDDAY
BUT ARE EXPECTED TO INCREASE AGAIN AFT 22-03Z SATURDAY EVENING AS
A SECOND DISTURBANCES COMES THROUGH. WINDS WILL REMAIN IN THE BREEZY
CATEGORY...WITH INCREASING GUSTS IN THE AFTERNOON. /JCOTE
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 45 34 43 32 46 35 / 90 80 20 10 0 50
COEUR D`ALENE 45 34 43 32 47 34 / 90 80 20 10 0 40
PULLMAN 47 35 48 30 53 36 / 70 70 20 0 0 40
LEWISTON 54 38 53 36 55 41 / 40 40 20 0 0 30
COLVILLE 45 34 46 32 46 32 / 70 90 20 10 0 60
SANDPOINT 42 35 41 32 43 33 / 100 90 40 10 0 50
KELLOGG 40 33 38 31 43 33 / 90 100 50 10 0 60
MOSES LAKE 52 34 50 32 50 33 / 20 70 10 10 10 30
WENATCHEE 50 35 48 35 47 36 / 10 30 0 10 10 50
OMAK 48 33 46 34 46 29 / 20 70 10 10 10 60
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...WINTER STORM WARNING FROM 7 AM THIS MORNING TO 4 AM PST SUNDAY
ABOVE 3500 FEET FOR NORTHERN PANHANDLE.
WINTER STORM WARNING FROM 7 AM THIS MORNING TO 4 AM PST SUNDAY
ABOVE 4000 FEET FOR CENTRAL PANHANDLE MOUNTAINS.
WA...WINTER STORM WARNING FROM 7 AM THIS MORNING TO 4 AM PST SUNDAY
ABOVE 3500 FEET FOR NORTHEAST MOUNTAINS.
&&
$$
000
FXUS66 KPQR 071030
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
230 AM PST SAT NOV 7 2009
.SYNOPSIS...A COOL SHOWERY AIR MASS WILL CONTINUE TO SPREAD INTO THE
PACIFIC NORTHWEST TODAY AND EARLY TONIGHT AS A COUPLE OF SHORT WAVES
MOVE THROUGH IN A WESTERLY FLOW ALOFT. THIS WILL PRODUCE VALLEY RAIN
SHOWERS AND MOUNTAIN SNOW SHOWERS. THE AIR MASS WILL ALSO CONTINUE TO
BE A BIT UNSTABLE ESPECIALLY NEAR THE COAST. THE UPPER FLOW WILL
BUCKLE AS A FRONTAL SYSTEM DEVELOPS OFF THE COAST SUNDAY...BRUSHING
THE AREA WITH A WEAK WARM FRONT. THE ASSOCIATED RATHER STRONG COLD
FRONT WILL MOVE THROUGH MONDAY AND EARLY MONDAY EVENING WITH MORE
RAIN...MOUNTAIN SNOW AND BRISK WINDS.
&&
.SHORT TERM...A WESTERLY FLOW ALOFT IN THE WAKE OF THE COLD FRONT
THAT MOVED THROUGH SOUTHWEST WASHINGTON AND NORTHWEST OREGON THURSDAY
NIGHT WILL CONTINUE TODAY AND INTO EARLY TONIGHT. ONE SHORT WAVE IN
THIS FLOW CAME THROUGH OVERNIGHT WITH SOME PRETTY GOOD RAIN
SHOWERS...AND A FEW THUNDERSTORMS NEAR THE COAST. ONE STRONG STORM
CAME THROUGH THE NORTH LINCOLN CITY AND ROADS END AREA AROUND 930 PM
AND APPARENTLY DID SOME DAMAGE. THIS SHORT WAVE WILL MOVE MOSTLY EAST
OF OUR AREA BY SUNRISE.
A SECOND SHORT WAVE IS JUST NOW CROSSING 130W AND WILL REACH THE
COAST THIS MORNING AND PUSH INLAND IN THE LATE MORNING AND AFTERNOON.
THIS SHORT WAVE WILL PRODUCE A GOOD BAND OF SHOWERS AGAIN. IT SHOULD
ALSO BE A BIT UNSTABLE WITH THIS BAND...ESPECIALLY AT THE COAST BUT
POSSIBLY INLAND AGAIN AS WELL. SHEAR PROFILES LOOK SIMILAR TO
OVERNIGHT...NOT A LOT OF DIRECTIONAL SHEAR BUT GOOD SPEED SHEAR...AND
THUS THE THUNDERSTORMS NEAR THE COAST TODAY COULD AGAIN BE ON THE
STRONGER SIDE. THIS SHORT WAVE DOES NOT APPEAR TO CLEAR OUR FORECAST
AREA UNTIL SOME TIME TONIGHT...AFTER WHICH THE SHOWERS SHOULD EASE.
AS A RESULT...THE WINTER WEATHER ADVISORY FOR THE CASCADES CONTINUES
TO LOOK GOOD INTO TONIGHT AS WELL. SNOW LEVELS WILL BE AROUND 3000 TO
3500 FEET TODAY AND TONIGHT.
WINDS WILL BE A BIT BREEZY AT TIMES WITH THIS SHORT WAVE TODAY...
ESPECIALLY AT THE COAST. IN ADDITION...WINDS WILL BE GUSTY AT TIMES
WITH THE SHOWERS.
THE UPPER FLOW BEGINS TO BUCKLE AND BACK SUNDAY AND MONDAY AS THE
NEXT FRONTAL SYSTEM DEVELOPS OFF THE COAST. THE MODELS SAY SOME SORT
OF WARM ADVECTION PRECIPITATION MAY AFFECT PART OF OUR AREA
SUNDAY...THEN LIFT NORTH SUNDAY NIGHT. THE ASSOCIATED STRONG COLD
FRONT WILL MOVE IN MONDAY AND MOVE EAST MONDAY NIGHT. THIS FRONT
SHOULD PRODUCE GALES AGAIN ALONG THE COAST WITH GUSTY WINDS ALONG THE
COASTAL STRIP...AND BREEZY CONDITIONS INLAND. SNOW LEVELS LIFT SOME
AHEAD OF THIS FRONT...SO WE WILL HAVE TO SEE IF THEY LOWER SOON
ENOUGH TO GET ENOUGH SNOW FOR ANOTHER WINTER WEATHER ADVISORY IN THE
CASCADES. RIGHT NOW IT IS LOOKING RATHER IFFY. TOLLESON
.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...SNOW LEVELS
WILL START FALLING AGAIN MONDAY NIGHT AS THE NEXT STRONG FRONTAL
SYSTEM MOVES ACROSS THE CASCADES AND THE COOL UPPER LEVEL TROUGH
MOVES IN BEHIND IT. SHOWERY WEATHER WITH SNOW LEVELS BETWEEN 3000
AND 4000 FT WILL PERSIST THROUGH WEDNESDAY MORNING. EXTENDED MODELS
ARE CURRENTLY SHOWING THE UPPER LEVEL TROUGH WEAKENING OUT ON
WEDNESDAY TO BE REPLACE BY A RIDGE ON THURSDAY AND FRIDAY. IF THIS
TREND HOLDS TRUE DRIER WEATHER IS POSSIBLE FOR A COUPLE OF DAYS.
