[ W WA | SW WA and W OR | SE WA and NE OR | NE WA and N ID ]

Western Washington


250 
FXUS66 KSEW 202208
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
300 PM PDT MON APR 20 2015

.SYNOPSIS...THE WARM SUNNY WEATHER TODAY WILL BE FOLLOWED BY COOL 
MARINE AIR PUSHING INTO WESTERN WASHINGTON TUESDAY. AN UPPER TROUGH 
AND COLD FRONT WILL REACH WESTERN WASHINGTON BY TUESDAY NIGHT. 
ANOTHER FRONT FRONT WILL ARRIVE LATER THURSDAY. A STRONGER WEATHER 
SYSTEM IS LIKELY TO REACH THE AREA OVER THE WEEKEND.

&&

.SHORT TERM...THE RIDGE IS WEAKENING AND WILL MOVE SLOWLY INLAND 
THROUGH TUESDAY. AN UPPER TROUGH AND COLD FRONT ARE CROSSING 130W 
THIS AFTERNOON. ONSHORE FLOW WILL INCREASE TONIGHT AND TUESDAY AND 
AS THE TROUGH AND REMNANTS OF THE COLD FRONT ARRIVE THE CHANCE OF 
SHOWERS WILL INCREASE TUESDAY AFTERNOON AND NIGHT. THERE IS A GOOD 
CHANCE OF A PUGET SOUND CONVERGENCE ZONE TUESDAY NIGHT INTO 
WEDNESDAY MORNING. ANOTHER FRONT SHOULD REACH WRN WA THU AFTERNOON.

.LONG TERM...THERE MAY BE A BRIEF PERIOD OF WEAK RIDGING TOWARD THE 
END OF THE WORK WEEK BEFORE A COUPLE OF STRONGER FRONTAL WAVES REACH 
THE AREA. A LARGE UPPER TROUGH WILL TAKE UP RESIDENCE IN THE NE 
PACIFIC AND SPIN OUT SEVERAL SYSTEMS BETWEEN SATURDAY AND THE MIDDLE 
OF NEXT WEEK. THE EXTENDED FORECAST IS JUST A BROADBRUSH FORECAST 
FOR RAIN LIKELY AS IT IS TOO EARLY TO TIME THE BREAKS BETWEEN 
FRONTS...FOR THE MOMENT SATURDAY NIGHT AND SUNDAY MORNING LOOK THE 
WETTEST.

&&

.AVIATION...THE UPPER LEVEL RIDGE OVER WESTERN WASHINGTON THIS 
AFTERNOON WILL WEAKEN AS IT MOVES EAST OF THE CASCADES TONIGHT. A 
WEAK COLD FRONT WILL MOVE THROUGH THE FORECAST AREA TUESDAY... 
FOLLOWED BY ITS UPPER TROUGH TUESDAY NIGHT. SOUTHWEST FLOW ALOFT 
WILL DEVELOP TONIGHT AND CONTINUE TUESDAY. THE AIR MASS WILL BECOME 
MOIST LATE TONIGHT AND TUESDAY AS LOW LEVEL ONSHORE FLOW INCREASES.

MARINE STRATUS ALONG THE COAST THIS AFTERNOON WILL DEEPEN AND PUSH 
INLAND AT LEAST WEAKLY TONIGHT. THE MAIN FORECAST PROBLEM IS HOW 
STRONG THE MARINE PUSH WILL BE...AND WHETHER THERE WILL BE MUCH 
MORNING STRATUS OVER THE WESTERN WASHINGTON INTERIOR LOWLANDS 
TUESDAY MORNING. AT THIS TIME THE PUSH LOOKS RATHER WEAK. STRATUS IS 
LIKELY TO REACH OLYMPIA LATE TONIGHT...BUT IT WILL PROBABLY RATHER 
THIN AND SHORT LIVED IN THE CENTRAL PUGET SOUND REGION TUESDAY 
MORNING.

