Western Washington

601 
FXUS66 KSEW 071013
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
315 AM PDT MON OCT 7 2013

.SYNOPSIS...A TROUGH OF LOW PRES EXTENDING SOUTH OF A LOW MOVING 
INTO WEST CENTRAL BRITISH COLUMBIA WILL SWEEP THROUGH THE AREA TODAY 
GIVING SHOWERS AND BREEZY CONDITIONS. SHOWERS WILL CONTINUE TONIGHT 
INTO TUESDAY AS AN UPPER LOW DROPS SOUTH ACROSS THE AREA. IT WILL 
CLEAR FROM THE NORTH TUESDAY NIGHT AS HIGH PRES BUILDS INTO WESTERN 
WASHINGTON...THEN A SUNNY AND MILD DAY IS EXPECTED ON WEDNESDAY. THE 
WEAKENING REMNANTS OF A FRONTAL SYSTEM WILL BRING CLOUDS AND A 
CHANCE OF LIGHT RAIN TO THE AREA ON THURSDAY.

&&

.SHORT TERM...THE FRONT THAT SWEPT THROUGH WESTERN WASHINGTON LAST 
EVENING IS NOW EAST OF THE CASCADES AND MOVING AWAY FROM THE AREA. A 
VERTICALLY STACKED LOW HAS MOVED THROUGH THE QUEEN CHARLOTTE SOUND 
OVERNIGHT AND IS PUSHING INLAND OVER WEST CENTRAL BRITISH COLUMBIA. 
A TROUGH OF LOW PRESSURE EXTENDS SOUTHWARD FROM THIS LOW INTO THE 
OFFSHORE WATERS...THIS TROUGH WILL MOVE INLAND ACROSS WESTERN 
WASHINGTON TODAY.

PACIFIC NORTHWEST RADARS SHOW WIDESPREAD SHOWERS EXTENDING FROM 
CENTRAL VANCOUVER ISLAND AND THE NORTH COAST OF WESTERN WASHINGTON 
SOUTHWESTWARD. THESE WILL MOVE ONSHORE THIS MORNING AND THROUGH THE 
INTERIOR THIS AFTERNOON. MODERATE TO STRONG ONSHORE FLOW WILL 
ACCOMPANY THE TROUGH TODAY RESULTING BREEZY TO LOCALLY WINDY 
CONDITIONS. WHILE THERE WILL BE SOME RAIN SHADOWING AND BRIEF 
CLEARING AT TIMES ACROSS THE NORTH INTERIOR AND SAN JUANS...AND FROM 
ABOUT SEATAC TO SHELTON...THIS AFTERNOON POPS WILL BE HIGH WITH THE 
PASSING TROUGH.

FORECAST MODELS ARE SHOWING GOOD CONSISTENCY AND CONTINUITY THROUGH 
THE SHORT TERM. THE SURFACE TROUGH WILL PUSH EAST OF THE CASCADES 
TONIGHT. THIS WILL ALLOW SHOWERS TO DECREASE A BIT IN THE INTERIOR 
LOWLANDS AND ALONG THE COAST. STRONG ONSHORE FLOW WILL KEEP SHOWERS 
GOING IN THE CASCADES. SNOW LEVELS IN THE CASCADES WILL GENERALLY BE 
AROUND 4500 FEET TONIGHT KEEPING SNOWFALL AMOUNTS OF 3-5 INCHES 
LIMITED TO THE HIGHEST CASCADE PASSES AND THE VOLCANOES. 

SOME INCREASE IN SHOWER ACTIVITY IS EXPECTED ON TUESDAY AS THE OLD 
UPPER LOW OVER WESTERN BRITISH COLUMBIA DROPS SOUTHWARD THROUGH 
WESTERN WASHINGTON DURING THE DAY. SNOW LEVELS IN THE CASCADES WILL 
DROP TO AROUND 4000 FT WITH THE PASSING UPPER LOW. AT THIS TIME IT 
APPEARS THAT SNOWFALL AMOUNTS IN THE MOUNTAINS WILL REMAIN BELOW 
ADVISORY CRITERIA AS ONSHORE FLOW DIMINISHES EARLY IN THE DAY.