RUTHFORD.
&&
.AVIATION...MOSTLY VFR TODAY EXCEPT...LOCAL MVFR CIGS/VSBYS AND
SMALL HAIL POSSIBLE IN AFTERNOON SHOWERS AND THUNDERSTORMS AS WEAK
FRONT MOVES THROUGH. THESE SHOWERS/ISOLATED TSTMS SHOULD MOVE SE
ACROSS THE WILLAMETTE VALLEY BETWEEN 20Z-07Z.
KPDX AND APPROACHES...MAINLY VFR...BRIEF MVFR CIGS/VSBYS POSSIBLE IN
SHOWERS/ISOLATED TSTMS THIS AFTERNOON AND EVENING.
&&
.MARINE...MAIN CONCERN TODAY WILL BE THE VERY LARGE SEAS AND HIGH
WINDS. SEAS OF 23-27 FT WILL IMPACT THE COASTAL WATERS THROUGH THIS
AFTERNOON...THEN VERY GRADUALLY SUBSIDE TONIGHT THROUGH EARLY NEXT
WEEK. A COLD FRONT THIS AFTERNOON SHOULD BRING BRIEF GALES TODAY.
ANOTHER GOOD CHANCE FOR GALES WITH A STRONGER FRONT ANTICIPATED SUN
NIGHT/MON.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
WA/OR...GALE WARNING FROM CAPE SHOALWATER TO FLORENCE TODAY.
HIGH SURF WARNING SOUTH WASHINGTON...NORTH AND CENTRAL
OREGON COAST TODAY.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR IN
EFFECT THROUGH SUNDAY.
WINTER WEATHER ADVISORY FOR SNOW FOR THE SOUTH
WASHINGTON AND THE NORTH AND CENTRAL OREGON CASCADES
CONTINUES THROUGH TONIGHT.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
000
FXUS66 KOTX 070613
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
1013 PM PST FRI NOV 6 2009
.SYNOPSIS...
AN ACTIVE WEATHER PATTERN WILL CONTINUE THROUGH THE WEEKEND...
AS SYSTEMS CONTINUE TO MOVE IN FROM THE PACIFIC OCEAN. ISOLATED
VALLEY RAIN AND MOUNTAIN SNOW SHOWERS FRIDAY EVENING WILL BECOME
MORE NUMEROUS INTO SATURDAY. SIGNIFICANT HIGH ELEVATION SNOW
ACCUMULATIONS ARE LIKELY OVER THE CASCADES AND OVER THE MOUNTAINS
OF THE IDAHO PANHANDLE AND NORTHEAST WASHINGTON BY SUNDAY MORNING.
THE RISK FOR SHOWERS WILL CONTINUE INTO NEXT WEEK...WITH
SEASONABLE TEMPERATURES.
&&
.DISCUSSION...
REST OF TONIGHT...CLOUDS HAVE CLEARED OUT OF MUCH OF THE BASIN
AND EASTERN WASHINGTON...THOUGH STILL REMAIN TUCKED IN AROUND THE
CASCADES AND MUCH OF THE PANHANDLE (INCLUDING PARTS OF THE COEUR
D`ALENE AREA AS PER THE FOG SATELLITE PRODUCT). ONLY ISOLATED TO
SCATTERED SHOWERS ARE FOUND ABOUT THE MOUNTAINS AT THIS HOUR (06Z).
THE NEXT SHORT-WAVE IS ON THE APPROACH THOUGH...COMING RAPIDLY
TOWARD THE WA COAST AND ENHANCING SOME SHOWERS ON THE WEST SIDE OF
THE STATE. THERE ARE SOME COOLING AND EXPANDING CLOUD TOPS NEAR
THE CASCADES AS WELL...WHICH ARE SHOWING SIGNS OF EXPANDING EAST.
SO CLOUDS ARE EXPECTED TO INCREASE THROUGH THE AREA OVERNIGHT...EVEN
IF NOT UNTIL LATE. WITH THE MORE RAPID EXIT OF CLOUDS THIS
EVENING...TEMPERATURES WERE ADJUSTED DOWN ONLY A DEGREE OR TWO.
HOWEVER WITH THE WINDS STILL BREEZY IN SPOTS TEMPERATURES SHOULD
NOT DROP RAPIDLY.
THE MOST LIKELY RAIN AND MOUNTAIN SNOW SHOWER CHANCES FOR THE
OVERNIGHT REMAIN OVER THE CASCADES AND PANHANDLES...AS WELL AS
OVER THE OKANOGAN HIGHLANDS. POPS ELSEWHERE REMAIN ONLY SLIGHT IN
THE SLIGHT TO CHANCE CATEGORY...THE NEWEST RUNS SHOWING
MOISTURE/PRECIP ATTEMPTING TO COME TOWARD EASTERN WA/NRN TOWARD
DAYBREAK. /JCOTE
&&
.AVIATION...
PREDOMINANT VFR CONDITIONS AT TAF SITES WITH LCL MVFR/IFR CIGS
POSSIBLE OVERNIGHT/EARLY SATURDAY AROUND KGEG-KCOE IN THE SW FLOW
AND IN SHOWERS. ISOLATED SHOWERS AROUND THE MOUNTAINS FRIDAY NIGHT WILL
BECOME MORE NUMEROUS OVERNIGHT INTO SATURDAY AS THE NEXT SYSTEM
SLIDES THROUGH. THE SHOWERS WILL BECOME LESS NUMEROUS PAST MIDDAY
BUT ARE EXPECTED TO INCREASE AGAIN AFT 22-03Z SATURDAY EVENING AS
A SECOND DISTURBANCES COMES THROUGH. WINDS WILL REMAIN IN THE BREEZY
CATEGORY...WITH INCREASING GUSTS IN THE AFTERNOON. /JCOTE
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 34 45 34 42 31 46 / 20 80 80 20 10 0
COEUR D`ALENE 36 45 34 43 31 47 / 30 100 80 20 10 0
PULLMAN 35 48 35 46 30 53 / 20 80 70 20 0 0
LEWISTON 39 53 39 52 36 55 / 30 40 40 10 0 0
COLVILLE 34 45 34 45 30 46 / 50 60 70 20 10 0
SANDPOINT 39 41 34 41 30 43 / 50 100 90 40 10 0
KELLOGG 35 40 33 38 30 43 / 50 100 100 50 10 0
MOSES LAKE 34 50 35 50 31 49 / 20 30 50 10 10 10
WENATCHEE 33 48 37 48 34 46 / 20 30 40 0 10 10
OMAK 34 46 35 46 31 45 / 40 50 60 10 10 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...WINTER STORM WATCH FROM SATURDAY MORNING THROUGH LATE SATURDAY
NIGHT ABOVE 3500 FEET FOR NORTHERN PANHANDLE.
WINTER STORM WATCH FROM SATURDAY MORNING THROUGH LATE SATURDAY
NIGHT ABOVE 4000 FEET FOR CENTRAL PANHANDLE MOUNTAINS.
