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000
FXUS65 KSLC 211650
AFDSLC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
950 AM MST SAT NOV 21 2009
.SYNOPSIS...THE FIRST OF TWO UPPER LEVEL WEATHER DISTURBANCES WILL
CROSS NORTHERN UTAH TODAY. THE SECOND SYSTEM WILL PUSH A STRONGER
COLD FRONT ACROSS UTAH LATE SUNDAY THROUGH EARLY MONDAY. HIGH
PRESSURE ALOFT WILL SETTLE OVER UTAH EARLY NEXT WEEK...AND REMAIN
THE DOMINANT FEATURE THROUGH FRIDAY.
&&
.DISCUSSION...THE FIRST OF THE TWO EXPECTED UPPER LEVEL TROUGH TO
AFFECT UTAH WILL CROSS THE NRN HALF OF THE STATE TODAY...THEN EXIT
THE AREA EARLY THIS EVENING. A COUPLE OF DEFINABLE VORTICITY LOBES
CAN BE FOUND IN THE BASE OF THE TROUGH. THE FIRST MOVING ACROSS
NRN UTAH AT TIME PUSHED THE SURFACE FRONT THROUGH THE NORTH LAST
NIGHT. THIS FEATURE PRODUCED...AND IS STILL PRODUCING LIGHT SNOW
ACROSS THE FAR NRN ZONES THIS MORNING. THE SURFACE FRONT WILL
SETTLE INTO SRN UTAH THIS AFTERNOON AND REMAIN FAIRLY BENIGN AS
THE ASSOCIATED VORTICITY LOBE LIFTS E-NE INTO WY THIS AFTERNOON. A
SECOND VORTICITY LOBE MAY GENERATE ADDITIONAL LIGHT SNOW OVER THE
NRN/CNTRL ZONES AS THIS FEATURE DRAGS A LITTLE COOLER MID-LEVEL AIR
FURTHER SOUTH INTO THE STATE THIS AFTERNOON.
A SHORTWAVE RIDGE WILL DEVELOP TONIGHT AHEAD OF THE SECOND UPPER
TROUGH SCHEDULED TO ARRIVE FOR LATE SUNDAY THROUGH EARLY MONDAY.
THE VARIOUS MODEL GUIDANCE REMAIN CONSISTENT WITH THEIR RESPECTIVE
MODEL RUNS...WITH THE 00Z ECMWF STILL OFFERING THE BEST THREAT FOR
SUBSTANTIAL PRECIP SUNDAY NIGHT/MONDAY. FOR NOW WILL CONTINUE
ALONG WITH THE SOLUTION PUT FORTH BY THE BETTER PERFORMING ECMWF
AND KEEP THE HIGHER THREAT OF PRECIP GOING IN THE FORECAST.
MOUNTAIN SNOWS MAY BE SUFFICIENT FOR HIGHLIGHTS...THOUGH THESE
WOULD LIKELY BE ISSUED WITH TONIGHT FORECAST PACKAGE.
SOLID RIDGING BEGINNING EARLY IN THE COMING WEEK WILL MAINTAIN DRY
AND STABLE CONDITIONS STATEWIDE THROUGH AT LEAST EARLY FRIDAY.
THE HIGHER ELEVATIONS WILL SEE A WARMING TREND DURING THE WEEK...
WITH THE VALLEYS CLIMBING MORE SLOWLY BASED ON SNOW COVER AND
ELEVATION.
MAY ISSUED AN UPDATE FOR CLOUDS/PRECIP...THOUGH NO MAJOR CHANGES
ANTICIPATED AT THIS TIME.
&&
.AVIATION...WINDS AT THE SLC TERMINAL WILL REMAIN FROM THE NORTH
THROUGH THE DAY. CEILINGS ARE EXPECTED TO REMAIN AROUND 7000FT
THROUGH THE DAY...BUT MAY BRIEFLY DROP TO AROUND 6000FT. VFR
CONDITIONS WILL PREVAIL THROUGH THE TAF FORECAST PERIOD.
&&
.SLC WATCHES/WARNINGS/ADVISORIES...
UT...NONE.
WY...NONE.
&&
$$
PUBLIC...CONGER
AVIATION...HOSENFELD
FOR MORE INFORMATION FROM NOAA/S NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY (ALL LOWER CASE)
000
FXUS65 KSLC 210945
AFDSLC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
245 AM MST SAT NOV 21 2009
.SYNOPSIS...A COLD FRONT WILL MOVE THROUGH THE REGION TODAY. A SECOND
STRONGER COLD FRONT WILL FOLLOW LATE IN THE WEEKEND. HIGH PRESSURE
ALOFT WILL SETTLE OVER UTAH EARLY NEXT WEEK....AND REMAIN THE
DOMINANT FEATURE INTO THE LATE WORK WEEK.
&&
.DISCUSSION...WATER VAPOR LOOP SHOWS A TROUGH APPROACHING THE
NORTHERN ROCKIES AND CROSSING NORTHERN NEVADA. THE NEXT SYSTEM
UPSTREAM IS CROSSING THE GULF OF ALASKA RATHER QUICKLY IN FLAT FLOW.
400-250MB ACARS WIND OBSERVATIONS CONFIRMS THE POSITION OF THE UPPER
LEVEL TROUGH...AND SHOWS A 70-105KT CYCLONIC JET CARVING THE
AFOREMENTIONED TROUGH. MUCH OF THE JET HAS ALREADY EXITED THE BASE
OF THE TROUGH AND IS OVER THE NORTHERN ROCKIES. 00Z 700MB ANALYSIS
SHOWS RIDGING HAS SLID TO THE SOUTHEAST ACROSS NEW MEXICO...WITH
THE COLD FRONT CROSSING NEVADA. ADVECTION IS NEUTRAL LOCALLY...WITH
+3C BEING REPORTED AT BOTH KSLC AND UPSTREAM AT KDRA.