CONDITIONS WILL CLEAR FROM THE NORTH TUESDAY NIGHT AND NORTHERLY LOW 
LEVEL FLOW WILL DECREASE OVERNIGHT. THIS WILL ALLOW AREAS OF FOG TO 
FORM...PARTICULARLY IN FAVORED FOG-PRONE VALLEYS AND IN THE SOUTH 
INTERIOR. TUESDAY NIGHT WILL ALSO GET QUITE COOL WITH LOWS DROPPING 
INTO THE MID 30S IN OUTLYING VALLEYS AND THE SOUTH INTERIOR...AND IN 
THE MID 40S ON HILLTOPS IN THE SEATTLE AREA. 

A RIDGE OF HIGH PRES AT THE SURFACE AND ALOFT WILL MOVE SOUTHWARD 
ACROSS THE AREA ON WEDNESDAY. AREAS OF FOG WILL BURN OFF MIDDAY 
GIVING A FINE AND SUNNY AUTUMN AFTERNOON WITH HIGHS APPROACHING 60 
MOST AREAS. ALBRECHT
 
.LONG TERM...FORECAST MODELS CONTINUE TO SHOW RATHER GOOD 
CONSISTENCY AND CONTINUITY ACROSS THE PACIFIC NORTHWEST WEDNESDAY 
NIGHT THROUGH FRIDAY. THEY AGREE THAT A WEAKENING FRONTAL SYSTEM 
WILL PRETTY MUCH DISSIPATE AS IT MOVES THROUGH THE AREA THURSDAY. 
NOT MUCH RAIN IS EXPECTED WITH THIS VERY WEAK FRONT...BUT CLOUDS AND 
A CHANCE OF SOME RAIN WILL NEED TO BE MAINTAINED. A VERY WEAK AND 
SOMEWHAT DIRTY SHORT WAVE RIDGE MOVES ACROSS THE AREA ON FRIDAY. IT 
APPEARS THAT IT WILL BE DRY AND PARTLY SUNNY. 

MODEL SOLUTIONS BEGIN DIVERGING FRIDAY NIGHT THROUGH NEXT WEEKEND AS 
ANOTHER SYSTEM MOVES ACROSS THE AREA. THE ECMWF BRINGS A STRONGER 
TROUGH FOR MORE SHOWERS AND ONSHORE FLOW. THE GFS TAKES A WEAK LOW 
INTO NORTHERN CALIFORNIA AND KEEPS CONDITIONS DRIER OVER WASHINGTON. 
NO CHANGES WERE MADE TO THE FORECAST BEYOND FRIDAY. ALBRECHT

&&

.AVIATION...UPPER LEVEL TROUGH MOVING THROUGH THE AREA THIS MORNING 
WITH STRONG LOW LEVEL ONSHORE FLOW.  SOUTHWESTERLY FLOW ALOFT 
BECOMING NORTHWESTERLY BEHIND THE TROUGH. 

MULTIPLE CLOUD LAYERS THIS MORNING BETWEEN 2000 AND 6000 FEET WITH 
CEILINGS MOSTLY IN THE 4000 FOOT RANGE. TROUGH AXIS MOVING THROUGH 
12Z-18Z WITH CEILINGS LOWERING DOWN TO NEAR 2000 FEET WITH SHOWERS 
ASSOCIATED WITH THE TROUGH. SHOWER ACTIVITY WILL CONTINUE INTO THE 
AFTERNOON ALONG THE COAST AND IN THE MOUNTAINS. SHOWER ACTIVITY WILL 
ALSO CONTINUE IN THE CONVERGENCE ZONE NEAR KPAE. CEILINGS IN THE 
VICINITY OF THE SHOWERS WILL CONTINUE NEAR 2000 FEET WITH THE 
REMAINDER OF THE AREA IN THE 4000-5000 FOOT RANGE.  