WA...WINTER STORM WATCH FROM SATURDAY MORNING THROUGH LATE SATURDAY
NIGHT ABOVE 3500 FEET FOR NORTHEAST MOUNTAINS.
&&
$$
000
FXUS66 KSEW 070505
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
900 PM PST FRI NOV 6 2009
.SYNOPSIS...A BROAD UPPER LEVEL TROUGH WITH COOL MOIST UNSTABLE AIR
WILL CONTINUE TO DIRECT SHOWERS AND BREEZY WEATHER INTO WESTERN
WASHINGTON THROUGH SATURDAY. THE SHOWER ACTIVITY WILL DECREASE
SATURDAY NIGHT AND SUNDAY AS THE AIR MASS DRIES SOMEWHAT AND
STABILIZES. A WARM FRONT WILL MOVE THROUGH THE AREA SUNDAY NIGHT
WITH A COLD FRONT MONDAY NIGHT...AND PERHAPS ANOTHER COLD FRONT ON
TUESDAY. A COLD UPPER TROF COULD CLIP WASHINGTON WEDNESDAY. A
TEMPORARY RIDGE OF HIGH PRESSURE IS POSSIBLE NEXT THURSDAY AND
FRIDAY.
&&
.SHORT TERM...SHOWERS...CHANCE OF TSTMS...AND BREEZY AT TIMES THRU
SAT. SEATTLE HAS BEEN GETTING MORE THAN ITS SHARE THIS EVENING AND
THE THREE HOUR PRECIP TOTAL FROM THE NWS 88D RADAR GIVES AROUND AN
INCH OF RAIN FROM DOWNTOWN TO THE KING/SNO COUNTY LINE. HEAVY SNOW
SHOWERS IN THE CASCADES...TRAVELERS CROSSING THE HIGHER PASSES WILL
HAVE WINTER DRIVING CONDITIONS AND LIKELY SEE SNOW ON THE ROADS WITH
VSBY DROPPING AT TIMES. BUT FOR SNOQUALMIE PASS IT HAS BEEN RIGHT AT
32F THIS EVENING AND I-90 IS LIKELY TO REMAIN MOSTLY BARE AND WET
DESPITE THE SNOWFALL...BUT DO CHECK THE ROAD REPORTS...A HEAVY
SHOWER CAN TURN EVEN I-90 TO A SLUSHY MESS...AT LEAST FOR AWHILE.
THERE WILL BE A BREAK IN THE WEATHER ON SUNDAY...PROBABLY DRY IN THE
LOWLANDS BUT CANNOT PROMISE TOO MUCH...IN FACT THE NAM KEEPS SNOW
GOING ON STEVENS PASS NORTHWARD TIL MIDDAY. THEN THE WARM FRONT FROM
THE NEXT FNTL SYS ARRIVES SUN NITE. THE MODELS TRACK A LOW PRES
CENTER INTO THE CHARLOTTES SUNDAY EVENING...AND THERE IS A FOLLOWUP
FNTL WAVE WITH ARND A 999MB LOW INTO VRISL MON MORNING. EXCEPT FOR
THE COAST....THERE IS NOT MUCH PRECIP OVER WRN WA MONDAY MORNING...A
BREAK IN THE WARM SECTOR...BUT FOR MON AFTERNOON AND EVENING THE
MODELS HAVE THE COLD FRONT PRECIP. 19
.LONG TERM...LATEST GFS HAS A SECOND COLD FRONT TO THE COAST LATER
TUE AFTERNOON AND A COLD TROF WITH PLENTY OF SHOWERS WED. SNOW
LEVELS ARE LIKELY TO BE ESPECIALLY LOW NEXT WED IF THE MODELS DO NOT
CHANGE MUCH...THE UPPER TROF WED IS A LITTLE SHARPER AND COOLER ON
THIS LATEST RUN. A CHANCE FOR A RIDGE NEXT THU/FRI. 19
&&
.HYDROLOGY...THERE ARE NO HYDROLOGY OR RIVER FLOODING CONCERNS
THROUGH THE WEEKEND. SNOW LEVELS WILL BE NEAR 3000 FEET THROUGH
SATURDAY...LIMITING RUNOFF CONCERNS FOR RIVERS WITH THEIR HEADWATERS
OVER THE MOUNTAINS. EVEN FOR LOWER ELEVATIONS...THE CONVECTIVE
NATURE OF PRECIPITATION WILL MEAN SIGNIFICANT DRY BREAKS BETWEEN
HEAVY SHOWERS AND THUNDERSTORMS.
A STRONG FRONTAL SYSTEM LATE SUNDAY NIGHT AND MONDAY WILL GIVE A
QUICK SHOT OF RAIN AND RAISE FREEZING LEVELS...BUT THE PROGRESSIVE
MOVEMENT OF THE FRONT WILL LIMIT THE DURATION OF HEAVY PRECIP AND
FLOOD CONCERN. BEYOND THE 7-DAY FORECAST...MODELS SOLUTIONS POINT TO
A COUPLE OF FRONTAL SYSTEMS THAT WILL NEED TO BE WATCHED. THE FIRST
WOULD BE EARLY NEXT WEEKEND...AND THE SECOND WOULD BE EARLY THE
FOLLOWING WEEK. HOWEVER...WHEN DEALING WITH WEATHER BEYOND A WEEK IN
THE FUTURE...ONLY BROAD GENERAL TRENDS CAN BE ASCRIBED. HOWEVER...
THE 8-14 DAY OUTLOOK FOR 11/14-20 FROM CPC CALLS FOR ABOVE NORMAL
PRECIPITATION. HANER
&&
.AVIATION...UNSETTLED WEATHER WILL CONTINUE ACROSS WESTERN
WASHINGTON TONIGHT. A STRONG UPPER LEVEL LOW CONTINUES TO SPIN OFF
THE AK PANHANDLE WITH CYCLONIC FLOW ALOFT ACROSS THE PAC NW. IR
SATELLITE SHOWS AN EXTENSIVE CU FIELD OVER THE OCEAN DRIFTING
INLAND. SHOWERS WILL BE HEAVIEST THROUGH THIS EVENING AS A SFC
TROUGH SHIFTS INLAND. WILL SEE ANOTHER UPTICK IN SHOWERS SAT
MORNING/AFTERNOON AS ANOTHER WAVE MOVES IN. IN BETWEEN...ANTICIPATE
OFF-AND-ON SHOWERS ACROSS THE ENTIRE AREA. WILL CONTINUE TO SEE A
THREAT FOR ISOLD-SCT THUNDERSTORMS AS WELL. WINDS ACROSS MOST AREAS
WILL REMAIN BREEZY WITH GUSTS IN THE 20S. 33
KSEA...SHOWERS WILL CONTINUE THIS EVENING AS THIS NEXT WAVE PASSES
THROUGH. BRIEF HEAVY DOWNPOURS WILL REDUCE VIS AND/OR CIGS INTO THE
MVFR RANGE. OFF-AND-ON SHOWERS EXPECTED EARLY SAT MORNING...THEN
ANOTHER INCREASE IN ACTIVITY LATE MORNING/AFTERNOON AS THE NEXT WAVE
MOVES THROUGH. WILL CONTINUE TO SEE GUSTY SLY WINDS THROUGH SAT. 33
&&
.MARINE...STRONG SOUTHWEST TO WEST FLOW WILL CONTINUE ACROSS WESTERN
WA TONIGHT. WINDS WILL PICK UP SAT MORNINGS AS A SFC TROUGH
SHIFTS EAST AND INLAND. WINDS WILL EASE A BIT SAT NIGHT. THE NEXT
COLD FRONT WILL ARRIVE ON MON AND MAY SEE SLY GALES ACROSS THE
COAST/ENTRANCES JDF/N INLAND WATERS JUST AHEAD OF THIS SYSTEM SUN
NIGHT INTO EARLY MON.