00Z KSLC RAOB INDICATES 7C OF WARMING BELOW 750MB...3C OF WARMING IN
THE MID LEVELS...WITH LITTLE THERMAL CHANGE ALOFT DURING THE PAST
24 HOURS. A STRONG VEERING WIND PROFILE WAS PRESENT.
GOES/RUC PRECIPITABLE WATER INDICATE VALUES HAVE DROPPED TO BETWEEN
A TENTH AND A QUARTER INCH ACROSS THE STATE.
WAS ABLE TO CANCEL THE WIND ADVISORY FOR NORTHWEST UTAH AS WINDS
HAVE DIMINISHED WITH THE PASSAGE OF THE COLD FRONT.
NOT IMPRESSED WITH THE APPROACHING SYSTEM FOR TWO REASONS.
FIRST...PREFRONTAL MOISTURE IS QUITE LIMITED...AND SECOND...ALL THE
DYNAMICAL SUPPORT IS LIFTING NORTHEAST ACROSS THE NORTHERN ROCKIES.
CURRENT IR SATELLITE IMAGERY SUPPORTS THIS THOUGHT...WITH COOLING
CLOUD TOPS ACROSS NORTHERN IDAHO AND WESTERN MONTANA...AND MUCH
WARMER CLOUD TOPS TRAVERSING NORTHERN NEVADA AND NORTHWEST UTAH.
THIS PRECIPITATION SHIELD IS TRAILING THE 700MB REFLECTION OF THE
COLD FRONT (ALREADY ACROSS NORTH CENTRAL UTAH PER THE RUC)
SIGNIFICANTLY DUE TO THE STRUGGLE FOR SATURATION.
STILL...CHANCES FOR MEASURABLE PRECIPITATION ARE QUITE GOOD THIS
MORNING ACROSS THE NORTHERN MOUNTAINS...TAPERING OFF FURTHER SOUTH.
CHANCES ACROSS THE NORTHERN VALLEYS WILL REMAIN LIMITED...AS
REFLECTED BY THE CHANCE POPS IN PLACE. GENERALLY THINKING 1-3" OF
SNOW ACROSS THE NORTHERN MOUNTAINS TODAY. BIGGEST IMPACT IN THE
NORTHERN VALLEYS WILL BE THE NOTICEABLE TEMPERATURE DROP TODAY
COMPARED TO YESTERDAY.
A SECOND SYSTEM LOOKS TO HAVE MORE OF AN IMPACT ACROSS THE REGION
LATER SUNDAY AND SUNDAY NIGHT. MODEL SUITE CONSISTING OF
NAM/GFS/CANADIAN/EUROPEAN ARE SHOWING THE NEXT SYSTEM ARRIVING
ABOUT 6 TO 12 HOURS SLOWER. HAVE REMOVED POPS SUNDAY MORNING...WITH
A COLD FRONT ARRIVING SOMETIME LATE SUNDAY AFTERNOON OR SUNDAY
EVENING. ITS IMPORTANT TO POINT OUT THAT GUIDANCE STILL HAS NOT
LOCKED INTO A PREFERRED SOLUTION FOR TIMING OR TRACK OF THE SYSTEM.
THIS CONTINUES TO BE A LOWER THAN TYPICAL CONFIDENCE FORECAST IN THE
48-60 HOUR TIME FRAME.
THE GFS WHICH BACKED AWAY FROM A POTENTIAL SYSTEM SUNDAY/SUNDAY
NIGHT A FEW DAYS AGO...CONTINUES TO TREND BACK TO THE COLDER
EUROPEAN/CANADIAN SOLUTION. BY 12Z MONDAY...THE
GFS/CANADIAN/EUROPEAN ARE ALL INDICATING -13C TEMPERATURES ACROSS
NORTHERN UTAH AT 700MB. AT 500MB...THERE CONTINUES TO BE SOME
DISAGREEMENT REGARDING HOW QUICKLY THE COLD AIR ALOFT MOVES THROUGH
AND HOW FAR SOUTH. THIS IS REFLECTED IN THE QPF FROM THESE
MODELS...WITH THE MORE UNSTABLE EUROPEAN YIELDING GREATER TOTALS
THAN THE GFS. SHOULD THE WETTER SOLUTIONS VERIFY...ADVISORY LEVEL
SNOWFALL MAY OCCUR IN THE MOUNTAINS OF NORTHERN UTAH...WITH MINOR
ACCUMULATIONS TO THE FLOOR OF THE NORTHERN VALLEYS.
GIVEN THE TIME FRAME OF THIS SECOND SYSTEM AND HOW THE MODELS ARE
STARTING TO AGREE ONCE AGAIN ON THE AMOUNT OF COOLING AT
700MB...HAVE DECIDED TO ADDRESS THE LAKE EFFECT SCENARIO SUNDAY
NIGHT MORE CLOSELY. THE AVHRR SENSOR SHOWS THE GREAT SALT LAKE WATER
TEMPERATURES HAVE COOLED TO +8C. WITH THE -13C 700MB TEMPERATURES BY
MONDAY MORNING...THE 00Z NAM SUGGESTS ABOUT 500 J/KG OF LAKE INDUCED
CAPE WITH EQUILIBRIUM LEVELS AT ABOUT 12KFT. THESE VALUES ARE NOT AS
FAVORABLE AS THE LAST SIGNIFICANT LAKE EFFECT SETUP...THOUGH ARE
HIGH ENOUGH TO START INCREASING POPS/QPF/SNOWFALL ACROSS THE WEST
END OF THE SALT LAKE VALLEY. THIS WILL BE SEEN IN THE POINT AND
CLICK FORECAST ONLINE...NOT MAKING INTO THE BROADER TEXT FORECASTS
AT THIS TIME.
