000
FXUS65 KPIH 230402
AFDPIH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
902 PM MST SUN NOV 22 2009

.UPDATE...

SNOWFALL IS BEGINNING TO COME TO AN END ACROSS THE REGION. LIGHT
TO MODERATE SNOWS CONTINUE ACROSS THE EASTERN HIGHLANDS WHERE
ADVISORIES CONTINUE FOR NOW. A SIGNIFICANT WEATHER ADVISORY WAS
ISSUED FOR THE BURLEY AREA WHERE REPORTS OF ICY ROADS AND SLIDE
OFFS HAVE BEEN NOTED WHEN THE LAST BAND OF SNOW CAME THROUGH. WILL
UPDATE THE OVERNIGHT FORECAST TO REDUCE PRECIPITATION CHANCES IN
THE VALLEYS AND INTRODUCE SOME ADDITIONAL CLEARING AS INDICATED BY
SATELLITE. ANTICIPATE CANCELLING THE ADVISORIES BEFORE MIDNIGHT
WHEN MOST OF THE SNOW OVER THE EASTERN HIGHLANDS SHOULD COME TO AN
END. IN THE PROCESS OF UPDATING SNOW TOTALS. THE VALLEYS GENERALLY
SAW AROUND AN INCH OR TWO OF SNOW...HIGHER ELEVATIONS HAD 3 TO 5
INCHES WHILE SOME LOCATIONS ABOVE 7000 FEET IN THE CENTRAL
MOUNTAINS HAD UP TO 10 INCHES OF SNOW.

&&

.PREV DISCUSSION... /ISSUED 200 PM MST SUN NOV 22 2009/

SHORT TERM...TONIGHT THROUGH WEDNESDAY. LEADING EDGE OF UPPER
TROUGH WORKING THROUGH REGION EARLY THIS AFTERNOON WITH ASSOCIATED
PRECIPITATION BAND EXTENDING FROM REXBURG WSW THROUGH JACKPOT AND
MOVING AT A GOOD CLIP TO THE EAST. EXPECTATION IS THAT THIS BAND
WILL EXIT EAST INTO THE ERN HIGHLANDS BY LATE AFTERNOON/EARLY
EVENING WITH LINGERING SHOWERS AND BREEZY WEST-NW WINDS CONTINUING
OVER THE REGION AS UPPER TROUGH WORKS EAST INTO WYOMING OVERNIGHT.
HEAVY SNOWFALL HAS ALL BUT ENDED BEHIND THE MAIN PRECIP BAND AND
THUS HAVE CANCELLED THE WINTER STORM WARNING FOR SAWTOOTH MOUNTAINS
AND DROPPED THE ADVISORY FOR THE LOST RIVER REGION AND SOUTH CENTRAL
HIGHLANDS. UPPER RIDGE EXPANDS ACROSS REGION MONDAY AS A SECONDARY
SHORT-WAVE TOPS RIDGE AND SHEARS EAST THROUGH CANADA. THUS DRIER
CONDITIONS SHOULD PREVAIL MONDAY AND ON INTO WEDNESDAY AS RIDGE
DOMINATES. TEMPERATURES WILL BE SOMEWHAT TRICKY WITH CLEARING SKIES
ALLOWING OVERNIGHT LOWS THE NEXT COUPLE OF NIGHTS TO DROP SHARPLY
WHILE DAYTIME HIGHS STRUGGLE TO BURN THROUGH THE COLD AIR TRAPPED IN
THE VALLEYS. THUS AM TRYING NOT TO STRAY TOO FAR FROM GUIDANCE
THROUGH THE PERIOD. HUSTON

LONG TERM...WEDNESDAY NIGHT THROUGH NEXT SUNDAY.  STRONG UPPER
LEVEL RIDGING STARTS THIS PERIOD...BUT BREAKS DOWN AT THE 36 HOUR
POINT.  HOW MUCH IT BREAKS DOWN IS THE MAIN FORECAST PROBLEM.  GFS
KEEPS A DRIER FORECAST WITH THE STORM TRACK FARTHER NORTH...BUT MORE
STABLE ECMWF KEEPS A STEADY STREAM OF SHORTWAVES CLIPPING THE
NORTHERN HALF OF THE FORECAST AREA.  HAVE GONE WITH THE
NCEP-PREFERRED ECMWF AND THUS HAVE HIGHER THAN GFS POPS AND COLDER
TEMPERATURES FOR AFTERNOON HIGHS.  DO NOT SEE ANY SIGNIFICANT WIND
EVENTS DURING THIS PERIOD.  THE FRI/FRI NIGHT STORM IS THE HEAVIEST
PRECIPITATION MAKER...AND MAY NEED SOME LOW-LEVEL ADVISORY
HIGHLIGHTS EVENTUALLY.  MESSICK

AVIATION...FRONT IS PASSING THROUGH THIS AFTERNOON WITH ISOLATED TO
WIDELY SCATTERED LIGHT SHOWERS BEHIND.  MAIN PROBLEMS WILL BE THE
WIND SHIFT AND THE RISK OF FOG AND STRATUS IN THE MORNING.  WITH
STRONG WIND CONTINUING ALOFT...DO NOT EXPECT FOG...BUT VERY LIKELY
CEILING WILL BE AFFECTED...MAINLY IN THE SNAKE RIVER PLAIN
AIRPORTS.  KSUN APPEARS TO BE FAIRLY DRY ONCE THEY RE-OPEN MON
MORNING.  DRYING TREND THROUGH THU...SO ONLY THREAT IS MORNING
STRATUS AND FOG.  MESSICK

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 5 AM MST MONDAY FOR IDZ019-023-025.

&&

$$

000
FXUS65 KBOI 230347
AFDBOI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
847 PM MST SUN NOV 22 2009

.DISCUSSION...SNOW SHOWER ACTIVITY WAS DIMINISHING OVER THE
BOISE/WEST CENTRAL MOUNTAINS BUT FLURRIES WERE STILL OCCURRING PER
WEBCAMS. THIS TREND WILL CONTINUE  WITH SCATTERED MTN SNOW SHOWERS
BECOMING ISOLATED OVERNIGHT AS THE UPPER TROUGH RESPONSIBLE FOR THE
ACTIVITY MOVES EAST. SKIES HAVE BEGUN CLEARING IN MANY AREAS OUTSIDE
OF THE BOISE/WEST CENTRAL MOUNTAINS. WINDS REMAIN GUSTY WITH SOME
GUSTS TOPPING 20 MPH BUT THOSE TOO WERE DIMINISHING. AREAS OF
CLEARING COINCIDING WITH LIGHT WINDS OVERNIGHT WILL BE LOCATIONS
PRONE TO FOG. WILL UPDATE FOR LOWER POPS AND LESS CLOUDS FOR THE
REMAINDER OF TONIGHT....OTHERWISE FORECAST IS IN GOOD SHAPE.

&&

.AVIATION...ISOLATED IFR CONDITIONS IN THE MOUNTAINS TONIGHT DUE TO
LOW CEILINGS...OTHERWISE VFR TONIGHT AND MONDAY.  SURFACE WINDS
GENERALLY 10 KTS OR LESS TONIGHT WITH WINDS ALOFT MODERATE FROM THE
NORTHWEST.  AS CLOUDS DECREASE TONIGHT AND WINDS BECOME
LIGHT...ESPECIALLY IN SHELTERED VALLEYS...CAN NOT RULE OUT AREAS OF
VALLEY FOG BY MONDAY MORNING.  CAN EXPECT LOCAL MVFR CONDITIONS AND
ISOLATED IFR CONDITIONS IN VALLEY FOG THROUGH 17Z.

&&

.PREV DISCUSSION...
SHORT TERM...TONIGHT THROUGH TUESDAY...SNOW SHOWERS IN CENTRAL IDAHO
ASSOCIATED WITH AN EXITING UPPER LEVEL TROUGH WILL ALLOW UP TO AN
ADDITIONAL 2 INCHES ACCUMULATION IN EASTERN VALLEY COUNTY AND THE
BOISE MOUNTAINS AND UP TO AN INCH OF WET SNOW GRASSY/BARE AREAS IN
THE WESTERN MAGIC VALLEY...UNTIL AROUND 6 PM. LOCALLY GUSTY WEST
WINDS TO 35 MPH LOOK TO DIMINISH TO LIGHT EARLY THIS EVENING EXCEPT
IN THE MAGIC VALLEY WHERE 15-20 MPH SUSTAINED WIND ARE EXPECTED
TONIGHT. SO PATCHY FOG IS POSSIBLE WHERE WINDS DROP OFF. QUICK
MOVING STORM WILL LEAVE COOL NW FLOW AND DRYING ACROSS THE REGION
THROUGH MONDAY NOON RESULTING TEMPERATURES 3-5F BELOW NORMAL THOUGH
HIGH ELEVATION SHELTERED AREAS /I.E. FAFI1/ COULD SEE SINGLE DIGIT
LOWS THE NEXT COUPLE NIGHTS. A SYSTEM THAT BRUSHES PRECIP NORTH OF
US IS EXPECTED TO BRING SOME CLOUDS ACROSS SE OREGON AND SW IDAHO
MONDAY AFTERNOON AND FAR NORTHERN ZONES TUESDAY AS A RIDGE/INVERSION
BUILDS NORTHWARD INTO THE AREA. COULD SEE STRATUS EARLY TUESDAY
MORNING IN THE UPPER WEISER ZONE WHERE SNOW ACCUMULATED AND INTO THE
OREGON LOWER TREASURE VALLEY WHERE DIURNAL WINDS TEND TO ACCUMULATE
SUCH LOW LEVEL MOISTURE.