MEANWHILE...LARGE WESTERLY SWELLS OVER 25 FT EXPECTED ACROSS THE
COASTAL WATERS TONIGHT THROUGH SAT AFTERNOON...THEN GRADUALLY
SUBSIDING TO AROUND 20 FT SAT NIGHT. THUS WILL CONTINUE THE HIGH
SURF WARNING FOR THE BEACHES. THE PREDICTED HIGH TIDES SAT MORNING
WILL BE LOWER THAN FRI AFTERNOON...AND EVEN WITH A 1-1.5 FT ANOMALY
SHOULD NOT SEE COASTAL FLOODING. 33
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...WINTER STORM WARNING FOR THE CASCADES THROUGH SATURDAY
NIGHT.
WEATHER ADVISORY FOR THE OLYMPIC MOUNTAINS THROUGH SATURDAY
EVENING FOR THE OLYMPIC MOUNTAINS.
HIGH SURF WARNING FOR THE COAST THROUGH 4 PM SATURDAY.
PZ...SMALL CRAFT ADVISORY ALL WATERS.
SMALL CRAFT ADVISORY FOR ROUGH GRAYS HARBOR BAR.
$$
WWW.WEATHER.GOV/SEATTLE
FOR AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION...PLEASE SEE
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML.
000
FXUS66 KPQR 070433
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
825 PM PST FRI NOV 6 2009
.SYNOPSIS...A COOL AIR MASS WILL REMAIN OVER THE REGION THROUGH THE
WEEKEND. THIS PATTERN WILL MAINTAIN SHOWERS AND EVEN A FEW
THUNDERSTORMS THROUGH SAT. EXPECT HEAVY SNOW AT TIMES IN THE
CASCADES. CONDITIONS WILL DRY OUT A BIT SUNDAY...BUT WET WEATHER
RETURNS FOR MONDAY.
&&
.SHORT TERM...KRTX RADAR INDICATES AN ENHANCED BATCH OF SHOWERS
APPROACHING THE NORTH OREGON COAST THIS EVENING. A FEW THUNDERSTORMS
ARE POSSIBLE AS WELL AS THIS AREA OF SHOWERS MOVES ONSHORE AND INTO
THE NORTH OREGON COAST RANGE. ANY THUNDERSTORMS THAT DO DEVELOP MAY
STILL PRODUCE SMALL HAIL AND BRIEF GUSTY WINDS.
OVERALL PATTERN NOT CHANGING MUCH OVER THE NEXT DAY OR SO. A STRONG
UPPER LOW OVER THE EASTERN GULF OF ALASKA WILL MAINTAIN MODERATE
ONSHORE FLOW THROUGH SAT EVENING. EMBEDDED DISTURBANCES WILL KEEP
ROUNDS OF SHOWERS...AND EVEN A COUPLE BANDS OF STEADY
PRECIP...ARRIVING. MODELS ARE IN GOOD AGREEMENT SHOWING THE ENHANCED
BAND CURRENTLY APPROACHING THE COAST MOVING THROUGH LATER TONIGHT
WITH A STRONGER BAND LATE SAT OR SAT EVENING WHICH MAY GIVE A PERIOD
OF STEADY PRECIP.
SNOW LEVELS WILL HOVER BETWEEN 3500 AND 4000 FEET THROUGH SAT...THEN
POSSIBLY DROP SLIGHTLY SAT NIGHT BEHIND THAT DISTURBANCE. WITH PLENTY
OF PRECIP AND FAVORABLE W 850 MB FLOW...2 TO 3 FT OF NEW SNOW SEEMS
REASONABLE BETWEEN NOW AND LATE SAT NIGHT FOR THE CASCADES. CURRENT
WINTER WEATHER ADVISORY OKAY RATHER THAN WINTER STORM WARNING DUE TO
FACT THAT THE ACCUMULATIONS WILL BE MODERATE BUT MAINLY SPREAD OUT
OVER TIME.
MODELS CONTINUE TO SHOW ANOTHER STRONG LOW SPINNING UP IN THE E GULF
OF ALASKA ON SUN AND MON. THIS WILL RESULT IN SOME RIDGING OVER PAC
NW LATER SUN AND SUN NIGHT...WITH MOSTLY DRY WEATHER. HOWEVER...
WILL BE A SHORT LIVED BREAK AS THAT SYSTEM WILL SEND A FRONT INTO
PAC NW ON MON.
.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...SNOW LEVELS
WILL START FALLING AGAIN MONDAY NIGHT AS THE NEXT STRONG FRONTAL
SYSTEM MOVES ACROSS THE CASCADES AND THE COOL UPPER LEVEL TROUGH
MOVES IN BEHIND IT. SHOWERY WEATHER WITH SNOW LEVELS BETWEEN 3000
AND 4000 FT WILL PERSIST THROUGH WEDNESDAY MORNING. EXTENDED MODELS
ARE CURRENTLY SHOWING THE UPPER LEVEL TROUGH WEAKENING OUT ON
WEDNESDAY TO BE REPLACE BY A RIDGE ON THURSDAY AND FRIDAY. IF THIS
TREND HOLDS TRUE DRIER WEATHER IS POSSIBLE FOR A COUPLE OF DAYS.
RUTHFORD.
&&
.AVIATION...MOSTLY VFR WITH LOCAL MVFR CIGS/VSBYS AND SMALL HAIL ARE
POSSIBLE IN SHOWERS AND THUNDERSTORMS AS ANOTHER TROUGH MOVES INLAND
TONIGHT. THESE SHOWERS/ISOLATED TSTMS SHOULD MOVE SE ACROSS THE
WILLAMETTE VALLEY BETWEEN 05Z-09Z. YET ANOTHER FRONT EXPECTED TO
MOVE ONSHORE WITH MORE SHOWERS DURING THE DAY SAT.
KPDX AND APPROACHES...MAINLY VFR...BUT BRIEF MVFR CIGS/VSBYS
POSSIBLE IN SHOWERS/ISOLATED TSTMS AS TROUGH MOVES THROUGH PDX METRO
BETWEEN 06Z-09Z.