THE EFFECT OF THIS SYSTEM WILL WANE ACROSS THE REGION LATE SUNDAY
NIGHT INTO MONDAY MORNING AS THE MID LEVEL SYSTEM DEEPENS ACROSS THE
PLAINS.
RIDGING AT 700MB IS EXPECTED TO BUILD INTO THE REGION FROM THE
SOUTHWEST CONUS THROUGH THE MID WEEK...WITH THE NEXT SYSTEM
APPROACHING FROM THE PACIFIC NORTHWEST LATE DURING THE WORK WEEK.
EXPECT TO SEE PLENTY OF SUNSHINE AS TEMPERATURES WARM TO...THEN
ABOVE CLIMATOLOGY NEXT WEEK.
&&
.AVIATION...PASSAGE OF A COLD FRONT OCCURRED AT 09Z HAS SWITCHED
WINDS TO THE NORTHWEST AT THE KSLC TERMINAL...AND THEY ARE
EXPECTED TO REMAIN OUT OF THE NORTHWEST FOR THE REMAINDER OF THE
DAY. ALTHOUGH ELEVATED WIND SPEEDS ARE OCCURRING NOW...WIND GUSTS
ARE EXPECTED TO DROP BELOW AIRPORT WEATHER CRITERIA OF 26 KNOTS
BETWEEN 10-11Z. CIGS ARE EXPECTED TO LOWER BELOW 6000FT AGL
BETWEEN 12Z-15Z...WITH A 30 PERCENT CHANCE OF CIGS REMAINING NEAR
6000FT THIS AFTERNOON. VFR IS EXPECTED TO PREVAIL...BUT A 20
PERCENT CHANCE EXISTS THAT BRIEF MVFR PERIODS WILL OCCUR DUE TO
LOW CIGS AND LIGHT SNOW SHOWERS THIS MORNING.
&&
.SLC WATCHES/WARNINGS/ADVISORIES...
UT...NONE.
WY...NONE.
&&
$$
PUBLIC...ROGOWSKI
AVIATION...MERRILL
FOR MORE INFORMATION FROM NOAA/S NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY (ALL LOWER CASE)
000
FXUS65 KSLC 210442
AFDSLC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
942 PM MST FRI NOV 20 2009
.SYNOPSIS...A COLD FRONT WILL REACH NORTHERN UTAH LATE TONIGHT...
THEN MOVE ACROSS THE MOVE EAST ACROSS THE AREA SATURDAY. A SECOND
STRONGER COLD FRONT WILL FOLLOW LATE IN THE WEEKEND. HIGH PRESSURE
ALOFT WILL SETTLE OVER UTAH EARLY NEXT WEEK....AND REMAIN THE
DOMINANT FEATURE THROUGH THE END OF THE WEEK.
&&
.DISCUSSION...GUSTY WINDS PERSIST ACROSS PARTS OF NORTHERN AND
WESTERN UTAH THIS EVENING...WITH WINDS EVEN STRENGTHENING IN SOME
LOCATIONS AFTER THE SUN WENT DOWN. AS SUCH...HAVE EXTENDED THE
WIND ADVISORY THROUGH 11Z IN THE GREAT SALT LAKE DESERT AND THE
SALT LAKE AND TOOELE VALLEYS. WITH WINDS DECREASING IN SOUTHWEST
AND WEST CENTRAL UTAH...HAVE ALLOWED THE WIND ADVISORIES TO EXPIRE
THERE.
APPROACHING COLD FRONT IS EVIDENT ON SATELLITE IMAGERY AND MSAS
PRESSURE ANALYSIS...WITH GOOD PRESSURE RISES OVER NORTH-CENTRAL
NEVADA WITH THE FRONT. THE FRONT IS WELL ON PACE TO ENTER UTAH
SHORTLY AFTER 06Z...AND SWEEP THROUGH THE NORTHERN HALF OF UTAH
AND SOUTHWEST WYOMING BY 18Z SATURDAY. THIS CONTINUES TO LOOK LIKE
A QUICK HITTING AND LOW QPF STORM. THE GFS IS STILL THE LEAST
ENTHUSIASTIC MODEL FOR THIS SYSTEM...WITH NO MORE THAN 0.10 INCHES
OF PRECIP FALLING ON ANY LOCATION IN THE CWA. OTHER MODELS
INCLUDING THE CANADIAN AND THE NAM ARE SLIGHTLY HEAVIER WITH THE
PRECIP...BUT ALL MODELS AGREE THAT THE GEOGRAPHIC EXTENT OF THIS
SNOWFALL WILL BE SMALL...WITH A MAJOR FOCUS ON FAR NORTHERN UTAH.