LONG TERM...TUESDAY NIGHT THROUGH SUNDAY...SHORTWAVE RIDGE WILL KEEP
INVERSION IN PLACE THROUGH THURSDAY. RESULT WILL BE ABOVE NORMAL
TEMPS IN THE MOUNTAINS WITH COLDER AIR TRAPPED IN THE VALLEYS.
MODELS HAVE HINT OF A SE WIND IN BOISE WHICH COULD BE ENOUGH TO KEEP
FOG/STRATUS OUT OF THE CITY. LOOKS LIKE A BETTER CHANCE IN LOWER
TREASURE/WEISER AND BAKER VALLEYS FOR WEDNESDAY AND THURSDAY MORNING
WITH LITTLE WIND. WHILE INVERSION REMAINS IN PLACE ON THURSDAY...
SURFACE WINDS WILL INCREASE DURING THE DAY HELPING TO SCOUR OUT THE
FOG/STRATUS IN MOST LOCATIONS. SHORTWAVE MOVES INTO THE REGION ON
FRIDAY BRINGING CHANCE OF SNOW TO THE MTNS AND RAIN TO THE VALLEYS.
CONDITIONS DRY OUT FOR SAT/SUN IN N-NW FLOW WITH NEAR NORMAL TEMPS.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...NONE.
OR...NONE.
&&

$$

WEATHER.GOV/BOISE

DISCUSSION...BW
AVIATION.....JA
PREV SHORT TERM...VM
PREV LONG TERM....DG/DD

000
FXUS65 KBOI 222202
AFDBOI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
302 PM MST SUN NOV 22 2009

.SHORT TERM...TONIGHT THROUGH TUESDAY...SNOW SHOWERS IN CENTRAL
IDAHO ASSOCIATED WITH AN EXITING UPPER LEVEL TROUGH WILL ALLOW UP
TO AN ADDITIONAL 2 INCHES ACCUMULATION IN EASTERN VALLEY COUNTY AND
THE BOISE MOUNTAINS AND UP TO AN INCH OF WET SNOW GRASSY/BARE
AREAS IN THE WESTERN MAGIC VALLEY...UNTIL AROUND 6 PM. LOCALLY
GUSTY WEST WINDS TO 35 MPH LOOK TO DIMINISH TO LIGHT EARLY THIS
EVENING EXCEPT IN THE MAGIC VALLEY WHERE 15-20 MPH SUSTAINED WIND
ARE EXPECTED TONIGHT. SO PATCHY FOG IS POSSIBLE WHERE WINDS DROP
OFF. QUICK MOVING STORM WILL LEAVE COOL NW FLOW AND DRYING
ACROSS THE REGION THROUGH MONDAY NOON RESULTING TEMPERATURES 3-5F
BELOW NORMAL THOUGH HIGH ELEVATION SHELTERED AREAS /I.E. FAFI1/
COULD SEE SINGLE DIGIT LOWS THE NEXT COUPLE NIGHTS. A SYSTEM THAT
BRUSHES PRECIP NORTH OF US IS EXPECTED TO BRING SOME CLOUDS ACROSS
SE OREGON AND SW IDAHO MONDAY AFTERNOON AND FAR NORTHERN ZONES
TUESDAY AS A RIDGE/INVERSION BUILDS NORTHWARD INTO THE AREA. COULD
SEE STRATUS EARLY TUESDAY MORNING IN THE UPPER WEISER ZONE WHERE
SNOW ACCUMULATED AND INTO THE OREGON LOWER TREASURE VALLEY WHERE
DIURNAL WINDS TEND TO ACCUMULATE SUCH LOW LEVEL MOISTURE.

.LONG TERM...TUESDAY NIGHT THROUGH SUNDAY...SHORTWAVE RIDGE WILL KEEP
INVERSION IN PLACE THROUGH THURSDAY. RESULT WILL BE ABOVE NORMAL
TEMPS IN THE MOUNTAINS WITH COLDER AIR TRAPPED IN THE VALLEYS.
MODELS HAVE HINT OF A SE WIND IN BOISE WHICH COULD BE ENOUGH TO KEEP
FOG/STRATUS OUT OF THE CITY. LOOKS LIKE A BETTER CHANCE IN LOWER
TREASURE/WEISER AND BAKER VALLEYS FOR WEDNESDAY AND THURSDAY MORNING
WITH LITTLE WIND. WHILE INVERSION REMAINS IN PLACE ON THURSDAY...
SURFACE WINDS WILL INCREASE DURING THE DAY HELPING TO SCOUR OUT THE
FOG/STRATUS IN MOST LOCATIONS. SHORTWAVE MOVES INTO THE REGION ON
FRIDAY BRINGING CHANCE OF SNOW TO THE MTNS AND RAIN TO THE VALLEYS.
CONDITIONS DRY OUT FOR SAT/SUN IN N-NW FLOW WITH NEAR NORMAL TEMPS.

&&

.AVIATION...LOCAL IFR IN THE SW IDAHO MTNS AND MVFR IN THE WESTERN
MAGIC VALLEY THIS AFTERNOON WILL GRADUALLY IMPROVE THIS EVENING.
ISOLATED IFR IN THE MTNS OVERNIGHT DUE TO LOW CEILINGS...OTHERWISE
VFR TONIGHT AND MONDAY. SURFACE WINDS GENERALLY DECREASING TO 10 KTS
OR LESS FOR MONDAY. WINDS ALOFT DECREASE TO 20 KTS OR LESS BELOW 10K
FEET MSL.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...NONE.
OR...NONE.
&&

$$

WEATHER.GOV/BOISE

SHORT TERM...VM
LONG TERM....DG/DD
AVIATION.....DG

000
FXUS65 KPIH 222059
AFDPIH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
200 PM MST SUN NOV 22 2009

.SHORT TERM...TONIGHT THROUGH WEDNESDAY. LEADING EDGE OF UPPER
TROUGH WORKING THROUGH REGION EARLY THIS AFTERNOON WITH ASSOCIATED
PRECIPITATION BAND EXTENDING FROM REXBURG WSW THROUGH JACKPOT AND
MOVING AT A GOOD CLIP TO THE EAST. EXPECTATION IS THAT THIS BAND
WILL EXIT EAST INTO THE ERN HIGHLANDS BY LATE AFTERNOON/EARLY
EVENING WITH LINGERING SHOWERS AND BREEZY WEST-NW WINDS CONTINUING
OVER THE REGION AS UPPER TROUGH WORKS EAST INTO WYOMING OVERNIGHT.
HEAVY SNOWFALL HAS ALL BUT ENDED BEHIND THE MAIN PRECIP BAND AND
THUS HAVE CANCELLED THE WINTER STORM WARNING FOR SAWTOOTH MOUNTAINS
AND DROPPED THE ADVISORY FOR THE LOST RIVER REGION AND SOUTH CENTRAL
HIGHLANDS. UPPER RIDGE EXPANDS ACROSS REGION MONDAY AS A SECONDARY
SHORT-WAVE TOPS RIDGE AND SHEARS EAST THROUGH CANADA. THUS DRIER
CONDITIONS SHOULD PREVAIL MONDAY AND ON INTO WEDNESDAY AS RIDGE
DOMINATES. TEMPERATURES WILL BE SOMEWHAT TRICKY WITH CLEARING SKIES
ALLOWING OVERNIGHT LOWS THE NEXT COUPLE OF NIGHTS TO DROP SHARPLY
WHILE DAYTIME HIGHS STRUGGLE TO BURN THROUGH THE COLD AIR TRAPPED IN
THE VALLEYS. THUS AM TRYING NOT TO STRAY TOO FAR FROM GUIDANCE
THROUGH THE PERIOD. HUSTON

.LONG TERM...WEDNESDAY NIGHT THROUGH NEXT SUNDAY.  STRONG UPPER
LEVEL RIDGING STARTS THIS PERIOD...BUT BREAKS DOWN AT THE 36 HOUR
POINT.  HOW MUCH IT BREAKS DOWN IS THE MAIN FORECAST PROBLEM.  GFS
KEEPS A DRIER FORECAST WITH THE STORM TRACK FARTHER NORTH...BUT MORE
STABLE ECMWF KEEPS A STEADY STREAM OF SHORTWAVES CLIPPING THE
NORTHERN HALF OF THE FORECAST AREA.  HAVE GONE WITH THE
NCEP-PREFERRED ECMWF AND THUS HAVE HIGHER THAN GFS POPS AND COLDER
TEMPERATURES FOR AFTERNOON HIGHS.  DO NOT SEE ANY SIGNIFICANT WIND
EVENTS DURING THIS PERIOD.  THE FRI/FRI NIGHT STORM IS THE HEAVIEST
PRECIPITATION MAKER...AND MAY NEED SOME LOW-LEVEL ADVISORY
HIGHLIGHTS EVENTUALLY.  MESSICK
&&

.AVIATION...FRONT IS PASSING THROUGH THIS AFTERNOON WITH ISOLATED TO
WIDELY SCATTERED LIGHT SHOWERS BEHIND.  MAIN PROBLEMS WILL BE THE
WIND SHIFT AND THE RISK OF FOG AND STRATUS IN THE MORNING.  WITH
STRONG WIND CONTINUING ALOFT...DO NOT EXPECT FOG...BUT VERY LIKELY
CEILING WILL BE AFFECTED...MAINLY IN THE SNAKE RIVER PLAIN
AIRPORTS.  KSUN APPEARS TO BE FAIRLY DRY ONCE THEY RE-OPEN MON
MORNING.  DRYING TREND THROUGH THU...SO ONLY THREAT IS MORNING
STRATUS AND FOG.  MESSICK
&&

.PIH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 5 AM MST MONDAY FOR IDZ019-023-025.
&&

$$

000
FXUS65 KBOI 221700
AFDBOI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
1000 AM MST SUN NOV 22 2009

.DISCUSSION...WEBCAMS SHOW MANY SNOW COVERED ROADS AS LOW AS 3100
FT MSL IN SE OREGON AND SW IDAHO. RADAR AND SATELLITE IMAGERY AND
SURFACE OBS INDICATE THE COLD FRONT ACROSS CENTRAL OREGON. SNOW
SHOWERS HAVE DECERASED IN COVERAGE IN HARNEY COUNTY WHERE THE
SN/BLSN ADVISORY HAS BEEN DISCONTINUED. A BAND OF HEAVIER SNOW
SHOWERS IS MOVING THROUGH BOISE AND MCCALL. A SPOTTER IN PINE
REPORTED 4 INCHES AS OF 959 AM. GUSTY SE WINDS TO 30 MPH SHIFTING
TO SW/NW BEHIND FRONT STILL ON TRACK. NO OTHER CHANGES THIS
MORNING.