&&
.MARINE...MAIN CONCERN THROUGH SATURDAY WILL BE THE VERY LARGE SEAS
BEGINNING TO MOVE INTO THE COASTAL WATERS. THESE SWELLS WERE
GENERATED BY A STRONG LOW IN THE GULF OF ALASKA. W-NW SWELLS OF
23-27 FT WILL IMPACT THE COASTAL WATERS THROUGH SAT AFTERNOON...THEN
VERY GRADUALLY SUBSIDE SAT NIGHT THROUGH EARLY NEXT WEEK. A COLD
FRONT SAT AFTERNOON MAY BRING BRIEF GALES...WITH A BETTER CHANCE FOR
GALES WITH A STRONGER FRONT ANTICIPATED SUN NIGHT/MON.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
WA/OR...SMALL CRAFT ADVISORY FOR WINDS FROM CAPE SHOALWATER TO
FLORENCE THROUGH SATURDAY EVENING.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM CAPE SHOALWATER
TO FLORENCE THROUGH SUNDAY.
HIGH SURF WARNING SOUTH WASHINGTON...NORTH AND CENTRAL
OREGON COAST THROUGH SATURDAY.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR IN
EFFECT THROUGH SUNDAY.
WINTER WEATHER ADVISORY FOR SNOW FOR THE CASCADES OF SOUTH
WASHINGTON...NORTH AND CENTRAL OREGON CONTINUES THROUGH
SAT NIGHT.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
000
FXUS66 KOTX 070355
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
755 PM PST FRI NOV 6 2009
.SYNOPSIS...
AN ACTIVE WEATHER PATTERN WILL CONTINUE THROUGH THE WEEKEND...
AS SYSTEMS CONTINUE TO MOVE IN FROM THE PACIFIC OCEAN. ISOLATED
VALLEY RAIN AND MOUNTAIN SNOW SHOWERS FRIDAY EVENING WILL BECOME
MORE NUMEROUS INTO SATURDAY. SIGNIFICANT HIGH ELEVATION SNOW
ACCUMULATIONS ARE LIKELY OVER THE CASCADES AND OVER THE MOUNTAINS
OF THE IDAHO PANHANDLE AND NORTHEAST WASHINGTON BY SUNDAY MORNING.
THE RISK FOR SHOWERS WILL CONTINUE INTO NEXT WEEK...WITH
SEASONABLE TEMPERATURES.
&&
.DISCUSSION...
REST OF TONIGHT...FORECAST UPDATE SENT TO MAKE ADJUSTMENTS TO
FINE-TUNE POPS AND QPF AMOUNTS AND CLOUD COVER FOR THIS EVENING
AND OVERNIGHT. MAINLY ISOLATED SHOWERS OVER THE VALLEY/BASIN
AREAS AND SCATTERED SHOWERS OVER THE MOUNTAINS NOW...WITH DECENT
CLEARING OVER THE BASIN. BUT SHOWERS AND CLOUDS ARE STILL ON TRACK
TO BECOME MORE NUMEROUS OVERNIGHT INTO SATURDAY...AS THE NEXT
MID-LEVEL WAVES COME IN. CUMULI-FORM CLOUDS ON WV/IR IMAGERY
CONTINUES TO INDICATE SOME UNSTABLE LAPSE RATES...WITH THE FIRST
WAVE NEAR 130W AT 03Z. ALL GUIDANCE INDICATES SHOWERS INCREASING
AFTER ABOUT 09-12Z TONIGHT...ESPECIALLY AWAY FROM THE LEE-SIDE OF
THE CASCADES WHICH MODELS CONTINUE TO INDICATE WILL EXPERIENCE
SOME SHADOWING. MAIN CHANGE WAS TO REDUCE THE RISK FOR PRECIPITATION
OVER THE SPOKANE/C`DA AREA SOUTHWARD...AS PRECIPITATION SHOULD
REMAIN MAINLY ISOLATED. THE BEST CHANCE OF RENEWED PRECIPITATION
REMAINS NORTH AND NORTHWEST OF THESE AREAS TOWARD THE OKANOGAN
HIGHLANDS.
WINDS REMAIN BREEZY BUT HAVE DIMINISHED FROM EARLIER FRIDAY AND THE
WIND ADVISORY WAS REMOVED EARLIER THIS EVENING. MINOR TWEAKS MADE TO
THESE WINDS FOR A CONTINUE DECLINE. OTHER MINOR TWEAKS WERE MADE
TO OVERNIGHT LOWS...BUT IN GENERAL THEY LOOK ON TRACK TO COME IN
COOLER THAN LAST NIGHT.
A WINTER STORM WATCH REMAINS IN PLACE FOR LATE MORNING SATURDAY
THROUGH SATURDAY NIGHT. AT LEAST A COUPLE WAVES PASS DURING THIS
TIME FRAME...TO BRING STEADIER PERIODS OF SNOW OVER THE NORTHEAST
WA AND PANHANDLE MTNS ABOVE 3.5 TO 4KFT...ESPECIALLY LATE SATURDAY
MORNING AND AGAIN LATER SATURDAY NIGHT. THIS LOOKS TO BE INTERMINGLED
WITH AT LEAST BRIEF SNOW-FREE OR NEARLY SNOW-FREE BREAKS. HOW
UNSTABLE THE ATMOSPHERE IS AND HOW PERSISTENT SNOW IS IN THE
MOUNTAINS IS STILL BEING FINE-TUNED. /JCOTE
&&
.AVIATION...
SCATTERED SHOWERS WILL CONTINUE OVER FAR EASTERN WA AND THE IDAHO
PANHANDLE THIS AFTERNOON THEN DIMINISH AFTER SUNSET. GUSTY
SOUTHWEST WINDS ARE ALSO SLACKENING WITH MOST SITES SUSTAINED AT
15 TO 20 KTS WITH GUSTS OF 25 TO 30KTS. WINDS WILL DIMINISH
FURTHER OVERNIGHT. LIGHT UPSLOPE WINDS WILL BRING THE THREAT OF
IFR CEILINGS IN LOW STRATUS TO THE KGEG-KCOE CORRIDOR AFTER 09Z.
PRECIPITATION WILL DEVELOP AGAIN ACROSS THE AREA...MAINLY BETWEEN
12Z-18Z...AS A SHORTWAVE TROUGH MOVES THROUGH THE REGION. /EK
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 36 45 34 42 31 46 / 20 80 80 20 10 10
COEUR D`ALENE 36 45 34 43 31 47 / 30 100 80 20 10 10
PULLMAN 35 48 35 46 30 53 / 20 80 70 20 10 10
LEWISTON 40 53 39 52 36 55 / 10 40 40 10 10 0
COLVILLE 34 45 34 45 30 46 / 60 60 70 20 20 20
SANDPOINT 37 41 34 41 30 43 / 60 100 90 50 10 10
KELLOGG 37 40 33 38 30 43 / 60 100 100 50 10 10
MOSES LAKE 35 50 35 50 31 49 / 30 30 50 10 10 20
WENATCHEE 37 48 37 48 34 46 / 20 30 40 0 10 20
OMAK 32 46 35 46 31 45 / 40 50 60 10 10 30
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...WINTER STORM WATCH FROM SATURDAY MORNING THROUGH LATE SATURDAY
NIGHT ABOVE 3500 FEET FOR NORTHERN PANHANDLE.