KSEA...NORTH WIND TO 10 KT...BECOMING SOUTHERLY TO 8 KT LATE 
TONIGHT...AND SOUTHWEST 6-12 KT TUESDAY AFTERNOON. MARINE STRATUS 
WILL PROBABLY REACH KSEA AROUND 13Z WITH SEVERAL HOURS OF SCT-BKN005 
TUESDAY MORNING.   MCDONNAL

&&

.MARINE...ONSHORE FLOW WILL STRENGTHEN TONIGHT AS LOW PRESSURE OVER 
WESTERN WASHINGTON MOVES EAST OF THE CASCADES. SMALL CRAFT ADVISORY 
WINDS ARE LIKELY OVER THE COASTAL WATERS...WESTERN AND CENTRAL 
STRAIT OF JUAN DE FUCA...ADMIRALTY INLET...AND NORTHERN INLAND 
WATERS. THE STRONGEST WINDS SHOULD OCCUR IN THE CENTRAL AND EASTERN 
STRAIT. 

ONSHORE FLOW WILL INCREASE FURTHER TUESDAY AND TUESDAY NIGHT AS A 
WEAK COLD FRONT MOVES INLAND. GALE WESTERLIES ARE A VERY GOOD BET 
FOR THE CENTRAL AND EASTERN STRAIT...AND I HAVE UPGRADED THE GALE 
WATCH TO A WARNING WITH THE AFTERNOON FORECAST PACKAGE. MARGINAL 
GALES ARE POSSIBLE OVER THE NORTHWEST COASTAL WATERS TOO...BUT I 
WILL LEAVE THAT AS A GALE WATCH FOR NOW. SMALL CRAFT ADVISORY WINDS 
SHOULD OCCUR...OR CONTINUE...FOR ALL OTHER MARINE ZONES EXCEPT MAYBE 
PUGET SOUND AND HOOD CANAL.

ANOTHER WEAK COLD FRONT WILL CROSS THE FORECAST AREA THURSDAY AND 
THURSDAY NIGHT...WITH A STRONGER FRONTAL SYSTEM REACHING THE AREA 
SATURDAY.

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE. 
PZ...SMALL CRAFT ADVISORY COASTAL WATERS...CENTRAL AND EASTERN
       STRAIT OF JUAN DE FUCA...ADMIRALTY INLET...NORTHERN INLAND 
       WATERS.
    .GALE WARNING FOR TUESDAY NIGHT CENTRAL AND EASTERN STRAIT.
    .GALE WATCH FOR TUESDAY NIGHT COASTAL WATERS ZONES 150 170 173.

&&

$$

YOU CAN SEE AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION AT 
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML





[ W WA | SW WA and W OR | SE WA and NE OR | NE WA and N ID ]

Southwestern Washington and Western Oregon


456 
FXUS66 KPQR 202156
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND 
236 PM PDT MON APR 20 2015

.SYNOPSIS...INCREASING ONSHORE FLOW WILL LEAD TO NEAR AVERAGE
TEMPERATURES AND AN INCREASE IN MARINE CLOUDS TUESDAY THROUGH FRIDAY.
THERE WILL BE A SMALL CHANCE OF A SHOWER EACH DAY DURING THIS
PERIOD...PARTICULARLY ALONG THE COAST AND CASCADES...BUT MOST
LOCATIONS WILL GENERALLY REMAIN DRY. A WETTER PATTERN LOOKS TO
DEVELOP LATE SATURDAY AND SUNDAY...WITH PERHAPS ANOTHER ROUND OF WET
WEATHER EARLY NEXT WEEK.  