&&

.AVIATION...WIDESPREAD IFR IN SNOW OVER SW IDAHO MTNS THIS MORNING
BECOMING SCATTERED IN COVERAGE THIS AFTERNOON. VFR/MVFR IN LOWER
VALLEYS WITH RAIN/SNOW MIX ENDING FROM WEST TO EAST. IN SE OREGON
WIDELY SCATTERED SNOW SHOWERS AND ACCOMPANYING IFR CONDITIONS INTO
EARLY AFTERNOON. STRONG WINDS SURFACE AND ALOFT TODAY DECREASING
TONIGHT. GUSTS TO 35 KTS AT THE SURFACE WITH WEST WINDS OVER 50 KTS
ALOFT.

&&

.PREV DISCUSSION...
SHORT TERM...VIGOROUS STORM SYSTEM CURRENTLY PUSHING INTO THE
FORECAST AREA WITH SNOW AND WIND. SYSTEM IS FAST MOVING EMBEDDED
WITHIN 120-140 KNOT JETSTREAM CORE...THUS MAIN IMPACTS NOT EXPECTED
TO LAST MORE THAN A FEW HOURS OVER ANY ONE AREA TODAY. HAVE ADDED
HARNEY AND MALHEUR COUNTIES IN OREGON TO THE WINTER WEATHER
ADVISORIES WITH LIGHT TO MODERATE SNOW AND INCREASING WINDS.
SYNOPTICALLY...A WARM FRONT IS MOVING THROUGH SOUTHEAST OREGON WITH
A COLD FRONT ALIGNED NORTH SOUTH JUST EAST OF THE CASCADES. SYSTEM
EXPECTED TO OCCLUDE LATER THIS AFTERNOON OVER OUR AREA AND WEAKEN.
NEVERTHELESS...SEVERAL INCHES OF NEW SNOW CAN BE EXPECTED IN THE
NORTHERN MOUNTAINS WITH 1 TO 3 INCHES IN VALLEYS SOUTH TO THE SNAKE
RIVER. LESS SNOW IS FORECAST SOUTHWARD TOWARD THE NEVADA STATE LINE.
DUE TO THE QUICK MOVEMENT TO THE SYSTEM...HEAVY PRECIP IS NOT
EXPECTED TO LAST FOR A LONG TIME BUT INCREASING WINDS WITH BLOWING
SNOW WILL BE JUST AS IMPORTANT AN IMPACT AS THE ACTUAL SNOW FALL.
TREASURE AND MAGIC VALLEYS A LITTLE MORE TRICKY WITH SOUNDING
PROFILES INDICATING LIGHT SNOW EARLY THIS MORNING FOLLOWED BY A
MIXTURE...THEN TO ALL RAIN BY THIS AFTERNOON AS WINDS TURN WESTERLY
BEHIND FRONT...ALTHOUGH NOT EXPECTING SIGNIFICANT SNOW
ACCUMULATIONS. LINGERING SNOW SHOWERS TO REMAIN TONIGHT IN THE UPPER
TROF AXIS WITH DRIER CONDITIONS ANTICIPATED FOR MONDAY AS YET
ANOTHER RIDGE BUILDS OVER THE AREA.

LONG TERM..MONDAY NIGHT THROUGH SUNDAY...DRY CONDITIONS MONDAY
THROUGH THURSDAY AS AN UPPER LEVEL RIDGE AMPLIFIES OVER NRN
CALIFORNIA/NEVADA. THUS...STRENGTH OF SURFACE INVERSION CONTINUES TO
BE THE MAIN FORECAST CHALLENGE. MODEL SOUNDINGS INDICATE SOME MIXING
TUESDAY AFTERNOON...NOT UNTIL WEDNESDAY DOES INVERSION LOOK TO REACH
ITS FULL POTENTIAL. EXPECT BELOW NORMAL VALLEY TEMPERATURES /ABOVE
NORMAL TEMPS IN MTN VALLEYS/ AND FOG ON WEDNESDAY...AND POSSIBLY
EVEN THURSDAY. MODELS IN BETTER AGREEMENT WITH AN UPPER LEVEL TROUGH
PROGGED TO MOVE INTO THE FORECAST AREA EARLY FRIDAY. EXPECT CHANCES
FOR VALLEY RAIN/SNOW AND MOUNTAIN SNOW ON FRIDAY...THEN DRIER ON
SATURDAY AND SUNDAY AS SYSTEM QUICKLY EXITS THE FORECAST AREA.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...WINTER WEATHER ADVISORY UNTIL 2 PM MST THIS AFTERNOON FOR IDZ011-
     IDZ013-IDZ033.
OR...WINTER WEATHER ADVISORY UNTIL 11 AM MST /10 AM PST/ THIS MORNING
     FOR ORZ063.
     WINTER WEATHER ADVISORY UNTIL 10 AM PST THIS MORNING FOR ORZ062.
&&

$$

WEATHER.GOV/BOISE

DISCUSSION...VM
AVIATION.....DG
PREV SHORT TERM...GS
PREV LONG TERM....MT/JT

000
FXUS65 KPIH 221602
AFDPIH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
910 AM MST SUN NOV 22 2009

.SHORT TERM...TODAY THROUGH MONDAY NIGHT. A QUICK UPDATE THIS
MORNING TO ACCOUNT FOR TIMING ISSUES WITH INCOMING VERY LIGHT
WARM-FRONTAL SNOWFALL SPREADING UP THE SNAKE RIVER PLAIN. MAIN
COLD-FRONTAL PRECIPITATION BAND IS STILL LOCATED TO OUR WEST ALONG A
MCCALL TO ROME OREGON LINE AND WILL BE SPREADING EAST INTO THE
REGION THIS AFTERNOON. REMAINDER OF FORECAST LOOKS GOOD...SEE
PREVIOUS DISCUSSION BELOW. HUSTON

UPPER SYSTEM CONTINUES TO PUSH ONSHORE THIS MORNING IN THE PACIFIC
NORTHWEST. WEAK RIDGE OVER IDAHO IS QUICKLY BREAKING DOWN AS THE
SYSTEM APPROACHES OUR REGION. SNOW WILL MOVE ACROSS THE EASTERN
BORDER BEGINNING AROUND 9 AM AND SPREAD EASTWARD THROUGH THE REST OF
THE MORNING. THE MAIN FOCUS OF ACTIVITY WILL BE IN THE CENTRAL
MOUNTAINS...IN PARTICULAR THE SAWTOOTH AREA AND THE EASTERN
HIGHLANDS ALONG THE WYOMING BORDER. WINDS WILL BEGIN TO PICK UP
ACROSS THE AREA LATER THIS MORNING AHEAD OF A FRONT MOVING THROUGH
EASTERN IDAHO THIS AFTERNOON...AND PERSIST POST FRONTAL THROUGH
MIDNIGHT. WINDS WILL BE STRONGEST IN THE SNAKE RIVER PLAIN...GUSTING
TO 35 MPH AND PEAKING OUT AT AROUND 40 MPH LATE THIS EVENING. WITH
GUSTY WINDS EXPECTED ALONG WITH SNOWFALL...A WINTER STORM WARNING
REMAINS IN EFFECT FOR ZONES 18 AND 31 WHILE A WINTER WEATHER
ADVISORY REMAINS IN EFFECT FOR ZONES 32-19-23-25. WILL ADD ZONE 22
TO THE WINTER WEATHER ADVISORY. WITH HEAVIER SNOW EXPECTED AND GUSTY
WINDS...VISIBILITIES ARE EXPECTED TO REACH A QUARTER MILE AT TIMES
IN THE SAWTOOTH AND WOOD RIVER AREAS. WILL EXTEND THE TIMING FOR THE
WINTER STORM WARNING AND THE ADVISORY FOR LOST RIVER AREA UNTIL 11
PM GIVEN THE MODEL TREND TOWARDS SOME LINGER SNOW SHOWERS BRINGING
ADDITIONAL ACCUMULATIONS LATER THIS EVENING. SNOW WILL TAPER OFF
FIRST IN THE SNAKE PLAIN AND MUCH OF THE EASTERN HALF OF THE REGION
THIS EVENING...LINGERING OVERNIGHT IN THE EASTERN HIGHLANDS WITH A
RIDGE BEGINNING TO BUILD BACK INTO THE INTERMOUNTAIN WEST. DRY BUT
CONDITION CONDITIONS ARE EXPECTED FOR MUCH OF THE AREA MONDAY AND
MONDAY NIGHT. KH

.LONG TERM...TUESDAY THROUGH SATURDAY...MODEL TREND CONTINUES TO
BUILD A HIGH PRESSURE RIDGE OVER SOUTHEAST IDAHO TUESDAY THROUGH
THURSDAY NIGHT. A VERY SLIGHT CHANCE OF SHOWERS REMAINS TUESDAY NEAR
THE MONTANA BORDER...OTHERWISE MOISTURE SHIFTS WELL TO THE NORTH OF
THIS AREA. THE MAIN DEVELOPMENT WITH THE LATEST MODEL RUNS IS THE
ECM BEING SLOWER AND MORE IN AGREEMENT WITH THE GFS WITH RESPECT TO
THE DISTURBANCE COMING IN ON FRIDAY. FORECAST WAS UPDATED TO DRY OUT
EVERYTHING FROM THE SNAKE PLAIN EASTWARD THURSDAY NIGHT. RS
&&

.AVIATION...PACIFIC COLD FRONT WILL BRING MVFR AND LIFR CEILINGS IN
SNOW TO MOST SITES TODAY. PRECIPITATION AT KSUN 17Z-01Z...KBYI ABOUT
19Z-02Z...AND KIDA AND KPIH 20Z-03Z. SNOW LEVELS SHOULD QUICKLY
LOWER TO VALLEY FLOORS WITH UNSET OF PRECIPITATION. AT KBYI AND KPIH
BREEZY SOUTHWEST TO WEST WINDS ENHANCE TO 15 TO 25 MPH 00-03Z AS
PRECIPITATION DRAWS DAWN. DECREASING CLOUDS EXPECTED OVERNIGHT BUT
LOW STRATUS MAY LINGER ALONG THE EAST BENCH AREAS THROUGH 22/18Z.
LOW STRATUS WILL REDEVELOP IN THE UPPER SNAKE PLAIN TUESDAY MORNING.
RS
&&

.PIH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 11 PM MST THIS EVENING FOR IDZ022-
032.