GLOBAL MODELS STILL IN RELATIVELY POOR AGREEMENT ABOUT THE SECOND
SYSTEM MOVING THROUGH THE AREA ON SUNDAY. NOT MUCH HAS CHANGED IN
THE LAST 72 HOURS...WITH THE GFS KEEPING THE SYSTEM MOSTLY TO THE
NORTH OF THE CWA...AND THE CANADIAN...NAM...AND ECMWF BEING THE
MOST ENTHUSIASTIC MODELS AS FAR AS QPF AND AREAL EXTENT OF PRECIP
WITH THE STORM GOES. FORECAST IS STILL LEANED TOWARD THE WETTER
SOLUTION OF THE LATTER THREE MODELS...THOUGH THE CONTINUED
INSISTENCE BY THE GFS ONLY 48 HOURS OUT IS IMPRESSIVE AND BEARS
FURTHER WATCHING.
OTHER THAN THE PREVIOUSLY MENTIONED UPDATES TO THE WIND
ADVISORIES...NO FURTHER UPDATES ARE PLANNED THIS EVENING.
&&
.AVIATION...VFR CONDITIONS WILL CONTINUE AT THE KSLC TERMINAL
THROUGH THE NIGHT. GUSTY SOUTH WINDS IN EXCESS OF 25 KNOTS WILL
CONTINUE THROUGH MUCH OF THE NIGHT AS WELL. WINDS WILL REMAIN GUSTY
AND TURN WEST NORTHWEST AROUND 13Z TO 14Z WITH THE PASSAGE OF THE
COLD FRONT.
&&
.SLC WATCHES/WARNINGS/ADVISORIES...
UT...WIND ADVISORY UNTIL 4 AM SATURDAY FOR UTZ003-UTZ005.
WY...NONE.
&&
$$
PUBLIC...SCHOENING
AVIATION...YOUNG
FOR MORE INFORMATION FROM NOAA/S NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY (ALL LOWER CASE)
000
FXUS65 KSLC 202310
AFDSLC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
410 PM MST FRI NOV 20 2009
.SYNOPSIS...A COLD FRONT WILL REACH NORTHERN UTAH LATE TONIGHT...
THEN MOVE ACROSS THE MOVE EAST ACROSS THE AREA SATURDAY. A SECOND
STRONGER COLD FRONT WILL FOLLOW LATE IN THE WEEKEND. HIGH PRESSURE
ALOFT WILL SETTLE OVER UTAH EARLY NEXT WEEK....AND REMAIN THE
DOMINATE FEATURE THROUGH THE END OF THE WEEK.
&&
.DISCUSSION...ACTIVE WEEKEND IN STORE FOR MUCH OF NRN/CNTRL UTAH.
THE FIRST OF TWO COLD PACIFIC TROUGHS WILL REACH UTAH EARLY
SATURDAY. THE COLD FRONT ASSOCIATED WITH THIS FEATURE APPEARS AS
IF IT WILL MAINTAIN GOOD STRUCTURE AS IT ENTERS NW UTAH LATE
TONIGHT. WILL EXTEND THE WIND ADVISORY INTO MID-EVENING AS STRONG
LATE AFTERNOON SOUTH WINDS WILL TAPER OFF MORE SLOWLY WITH THE
FRONT APPROACHING. STRONG LOW-LEVEL COLD ADVECTION SPREAD ACROSS
NRN UTAH EARLY SATURDAY...THEN INTO CNTRL UTAH LATER IN THE DAY.
ORGANIZED PRECIP ALONG THIS BOUNDARY COULD THIN OUT A BIT AS THE
FRONT MOVES SE. THE UPPER TROUGH IS EXPECTED TO LIFT E-NE AS IT
CROSSES THE GREAT BASIN...TAKING THE BEST DYNAMIC LIFT AND MID-LEVEL
COLD AIR ALONG THE UT/ID BORDER. WILL KEEP THE BEST THREAT OF
PRECIP OVER THE FAR NORTH EARLY SATURDAY...WITH SPOTTY PRECIP
ALONG THE SURFACE BOUNDARY OVER CNTRL UTAH LATER IN THE DAY.
WILL FOLLOW THE MORE AGGRESSIVE ECMWF SOLUTION OVER THE FURTHER
NORTH AND LESS ENERGETIC GFS FOR THE LATE WEEKEND TROUGH. SOLID
BAROCLINIC STRUCTURE ADVERTISED WITH THIS SECOND TROUGH SHOULD
BRING SUBSTANTIAL SNOW TO THE NRN ZONES...WITH SEVERAL INCHES OF
SNOW FOR THE NRN MOUNTAINS.
SOLID HIGH PRESSURE ALOFT WILL SETTLE OVER THE INTERIOR EARLY NEXT
WEEK...AND REMAIN THROUGH AT LEAST FRIDAY AFTERNOON. DRY
CONDITIONS WITH A SOLID WARMING TREND AT THE HIGHER ELEVATIONS IS
EXPECTED. SNOW COVERED NRN VALLEYS WILL SEE GENERALLY FLAT TRENDS
IN TEMPS AS THE VALLEY INVERSIONS STRENGTHEN...WHILE THE SRN
VALLEYS WILL SEE A GRADUAL WARMING TREND. A SPLITTING TROUGH LATE
IN THE WEEK COULD BRING LIGHT PRECIP TO THE AREA LATE
FRIDAY/SATURDAY.
&&
.AVIATION...VFR CONDITIONS WILL CONTINUE AT THE KSLC TERMINAL
THROUGH THE EVENING. GUSTY SOUTH WINDS IN EXCESS OF 25 KNOTS WILL
CONTINUE THROUGH THE EVENING AS WELL. THE SOUTH WINDS ARE EXPECTED
TO DECREASE AFTER 02Z...THOUGH WINDS WILL AGAIN INCREASE AROUND
12Z IMMEDIATELY AHEAD OF THE COLD FRONT...WHICH IS EXPECTED TO
CROSS THE TERMINAL AROUND 14Z.