WINTER STORM WATCH FROM SATURDAY MORNING THROUGH LATE SATURDAY
NIGHT ABOVE 4000 FEET FOR CENTRAL PANHANDLE MOUNTAINS.
WA...WINTER STORM WATCH FROM SATURDAY MORNING THROUGH LATE SATURDAY
NIGHT ABOVE 3500 FEET FOR NORTHEAST MOUNTAINS.
&&
$$
000
FXUS66 KOTX 070007
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
407 PM PST FRI NOV 6 2009
.SYNOPSIS...
THIS EVENING WILL BE OCCASIONALLY WINDY...WITH PORTIONS OF
NORTHEAST WASHINGTON AND FAR NORTHERN IDAHO EVEN EXPERIENCING
THUNDERSTORMS. THE ACTIVE WEATHER WILL CONTINUE THROUGH THE
WEEKEND. SIGNIFICANT HIGH ELEVATION SNOW ACCUMULATIONS WILL BE LIKELY
OVER THE CASCADES AND OVER THE MOUNTAINS OF THE IDAHO PANHANDLE
AND NORTHEAST WASHINGTON BY SUNDAY MORNING.
&&
.DISCUSSION...
TONIGHT...CONSIDERABLE CONDITIONALLY UNSTABLE AIRMASS RESIDES OVER
EASTERN WASHINGTON AND NORTHERN IDAHO AND WITH NUISANCE SHORTWAVES
MIGRATING THROUGH IT SHOWERS REMAIN IN SOME SHAPE OR FORM IN THE
FORECAST TONIGHT...WITH POPS AND QPF SHOWING THE LARGER PRECIP
AMOUNTS OVER THE HIGHER TERRAIN. ENOUGH WESTERLY FLOW TO STILL
SHOW A RAINSHADOW OF SORTS IN THE LEE OF THE CASCADES BUT AFTER 6Z
MODELS ARE HINTING AT A MORE RESOLVED SHORTWAVE MAKING THE TRIP
OVER THE CASCADES WITH ENOUGH INTEGRITY TO KEEP SOME MENTION OF
CONVECTIVE SHOWER OCCURRENCE IN THE 06-12Z TONIGHT TIME
INTERVAL. HAVE BEEN ATTEMPTING TO A FEW HOURS NOW TO BETTER
IDENTIFY THIS SHORTWAVE IN QUESTION BY CLOSER EXAMINATION OF THE
COLD SHALLOW CUMULUS FIELDS IN THE COLD CONDITIONALLY UNSTABLE
AIRMASS GETTING CLOSER TO THE PACIFIC NORTHWEST...LOOKING FOR
HINTS OF PATTERNS IN THE COOLING CLOUD TOPS OFF THE WASHINGTON AND
SOUTHERN BRITISH COLUMBIA COAST BUT HAVE NOT BEEN TOO SUCCESSFUL
IN IDENTIFYING A FEATURE WITH CERTAINTY EXCEPT PERHAPS THOSE WHICH
HAVE DEVELOPED COLD ENOUGH TOPS TO SPARK OFF SOME LIGHTNING STRIKES.
OTHERWISE SURFACE WINDS ARE ON THE DECREASE AND THE EXPECTATION IS
THAT THE WIND ADVISORY THAT WAS IN EFFECT FOR MUCH OF THE DAY WILL
SOON NO LONGER BE NECESSARY. /PELATTI
SAT THROUGH SUNDAY...THE WEEKEND FCST WILL BE THE BIGGEST
CHALLENGE AS FAR AS TIMING TWO QUICK-MOVING SHORT-WAVES THAT WILL
CROSS THE PAC NW AND KEEP A PROLONGED THREAT OF HEAVY MTN SNOW
ACCUMULATIONS IN THE FCST. THE FIRST WAVE...THE WEAKEST ONE...WILL
MOVE THRU THE ID PANHANDLE BY LATE MORNING SAT...FOLLOWED BY A
STRONGER VORT MAX SAT NT. AS CAN BE EXPECTED IN THIS QUICK
STEERING FLOW PATTERN...THERE IS LITTLE IN THE WAY OF GOOD
AGREEMENT CONCERNING THE SHORT-RANGE GUIDANCE WHEN IT COMES TO
PCPN AMNTS AND SNOW LEVELS. THE MAIN REASON FOR THE DIFFERENCES IS
THE INSTABILITY. THE NAM IS MORE UNSTABLE...ESPECIALLY IN THE LYR
THAT SHOWS THE MOST POTENTIAL FOR OROGRAPHIC ASCENT OVER N ID.
WE`VE GONE WITH A SNOW AMNT FCST THAT LEANS HEAVILY IN THE
DIRECTION OF THE WETTER NAM FOR THE MTNS OF NE WA AND ALL OF THE
ID PANHANDLE THIS WEEKEND. EVEN SO...THE HEAVIEST ACCUMULATIONS
BARELY REACH WARNING CRITERIA. IN ADDITION...IT LOOKS LIKE THE
SECOND WAVE (LATE SAT/SAT NT) WILL BE THE ONE THAT WILL PRODUCE
THE LARGEST SNOW AMNTS FOR THE MTNS. THAT SAID...WE`VE DELAYED THE
START TIME OF THE WATCH TO BEGIN MIDDAY SAT RATHER THAN SAT
MORNING. THE ONLY OTHER CHANGE TO THE PREVIOUS FCST WAS TO LOWER
SNOW LEVELS ABOUT 500 FT FOR THE OKANOGAN VLY AND ADD SOME BRIEF
SNOW ACCUMULATIONS SAT NT. BZ
SUNDAY NIGHT THROUGH FRIDAY...A COOL AND UNSETTLED WEATHER PATTERN
WILL PREVAIL THROUGH MIDWEEK. WEAK RIDGING SUNDAY NIGHT WILL BE
REPLACED BY MOIST SOUTHWEST FLOW ALOFT AS A PACIFIC FRONTAL SYSTEM
APPROACHES THE REGION. WARM FRONTAL PRECIPITATION WILL SPREAD EAST
ACROSS THE FORECAST AREA ON MONDAY...THEN THE COLD FRONT WILL
SWEEP THROUGH MONDAY NIGHT AND TUESDAY. THE FORECAST AREA WILL
HAVE A GOOD CHANCE OF PRECIPITATION ON TUESDAY WITH RAIN AND SNOW
LIKELY IN THE MOUNTAINS. WARM AIR ADVECTION WILL CAUSE SNOW LEVELS
TO RISE TO ABOUT 4K FT ON MONDAY...THEN DROP TO AROUND 2000 TO
2500 FT WITH THE PASSAGE OF THE COLD FRONT TUESDAY NIGHT. ON
WEDNESDAY THE UPPER TROUGH WILL BE OVERHEAD BRINGING MORE UNSTABLE
CONDITIONS TO THE INLAND NORTHWEST. THIS WILL RESULT IN SNOW OR
GRAUPLE SHOWERS REACHING MOST VALLEYS BUT COVERAGE WILL BE MORE
SCATTERED WITH LITTLE ACCUMULATION EXPECTED. MODEL SOLUTIONS
DIVERGE FOR THE END OF THE WORKWEEK BUT WHILE THE UPPER LEVEL
PATTERN DIFFERS QUITE A BIT...BOTH THE GFS AND ECMWF INDICATE
DRIER CONDITIONS FOR THE INLAND NORTHWEST. TEMPERATURES WILL START
OUT SLIGHTLY ABOVE SEASONAL NORMALS FOR MONDAY AND TUESDAY...THEN
GRADUALLY COOL TO NEAR NORMAL BY FRIDAY. /KELCH
&&
.AVIATION...