WINTER WEATHER ADVISORY FROM 11 AM THIS MORNING TO 5 AM MST
MONDAY FOR IDZ019-023-025.

WINTER STORM WARNING UNTIL 11 PM MST THIS EVENING FOR IDZ018-031.

&&

$$

000
FXUS65 KBOI 221039
AFDBOI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
340 AM MST SUN NOV 22 2009

.SHORT TERM...VIGOROUS STORM SYSTEM CURRENTLY PUSHING INTO THE
FORECAST AREA WITH SNOW AND WIND. SYSTEM IS FAST MOVING EMBEDDED
WITHIN 120-140 KNOT JETSTREAM CORE...THUS MAIN IMPACTS NOT EXPECTED
TO LAST MORE THAN A FEW HOURS OVER ANY ONE AREA TODAY. HAVE ADDED
HARNEY AND MALHEUR COUNTIES IN OREGON TO THE WINTER WEATHER
ADVISORIES WITH LIGHT TO MODERATE SNOW AND INCREASING WINDS.
SYNOPTICALLY...A WARM FRONT IS MOVING THROUGH SOUTHEAST OREGON WITH
A COLD FRONT ALIGNED NORTH SOUTH JUST EAST OF THE CASCADES. SYSTEM
EXPECTED TO OCCLUDE LATER THIS AFTERNOON OVER OUR AREA AND WEAKEN.
NEVERTHELESS...SEVERAL INCHES OF NEW SNOW CAN BE EXPECTED IN THE
NORTHERN MOUNTAINS WITH 1 TO 3 INCHES IN VALLEYS SOUTH TO THE SNAKE
RIVER. LESS SNOW IS FORECAST SOUTHWARD TOWARD THE NEVADA STATE LINE.
DUE TO THE QUICK MOVEMENT TO THE SYSTEM...HEAVY PRECIP IS NOT
EXPECTED TO LAST FOR A LONG TIME BUT INCREASING WINDS WITH BLOWING
SNOW WILL BE JUST AS IMPORTANT AN IMPACT AS THE ACTUAL SNOW FALL.
TREASURE AND MAGIC VALLEYS A LITTLE MORE TRICKY WITH SOUNDING
PROFILES INDICATING LIGHT SNOW EARLY THIS MORNING FOLLOWED BY A
MIXTURE...THEN TO ALL RAIN BY THIS AFTERNOON AS WINDS TURN WESTERLY
BEHIND FRONT...ALTHOUGH NOT EXPECTING SIGNIFICANT SNOW
ACCUMULATIONS. LINGERING SNOW SHOWERS TO REMAIN TONIGHT IN THE UPPER
TROF AXIS WITH DRIER CONDITIONS ANTICIPATED FOR MONDAY AS YET
ANOTHER RIDGE BUILDS OVER THE AREA.

.LONG TERM..MONDAY NIGHT THROUGH SUNDAY...DRY CONDITIONS MONDAY
THROUGH THURSDAY AS AN UPPER LEVEL RIDGE AMPLIFIES OVER NRN
CALIFORNIA/NEVADA. THUS...STRENGTH OF SURFACE INVERSION CONTINUES TO
BE THE MAIN FORECAST CHALLENGE. MODEL SOUNDINGS INDICATE SOME MIXING
TUESDAY AFTERNOON...NOT UNTIL WEDNESDAY DOES INVERSION LOOK TO REACH
ITS FULL POTENTIAL. EXPECT BELOW NORMAL VALLEY TEMPERATURES /ABOVE
NORMAL TEMPS IN MTN VALLEYS/ AND FOG ON WEDNESDAY...AND POSSIBLY
EVEN THURSDAY. MODELS IN BETTER AGREEMENT WITH AN UPPER LEVEL TROUGH
PROGGED TO MOVE INTO THE FORECAST AREA EARLY FRIDAY. EXPECT CHANCES
FOR VALLEY RAIN/SNOW AND MOUNTAIN SNOW ON FRIDAY...THEN DRIER ON
SATURDAY AND SUNDAY AS SYSTEM QUICKLY EXITS THE FORECAST AREA.

&&

.AVIATION...WIDESPREAD IFR CONDITIONS IN SNOW /ALL AREAS/ THROUGH
20Z. AFTER 20Z...SHOWERS WILL SLOWLY TAPER OFF ACROSS SE OREGON BUT
PERSIST ACROSS SW ID. STILL EXPECTING SEVERAL HOURS OF IFR
CONDITIONS AT KBOI LATE SUNDAY MORNING...GENERALLY 14Z-19Z. MODERATE
SE SURFACE WINDS WITH LOCALIZED GUSTS TO 35 KTS...WILL BECOME
MODERATE WESTERLY THIS AFTERNOON. STRONG /40-50 KTS/ WESTERLY WINDS
ALOFT.

OUTLOOK...DEVELOPMENT OF INVERSION NEXT WEEK WILL BRING CHANCE OF
IFR CONDITIONS IN FOG/STRATUS TO TREASURE/BAKER/WEISER VALLEYS ON
WEDNESDAY.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...WINTER WEATHER ADVISORY FROM 4 AM TO 2 PM MST SUNDAY FOR IDZ033.
     WINTER WEATHER ADVISORY FROM 4 AM TO 2 PM MST SUNDAY FOR IDZ011-
     IDZ013.
OR...WINTER WEATHER ADVISORY FROM 1 AM TO 10 AM PST SUNDAY FOR
     ORZ061-ORZ62-ORZ63.
&&

$$

WEATHER.GOV/BOISE

SHORT TERM...GS
LONG TERM....MT/JT
AVIATION.....MT

000
FXUS65 KPIH 220949
AFDPIH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
249 AM MST SUN NOV 22 2009

.SHORT TERM...TODAY THROUGH MONDAY NIGHT. UPPER SYSTEM CONTINUES
TO PUSH ONSHORE THIS MORNING IN THE PACIFIC NORTHWEST. WEAK RIDGE
OVER IDAHO IS QUICKLY BREAKING DOWN AS THE SYSTEM APPROACHES OUR
REGION. SNOW WILL MOVE ACROSS THE EASTERN BORDER BEGINNING AROUND
9 AM AND SPREAD EASTWARD THROUGH THE REST OF THE MORNING. THE MAIN
FOCUS OF ACTIVITY WILL BE IN THE CENTRAL MOUNTAINS...IN PARTICULAR
THE SAWTOOTH AREA AND THE EASTERN HIGHLANDS ALONG THE WYOMING
BORDER. WINDS WILL BEGIN TO PICK UP ACROSS THE AREA LATER THIS
MORNING AHEAD OF A FRONT MOVING THROUGH EASTERN IDAHO THIS
AFTERNOON...AND PERSIST POST FRONTAL THROUGH MIDNIGHT. WINDS WILL
BE STRONGEST IN THE SNAKE RIVER PLAIN...GUSTING TO 35 MPH AND
PEAKING OUT AT AROUND 40 MPH LATE THIS EVENING. WITH GUSTY WINDS
EXPECTED ALONG WITH SNOWFALL...A WINTER STORM WARNING REMAINS IN
EFFECT FOR ZONES 18 AND 31 WHILE A WINTER WEATHER ADVISORY REMAINS
IN EFFECT FOR ZONES 32-19-23-25. WILL ADD ZONE 22 TO THE WINTER
WEATHER ADVISORY. WITH HEAVIER SNOW EXPECTED AND GUSTY
WINDS...VISIBILITIES ARE EXPECTED TO REACH A QUARTER MILE AT
TIMES IN THE SAWTOOTH AND WOOD RIVER AREAS. WILL EXTEND THE TIMING
FOR THE WINTER STORM WARNING AND THE ADVISORY FOR LOST RIVER AREA
UNTIL 11 PM GIVEN THE MODEL TREND TOWARDS SOME LINGER SNOW SHOWERS
BRINGING ADDITIONAL ACCUMULATIONS LATER THIS EVENING. SNOW WILL
TAPER OFF FIRST IN THE SNAKE PLAIN AND MUCH OF THE EASTERN HALF OF
THE REGION THIS EVENING...LINGERING OVERNIGHT IN THE EASTERN
HIGHLANDS WITH A RIDGE BEGINNING TO BUILD BACK INTO THE
INTERMOUNTAIN WEST. DRY BUT CONDITION CONDITIONS ARE EXPECTED FOR
MUCH OF THE AREA MONDAY AND MONDAY NIGHT.

.LONG TERM...TUESDAY THROUGH SATURDAY...MODEL TREND CONTINUES TO
BUILD A HIGH PRESSURE RIDGE OVER SOUTHEAST IDAHO TUESDAY THROUGH
THURSDAY NIGHT. A VERY SLIGHT CHANCE OF SHOWERS REMAINS TUESDAY NEAR
THE MONTANA BORDER...OTHERWISE MOISTURE SHIFTS WELL TO THE NORTH OF
THIS AREA. THE MAIN DEVELOPMENT WITH THE LATEST MODEL RUNS IS THE
ECM BEING SLOWER AND MORE IN AGREEMENT WITH THE GFS WITH RESPECT TO
THE DISTURBANCE COMING IN ON FRIDAY. FORECAST WAS UPDATED TO DRY OUT
EVERYTHING FROM THE SNAKE PLAIN EASTWARD THURSDAY NIGHT. RS


&&

.AVIATION...PACIFIC COLD FRONT WILL BRING MVFR AND LIFR CEILINGS IN
SNOW TO MOST SITES TODAY. PRECIPITATION AT KSUN 17Z-01Z...KBYI ABOUT
19Z-02Z...AND KIDA AND KPIH 20Z-03Z. SNOW LEVELS SHOULD QUICKLY
LOWER TO VALLEY FLOORS WITH UNSET OF PRECIPITATION. AT KBYI AND KPIH
BREEZY SOUTHWEST TO WEST WINDS ENHANCE TO 15 TO 25 MPH 00-03Z AS
PRECIPITATION DRAWS DAWN. DECREASING CLOUDS EXPECTED OVERNIGHT BUT
LOW STRATUS MAY LINGER ALONG THE EAST BENCH AREAS THROUGH 22/18Z.
LOW STRATUS WILL REDEVELOP IN THE UPPER SNAKE PLAIN TUESDAY MORNING. RS


&&

.PIH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 11 PM MST THIS EVENING FOR IDZ022-
032.