&&

.SHORT TERM...VISIBLE SATELLITE IMAGERY REVEALS MAINLY CLEAR SKIES
ACROSS THE AREA EXCEPT FOR SOME LOW CLOUDS SKIRTING THE COASTLINE
UNDER LOW LEVEL NORTHERLY FLOW. SURFACE LOW PRESSURE IS SHIFTING
INLAND THIS AFTERNOON...WHICH WILL RESULT IN LOW CLOUDS PUSHING INTO
THE COAST RANGE GAPS THIS EVENING...AND PERHAPS A BRIEF SURGE OF
WESTERLY WINDS. LOW CLOUDS SHOULD SPREAD INTO THE WILLAMETTE VALLEY
OVERNIGHT AND TUESDAY MORNING...BUT DUE TO THE SHALLOW NATURE OF THE
THIS MARINE PUSH...THE CURRENT CLOUD COVER FORECAST IN THE WILLAMETTE
VALLEY MAY BE A BIT TOO PESSIMISTIC...ESPECIALLY ACROSS THE SOUTHERN
AND WESTERN PORTIONS OF THE VALLEY.

TEMPERATURES ON TUESDAY SHOULD TOP OUT APPROXIMATELY 10F COOLER THAN 
TODAY DUE TO THE MUCH STRONGER MARINE INFLUENCE EXPECTED IN THE 
WILLAMETTE VALLEY. ONSHORE PRESSURE GRADIENTS LOOK TO INCREASE 
FURTHER TUESDAY AFTERNOON AND EVENING SO EXPECT BREEZY CONDITIONS TO 
DEVELOP...ESPECIALLY NEAR THE COAST RANGE GAPS AND CENTRAL COLUMBIA 
RIVER GORGE IN THE LATE AFTERNOON AND EVENING HOURS. 

SHALLOW INSTABILITY AND MOISTURE MAY PRODUCE A FEW VERY LIGHT SHOWERS
TUESDAY NIGHT INTO EARLY WEDNESDAY...PARTICULARLY ACROSS THE NORTH
AND IN THE UPSLOPE AREAS...BUT CONFIDENCE IS LOW. A WEAKENING FRONT
MAY BRING INCREASING LIGHT RAIN CHANCES TO OUR FAR NORTHWEST ZONES 
ON THURSDAY. ALL IN ALL...MOST LOCATIONS LOOK TO REMAIN GENERALLY 
DRY THE NEXT FEW DAYS WITH TEMPERATURES TOPPING OUT NEAR AVERAGE. 
/NEUMAN

.LONG TERM...THURSDAY NIGHT THROUGH MONDAY...MODELS CONTINUE TO
STRUGGLE ON THE DETAILS...BUT SUGGEST ONSHORE FLOW WILL CONTINUE NEAR
AVERAGE TEMPERATURES WITH A CHANCE FOR SOME LIGHT SHOWERS THURSDAY
NIGHT AND FRIDAY. WHILE MODELS DIFFER ON TIMING...BUT THE GFS AND EC
SUGGEST A WETTER FRONTAL STORM SYSTEM WILL SLOWLY SAG SOUTHWARD
ACROSS THE AREA LATE SATURDAY THROUGH SUNDAY NIGHT. AS A
RESULT...POPS WERE INCREASED IN THE LIKELY TO CATEGORICAL RANGE FOR
THE PRIME WINDOW OF SATURDAY NIGHT AND SUNDAY. BOTH MODELS SUGGEST
ANOTHER STORM SYSTEM IS LIKELY NEXT WEEK...BUT ONCE AGAIN DIFFER ON
TIMING SO POPS WERE TRENDED MORE INTO THE HIGH END CHANCE TO LOW END
LIKELY RANGE. /NEUMAN

&&

.AVIATION...MOSTLY VFR UNDER HAZY SKIES THROUGH THIS EVENING. THE
FLOW PATTERN WILL CONTINUE TO TURN ONSHORE THIS AFTERNOON AS A
WEAK FRONT APPROACHES THE REGION ALLOWING MARINE STRATUS TO FILL
BACK IN ALONG THE COAST BETWEEN 00Z AND 03Z. EXPECT IFR CIGS
BETWEEN 500 AND 1000 FT AND REDUCED VSBY ALONG THE COAST THROUGH
LATE TUE MORNING. CLOUDS CONTINUE TO PUSH INLAND TONIGHT...WITH
INTERIOR SITE LIKELY SEEING MVFR CIGS BETWEEN 1500 AND 2000 FT BY
15Z. CONDITIONS TURN VFR UNDER MOSTLY CLOUDY SKIES TUE AFTERNOON.