&&
.SLC WATCHES/WARNINGS/ADVISORIES...
UT...WIND ADVISORY UNTIL 9 PM FRIDAY FOR UTZ003-UTZ005-UTZ015-UTZ016.
WY...NONE.
&&
$$
PUBLIC...CONGER
AVIATION...YOUNG
FOR MORE INFORMATION FROM NOAA/S NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY (ALL LOWER CASE)
000
FXUS65 KSLC 201632
AFDSLC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
932 AM MST FRI NOV 20 2009
.SYNOPSIS...THE FIRST OF TWO COLD FRONTS WILL MOVE ACROSS UTAH
LATE TONIGHT THROUGH SATURDAY. THE SECOND COLD FRONT WILL FOLLOW
LATE IN THE WEEKEND. HIGH PRESSURE ALOFT WILL SETTLE OVER THE
INTERIOR WEST EARLY NEXT WEEK.
&&
.DISCUSSION...THE FIRST OF TWO PACIFIC TROUGHS TO AFFECT UTAH THIS
WEEKEND HAS REACHED THE PACIFIC NW COAST EARLY THIS MORNING.THIS
TROUGH WILL PROGRESS STEADILY EASTWARD TODAY...THEN LIFT E-NE AS IT
MOVES THROUGH THE NRN GREAT BASIN/NRN ROCKIES LATE TONIGHT/SATURDAY.
THE SECOND TROUGH SCHEDULED TO ARRIVE LATE THIS WEEKEND APPEARS TO
STRENGTHEN AS IT MOVES INTO THE BASIN...LEADING TO WHAT SHOULD BE
AN INCREASED CHANCE OF PRECIP SUNDAY NIGHT/EARLY MONDAY.
THE WELL-DEFINED SURFACE FRONT ASSOCIATED WITH THE FIRST TROUGH
SHOULD HOLD TOGETHER AS IT MOVES INTO UTAH LATE TONIGHT. AHEAD OF
THE TROUGH INCREASING SW FLOW ALOFT NEAR 700MB WITH SUBSTANTIAL
PRESSURE FALLS OVER NV SHOULD RESULT IN STRONG WINDS ACROSS THE
WRN VALLEYS THIS AFTERNOON. MUCH COLDER TEMPS ALSO A GIVEN AS THE
LOW-LEVEL COLD AIR SURGES INTO CNTRL UTAH SATURDAY. SIGNIFICANT
PRECIP MAY BE HARD TO GENERATE WITH THE TROUGH LIFTING OFF TO
THE E-NE. THE STRONGEST DYNAMIC LIFT AND DEEP LAYER COLD ADVECTION
REMAINS NEAR THE UT/ID BORDER...WITH LITTLE IN THE WAY OF DEEP
LIFT FURTHER SOUTH.
THE SECOND TROUGH ARRIVING LATE IN THE WEEKEND WILL OFFER A BETTER
THREAT FOR PRECIP AS IT DIGS E-SE THROUGH THE NRN/CNTRL UTAH. THE
THREAT OF PRECIP NOT AS UNCERTAIN AS IS THE INTENSITY OF SAID
PRECIP. THE LATEST GUIDANCE IS SPLIT AS TO HOW DEEP THE COLD
ADVECTION WILL BE...WHICH WOULD HAVE AN EFFECT ON LIFT. THE ECMWF
HAS BEEN THE BETTER MODEL OF LATE...AND IS FAR MORE SUPPORTIVE OF
PRECIP SUNDAY NIGHT/EARLY MONDAY. THE PRECIP EVENT WILL BE
RELATIVELY SHORT AS WARMING ALOFT DEVELOPS RAPIDLY BEGINNING LATE
SUNDAY NIGHT/EARLY MONDAY.
HIGH PRESSURE ALOFT WILL SETTLE OVER THE INTERIOR WEST FOR THE
FIRST HALF OF THE COMING HOLIDAY WEEK. THE NEXT REAL THREAT OF
PRECIP LIKELY TO HOLD OFF UNTIL FRIDAY/SATURDAY IN THE EXTENDED PERIOD.
CLOUD COVER APPEARS TO BE A BIT UNDERDONE IN THE CURRENT FORECAST. WILL
ADDRESS THIS IN AN UPDATE. REMAINDER OF FORECAST LOOKS FINE FOR NOW.
&&
.AVIATION...VFR CONDITIONS WILL CONTINUE AT THE KSLC TERMINAL
THROUGH THE DAY. SOUTH WINDS WILL INCREASE LATE THIS MORNING AND AN
AWW FOR SOUTH WINDS IN EXCESS OF 25 KNOTS IS LIKELY THIS AFTERNOON.
THE SOUTH WINDS ARE EXPECTED TO DECREASE IN INTENSITY AROUND SUNSET.
&&
.SLC WATCHES/WARNINGS/ADVISORIES...
UT...WIND ADVISORY FROM NOON FRIDAY TO 6 PM FRIDAY FOR UTZ005-UTZ015-
UTZ016.
WY...NONE.