WINTER WEATHER ADVISORY FROM 11 AM THIS MORNING TO 5 AM MST
MONDAY FOR IDZ019-023-025.

WINTER STORM WARNING UNTIL 11 PM MST THIS EVENING FOR IDZ018-031.

&&

$$

000
FXUS65 KBOI 220339
AFDBOI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
838 PM MST SAT NOV 21 2009

.DISCUSSION...THE LATEST DATA AND NAM MODEL RUN FIT FORECAST TRENDS
WELL...SO NOT PLANNING ON MAKING ANY CHANGES THIS EVENING. WILL...
HOWEVER...UPDATE THE WINTER WEATHER BULLETIN TO INCLUDE THE UPPER
WEISER RIVER ZONE 33. MOST OF THE SNOWFALL...WHICH WILL BE LOCALLY
HEAVY IN THE MOUNTAINS...WILL OCCUR IN A 3-6 HOUR PERIOD IN THE WARM
SECTOR AHEAD OF THE FRONT...STARTING LATE TONIGHT IN SE OREGON
ENDING IN SW IDAHO EARLY SUNDAY AFTERNOON. THE SNOW WILL TAPER OFF
TO SNOW SHOWERS AFTER THE COLD FRONT MOVES THROUGH PROVIDING
ADDITIONAL LIGHT SNOW ACCUMS. WINDS WILL INCREASE AS WELL AND
COMBINE WITH THE SNOWFALL FOR AREAS OF BLOWING AND DRIFTING SNOW.

&&

.AVIATION...THICKENING AND LOWERING CLOUDS TONIGHT.  WIDESPREAD
MOUNTAIN OBSCURATION AND IFR CONDITIONS IN SNOW SHOWERS DEVELOPING
OVER SOUTHEAST OREGON AFTER 09Z AND SOUTHWEST IDAHO AFTER 12Z.  IFR
CONDITIONS WILL CONTINUE IN SOUTHWEST IDAHO MOUNTAINS AND WESTERN
MAGIC VALLEY THROUGH SUNDAY AFTERNOON.  CONDITIONS WILL IMPROVE TO
VFR IN SOUTHEAST OREGON AND THE TREASURE VALLEY OF SOUTHWEST IDAHO
BY SUNDAY AFTERNOON.  GUSTY SOUTHEAST SURFACE WINDS TONIGHT WILL
SHIFT TO THE WEST BY SUNDAY AFTERNOON.  WINDS ALOFT WILL BE STRONG
FROM THE NORTHWEST.

&&

.PREV DISCUSSION...
SHORT TERM...TONIGHT THROUGH MONDAY...WINDS WILL BUILD TONIGHT FROM
THE SOUTHEAST AND SOUTH THEN SHIFT TO SW AND NW SUNDAY BEHIND A FAST
MOVING COLD FRONT. HUGE..IE...-4/-6 TO +10/+15 MB PRESSURE FALL/RISE
COUPLET STAYS TO OUR NW AND N FOR LOCALLY VERY WINDY CONDITIONS
ACROSS SE OREGON AND BREEZY AREAS FOR SW IDAHO...BUT NO HEADLINES
FOR WIND. SNOW AND AREAS OF BLOWING/DRIFTING SNOW ARE EXPECTED WITH
THIS FAST MOVING SYSTEM SUNDAY SO AN ADVISORY FOR SNOW AND BLOWING
SNOW HAS BEEN HOISTED ACROSS BAKER COUNTY...THE WEST CENTRAL AND
BOISE MOUNTAINS. GUSTY NW WINDS DIMINISH RAPIDLY MONDAY NIGHT AS
HIGH PRESSURE BUILDS IN...WITH LIGHT WINDS AND MOSTLY CLEAR SKIES.
COUPLED WITH NEW SNOW COVER...GENERALLY ABOVE 3500 FEET...LOW TEMPS
WILL PLUMMET TO SINGLE DIGITS COLDEST SPOTS SUCH AS FAIRFIELD AND
MID 20S...TEENS ACROSS THE RELATIVELY MILDER LOCALES. LIGHT WINDS
AND A COLD START MONDAY LOOK TO KEEP TEMPS BELOW NORMAL AND NEAR TO
BELOW MOS.

LONG TERM...MONDAY NIGHT THROUGH SATURDAY...UPPER RIDGE BUILDS INTO
THE PACIFIC NW ON TUESDAY. WEAK SYSTEM MOVING THROUGH THE PANHANDLE
TUESDAY AFTERNOON WILL DO LITTLE MORE THAT INCREASE CLOUDS OVER THE
WEST CENTRAL MTNS. WITH WARMING ALOFT...INVERSION SETS UP IN THE
LOWER ELEVATIONS FOR TUE/WED. INTRODUCED FOG INTO THE FORECAST FOR
TUESDAY NIGHT AND WEDNESDAY IN THE LOWER TREASURE...WEISER AND BAKER
VALLEYS. LESS CONFIDENT ON DEVELOPMENT OF FOG/STRATUS OVER BOISE
WEDNESDAY MORNING SO HAVE LEFT IT OUT FOR NOW. GOOD MODEL AGREEMENT
THAT INVERSION IS SHORT-LIVED...AS ANOTHER STORM ENTERS THE PAC NW
LATE IN THE WEEK. THE 12Z SOLUTIONS ARE IN BETTER AGREEMENT ON
BRINGING THE STORM THROUGH THE INTERMOUNTAIN NW ON FRIDAY. WINDS
AHEAD OF THE SYSTEM WOULD LIKELY CLEAR OUT ANY FOG/STRATUS IN THE
LOWER VALLEYS THANKSGIVING DAY. LOOKS LIKE RAIN IN THE VALLEYS ON
FRIDAY WITH MTN SNOW. PATTERN REMAINS ACTIVE THROUGH NEXT WEEKEND.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...WINTER WEATHER ADVISORY FROM 4 AM TO 2 PM MST SUNDAY FOR IDZ033.
     WINTER WEATHER ADVISORY FROM 4 AM TO 2 PM MST SUNDAY FOR IDZ011-
     IDZ013.
OR...WINTER WEATHER ADVISORY FROM 1 AM TO 10 AM PST SUNDAY FOR
     ORZ062.
&&

$$

WEATHER.GOV/BOISE

DISCUSSION...BW
AVIATION.....JA
PREV SHORT TERM...VM
PREV LONG TERM....DG/DD

000
FXUS65 KBOI 212205
AFDBOI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
305 PM MST SAT NOV 21 2009

.SHORT TERM...TONIGHT THROUGH MONDAY...WINDS WILL BUILD TONIGHT
FROM THE SOUTHEAST AND SOUTH THEN SHIFT TO SW AND NW SUNDAY BEHIND
A FAST MOVING COLD FRONT. HUGE..IE...-4/-6 TO +10/+15 MB PRESSURE
FALL/RISE COUPLET STAYS TO OUR NW AND N FOR LOCALLY VERY WINDY
CONDITIONS ACROSS SE OREGON AND BREEZY AREAS FOR SW IDAHO...BUT NO
HEADLINES FOR WIND. SNOW AND AREAS OF BLOWING/DRIFTING SNOW ARE
EXPECTED WITH THIS FAST MOVING SYSTEM SUNDAY SO AN ADVISORY FOR
SNOW AND BLOWING SNOW HAS BEEN HOISTED ACROSS BAKER COUNTY...THE
WEST CENTRAL AND BOISE MOUNTAINS. GUSTY NW WINDS DIMINISH RAPIDLY
MONDAY NIGHT AS HIGH PRESSURE BUILDS IN...WITH LIGHT WINDS AND
MOSTLY CLEAR SKIES. COUPLED WITH NEW SNOW COVER...GENERALLY ABOVE
3500 FEET...LOW TEMPS WILL PLUMMET TO SINGLE DIGITS COLDEST SPOTS
SUCH AS FAIRFIELD AND MID 20S...TEENS ACROSS THE RELATIVELY MILDER
LOCALES. LIGHT WINDS AND A COLD START MONDAY LOOK TO KEEP TEMPS
BELOW NORMAL AND NEAR TO BELOW MOS.


.LONG TERM...MONDAY NIGHT THROUGH SATURDAY...UPPER RIDGE BUILDS INTO
THE PACIFIC NW ON TUESDAY. WEAK SYSTEM MOVING THROUGH THE PANHANDLE
TUESDAY AFTERNOON WILL DO LITTLE MORE THAT INCREASE CLOUDS OVER THE
WEST CENTRAL MTNS. WITH WARMING ALOFT...INVERSION SETS UP IN THE
LOWER ELEVATIONS FOR TUE/WED. INTRODUCED FOG INTO THE FORECAST FOR
TUESDAY NIGHT AND WEDNESDAY IN THE LOWER TREASURE...WEISER AND BAKER
VALLEYS. LESS CONFIDENT ON DEVELOPMENT OF FOG/STRATUS OVER BOISE
WEDNESDAY MORNING SO HAVE LEFT IT OUT FOR NOW. GOOD MODEL AGREEMENT
THAT INVERSION IS SHORT-LIVED...AS ANOTHER STORM ENTERS THE PAC NW
LATE IN THE WEEK. THE 12Z SOLUTIONS ARE IN BETTER AGREEMENT ON
BRINGING THE STORM THROUGH THE INTERMOUNTAIN NW ON FRIDAY. WINDS
AHEAD OF THE SYSTEM WOULD LIKELY CLEAR OUT ANY FOG/STRATUS IN THE
LOWER VALLEYS THANKSGIVING DAY. LOOKS LIKE RAIN IN THE VALLEYS ON
FRIDAY WITH MTN SNOW. PATTERN REMAINS ACTIVE THROUGH NEXT WEEKEND.