KSEA...CEILINGS NEAR 4000 FEET LOWER TO NEAR 2000 FEET IN SHOWERS 
THROUGH THE MORNING HOURS. CONDITIONS IMPROVING THIS AFTERNOON 
INTO THE EVENING WITH THE TERMINAL IN THE RAIN SHADOW OF THE 
OLYMPICS. SOUTHERLY WINDS 10 TO 15 KNOTS WITH GUSTS 20 TO 25 KNOTS 
THIS MORNING EASING THIS AFTERNOON. FELTON

&&

.MARINE...STRONG ONSHORE FLOW IN THE WAKE OF SUNDAY NIGHTS COLD 
FRONT WITH GALE WARNINGS UP FOR THE CENTRAL AND EASTERN STRAIT AND 
SMALL CRAFT ADVISORIES FOR THE REMAINDER OF THE WATERS INTO TONIGHT. 
ONSHORE FLOW WILL EASE TUESDAY AS SURFACE PRESSURES RISE OVER THE 
AREA WITH THE SMALL CRAFT ADVISORY WINDS CONFINED TO THE OUTER 
COASTAL WATERS. HIGH PRESSURE OVER THE INLAND WATERS ON WEDNESDAY 
WILL RESULT IN LIGHT LOW LEVEL FLOW OVER THE WATERS. THE LIGHT FLOW 
PATTERN WILL CONTINUE ON THURSDAY. FELTON

&&

.SEW WATCHES/WARNINGS/ADVISORIES...

WA...NONE.
PZ...GALE WARNING CENTRAL AND EAST ENTRANCE TO THE STRAIT 
       THROUGH TONIGHT.
     SMALL CRAFT ADVISORY REMAINDER OF THE WATERS.
 


&&

$$

WWW.WEATHER.GOV/SEATTLE

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

Southwestern Washington and Western Oregon

678 
FXUS66 KPQR 070933
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
233 AM PDT MON OCT 7 2013

.SYNOPSIS...A FRONT WILL MOVE EAST OF THE CASCADES THIS
MORNING...WITH POST FRONTAL SHOWERS LINGERING THROUGH THIS EVENING.
AN UPPER LEVEL TROUGH WILL BRING ANOTHER ROUND OF SHOWERS AND COOLER
CONDITIONS TUESDAY. HIGH PRESSURE WILL RESULT IN A DRY AND MOSTLY
SUNNY...BUT COOL DAY ON WEDNESDAY. A WEAK FRONT MAY MOVE OVER THE
AREA THURSDAY BEFORE ANOTHER DRY DAY ON FRIDAY.   

&& 

.SHORT TERM...A COLD FRONT PUSHED THROUGH THE REGION EARLY THIS
MORNING AND IS CURRENTLY OVER THE CASCADES AND CASCADE FOOTHILLS.
SHOWERS HAVE FILLED IN BEHIND THE FRONT AND WILL PERSIST THROUGH THIS
AFTERNOON...WITH SHOWERS MAINLY OVER THE CASCADES THIS EVENING AND
TONIGHT. A COOLER AIRMASS WILL RESULT IN MUCH COOLER AFTERNOON
TEMPERATURES TODAY.

ANOTHER ROUND OF SHOWERS ARE IN STORE FOR TUESDAY AS AN UPPER LEVEL
SHORTWAVE WILL DROP SOUTHWARD FROM ALASKA. COOLER TEMPERATURES ALOFT
WILL ACCOMPANY THIS DISTURBANCE AND EXPECT SMALL HAIL EMBEDDED WITH
SOME OF THE SHOWERS TUESDAY AFTERNOON AND EVENING. SKIS SHOULD CLEAR
TUESDAY NIGHT AS THE UPPER WAVE SHIFTS FURTHER SOUTH AND WEAK
OFFSHORE WINDS DEVELOP ACROSS WASHINGTON AND OREGON. RADIATION
COOLING SHOULD RESULT IN FOG FOR THE INTERIOR VALLEYS BY WED MORNING.
 THERE IS POTENTIAL FOR THE OVERNIGHT TEMPERATURES TO DROP INTO THE
30S AT MOST LOCATIONS. 