KPDX AND APPROACHES...VFR UNDER HAZY SKIES THROUGH THIS EVENING.
LOWER CLOUDS RETURN TONIGHT...WITH MVFR STRATUS AFFECTING THE
TERMINAL BY 14Z.

&&

.MARINE...A WEAK FRONT WILL MOVE ACROSS THE WATERS TOMORROW
MORNING BRINGING GUSTY NORTHWESTERLY WINDS AND BUILDING SEAS.
EXPECT GUSTS TO 35 KT AND SEAS AROUND 11 FT FROM TUE MORNING TO
WED. HIGH PRES BRIEFLY RETURNS WED AFTERNOON BEFORE ANOTHER WEAK
FRONT MOVES ACROSS THE WATERS ON THU. NOT EXPECTING MUCH IN THE
WAY OF IMPACTS WITH THIS SECOND FRONT. A MUCH STRONGER FRONT LOOKS
TO MOVE ACROSS THE WATERS OVER THE WEEKEND AND WILL LIKELY BRING
GUSTY SOUTHERLY WINDS AND ANOTHER ROUND OF BUILDING SEAS.

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS FROM 7 AM TUESDAY TO NOON PDT 
     WEDNESDAY FOR WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR 
     FROM 10 TO 60 NM.

     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 4 PM TUESDAY TO 6 
     PM PDT WEDNESDAY FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO 
     FLORENCE OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR WINDS FROM 1 PM TUESDAY TO NOON PDT 
     WEDNESDAY FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO 
     FLORENCE OR OUT 10 NM.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR FROM 5 AM 
     TO 10 AM PDT WEDNESDAY.

&&

$$

INTERACT WITH US VIA SOCIAL MEDIA     
WWW.FACEBOOK.COM/NWSPORTLAND	
WWW.TWITTER.COM/NWSPORTLAND

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.

[ W WA | SW WA and W OR | SE WA and NE OR | NE WA and N ID ]