&&
$$
PUBLIC...CONGER
AVIATION...HOSENFELD
FOR MORE INFORMATION FROM NOAA/S NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY (ALL LOWER CASE)
000
FXUS65 KSLC 201049
AFDSLC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
349 AM MST FRI NOV 20 2009
.SYNOPSIS...SOUTHWEST FLOW WILL INCREASE OVER THE AREA TODAY AHEAD
OF A WEAKENING PACIFIC STORM. A COLD FRONT WILL MOVE THROUGH THE
AREA SATURDAY. ANOTHER PACIFIC FRONT WILL MOVE THROUGH THE AREA
SUNDAY AND SUNDAY NIGHT.
&&
.DISCUSSION...WATER VAPOR LOOP SHOWS RIDGING EXTENDING FROM THE
SOUTHWEST CONUS NORTHEAST INTO THE UPPER MIDWEST. THE NEXT SYSTEM
WAS SPLITTING FROM THE GULF OF ALASKA...WITH A DISTURBANCE
APPROACHING 40N/130W. 400-250MB ACARS WIND OBSERVATIONS SHOWS LIGHT
ANTICYCLONIC FLOW OVERHEAD...WITH A 100-125KT ANTICYCLONIC JET
ACROSS THE PACIFIC NORTHWEST AND SOUTHWEST CANADA. 00Z 700MB
ANALYSIS SHOWS RIDGING BUILDING FROM THE SOUTHWEST CONUS...AS A DEEP
CYCLONE NEARS THE BRITISH COLUMBIA COAST. WARM ADVECTION WAS SETTING
UP LOCALLY...WITH -2C AT KSLC AND -1C UPSTREAM AT KLKN. 00Z KSLC
RAOB INDICATES 1-3C OF COOLING BELOW 750MB...WITH 1-3C OF WARMING
ALOFT DURING THE PAST 24 HOURS.
GOES/RUC PRECIPITABLE WATER INDICATE VALUES REMAIN BETWEEN A
QUARTER AND A THIRD OF AN INCH ACROSS THE STATE.
700MB WINDS ARE FORECAST TO INCREASE TO BETWEEN 40 AND 50KTS OVER
WESTERN UTAH THIS AFTERNOON. AT THE SURFACE...PRESSURE GRADIENT
TIGHTENS WITH A PRESSURE FALL BULLSEYE ACROSS NORTHWEST UTAH THIS
AFTERNOON. THIS SHOULD PROVIDE A FAVORABLE ENVIRONMENT FOR THE
DEVELOPMENT OF STRONG GUSTY SOUTHERLY WINDS AT THE SURFACE ACROSS
THE WESTERN VALLEYS. HAVE ISSUED A WIND ADVISORY FOR THE AFTERNOON
HOURS. GIVEN THE ANTICIPATED MECHANICAL MIXING...700MB TEMPERATURES
RISING TO +1 OR +2C MAY SUPPORT TEMPERATURES CLIMBING ABOVE 60F
ALONG THE WASATCH FRONT. WHILE STILL WELL UNDER WHAT WOULD BE
EXPECTED IN A WELL MIXED ENVIRONMENT...AM TAKING THE COOL START AND
SHORTER DAYLIGHT INTO ACCOUNT. NOTEWORTHY THAT THE MAV AND MET
GUIDANCE AT SLC ONLY SUGGESTS HIGHS IN THE UPPER 40S OR MID 50S.
00Z GFS/EUROPEAN/CANADIAN ARE ALL IN GOOD AGREEMENT INDICATING THE
NEXT COLD FRONT ENTERING NORTHWEST UTAH TONIGHT AND MOVING THROUGH
MUCH OF NORTHERN UTAH BY SATURDAY MORNING. CURRENT FRONTAL TIMING
WOULD SUPPORT LIGHT PRECIPITATION DEVELOPING LATE TONIGHT ACROSS
NORTHERN UTAH...WITH INDICATIONS BEING THAT THE MOUNTAINS OF
NORTHERN UTAH STAND THE BEST CHANCE OF SEEING MEASURABLE
PRECIPITATION. NOT AS ENTHUSIASTIC ABOUT VALLEYS RECEIVING
MEASURABLE PRECIPITATION AS GUIDANCE CONTINUES TO SUGGEST THE MID
LEVEL COLD CORE WILL PASS TO THE NORTH ACROSS THE NORTHERN
ROCKIES...LIMITING INSTABILITY. HOWEVER...A VERY NOTICEABLE
TEMPERATURE DROP WILL OCCUR BETWEEN TODAY AND TOMORROW.
A TRAILING SYSTEM IS ANTICIPATED SUNDAY. THE 00Z GFS HAS CONTINUED
ITS TREND WITH LIMITING THE INFLUENCE OF THIS SYSTEM ACROSS
UTAH...MAKING IT MORE A NORTHERN ROCKIES STORM WITH THE COLDER AIR
REMAINING TO THE NORTH.
THE EUROPEAN AND CANADIAN CONTINUE TO SHOW THE MID LEVEL REFLECTION
OF THE STORM MOVING ACROSS NORTHERN UTAH...BRINGING THE COLDER AIR
FURTHER SOUTH. THIS SET OF GUIDANCE IS EVEN COLDER AT 700MB BY
MONDAY MORNING THAN YESTERDAYS RUNS (-13 TO -15C VS. -12C
YESTERDAY). EVEN THE 00Z GFS IS TRENDING COLDER BY 12Z MONDAY (-9C
VS. -5C YESTERDAY). WITH THE GFS ENSEMBLE MEAN DEEPER THAN THE
OPERATIONAL RUN...AM INCLINED TO CONTINUE TO FAVOR THE COLDER
SOLUTION OFFERED BY THE CANADIAN AND EUROPEAN. SHOULD THIS SOLUTION
MATERIALIZE...ADVISORY SNOWFALL TOTALS MAY OCCUR IN THE NORTHERN
MOUNTAINS...WITH ACCUMULATIONS TO THE VALLEY FLOOR ACROSS NORTHERN
UTAH. ALSO IF THE COLDER SOLUTION COMES TO FRUITION...WILL HAVE TO
CONSIDER LAKE EFFECT SNOW SOUTHEAST OF THE GREAT SALT LAKE SUNDAY
NIGHT.