A SHORTWAVE RIDGE WILL MOVE OVER THE PACIFIC NW ON WEDNESDAY WITH
MOSTLY SUNNY SKIES AND DRY WEATHER. WITH A COOL START TO THE DAY
TEMPERATURES SHOULD PEAK IN THE 60S DESPITE THE ABUNDANT SUNSHINE.
SKIES WILL BECOME INCREASINGLY CLOUDY WEDNESDAY NIGHT AS A DECAYING
FRONT WILL APPROACH.

.LONG TERM...A WEAKENING FRONT WILL LIKELY PUSH INTO OUR NORTHWEST
ZONES THURSDAY BRINGING A CHANCE FOR SHOWERS. MODELS THEN DIVERGE
AFTER THIS POINT WITH THE EC BRINGING ANOTHER SHORTWAVE TROUGH INTO
THE AREA SATURDAY WHILE THE GFS KEEPS THE REGION GENERALLY DRY UNDER
A DIRTY NORTHWEST FLOW PATTERN OVER THE WEEKEND. AS A RESULT...POPS
WERE KEPT IN THE SLIGHT CHANCE TO CHANCE RANGE UNTIL CONFIDENCE
INCREASES. /NEUMAN 

&&

.AVIATION...VFR WITH AREAS OF MVFR ASSOCIATED WITH THE FRONT
MOVING ACROSS THE WILLAMETTE VALLEY AT 09Z. EXPECT MUCH OF THE DAY
WILL BE VFR WITH OCCASIONAL MVFR AS POST FRONTAL SHOWERS MOVE
THROUGH. COASTAL AREAS ALSO A MIX OF VFR AND MVFR. BUT IFR CIGS
ARE HOLDING ON IN THE KONP AREA. CIGS SHOULD IMPROVE LATER THIS
MORNING AS INCREASING COLD AIR ADVECTION MIXES THE LOWER LAYER.

KPDX AND APPROACHES...VFR SHOULD PREDOMINATE TODAY BUT CAN
NOT RULE OUT OCCASIONAL CIGS AROUND 2500 FT INTO EARLY AFTERNOON. 

&&

.MARINE...COLD FRONT MOVED ASHORE AROUND MIDNIGHT.  GUSTY NW WINDS
UNDER COLD ADVECTION SHOULD BRING SMALL CRAFT ADVISORY WIND GUST
TO 25 KT OVER THE NORTHERN WATERS TODAY. WINDS EASE TONIGHT AS
HIGH PRES BUILDS OVER THE WATERS TONIGHT. ANOTHER WEAK FRONTAL
SYSTEM APPROACHES WEDNESDAY NIGHT INTO THURSDAY POSSIBLY BRINGING
A FEW GUSTS NEAR 25 KT TO THE OUTER WATERS THURSDAY.

A WESTERLY SWELL IN THE LOW TEENS ARRIVES THIS MORNING.
THIS SWELL TRAIN AND ALIGNED WIND WAVES WILL MAINTAIN SEAS IN THE
10 TO 13 FT RANGE THROUGH LATE TUESDAY...POSSIBLY LINGERING INTO
EARLY WEDNESDAY. HOWEVER THE LARGE SEAS WILL START LATER AND END
EARLIER SO HAVE MADE ADJUSTMENTS TO HEADLINES.

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL 11 AM PDT THIS MORNING FOR 
     COASTAL WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR OUT 60
     NM.

     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 5 AM EARLY THIS 
     MORNING TO 11 AM PDT TUESDAY FOR COASTAL WATERS FROM CAPE 
     SHOALWATER WA TO CASCADE HEAD OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 11 AM THIS MORNING 
     TO MIDNIGHT PDT TONIGHT FOR COASTAL WATERS FROM CASCADE HEAD OR
     TO FLORENCE OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 
     8 AM PDT THIS MORNING.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR FROM 4 PM
     THIS AFTERNOON TO 10 PM PDT THIS EVENING.