Southeastern Washington and Northeastern Oregon


208 
FXUS66 KPDT 202338 AAA
AFDPDT

AREA FORECAST DISCUSSION...UPDATE
NATIONAL WEATHER SERVICE PENDLETON OR
438 PM PDT MON APR 20 2015

UPDATED AVIATION DISCUSSION

.SHORT TERM...TONIGHT THROUGH THURSDAY...AN UPPER LEVEL HIGH 
PRESSURE RIDGE WILL CONTINUE OVER THE PACIFIC NORTHWEST THROUGH 
TONIGHT. THIS RIDGE WILL SHIFT EAST TUESDAY DUE TO THE APPROACH OF 
AN UPPER TROUGH. CONDITIONS TONIGHT THROUGH TUESDAY MORNING WILL BE 
FAIR AND DRY WITH MAINLY LIGHT WINDS. OVERNIGHT LOWS WILL BE A BIT 
WARMER THAN THIS MORNING DUE TO A WARMER DAY TODAY. INCREASING 
SOUTHERLY FLOW ALOFT AHEAD OF THE APPROACHING PACIFIC TROUGH WILL 
PUSH MOISTURE AND INSTABILITY NORTH FROM CALIFORNIA TUESDAY 
AFTERNOON AND EVENING. AS SUCH ISOLATED TO SCATTERED SHOWERS WILL 
DEVELOP OVER SOUTH CENTRAL OREGON TUESDAY AFTERNOON AND THEN WORK 
THEIR WAY NORTH INTO CENTRAL AND EAST CENTRAL OREGON LATER TUESDAY 
AFTERNOON AND TUESDAY EVENING. THERE WILL BE ENOUGH INSTABILITY FOR 
A FEW THUNDERSTORMS OVER CENTRAL AND EAST CENTRAL OREGON LATE 
AFTERNOON INTO THE EVENING AS WELL. A FEW SHOWERS MAY BE POSSIBLE 
OVER THE WASHINGTON CASCADE EAST SLOPES THOUGH INCREASING WEST WINDS 
SHOULD BE A LIMITING FACTOR. THE AREA OF SHOWERS IN CENTRAL AND EAST 
CENTRAL OREGON WILL MOVE NORTH-NORTHEAST OVERNIGHT INTO WEDNESDAY. 
THUS THESE SHOWERS ARE EXPECTED TO AFFECT THE BLUE MOUNTAINS AND 
THEIR ADJACENT FOOTHILLS, THE GRANDE RONDE VALLEY AND WALLOWA COUNTY 
AT VARIOUS TIMES WEDNESDAY. WINDS WILL INCREASE ACROSS THE COLUMBIA 
BASIN, THE COLUMBIA GORGE AND THE KITTITAS VALLEY TUESDAY NIGHT. 
THESE WINDS WILL PERSIST INTO WEDNESDAY. WINDS IN THE KITTITAS 
VALLEY ARE EXPECTED TO REACH 30 TO 35 MPH SUSTAINED WITH HIGHER 
GUSTS, AND WILL ISSUE A WIND ADVISORY FOR THIS AREA. MOST OF THE 
SHOWERS WILL END WEDNESDAY NIGHT. MAY SEE A FEW SHOWERS NEAR THE 
CASCADE CREST THURSDAY, AND POSSIBLY A FEW OVER EASTERN WALLOWA 
COUNTY. OTHERWISE THURSDAY SHOULD BE DRY WITH SEASONAL TEMPS. 90 

.LONG TERM...THURSDAY NIGHT THROUGH MONDAY NIGHT...THE LONG TERM 
PERIOD WILL BE QUITE ACTIVE WITH SEVERAL SYSTEMS MOVING THROUGH THE 
AREA. THE FIRST AND WEAKER TROUGH WILL BE OVER THE FORECAST AREA 
THURSDAY NIGHT INTO FRIDAY. THIS SYSTEM LOOKS FAIRLY MOISTURE 
STARVED AND THEREFORE JUST ADDED A SLIGHT CHANCE TO CHANCE FOR 
SHOWERS INTO THE FORECAST DURING THIS TIME. WESTERLY WINDS COULD 
TURN A BIT BREEZY LATE THURSDAY NIGHT INTO FRIDAY NIGHT OVER PARTS 
OF THE AREA. THIS WEATHER SYSTEM THEN EXITS THE AREA WITH A BRIEF  
BREAK FOR FRIDAY NIGHT INTO SATURDAY MORNING. BY LATER SATURDAY AND 
INTO SUNDAY A VERY DIFFLUENT UPPER LEVEL FLOW PATTERN DEVELOPS OVER 
THE PACIFIC NORTHWEST WITH A LARGE PLUME OF MOISTURE BEING PUSHED 
INTO THE AREA IN RESPONSE TO THE CYCLONIC FLOW AROUND A LARGE UPPER 
LEVEL LOW LOCATED IN THE SOUTHERN GULF OF ALASKA. THIS PATTERN WILL  
BRING A GOOD CHANCE FOR RAIN AND HIGH ELEVATION SNOW SATURDAY NIGHT 
THROUGH SUNDAY NIGHT...SNOW LEVELS WILL BE QUITE HIGH...GENERALLY 
ABOVE 6000 FEET. THERE WILL LIKELY BE A SHORT BREAK IN BETWEEN 
SYSTEMS EARLY MONDAY...WITH THE NEXT WAVE APPROACHING THE REGION  
MONDAY NIGHT AND CONTINUING BEYOND THE EXTENDED PERIOD. WITH THE 
SERIES OF SYSTEMS OVER THE CWA LOOK FOR BREEZY OR EVEN WINDY 
CONDITIONS FOR MANY LOCATIONS SUNDAY AND MONDAY...AT THIS TIME 
SOUTHWEST WINDS OF 15-25 MPH WITH HIGHER GUSTS ARE LOOKING POSSIBLE 
BOTH SUNDAY AND MONDAY AFTERNOON. THIS WILL BE SOMETHING TO CONTINUE 
TO WATCH AS WE DRAW CLOSER AND GUIDANCE IS ABLE TO BETTER HONE IN ON 
THE DETAILS. OVERALL EXPECT BOTH HIGH AND LOW TEMPERATURES TO REMAIN 
VERY CLOSE TO THE SEASONAL AVERAGE THROUGHOUT THE EXTENDED PERIOD 
FOR MOST LOCATIONS. 77 