SCATTERED SHOWERS WILL CONTINUE OVER FAR EASTERN WA AND THE IDAHO
PANHANDLE THIS AFTERNOON THEN DIMINISH AFTER SUNSET. GUSTY
SOUTHWEST WINDS ARE ALSO SLACKENING WITH MOST SITES SUSTAINED AT
15 TO 20 KTS WITH GUSTS OF 25 TO 30KTS. WINDS WILL DIMINISH
FURTHER OVERNIGHT. LIGHT UPSLOPE WINDS WILL BRING THE THREAT OF
IFR CEILINGS IN LOW STRATUS TO THE KGEG-KCOE CORRIDOR AFTER 09Z.
PRECIPITATION WILL DEVELOP AGAIN ACROSS THE AREA...MAINLY BETWEEN
12Z-18Z...AS A SHORTWAVE TROUGH MOVES THROUGH THE REGION. /EK
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 37 45 34 42 31 46 / 20 80 80 20 10 10
COEUR D`ALENE 36 45 34 43 31 47 / 30 100 80 20 10 10
PULLMAN 35 48 35 46 30 53 / 30 80 70 20 10 10
LEWISTON 41 53 39 52 36 55 / 10 40 40 10 10 0
COLVILLE 34 45 34 45 30 46 / 60 60 70 20 20 20
SANDPOINT 37 41 34 41 30 43 / 50 100 90 50 10 10
KELLOGG 38 40 33 38 30 43 / 50 100 100 50 10 10
MOSES LAKE 35 50 35 50 31 49 / 50 30 50 10 10 20
WENATCHEE 38 48 37 48 34 46 / 20 30 40 0 10 20
OMAK 32 46 35 46 31 45 / 50 50 60 10 10 30
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...WIND ADVISORY UNTIL 7 PM PST THIS EVENING FOR COEUR D`ALENE
AREA...IDAHO PALOUSE.
WINTER STORM WATCH FROM SATURDAY MORNING THROUGH LATE SATURDAY
NIGHT ABOVE 3500 FEET FOR NORTHERN PANHANDLE.
WINTER STORM WATCH FROM SATURDAY MORNING THROUGH LATE SATURDAY
NIGHT ABOVE 4000 FEET FOR CENTRAL PANHANDLE MOUNTAINS.
WA...WIND ADVISORY UNTIL 7 PM PST THIS EVENING FOR LOWER GARFIELD AND
ASOTIN COUNTIES...SPOKANE AREA...UPPER COLUMBIA BASIN...
WASHINGTON PALOUSE.
WINTER STORM WATCH FROM SATURDAY MORNING THROUGH LATE SATURDAY
NIGHT ABOVE 3500 FEET FOR NORTHEAST MOUNTAINS.
&&
$$
000
FXUS66 KSEW 062349
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
348 PM PST FRI NOV 6 2009
.SYNOPSIS...A BROAD UPPER LEVEL TROUGH CONTAINING COLD SHOWERY
UNSTABLE AIR WILL PERSIST OVER WESTERN WASHINGTON THROUGH SATURDAY.
THE TROUGH WILL SHIFT INLAND SATURDAY NIGHT WITH A WEAK RIDGE OF
HIGH PRESSURE TRYING TO BUILD ON SUNDAY. ANOTHER STRONG FRONT WILL
REACH THE AREA EARLY MONDAY. UNSETTLED WEATHER WILL CONTINUE INTO
THE MIDDLE OF NEXT WEEK. UPPER RIDGING AND DRIER WEATHER WILL TRY TO
BUILD IN NEXT THURSDAY AND FRIDAY.
&&
.SHORT TERM...SATELLITE IMAGERY CONTINUES TO SHOW A LONG FETCH OF
COLD-TOPPED CU AND CB EXTENDING FROM WRN WA TO WAY OFF THE COAST.
NOT SURPRISINGLY...THE 12Z KUIL SOUNDING LOOKED VERY UNSTABLE
THROUGH A DEEP LAYER OF THE ATMOSPHERE WITH OBSERVED 500 MB TEMP OF
-32C. MODIFIED TO A SURFACE TEMP OF 53F...THE KUIL SOUNDING YIELDED
CAPE OF 500 J/KG AND LIFTED INDEX OF -2.6. CONSIDERING THE
THERMODYNAMIC PROFILE AND ALL THE WAYS THAT STRONG WINDS ALOFT COULD
HELP ORGANIZE CONVECTION INTO FAST-MOVING CLUSTERS...THUNDER HAS
ALREADY OCCURRED OFF-AND-ON OVER WRN WA SINCE LAST EVENING...AND
THAT SHOULD CONTINUE THROUGH SATURDAY. THOUGH SHOWERS COULD HAPPEN
ANYTIME...THERE ARE ALSO TWO SHORTWAVES WITHIN THE FAST WESTERLY
FLOW THAT WILL ENHANCE SHOWER ACTIVITY. THE FIRST WILL PASS BY
TONIGHT...AND SECOND SHOULD PASS WRN WA ON SAT AFTN/EVNG.
SNOW LEVELS HAVE FALLEN SIGNIFICANTLY TO NEAR 3000 FEET AT THIS
TIME. WITH ONSHORE FLOW PUSHING STRONG CONVECTIVE ELEMENTS INTO THE
MTNS...TWO SHORTWAVES IN THE NEXT 30 HOURS TO ENHANCE PRECIP...AND
GENEROUS SNOW RATIOS SUPPORTED BY VERY COLD AIR ALOFT...SNOW TOTALS
WILL BE HEAVY...PARTICULARLY IN THE CASCADES. OVER THE NEXT 36
HOURS...PARADISE COULD GET OVER TWO FEET OF SNOW WITH SIMILAR AMTS
NEAR MT. BAKER. THE PASSES WILL LIKELY GET AN ADDITIONAL 6 TO 12
INCHES THROUGH TOMORROW EVENING.
ONCE THE SECOND WAVE PASSES ON SAT NIGHT...WEAK UPPER LEVEL RIDGING
WILL TRY TO BUILD ON SUNDAY. STILL CAN NOT RULE OUT A SHOWER ON
SUNDAY...BUT THE COVERAGE AND VIGOR OF ANY REMAINING SHOWERS WILL BE
MUCH LESS THAN TODAY AND SAT. SUNDAY SHOULD BE MORE DRY THAN WET
OVER THE INTERIOR...COULD BE IFFY ALONG THE COAST.