&&


$$

MORE WEATHER INFORMATION ONLINE AT...
    HTTP://WEATHER.GOV/PORTLAND

INTERACT WITH US VIA SOCIAL MEDIA
    WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.PORTLAND.GOV
    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.

Southeastern Washington and Northeastern Oregon

642 
FXUS66 KPDT 071018 CCA
AFDPDT

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PENDLETON OR
318 AM PDT MON OCT 7 2013

UPDATED AVIATION DISCUSSION

.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT...A WEAK FRONT IS MOVING 
THROUGH WESTERN WASHINGTON AND OREGON AT THIS TIME. LIGHT RAIN WILL 
BEGIN IN THE CASCADES BY MORNING. THE FRONT WILL MOVE THROUGH 
EASTERN WASHINGTON AND OREGON TODAY. THE LOWER ATMOSPHERE IS STILL 
BE DRY. THIS WILL LIMIT FRONTAL PRECIPITATION TO THE CASCADES AND 
NORTHEAST OREGON MOUNTAINS THOUGH ALL AREAS WILL HAVE INCREASING 
CLOUDS TODAY AND COOLER TEMPERATURES AFTER THE FRONTAL PASSAGE. 
WINDS WILL BECOME BREEZY/WINDY BEHIND THE FRONT AS STRONGER WINDS 
ALOFT MIX TO THE SURFACE, PARTICULARLY IN THE LOWER COLUMBIA BASIN. 
PATCHY BLOWING DUST IS POSSIBLE THIS AFTERNOON IN THE COLUMBIA 
BASIN DUE TO WINDY DRY CONDITIONS. ANOTHER DISTURBANCE IS EXPECTED 
TO MOVE SOUTH OVER B.C. TONIGHT, MOVE INTO NORTHWESTERN WASHINGTON 
TUESDAY MORNING, AND THEN DIVE SOUTH SOUTHEAST INTO NORTHERN 
CALIFORNIA TUESDAY NIGHT. THIS SYSTEM WILL INCREASE CHANCES OF 
SHOWERS ACROSS THE REGION ON TUESDAY. SNOW LEVELS ON TUESDAY 
AFTERNOON WILL BE AROUND 5000 FEET, THEN DROP TO 3500-4500 FEET 
OVERNIGHT. LIGHT SNOW ACCUMULATIONS ARE POSSIBLE ABOVE THESE LEVELS. 
SOME WRAPAROUND MOISTURE MAY KEEP A FEW SHOWERS FROM GRANT COUNTY TO 
SOUTHERN WALLOWA COUNTY WEDNESDAY MORNING. DRY NORTHERLY FLOW WILL 
MOVE INTO EASTERN WASHINGTON AND OREGON WEDNESDAY AFTERNOON THROUGH 
THURSDAY MORNING.  COONFIELD