&&

.AVIATION...WIDESPREAD IFR CONDITIONS IN SNOW DEVELOPING SUNDAY
MORNING...OVER SE OREGON AFTER 06Z AND SW ID AFTER 09Z. WILL SEE 4-6
HOURS OF IFR CONDITIONS AT BOISE SUNDAY MORNING. IFR CONDITIONS
CONTINUE IN SW IDAHO MTNS AND WESTERN MAGIC VALLEY THROUGH SUNDAY
AFTERNOON. CONDITIONS IMPROVE TO VFR IN SE OREGON AND TREASURE
VALLEY OF SW IDAHO SUNDAY AFTERNOON. GUSTY SE SURFACE WINDS EARLY
SUNDAY MORNING SHIFTING TO THE WEST IN THE AFTERNOON. STRONG
WESTERLY WINDS ALOFT OF 40-60 KTS ON SUNDAY.

OUTLOOK...DEVELOPMENT OF INVERSION NEXT WEEK WILL BRING CHANCE OF
IFR CONDITIONS IN FOG/STRATUS TO TREASURE/BAKER/WEISER VALLEYS ON
WEDNESDAY.


&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...WINTER WEATHER ADVISORY FROM 4 AM TO 2 PM MST SUNDAY FOR IDZ011-
     IDZ013.
OR...WINTER WEATHER ADVISORY FROM 1 AM TO 10 AM PST SUNDAY FOR ORZ062.
&&

$$

WEATHER.GOV/BOISE

SHORT TERM...VM
LONG TERM....DG/DD
AVIATION.....DG

000
FXUS65 KPIH 212052
AFDPIH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
200 PM MST SAT NOV 21 2009

.SHORT TERM...TONIGHT THROUGH TUESDAY. A DIRTY(MOIST) SHORT-WAVE
RIDGE WILL SPREAD QUICKLY ACROSS THE REGION TONIGHT AHEAD OF THE
NEXT PACIFIC STORM SYSTEM WHICH WAS CLEARLY VISIBLE ON WATER VAPOR
SATELLITE IMAGERY OFF THE NW COAST. THIS SYSTEM WILL SPREAD INTO
WASHINGTON AND OREGON OVERNIGHT THEN THROUGH IDAHO SUNDAY WITH
LINGERING PRECIPITATION ACTIVITY ACROSS THE ERN HIGHLANDS THROUGH
SUNDAY EVENING. A STRONG UPPER JET (140KTS) WILL ACCOMPANY THE WAVE
THROUGH THE REGION WITH 700MB (10K FT) WINDS RAMPING UP TO 45KTS.
LOW LEVEL LAPSE RATES ARE UNSTABLE ENOUGH TO MIX DOWN A GOOD PORTION
OF THESE WINDS TO THE SURFACE AS GUSTS AND FOR NOW WE HAVE SUSTAINED
WINDS AND GUSTS RUNNING UP CLOSE TO ADVISORY LEVELS. THE STATISTICAL
GUIDANCE IS DOWNPLAYING THE STRENGTH OF THE WINDS HOWEVER SO WILL
HOLD OFF ON THAT PARTICULAR HIGHLIGHT FOR NOW.  AS FOR THE STORM
TOTAL SNOWFALL...WE HAVE ENOUGH WIND AND SNOW IN THE CNTRL MOUNTAINS
TO WARRANT A WARNING FOR SUNDAY WITH LESSER...ADVISORY AMOUNTS FOR
THE REMAINDER OF THE CNTRL AND ERN HIGHLANDS THROUGH SUNDAY NIGHT.
AFTER MIDNIGHT SUNDAY...A RIDGE OF HIGH PRESSURE WILL BEGIN TO BUILD
ACROSS THE REGION PROVIDING DRIER BUT COOL CONDITIONS. HUSTON

.LONG TERM...TUESDAY NIGHT THROUGH SATURDAY...WITH STORM EXITING TO
EAST...HIGH PRESSURE RIDGE WILL START TO DEVELOP.  MODEL CONSENSUS
FAVORS A HIGHER AMPLITUDE RIDGE AND DRYING CONDITIONS THROUGH
THURSDAY. CURRENT FORECAST REFLECTS MUCH LOWER POPS AND LESS CLOUDS
DURING THAT TIME PERIOD. A SLIGHT WARMING TREND EXPECTED WITH RIDGE
DEVELOPMENT.  STARTING FRIDAY MODELS SHOW SOME DIFFERENCES.  BOTH
THE EUROPEAN AND GFS MODELS PUSH A SHORTWAVE TROUGH THROUGH THE THE
NORTHWESTERN TIER OF STATES.  HOWEVER THE EUROPEAN IS MUCH DEEPER
THAN THE GFS.  MODELERS ARE TRENDING TOWARD A COMPROMISE...WHICH
MEANS WE WILL GET A BRUSHING FROM THE SYSTEM...BUT MOST ENERGY TO
REMAIN TO THE NORTH OF US.  CURRENT GRIDDED FORECASTS HAVE THIS
UNCERTAINTY REFLECTED. PRESTON
&&

.AVIATION...POST FRONTAL CLOUDS CONTINUE TO LINGER IN EASTERN
PORTIONS OF THE AREA WITH MVFR CONDITIONS POSSIBLE FOR PIH AND IDA
UNTIL 00Z.  BIGGEST CONCERN REMAINS THE GUSTY WINDS WHICH WILL BEGIN
TO DIMINISH WITH SUNSET.  NEXT WEATHER SYSTEM TO IMPACT AREA
STARTING TOMORROW MORNING AND EXPECT LOWERING CLOUDS BY SUNRISE AND
PRECIPITATION...MAINLY SNOW TO DEVELOP BETWEEN 15 AND 19Z AS FRONTAL
BOUNDARY AND ANOTHER SHOT OF GUSTY WINDS MOVES THROUGH.  PERIODS OF
LIGHT TO MODERATE SNOW PRODUCING MVFR TO IFR CONDITIONS EXPECTED
THROUGH EARLY EVENING. PRESTON
&&

.PIH WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING FOR THE SAWTOOTH MOUNTAINS AND WOOD RIVER
REGION FOR SUNDAY.

WINTER WEATHER ADVISORY FOR THE LOST RIVER/PAHSIMEROI REGION FOR
SUNDAY.

WINTER WEATHER ADVISORY FOR THE EASTERN MOUNTAINS SUNDAY AFTERNOON
THROUGH SUNDAY NIGHT.
&&

$$

000
FXUS65 KPIH 211655
AFDPIH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
1000 AM MST SAT NOV 21 2009

.SHORT TERM...TODAY THROUGH MONDAY. CURRENT FORECAST IN REASONABLY
GOOD SHAPE AS FAR AS TODAY IS CONCERNED. AFTER REVIEWING THE LATEST
GUIDANCE HOWEVER...WE ARE LOOKING AT NEAR WARNING SNOWFALL AMOUNTS
IN THE SAWTOOTH MOUNTAIN REGION SUNDAY WITH BRISK WINDS WHICH TIPS
THE SCALE TOWARD A WINTER STORM WARNING. THE REMAINDER OF THE CNTRL
AND ERN MOUNTAINS WILL LIKELY SEE ADVISORY LEVEL SNOWFALL WITH WIND
AS WELL SUNDAY AFTERNOON THROUGH SUNDAY NIGHT. THESE HIGHLIGHTS WILL
FOLLOW SHORTLY AFTER NOON TODAY WITH THE UPDATED FORECAST FOLLOWING
AS SOON AS WE COMPLETE THE GRIDS FOR THE AFTERNOON PACKAGE. SEE
PREVIOUS DISCUSSION BELOW. HUSTON

COLD FRONT HAS PUSHED THROUGH MUCH OF THE AREA THIS MORNING. AS A
RESULT...WINDS HAVE DROPPED BELOW ADVISORY LEVEL HOWEVER THEY REMAIN
GENERALLY ELEVATED. GAP FLOW HAS DIMINISHED WITH WINDS TURNING MORE
SOUTHWESTERLY BUT GUSTS TO 35 MPH REMAIN COMMON IN SNAKE PLAIN.
PRECIPITATION HAS SPREAD THROUGHOUT THE REGION BUT TEMPERATURES
REMAIN ABOVE FREEZING EVERYWHERE EXCEPT THE CENTRAL MOUNTAINS AND
THE HIGHER ELEVATIONS OF THE EASTERN HIGHLANDS. COLD AIR WILL FILTER
INTO THE REGION TODAY...SO EXPECT LITTLE DIURNAL TEMPERATURE RISE
TODAY BEFORE FALLING OFF THROUGH THIS AFTERNOON. PRECIPITATION WILL
CONTINUE THROUGH THE MORNING THEN DIMINISH AS THE TROUGH QUICKLY
LIFTS INTO WYOMING THIS AFTERNOON. PRECIPITATION AMOUNTS ARE
GENERALLY EXPECTED TO BE LIGHT WITH ONLY A FEW INCHES EXPECTED IN
THE HIGHEST ELEVATIONS. WINDS WILL REMAIN BREEZY
TODAY...ESPECIALLY IN THE SNAKE RIVER PLAIN. EXPECT WINDS TO BE
JUST BELOW ADVISORY LEVEL TODAY.