RIDGING AT 700MB IS EXPECTED TO BUILD INTO THE REGION FROM THE
SOUTHWEST CONUS THROUGH THE MID WEEK...WITH THE NEXT SYSTEM
APPROACHING FROM THE PACIFIC NORTHWEST LATE DURING THE WORK WEEK.
EXPECT TO SEE PLENTY OF SUNSHINE AS TEMPERATURES WARM TO...THEN
ABOVE CLIMATOLOGY NEXT WEEK.
&&
.AVIATION...VFR CONDITIONS WILL CONTINUE AT THE KSLC TERMINAL
THROUGH THE DAY. SOUTH WINDS WILL INCREASE LATE THIS MORNING AND AN
AWW FOR SOUTH WINDS IN EXCESS OF 25 KNOTS IS LIKELY THIS AFTERNOON.
THE SOUTH WINDS ARE EXPECTED TO DECREASE IN INTENSITY AROUND SUNSET.
&&
.SLC WATCHES/WARNINGS/ADVISORIES...
UT...WIND ADVISORY FROM NOON FRIDAY TO 6 PM FRIDAY FOR UTZ005-UTZ015-
UTZ016.
WY...NONE.
&&
$$
PUBLIC...ROGOWSKI
AVIATION...GRAHAM
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000
FXUS65 KSLC 200504
AFDSLC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
1004 PM MST THU NOV 19 2009
.SYNOPSIS...SOUTHWEST FLOW WILL INCREASE OVER THE AREA FRIDAY
AHEAD OF A WEAKENING PACIFIC STORM. A COLD FRONT WILL MOVE
THROUGH THE AREA SATURDAY. ANOTHER PACIFIC FRONT WILL MOVE THROUGH
THE AREA SUNDAY AND SUNDAY NIGHT.
&&
.DISCUSSION...HIGH PRESSURE AND MOSTLY CLEAR SKIES CONTINUE ACROSS
THE FORECAST AREA THIS EVENING...WITH ONLY A FEW HIGH LEVEL CLOUDS
MOVING ACROSS NORTHERN UTAH AND SOUTHWEST WYOMING. WARM ADVECTION
AND INCREASED SOUTHWESTERLY FLOW ALOFT WILL START TO RAMP UP
DURING THE OVERNIGHT HOURS...BUT IS NOT LIKELY TO BE REALIZED IN
MOST VALLEY LOCATIONS TONIGHT. THIS SOUTHWEST FLOW WILL INCREASE
DRAMATICALLY BETWEEN 12Z FRIDAY AND 00Z SUNDAY...WITH 700 MB WINDS
OVER WESTERN UTAH RANGING FROM 40 TO 50 KNOTS TOMORROW AFTERNOON.
WITH SUBSTANTIALLY BETTER MIXING EXPECTED TOMORROW...CONDITIONS
SHOULD BE GUSTY ACROSS MUCH OF THE WESTERN HALF OF UTAH BY THE
AFTERNOON HOURS.
THE SHORTWAVE TROUGH AND ASSOCIATED COLD FRONT IS STILL FORECAST
TO MOVE THROUGH THE NORTHERN HALF OF THE CWA ON SATURDAY...WITH
MODELS CONTINUING TO PRODUCE A QUICK SHOT OF PRECIP WITH VERY LOW
QPF VALUES. BEYOND SATURDAY...THE GFS FORECAST IS STILL
SIGNIFICANTLY DIFFERENT THAN THE SOLUTIONS PRODUCED BY THE ECMWF
OR CANADIAN MODEL. THE GFS KEEPS THE NEXT SHORTWAVE TO OUR
NORTH...WITH ONLY SOUTHWEST WYOMING AND SPOTS ALONG THE UTAH-IDAHO
BORDER RECEIVING ANY PRECIPITATION ON SUNDAY. THE EC AND CANADIAN
MEANWHILE CONTINUE TO BRING MORE SHORTWAVE ENERGY AND
PRECIPITATION TO A LARGER AREA ON SUNDAY AFTERNOON INTO EARLY
MONDAY MORNING. AT THE MOMENT THE EC SOLUTION IS PREFERRED...AND IS
THE ONE EXPRESSED IN THE CURRENT FORECAST...BUT THE STUBBORNNESS OF
ALL THREE MODELS BEARS CONTINUED EVALUATION ON FUTURE SHIFTS.
THE FORECAST FOR TONIGHT LOOKS TO BE ON TRACK AND NO UPDATES ARE
PLANNED FOR THIS EVENING.
&&
.AVIATION...WINDS AT THE SLC TERMINAL ARE EXPECTED TO REMAIN FROM
THE SOUTH THROUGH THE DAY...STRENGTHENING AND BECOMING GUSTY AROUND
21Z. VFR CONDITIONS WILL PREVAIL.
&&
.SLC WATCHES/WARNINGS/ADVISORIES...
UT...NONE.
WY...NONE.