.LONG TERM...THURSDAY THROUGH SUNDAY...A MID/UPPER LEVEL LONG WAVE 
RIDGE OF HIGH PRESSURE BUILDS ACROSS THE NE PACIFIC ON THURSDAY. THE 
PACIFIC NORTHWEST WILL BE ON THE EASTERN FLANK OF THE RIDGE, WHICH 
WILL YIELD A DRY NORTHWEST FLOW ALOFT PROVIDING SINKING AIR FOR DRY 
CONDITIONS ON THURSDAY. AN UPSTREAM SHORT WAVE RIDGE/TROUGH COUPLET  
MIGRATES EASTWARD THROUGH THE LONG WAVE RIDGE OVER THE NE PACIFIC 
THURSDAY NIGHT AND FRIDAY WHILE THE EASTERN FLANK OF THE LONG WAVE 
RIDGE REMAINS OVER THE PACIFIC NORTHWEST FOR A CONTINUATION OF DRY 
CONDITIONS IN THE FORECAST AREA THROUGH FRIDAY. THE AFOREMENTIONED 
SHORT WAVE TROUGH APPROACHES THE COAST FRIDAY AFTERNOON AND THEN 
MOVES INLAND TO THE CASCADES FRIDAY NIGHT, AND THEN MOVES THROUGH 
THE FORECAST AREA ON SATURDAY FOR INCREASING POPS AND A CHANCE OF 
SHOWERS. THE SNOW LEVEL ON SATURDAY WILL BE 6000-7000 FEET SO THE 
HIGHEST MOUNTAINS WILL SEE SOME SNOW SHOWERS WITH SNOW ACCUMULATIONS 
OF 1-2 INCHES ABOVE 6000 FEET AS THE SHORT WAVE PUSHES A COLD FRONT 
ACROSS THE FORECAST AREA DURING THE DAY ON SATURDAY. THE SHORT WAVE 
TROUGH MOVES INTO IDAHO/MONTANA SATURDAY NIGHT WITH SHOWERS TAPERING 
OFF OVERNIGHT IN THE BLUE MOUNTAINS WITH SHOWERS ENDING IN WALLOWA 
COUNTY BEFORE DAYBREAK ON SUNDAY. A RIDGE OF HIGH PRESSURE OFFSHORE 
WILL KEEP THE FORECAST AREA IN A DRY NORTHERLY FLOW ALOFT ON SUNDAY 
FOR DRY CONDITIONS. HOWEVER, THIS COULD YIELD SOME ISOLATED 
OROGRAPHIC SHOWERS IN THE BLUE MOUNTAINS AND IN WALLOWA COUNTY ON 
SUNDAY.  POLAN

&&

.AVIATION...12Z TAFS...VRF CONDITIONS WILL OCCUR FOR THE NEXT 24 
HOURS. A WEAK COLD FRONT WILL SWEEP ACROSS THE REGION TODAY FOR 
CLOUD BASES THIS MORNING LOWERING TO 5-7K FT AGL. THIS FRONTAL 
PASSAGE WILL BE MOSTLY DRY WITH ONLY ISOLATED SHOWERS EXPECTED OVER 
THE BLUE MOUNTAINS AND WITH NUMEROUS SHOWERS NEAR THE OREGON CASCADE 
CRESTS AND ALONG THE EAST SLOPES OF THE CENTRAL WASHINGTON CASCADES. 
LOOK FOR SUSTAINED WINDS INCREASING TO 20-25 KTS BY 18Z AT KDLS, 
KPSC, KPDT AND KALW. WINDS WILL INCREASE TO 15-20 KTS BY 18Z AT 
KYKM, KRDM AND KBDN. SOME PATCHY BLOWING DUST WILL OCCUR THIS 
AFTERNOON IN THE LOWER COLUMBIA BASIN. WINDS WILL DIMINISH AFTER 
8TH/03Z.  POLAN

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  64  44  57  39 /  10  10  30  20 
ALW  66  46  58  40 /  10  10  30  20 
PSC  69  49  63  39 /  10  10  30  10 
YKM  68  41  62  36 /  20  10  30  10 
HRI  68  43  63  36 /  10  10  30  20 
ELN  66  41  62  34 /  20  10  30  10 
RDM  64  32  56  30 /  10  10  30  30 
LGD  62  39  55  37 /  10  20  40  20 
GCD  63  35  57  34 /  10  10  30  30 
DLS  65  44  63  38 /  10  10  30  20 

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.

&&

THREAT INDEX
TODAY : GREEN
TUESDAY : GREEN
WEDNESDAY : GREEN

GREEN: NONE OR LIMITED NEED FOR WATCHES, WARNINGS, OR ADVISORIES.
YELLOW: A FEW WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
RED: NUMEROUS WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.

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

$$

76/99/99

Northeastern Washington and Northern Idaho

481 
FXUS66 KOTX 070940
AFDOTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
240 AM PDT Mon Oct 7 2013

.SYNOPSIS...
High pressure will shift east allowing cold front to move through
the Inland Northwest on today. Cooler temperatures are expected
with the front along with windy conditions and patchy blowing dust
in the Columbia Basin and on the Palouse. Scattered showers are
also expected mainly in the mountains. Even cooler and showery
weather is expected Tuesday as a weather system over British
Columbia moves into the Inland Northwest. A mostly dry weather
pattern is expected for the remainder of the week...but with
temperatures remaining below normal...before another wet cold
front reaches the area by the weekend. Confidence is low as to the
timing of this weekend feature. 