RIDGING AHEAD OF THE NEXT SYSTEM WILL BRING A BRIEF BREAK IN THE
WEATHER THIS AFTERNOON AND TONIGHT. THE NEXT FAST MOVING TROUGH
ARRIVES SUNDAY MORNING. WITH COLD AIR IN PLACE...THIS SYSTEM WILL
BRING SNOW ACROSS THE AREA WITH THE HIGHEST QPF AMOUNTS AGAIN
EXPECTED IN THE CENTRAL MOUNTAINS AND SOUTHEASTERN HIGHLANDS.
MODELS INDICATE AT LEAST ADVISORY LEVEL SNOW AMOUNTS ASSOCIATED
WITH THIS SYSTEM...HOWEVER WITH ITS FAST MOVING NATURE AND RECENT
MODEL TENDENCY TO OVER-ESTIMATE THE PRECIPITATION WILL HOLD OFF
ISSUING ANY HEADLINES FOR NOW. THE SNAKE RIVER PLAIN WILL ESCAPE
MUCH OF THE SNOWFALL HOWEVER AN INCH OR SO IS POSSIBLE. ALSO OF
CONCERN WILL BE ANOTHER ROUND OF GUSTY WINDS AHEAD OF THE COLD
FRONT ON SATURDAY NIGHT. HANKO


.LONG TERM...MONDAY NIGHT THROUGH SATURDAY...ISOLATED SHOWERS WILL
LINGER MAINLY IN THE NORTHERN MOUNTAINS MONDAY NIGHT AS A HIGH
PRESSURE RIDGE BEGINS TO BUILD. MODEL CONSENSUS FAVORS A HIGHER
AMPLITUDE HIGH PRESSURE RIDGE AND DRYING CONDITIONS TUESDAY THROUGH
THURSDAY. CURRENT FORECAST REFLECTS MUCH LOWER POPS AND LESS CLOUDS
DURING THAT TIME PERIOD. DIURNAL TEMPERATURE RANGE WAS ALSO
INCREASED. THE ECM IS FASTER THAN THE GFS WITH THE NEXT DISTURBANCE
AROUND FRIDAY MORNING AND DEPICTS MORE OF A STRETCHED...WEAK TROUGH.
THEREFORE STAYED CLOSE TO CLIMATOLOGY WITH POPS FOR FRIDAY AND
SATURDAY TIME FRAME. RS
&&

.AVIATION...POST FRONTAL PRECIPITATION JUST NOW MOVING THROUGH KIDA
AND KPIH AND SHOULD BE LIMITED TO THE NEXT COUPLE HOURS. COLD
ADVECTION AT OR JUST ABOVE CLOUD LEVEL INCREASING AND SNOW LEVELS
ESTIMATED ONLY 500 TO 1000 FT ABOVE THE VALLEY FLOOR. CLOUD COVER
CONTINUES TO MOVE UP THE MAGIC VALLEY AND COULD KEEP MVFR CEILINGS
PINNED AGAINST THE EAST BENCHES AS THE NAM12 SUGGEST UNTIL ABOUT
18Z. WESTERLY SURFACE PRESSURE GRADIENT WILL SUPPORT BREEZY 15 TO 25
MPH WINDS THROUGH 24Z. CEILINGS IMPROVE TO VFR TONIGHT. THE SECOND
OF TWO DISTURBANCES MOVES INTO SOUTHEAST IDAHO AFTER 22/1500Z...COLD
FRONTAL PASSAGE AT KIDA AND KPIH NEAR 22/2100Z...AND SNOW LEVELS
ABOUT 4400 FEET MSL.  RS
&&

.PIH WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING FOR THE SAWTOOTH MOUNTAINS AND WOOD RIVER
REGION FOR SUNDAY.

WINTER WEATHER ADVISORY FOR THE LOST RIVER/PAHSIMEROI REGION FOR
SUNDAY.

WINTER WEATHER ADVISORY FOR THE EASTERN MOUNTAINS SUNDAY AFTERNOON
THROUGH SUNDAY NIGHT.
&&

$$

000
FXUS65 KBOI 211638
AFDBOI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
938 AM MST SAT NOV 21 2009

.DISCUSSION...UPDATED FORECASTS. COLD FRONTAL COOLING WILL LIMIT
HIGHS TODAY TO THE 30S TO MID 40S...AND MORNING SOUNDING INDICATES
44 FOR A HIGH AT BOISE. VALLEY SHOWERS LAST EVENING SCRUBBED
DUST/DIRT OUT WITH REPORTS FROM MARSING TO MIDDLETON TO EMMETT
CONSISTENT WITH YESTERDDAY/S BLOWING DUST REPORTS AND MULTI SENSOR
PRECIPITATION ESTIMATES THOSE LOCATIONS AS WELL. COLD FRONT
BRINGING IN CLEANER AIR IN AS WELL. ABOUT 7C/KM LAPSE RATES BELOW
550 MBS AIDING FAST MOVING SNOW SHOWERS THROUGH THE BOISE
MOUNTAINS AS OF 9 AM. DRY ACROSS SE OREGON AND VALLEYS OF SW IDAHO
TODAY WITH DIMINISHING SNOW SHOWERS IN THE CENTRAL MOUNTAINS. NEXT
SYSTEM IS PROGGED 3HRS LATER IN THE SREF...6 NAM/GFS..AND 9 HRS
LATER IN 00Z EC. SO HAVE ADJUSTED TIMING BY 3 HRS FOR NOW. THIS
ALLOWS MINS TO BE A COUPLE DEGREES COLDER AND SUPPORTS UP TO AN
INCH OF WET SNOW ACCUMULATION ON GRASSY/GROUND AREAS ON THE NORTH
HALF OF THE TREASURE VALLEY ZONES. SOME ROADWAYS MAY GET A
DUSTING. SNOW ENDS IN THE VALLEYS TOWARDS NOON AND TEMPERATURES
WARM IN TO THE UPPER 30S BY NOON SUNDAY...WHILE MODERATE TO HEAVY
SNOW IS EXPECTED TO LINGER IN THE WEST CENTRAL AND BOISE MOUNTAINS
THROUGH EARLY TO MID-AFTERNOON. WILL UPDATE WX STORY AS WELL FOR
THIS NEW TIMING AND STILL EXPECTED AMOUNTS FROM LIGHT IN THE SRN
VALLEYS AND HARNEY/MALHEUR COUNTIES TO MODERATE...BKE/IDAHO
CITY/FAIRFIELD TO MODERATE OR HEAVY...ZONE 11/13 MOUNTAINS.

&&

.AVIATION...BRIEF IFR CONDITIONS WILL ACCOMPANY WIDELY SCATTERED
SNOW SHOWERS IN THE BOISE AND WEST CENTRAL MTNS TODAY. LOWER
VALLEYS OF SW IDAHO AND ALL OF SE OREGON WILL BE VFR. ANOTHER
STORM BRINGS IFR CONDITIONS TO SE OREGON AFTER 06Z SUNDAY MORNING
AND AFTER 10Z IN SW IDAHO. EXPECT A 4-6 HOUR PERIOD OF IFR
CONDITIONS AT KBOI WITH BRIEF PERIODS OF MODERATE SNOW POSSIBLE.
IFR CONDITIONS CONTINUE IN THE SW IDAHO MTNS AND WESTERN MAGIC
VALLEY THROUGH SUNDAY AFTERNOON. STRONG WESTERLY WINDS ALOFT ON
SUNDAY OF 40-60 KTS.

&&

.PREV DISCUSSION...
SHORT TERM...TODAY THROUGH SUNDAY...WEAK SYSTEM EXITING THE
FORECAST AREA AT THIS TIME WITH LINGERING SCATTERED RAIN AND SNOW
SHOWERS. THESE CURRENT CONVECTIVE SHOWERS ASSOCIATED WITH PASSAGE OF
THE UPPER LEVEL TROUGH. A DECENT WEATHER DAY TODAY WITH A DRIER PUSH
OF WEST TO NORTHWEST FLOW AND SEASONAL TEMPS AHEAD OF A MORE POTENT
PACIFIC SYSTEM FOR TONIGHT AND SUNDAY. THIS NEXT SYSTEM IS FAST
MOVING...EMBEDDED WITHIN A POWERFUL JETSTREAM FLOW. YET...QPF LOOKS
RATHER SUBSTANTIAL IN NORTHERN AREAS AND WITH WEST FLOW...OROGRAPHIC
ENHANCEMENT WILL AID STORM TOTAL SNOW ACCUMULATIONS. TIMING INTO
BAKER COUNTY OREGON TONIGHT ABOUT 03Z WHICH IS ABOUT 3 HOURS EARLIER
THEN START TIME OVER THE IDAHO ZONES. OVERALL DURATION TO EVENT
SHOULD NOT LAST PAST MID AFTERNOON SUNDAY WITH THE EXCEPTION OF A
FEW LINGERING SNOW SHOWERS. MAIN IMPACTS WITH TONIGHTS STORM
EXPECTED TO BE MODERATE TO LOCALLY HEAVY SNOWFALL AND POOR
VISIBILITY ON NORTH SOUTH RURAL ROADS. TEMPERATURES EXPECTED TO TURN
SHARPLY COLDER NORTH OF THE JET STREAM WHICH WILL PRODUCE A LESS
DENSE SNOW THAN IS EXPECTED IN THE SOUTHERN ZONES.  THIS IN TURN
SHOULD DROP VISIBILITY TO LESS THAN ONE HALF MILE AT TIMES. HAVE
OPTED TO ISSUE A WINTER STORM WATCH FOR THE NORTHERN MOUNTAIN ZONES
AND LET DAY CREW MAKE FINAL DECISION OF SPECIFIC WINTER HIGHLIGHTS
JUST BEFORE THE EVENT UNFOLDS.

LONG TERM..SUNDAY NIGHT THROUGH SATURDAY...SNOW SHOWERS WILL
PERSIST ACROSS SW IDAHO TERRAIN...BEFORE TAPERING OFF BY MONDAY
EVENING. TEMPERATURES WILL QUICKLY REBOUND TO ABOVE NORMAL VALUES ON
TUESDAY AS AN UPPER LEVEL RIDGE BUILDS OVER NRN CALIFORNIA/NEVADA.
BY WEDNESDAY...A STRENGTHENING SURFACE INVERSION WILL KEEP AFTERNOON
MIXING TO A MINIMUM - FOR COOLER VALLEY HIGHS. A SIMILAR ISSUE
POSSIBLE ON THURSDAY...BUT CURRENT FORECAST RELIES ON LOW-LEVEL WARM
ADVECTION /AHEAD OF AN APPROACHING TROUGH/ TO INCREASE MIXING AND
KEEP TEMPERATURES ABOVE NORMAL. UPPER TROUGH PROGGED TO MOVE INTO
THE REGION EARLY FRIDAY...BUT MODELS VARY SUBSTANTIALLY IN LOCATION.
THEREFORE HAVE REMAINED CONSERVATIVE WITH NEAR CLIMO POPS /FRIDAY
AND SATURDAY/ DUE TO UNCERTAINTY.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...WINTER STORM WATCH FROM LATE TONIGHT THROUGH SUNDAY AFTERNOON
     FOR IDZ011-IDZ013.
OR...WINTER STORM WATCH FROM THIS EVENING THROUGH SUNDAY AFTERNOON
     FOR ORZ062.
&&