&&
$$
PUBLIC...SCHOENING
AVIATION...HOSENFELD
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000
FXUS65 KSLC 192229
AFDSLC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
329 PM MST THU NOV 19 2009
.SYNOPSIS...SOUTHWEST FLOW WILL INCREASE OVER THE AREA FRIDAY
AHEAD OF A WEAKENING PACIFIC STORM. A COLD FRONT WILL MOVE
THROUGH THE AREA SATURDAY. ANOTHER PACIFIC FRONT WILL MOVE THROUGH
THE AREA SUNDAY AND SUNDAY NIGHT.
&&
.DISCUSSION...SOUTH WINDS SHOULD INCREASE FRIDAY AFTERNOON AHEAD
OF THE NEXT PACIFIC COLD FRONT DUE INTO THE AREA SATURDAY MORNING.
700 MB WINDS OF 40 TO 50 KNOTS AND A FAVORABLE BUT NOT STRONG
SURFACE PRESSURE GRADIENT SHOULD PRODUCE WIDESPREAD WINDS IN THE
WESTERN VALLEYS FROM CEDAR CITY TO THE IDAHO BORDER. EXPECT WINDS
TO BE ADVISORY LEVEL OR LESS MOST AREAS. HIGH PROFILE VEHICLE
TRAFFIC ON I-80 AND US HIGHWAY 6 MAY SEE SOME IMPACTS. WELL MIXED
AIRMASS SHOULD RESULT IN SIGNIFICANTLY WARMER TEMPERATURES MOST
WESTERN VALLEYS FRIDAY AND HAVE GONE WITH MUCH ABOVE AVERAGE MAX
TEMPS AND CONSIDERABLY ABOVE MOS GUIDANCE.
ALL MODELS VERY SIMILAR ON PACIFIC TROUGH/FRONT ON SATURDAY.
SYSTEM IS WEAKENING RAPIDLY AS IT MOVES INLAND FROM THE COAST AND
THE CENTER OF THE COLDEST AIR AT 500 MB IS PASSING THROUGH THE
NORTHERN ROCKIES. WITH LIMITED INSTABILITY DUE TO LACK OF UPPER
LEVEL COLD AIR...AND RAPID MOVEMENT OF THE TROUGH...EXPECT PRECIP
TO BE RELATIVELY LIGHT. PRECIP SHOULD START AS SNOW A FEW HOURS
BEHIND THE FRONT. LARGEST ACCUMULATIONS LIKELY TO BE IN THE
MOUNTAINS FROM I-80 NORTH TO THE IDAHO BORDER...BUT EVEN IN THESE
AREAS EXPECT LESS THAN ADVISORY LEVEL TOTALS. SNOW POTENTIAL IN
THE VALLEYS OF NORTHERN UTAH ALSO BEST CLOSER TO IDAHO AND AGAIN
EXPECT AN INCH OR TWO AT MOST AND WOULD NOT BE SURPRISED IF TRACE
AMOUNTS ARE MORE THE RULE.
MODELS HAVE LONG ADVERTISED A SECOND TROUGH ON SUNDAY. LAST FEW
RUNS OF THE GFS HAVE SIGNIFICANTLY WEAKENED THIS SECOND TROUGH AND
MOVED IT FURTHER NORTH. 12Z GFS WAS SO WEAK ON SUNDAY TROUGH THAT
THERE WAS NO 700 MB COLD ADVECTION AT ALL AND MODEL WAS BASICALLY
SHOWING THE SATURDAY FRONT RETREATING NORTH AS A WARM FRONT WITH
SOME LIGHT PRECIP OVER THE NORTHERN PART OF THE FORECAST AREA.
LATEST 18Z GFS HAS NOW GONE BACK TO THE IDEA OF A SECOND COLD FRONT
SUNDAY...BUT VERY WEAK. IN THE MEAN TIME THE 12Z CANADIAN GEM AND
THE 12Z EC HAVE MAINTAINED A MODERATE COLD FRONT/TROUGH MOVING
THROUGH THE AREA SUNDAY WITH 700 MB TEMPS BY MONDAY MORNING
ACTUALLY COLDER THAN THE SATURDAY TROUGH AND MUCH MUCH COLDER THAN
THE GFS. HAVE BASED THE FORECAST ON EC. WITH THIS IN
MIND...VALLEYS OF NORTHERN UTAH AND SOUTHWEST WYOMING AND
MOUNTAINS OF NORTHERN AND CENTRAL UTAH SHOULD SEE ANOTHER ROUND OF
SNOW SUNDAY AND SUNDAY NIGHT...AMOUNTS EXPECTED TO BE A BIT HIGHER
THAN SATURDAY TROUGH AND A SNOW ADVISORY FOR THE NORTHERN
MOUNTAINS MAY BE NEEDED IF CURRENT EC SOLUTION IS MAINTAINED OVER
THE NEXT FEW DAYS...BUT STILL JUST A SMALL SHORT LIVED EVENT.
DECREASING MOUNTAIN SHOWERS EARLY MONDAY AND THEN DRY WITH A
WARMING TREND THROUGH MID WEEK IN ALL MODELS.
&&
.AVIATION...VFR CONDITIONS WITH MOSTLY CLEAR SKIES WILL CONTINUE AT
THE SLC TERMINAL THROUGH THE MORNING AND AFTERNOON. LIGHT AND
VARIABLE OR LIGHT NORTHWEST WINDS ARE EXPECTED TO SHIFT TO THE
SOUTHEAST DRAINAGE BETWEEN 02Z AND 03Z.
&&
.SLC WATCHES/WARNINGS/ADVISORIES...
UT...NONE.
WY...NONE.
&&
$$
PUBLIC...DUNN
AVIATION...YOUNG
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