&&

.AVIATION...00Z TAFS...AN UPPER LEVEL RIDGE IS CENTERED OVER THE 
AREA AT THIS TIME AND WILL LEAD TO VFR CONDITIONS PREVAILING AT ALL 
TAF SITES OVER THE NEXT 24 HOURS. THERE WILL BE A FEW THIN CIRRUS 
CLOUDS (25-30 KFT AGL) OVER PARTS OF THE REGION THIS EVENING AND 
ESPECIALLY INTO TUESDAY. THERE ARE ALSO A FEW-SCT MID LEVEL CUMULUS 
CURRENTLY OVER THE NORTHERN BLUE MTNS AND THE EAST SLOPES OF THE 
WASHINGTON CASCADES...THESE WILL DISSIPATE OVERNIGHT. SURFACE WINDS 
WILL REMAIN DIURNALLY AND TERRAIN DRIVEN AOB 10 KTS THROUGH 15Z 
TUESDAY. THEN WEST-NORTHWEST WINDS INCREASE TO 10-15 KTS WITH HIGHER 
GUSTS AT KDLS...KBDN AND KRDM AFTER 17-21Z TUESDAY. 77 

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  44  78  47  63 /   0  10  10  30 
ALW  49  78  49  64 /   0  10  10  30 
PSC  40  81  48  68 /   0   0  10  10 
YKM  43  79  47  65 /   0  10  10  10 
HRI  39  81  47  67 /   0   0  10  10 
ELN  44  77  46  61 /   0  10  10  10 
RDM  32  73  35  61 /   0  20  20  10 
LGD  35  76  45  60 /   0  10  20  30 
GCD  36  76  40  62 /   0  10  30  40 
DLS  46  75  49  62 /   0  10  10  10 

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...WIND ADVISORY FROM MIDNIGHT TUESDAY NIGHT TO 8 PM PDT WEDNESDAY 
     WAZ026.

&&

FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON

$$

90/77/77




[ W WA | SW WA and W OR | SE WA and NE OR | NE WA and N ID ]

Northeastern Washington and Northern Idaho


266 
FXUS66 KOTX 202334
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
434 PM PDT MON APR 20 2015

.SYNOPSIS...

Tuesday will likely be the warmest day in the next 7 to 10 days as
strong high pressure remains over the region for one last day. A
cold front will arrive Tuesday night bringing cooler weather and
breezy conditions into Wednesday. A cool upper trough is expected
to bring showery conditions Friday and Saturday.

&&

.DISCUSSION...