$$

WEATHER.GOV/BOISE

DISCUSSION...VM
AVIATION.....DG
PREV SHORT TERM...GS
PREV LONG TERM....MT/JT

000
FXUS65 KBOI 211037
AFDBOI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
335 AM MST SAT NOV 21 2009

.SHORT TERM...TODAY THROUGH SUNDAY...WEAK SYSTEM EXITING THE
FORECAST AREA AT THIS TIME WITH LINGERING SCATTERED RAIN AND SNOW
SHOWERS. THESE CURRENT CONVECTIVE SHOWERS ASSOCIATED WITH PASSAGE OF
THE UPPER LEVEL TROUGH. A DECENT WEATHER DAY TODAY WITH A DRIER PUSH
OF WEST TO NORTHWEST FLOW AND SEASONAL TEMPS AHEAD OF A MORE POTENT
PACIFIC SYSTEM FOR TONIGHT AND SUNDAY. THIS NEXT SYSTEM IS FAST
MOVING...EMBEDDED WITHIN A POWERFUL JETSTREAM FLOW. YET...QPF LOOKS
RATHER SUBSTANTIAL IN NORTHERN AREAS AND WITH WEST FLOW...OROGRAPHIC
ENHANCEMENT WILL AID STORM TOTAL SNOW ACCUMULATIONS. TIMING INTO
BAKER COUNTY OREGON TONIGHT ABOUT 03Z WHICH IS ABOUT 3 HOURS EARLIER
THEN START TIME OVER THE IDAHO ZONES. OVERALL DURATION TO EVENT
SHOULD NOT LAST PAST MID AFTERNOON SUNDAY WITH THE EXCEPTION OF A
FEW LINGERING SNOW SHOWERS. MAIN IMPACTS WITH TONIGHTS STORM
EXPECTED TO BE MODERATE TO LOCALLY HEAVY SNOWFALL AND POOR
VISIBILITY ON NORTH SOUTH RURAL ROADS. TEMPERATURES EXPECTED TO TURN
SHARPLY COLDER NORTH OF THE JET STREAM WHICH WILL PRODUCE A LESS
DENSE SNOW THAN IS EXPECTED IN THE SOUTHERN ZONES.  THIS IN TURN
SHOULD DROP VISIBILITY TO LESS THAN ONE HALF MILE AT TIMES. HAVE
OPTED TO ISSUE A WINTER STORM WATCH FOR THE NORTHERN MOUNTAIN ZONES
AND LET DAY CREW MAKE FINAL DECISION OF SPECIFIC WINTER HIGHLIGHTS
JUST BEFORE THE EVENT UNFOLDS.

.LONG TERM..SUNDAY NIGHT THROUGH SATURDAY...SNOW SHOWERS WILL
PERSIST ACROSS SW IDAHO TERRAIN...BEFORE TAPERING OFF BY MONDAY
EVENING. TEMPERATURES WILL QUICKLY REBOUND TO ABOVE NORMAL VALUES ON
TUESDAY AS AN UPPER LEVEL RIDGE BUILDS OVER NRN CALIFORNIA/NEVADA.
BY WEDNESDAY...A STRENGTHENING SURFACE INVERSION WILL KEEP AFTERNOON
MIXING TO A MINIMUM - FOR COOLER VALLEY HIGHS. A SIMILAR ISSUE
POSSIBLE ON THURSDAY...BUT CURRENT FORECAST RELIES ON LOW-LEVEL WARM
ADVECTION /AHEAD OF AN APPROACHING TROUGH/ TO INCREASE MIXING AND
KEEP TEMPERATURES ABOVE NORMAL. UPPER TROUGH PROGGED TO MOVE INTO
THE REGION EARLY FRIDAY...BUT MODELS VARY SUBSTANTIALLY IN LOCATION.
THEREFORE HAVE REMAINED CONSERVATIVE WITH NEAR CLIMO POPS /FRIDAY
AND SATURDAY/ DUE TO UNCERTAINTY.

&&

.AVIATION...SW IDAHO - IFR SNOW SHOWERS ACROSS HIGHER TERRAIN
/MAINLY W CENTRAL AND BOISE MTNS/ WILL PERSIST THROUGH 21Z. MTNS
WILL BE OBSCURED. VFR RAIN SHOWERS ACROSS THE WRN SNAKE PLAIN /E OF
BOISE/ THROUGH 15Z. LIGHT TO MODERATE SURFACE WINDS - WITH GUSTS TO
25 KTS EAST AND SOUTH OF KMUO. SE OREGON - VFR UNDER BKN-OVC SKIES
OVERNIGHT. LIGHT WINDS.

IFR CONDITIONS WILL RETURN AFTER 06Z TONIGHT...AS ANOTHER STORM
SYSTEM MOVES INTO THE AREA. EXPECT WIDESPREAD IFR SNOW - ALL
ELEVATIONS.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...WINTER STORM WATCH FROM 06Z SUNDAY THROUGH 21Z FOR IDZ011 AND
     IDZ013.
OR...WINTER STORM WATCH FROM 03Z SUNDAY THROUGH 18Z FOR ORZ062.
&&

$$

WEATHER.GOV/BOISE

SHORT TERM...GS
LONG TERM....MT/JT
AVIATION.....MT

000
FXUS65 KPIH 211018
AFDPIH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
318 AM MST SAT NOV 21 2009

.SHORT TERM...TODAY THROUGH MONDAY. COLD FRONT HAS PUSHED THROUGH
MUCH OF THE AREA THIS MORNING. AS A RESULT...WINDS HAVE DROPPED
BELOW ADVISORY LEVEL HOWEVER THEY REMAIN GENERALLY ELEVATED. GAP
FLOW HAS DIMINISHED WITH WINDS TURNING MORE SOUTHWESTERLY BUT
GUSTS TO 35 MPH REMAIN COMMON IN SNAKE PLAIN. PRECIPITATION HAS
SPREAD THROUGHOUT THE REGION BUT TEMPERATURES REMAIN ABOVE
FREEZING EVERYWHERE EXCEPT THE CENTRAL MOUNTAINS AND THE HIGHER
ELEVATIONS OF THE EASTERN HIGHLANDS. COLD AIR WILL FILTER INTO THE
REGION TODAY...SO EXPECT LITTLE DIURNAL TEMPERATURE RISE TODAY
BEFORE FALLING OFF THROUGH THIS AFTERNOON. PRECIPITATION WILL
CONTINUE THROUGH THE MORNING THEN DIMINISH AS THE TROUGH QUICKLY
LIFTS INTO WYOMING THIS AFTERNOON. PRECIPITATION AMOUNTS ARE
GENERALLY EXPECTED TO BE LIGHT WITH ONLY A FEW INCHES EXPECTED IN
THE HIGHEST ELEVATIONS. WINDS WILL REMAIN BREEZY
TODAY...ESPECIALLY IN THE SNAKE RIVER PLAIN. EXPECT WINDS TO BE
JUST BELOW ADVISORY LEVEL TODAY.

RIDGING AHEAD OF THE NEXT SYSTEM WILL BRING A BRIEF BREAK IN THE
WEATHER THIS AFTERNOON AND TONIGHT. THE NEXT FAST MOVING TROUGH
ARRIVES SUNDAY MORNING. WITH COLD AIR IN PLACE...THIS SYSTEM WILL
BRING SNOW ACROSS THE AREA WITH THE HIGHEST QPF AMOUNTS AGAIN
EXPECTED IN THE CENTRAL MOUNTAINS AND SOUTHEASTERN HIGHLANDS.
MODELS INDICATE AT LEAST ADVISORY LEVEL SNOW AMOUNTS ASSOCIATED
WITH THIS SYSTEM...HOWEVER WITH ITS FAST MOVING NATURE AND RECENT
MODEL TENDENCY TO OVER-ESTIMATE THE PRECIPITATION WILL HOLD OFF
ISSUING ANY HEADLINES FOR NOW. THE SNAKE RIVER PLAIN WILL ESCAPE
MUCH OF THE SNOWFALL HOWEVER AN INCH OR SO IS POSSIBLE. ALSO OF
CONCERN WILL BE ANOTHER ROUND OF GUSTY WINDS AHEAD OF THE COLD
FRONT ON SATURDAY NIGHT. HANKO


.LONG TERM...MONDAY NIGHT THROUGH SATURDAY...ISOLATED SHOWERS WILL
LINGER MAINLY IN THE NORTHERN MOUNTAINS MONDAY NIGHT AS A HIGH
PRESSURE RIDGE BEGINS TO BUILD. MODEL CONSENSUS FAVORS A HIGHER
AMPLITUDE HIGH PRESSURE RIDGE AND DRYING CONDITIONS TUESDAY THROUGH
THURSDAY. CURRENT FORECAST REFLECTS MUCH LOWER POPS AND LESS CLOUDS
DURING THAT TIME PERIOD. DIURNAL TEMPERATURE RANGE WAS ALSO
INCREASED. THE ECM IS FASTER THAN THE GFS WITH THE NEXT DISTURBANCE
AROUND FRIDAY MORNING AND DEPICTS MORE OF A STRETCHED...WEAK TROUGH.
THEREFORE STAYED CLOSE TO CLIMATOLOGY WITH POPS FOR FRIDAY AND
SATURDAY TIME FRAME. RS


&&

.AVIATION...POST FRONTAL PRECIPITATION JUST NOW MOVING THROUGH KIDA
AND KPIH AND SHOULD BE LIMITED TO THE NEXT COUPLE HOURS. COLD
ADVECTION AT OR JUST ABOVE CLOUD LEVEL INCREASING AND SNOW LEVELS
ESTIMATED ONLY 500 TO 1000 FT ABOVE THE VALLEY FLOOR. CLOUD COVER
CONTINUES TO MOVE UP THE MAGIC VALLEY AND COULD KEEP MVFR CEILINGS
PINNED AGAINST THE EAST BENCHES AS THE NAM12 SUGGEST UNTIL ABOUT
18Z. WESTERLY SURFACE PRESSURE GRADIENT WILL SUPPORT BREEZY 15 TO 25
MPH WINDS THROUGH 24Z. CEILINGS IMPROVE TO VFR TONIGHT. THE SECOND
OF TWO DISTURBANCES MOVES INTO SOUTHEAST IDAHO AFTER 22/1500Z...COLD
FRONTAL PASSAGE AT KIDA AND KPIH NEAR 22/2100Z...AND SNOW LEVELS
ABOUT 4400 FEET MSL.  RS


&&

.PIH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$