THERE ARE TIMING DIFFERENCES REGARDING WHETHER THE NEXT LARGE
FRONTAL SYSTEM WILL ARRIVE ON SUNDAY NIGHT OR MONDAY...BUT THE 6-12
HOURS PRECEDING THE ARRIVAL OF THAT SYSTEM STILL LOOKS LIKE THE MOST
LIKELY TIME FOR DRY WEATHER IN THE NEXT 4-5 DAYS.
THE NEXT MAIN FRONTAL SYSTEM WILL ARRIVE EITHER LATE SUNDAY NIGHT OR
MONDAY. SOUTH-SOUTHEAST WINDS PICK UP IN ADVANCE OF THAT
SYSTEM...GETTING LOCALLY WINDY. EVEN ONCE THE COLD FRONT HAS PASSED
WRN WA...COOL UNSTABLE AND SHOWERY WEATHER WILL PERSIST. HANER
.LONG TERM...TUESDAY AND WEDNESDAY WILL CONTINUE TO BE SOMEWHAT
UNSETTLED AS UNSTABLE AIR UNDER AN UPPER TROUGH KEEPS THE WEATHER
COOL AND SHOWERY. THE UPPER TROUGH SHOULD MOVE EAST ON WED WITH AN
UPPER RIDGE TRYING TO BUILD ON THU AND FRI. WAS TEMPTED TO GO WITH A
DRY FORECAST NEXT FRIDAY...BUT THE WEIGHT OF CLIMATOLOGY IN A DAY 7
FORECAST AS WE HEAD INTO THE WETTEST TIME OF YEAR IS HARD TO
IGNORE...SO KEPT LOW-END CHANCE POPS IN THE FORECAST FOR NOW. HANER
&&
.HYDROLOGY...THERE ARE NO HYDROLOGY OR RIVER FLOODING CONCERNS
THROUGH THE WEEKEND. SNOW LEVELS WILL BE NEAR 3000 FEET THROUGH
SATURDAY...LIMITING RUNOFF CONCERNS FOR RIVERS WITH THEIR HEADWATERS
OVER THE MOUNTAINS. EVEN FOR LOWER ELEVATIONS...THE CONVECTIVE
NATURE OF PRECIPITATION WILL MEAN SIGNIFICANT DRY BREAKS BETWEEN
HEAVY SHOWERS AND THUNDERSTORMS.
A STRONG FRONTAL SYSTEM LATE SUNDAY NIGHT AND MONDAY WILL GIVE A
QUICK SHOT OF RAIN AND RAISE FREEZING LEVELS...BUT THE PROGRESSIVE
MOVEMENT OF THE FRONT WILL LIMIT THE DURATION OF HEAVY PRECIP AND
FLOOD CONCERN. BEYOND THE 7-DAY FORECAST...MODELS SOLUTIONS POINT TO
A COUPLE OF FRONTAL SYSTEMS THAT WILL NEED TO BE WATCHED. THE FIRST
WOULD BE EARLY NEXT WEEKEND...AND THE SECOND WOULD BE EARLY THE
FOLLOWING WEEK. HOWEVER...WHEN DEALING WITH WEATHER BEYOND A WEEK IN
THE FUTURE...ONLY BROAD GENERAL TRENDS CAN BE ASCRIBED. HOWEVER...
THE 8-14 DAY OUTLOOK FOR 11/14-20 FROM CPC CALLS FOR ABOVE NORMAL
PRECIPITATION. HANER
&&
.AVIATION...WESTERLY FLOW ALOFT WILL CONTINUE THROUGH SUNDAY...WITH
IMPULSES RIPPLING THROUGH THE FLOW AND BRINGING PERIODS OF SHOWERS
AND OCCASIONAL THUNDERSTORMS. CEILINGS WILL VARY BETWEEN NO CEILINGS
AND MVFR CEILINGS AND VISIBILITIES IN SHOWERS. THERE WILL BE SOME
DIURNAL SWING IN SHOWER FREQUENCY WITH FEWER TONIGHT AND MORE DURING
THE DAY TOMORROW.
KSEA...SAME AS ABOVE. WINDS WILL REMAIN SOUTHERLY 8-12 KT GUSTING
WELL INTO THE 20S IN SHOWERS. CHB
&&
.MARINE...SOUTHERLY GRADIENTS REMAIN STRONG AND WILL KEEP SMALL
CRAFT ADVISORIES GOING IN ALL WATERS OVERNIGHT AND SATURDAY. A
COUPLE OF IMPULSES IN THE WESTERLY FLOW WILL INCREASE SURFACE
PRESSURE GRADIENTS...AROUND 09Z TONIGHT AND AROUND 18Z SATURDAY.
MODELS HAVE BRIEF GALES ON THE COAST WITH THE SECOND IMPULSE AROUND
18Z...BUT OPTED TO KEEP WINDS AT 30 KT FOR NOW.
LARGE SWELLS ARE REACHING THE COAST NOW. BUOY 41 HAS REPORTED SWELL
IN THE 23-26 FT RANGE SINCE THIS MORNING. IT COULD GO SLIGHTLY
HIGHER TONIGHT. HIGH TIDE AT ABERDEEN IS AT 245 PM THIS AFTERNOON
WITH A MINUS LOW TIDE TONIGHT. SWELL SUBSIDES SLIGHTLY LATE TONIGHT
AS THE NEXT...LOWER...HIGH TIDE ROLLS AROUND AT 441 AM. SEA LEVEL
PRESSURE IS NOT LOW...MORE LIKE 1010 MB. THE UPSHOT IS THAT COASTAL
FLOODING IN GRAYS HARBOR IS UNLIKELY. SOME PROBLEMS ON OR NEAR THE
BEACHES ARE DEFINITELY POSSIBLE WITH SWELL OF THIS SIZE. SO FOR NOW
WILL KEEP THE HIGH SURF WARNING GOING.
A STRONGER SYSTEM ARRIVES SUNDAY NIGHT AND MONDAY. THIS LOOKS LIKE
IT WILL BRING GALES TO THE COAST...ENTRANCES...AND NORTHERN INLAND
WATERS. THE COASTAL GALE COULD BE AT THE HIGH END OF GALE...WELL
INTO THE 40 KT RANGE. THINGS CALM DOWN SOMEWHAT AFTER MONDAY. CHB
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...WINTER STORM WARNING FOR THE CASCADES THROUGH SATURDAY
NIGHT.
WEATHER ADVISORY FOR THE OLYMPIC MOUNTAINS THROUGH SATURDAY
EVENING FOR THE OLYMPIC MOUNTAINS.
HIGH SURF WARNING FOR THE COAST THROUGH 4 PM SATURDAY.
PZ...SMALL CRAFT ADVISORY ALL WATERS.
SMALL CRAFT ADVISORY FOR ROUGH GRAYS HARBOR BAR.
$$
WWW.WEATHER.GOV/SEATTLE
FOR AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION...PLEASE SEE
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML.
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