Tonight through Tuesday night...The axis of the ridge of high
pressure influencing the area moves east tomorrow. It does this at
slow enough of a speed to allow for temperatures of the seven day
forecast to peak for most locations tomorrow. Late in the
afternoon and evening with the axis to the east a weak marine push
of sorts allows for winds to increase in the gaps of the cascades
and close proximity to them late Tuesday afternoon and overnight.
The weak push may also fire off a bit of spotty convective showers
and perhaps a thunderstorm or two. Minimum temperatures Tuesday
night should be on the warm side of normal given the mixing
brought about by the wind. /Pelatti 

Wednesday: Cooler and breezy weather will arrive Tuesday night
into Wednesday. The high amplitude 500mb ridge responsible for our
recent warm weather will be replaced by a cool polar low
descending out of the Gulf of Alaska. A relatively high spread in
model solutions continues for a day 3 forecast leading to lower
than average confidence for precipitation chances and winds for
Wednesday. The GFS model continues to be an outlier digging an
upper low deeper south into Washington on Wednesday. The ECMWF,
Canadian and NAM models look to have a more reasonable progressive
solution. The deeper/slower low on GFS looks a bit suspect given
the strong upstream kicker in the Gulf of Alaska, so the forecast
for Wednesday and Thursday was largely based on the Canadian
which is a compromise between the ECMWF and NAM.

This Canadian compromise means less chance for thunderstorms since
the heart of the 500mb cold pool will only graze the northern
Washington zones. This solution also entrains a good deal of mid-
level dry air into the region on Wednesday limiting the amount of
deep layer instability. Precipitation chances region-wide don't
look very impressive. The Canadian and ECMWF solutions are a bit
breezier, so winds have been increased. We will likely see a 10
to 12 degree cool down from Tuesday into Wednesday as chilly
maritime air is squeezed through the gaps in the Cascades. The
change in air mass will likely be accompanied by typical breezy
spring time winds between 15 and 20 mph with some wind prone areas
in the lee of the Cascades gusting in excess of 30 mph on
Wednesday.

Thursday: If we discount the GFS, Thursday has the potential to be
a relatively dry day with fairly light winds. Precipitation
chances have been trimmed, limited to 20 percent or less in the
mountainous. Light winds and a good chance for mainly clear skies
suggest a fairly chilly morning on Thursday. Sheltered areas in
the Idaho Panhandle and northeast Washington will have a good shot
at low to mid 30s...perhaps a frost.

Friday and Saturday: By Friday, the main longwave trough over the
Gulf of Alaska is expected to move into Washington or southern
British Columbia. Seasonably chilly temperatures and showers will
likely accompany the arrival of this broad polar trough. Our
temperature forecast for Friday into Saturday has been cooled in
line with MOS guidance.

Sunday and Monday: Given the model uncertainty in the Wednesday
through Saturday time frame, it is a bit unusual to see the GFS,
ECMWF, and Canadian come into better agreement early next week.
The model consensus is for a mild and wet pattern Sunday and
Monday as a subtropical moisture plume becomes planted over the
Pacific Northwest. Early next week looks like our best shot of
widespread precipitation during the next 7 to 10 day period.
/GKoch

&&

.AVIATION...
00Z TAFS: High pressure will result in VFR conditions and weak
winds at all TAF sites through Tuesday afternoon. /SVH

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        46  74  50  61  36  62 /   0  10  10  20  10  10 
Coeur d'Alene  41  73  44  62  34  62 /   0  10  10  20  20  10 
Pullman        42  72  46  58  34  61 /   0  10  10  30  10  10 
Lewiston       46  78  49  65  38  66 /   0   0  10  30  10  10 
Colville       42  77  46  65  37  65 /   0  10  10  40  40  20 
Sandpoint      38  72  40  61  33  60 /   0  10  10  30  30  20 
Kellogg        40  71  43  59  34  62 /   0  10  10  30  20  20 
Moses Lake     44  78  50  67  37  66 /   0  10  10  10   0  10 
Wenatchee      51  77  53  65  41  65 /   0  10  10  10   0  10 
Omak           44  77  47  65  35  64 /   0  10  10  30  20  10 

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&

$$


[ W WA | SW WA and W OR | SE WA and NE OR | NE WA and N ID ]

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