&&

.DISCUSSION...

Today through Tuesday: Rather dramatic changes to the weather will
occur today. Our sunny and warm autumn weekend will be replaced by
clouds, showers, wind, and much cooler temperatures.

The cold front is currently moving into the Cascades and will
traverse eastern Washington this morning and be into the Panhandle
by noon. This narrow frontal band could bring an hour or two of
light rain or sprinkles this morning. This will transition to
afternoon instability showers. These will continue overnight
tonight as a second short wave dives south out of BC to keep the
showers going after sunset. On Tuesday the westerly winds cease so
there won't be any rain shadow. As a result, the entire area has a
chance of showers, mainly in the afternoon, and mainly in the
Panhandle and extreme eastern Washington.

Wind today and tonight will be the main weather story. The wind
should pick up behind the front today with gusts to 30 mph, which
could result in some blowing dust in the Basin. While the wind
will subside tonight in the lower elevations, a mountain wave will
bring strong winds to the higher elevations in the Cascades.

Temperatures will be markedly cooler today, down 5-10 degrees in
the lower elevations, and 10-20 degrees in the mountains. On
Tuesday some valley locations will struggle to make it up to 50.

Snow levels will drop from the current 6000' today down to about
4500' tonight and Tuesday. This will result in rain changing to
snow at some of the higher passes such as Lookout and
Washington/Rainy (i.e. North Cascades Highway 20). Doubtful that
the road surfaces will see any accumulation unless there's a heavy
snow shower at night. RJ


Tue Nt through Sunday: We'll have to deal with whats left of the
stalled frontal boundary/deformation axis across SE Wa and the
Cntrl Id Panhandle mtns Wed morning that will finally move
southeast of the region late Wed. Again...snow levels will fall to
around 4500 ft MSL by Wed morning, keeping Lookout Pass along I-90
under the threat of snow. Another quick- moving weak cold front
passage Thurs will not, by itself, produce much pcpn. However, the
GFS does try to merge this front with what's left of the shearing
deformation from Wed's front. The biggest challenge will be
trying to nail down the specifics of this merge since it could
mean a significant pcpn threat. The various model guidance in not
in agreement with this frontal placement with this scenario, so
we did not go too high with pcpn amnts. Thursday through Saturday will
be characterized by swift NW steering flow that will carry the
next wet system through the Pacific NW by Sat. Confidence in the
timing of this feature is low seven days out, especially with the
model differences. bz

&&

.AVIATION...
06Z TAFS: Cold front to cross central and eastern Washington in
the 14z-18z time frame. This front will have limited moisture
associated with it east of the Cascades. The mountains squeeze
the majority of the low level moisture from this shearing system.
Shallow post frontal instability combined with westerly upslope
flow will produce showers, mainly over the mountains of the Idaho
Panhandle and Cascade crest. Gusty west winds will be the main
aviation impact Monday afternoon with gusts to 22-28kts expected
between 18z and 00z.

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        58  40  50  37  56  37 /  20  20  70  20   0   0 
Coeur d'Alene  57  39  48  36  55  35 /  20  30  70  20   0   0 
Pullman        57  39  50  36  56  34 /  20  20  70  20   0   0 
Lewiston       64  44  55  40  61  39 /  10  10  70  20   0   0 
Colville       59  40  53  34  57  36 /  30  20  60  10   0   0 
Sandpoint      56  39  47  35  55  32 /  30  40  70  20   0   0 
Kellogg        53  39  43  35  53  35 /  30  50  70  20   0   0 
Moses Lake     64  40  59  35  61  37 /  20  10  30  10   0   0 
Wenatchee      60  43  58  40  62  41 /  10   0  30  10   0   0 
Omak           61  38  58  33  61  38 /  20  10  30  10   0  10 

&&

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

$$