Western Washington

916 
FXUS66 KSEW 231659
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
900 AM PST MON NOV 23 2009

.SYNOPSIS...A WARM FRONT WILL BRING SOME RAIN TO WESTERN WASHINGTON 
TODAY...MAINLY ALONG THE COAST AND IN THE NORTH. A WEAK COLD FRONT 
WILL MOVE INLAND TONIGHT. WEAK HIGH PRESSURE WILL MOVE ACROSS THE 
AREA TUESDAY. A WEAK WARM FRONT WILL MOVE THROUGH THE AREA TUESDAY 
NIGHT...FOLLOWED BY ANOTHER WEAK COLD FRONT WEDNESDAY NIGHT AND 
THANKSGIVING DAY....FOLLOWED BY AN UPPER TROUGH ON FRIDAY.

&&

.SHORT TERM...A WEAK WARM FRONT CLIPPING THE AREA THIS MORNING IS 
BRINGING SPOTTY LIGHT RAIN TO MUCH OF THE AREA. THE PRECIP CAME IN 
QUICKER AND FURTHER INLAND THAN WAS EXPECTED YESTERDAY. EVEN THE NEW 
12Z NAM IS DRY THIS MORNING WITH THE EXCEPTION OF THE COAST. THE 
GFS/ECMWF APPEAR TO HAVE A BETTER HANDLE ON THIS SHOWING SOME LIGHT 
QPF THIS MORNING...INTENSIFYING DURING THE AFTERNOON AS THE MAIN 
FRONT APPROACHES. QPF AMOUNTS APPEAR HIGHEST ON THE COAST/OLYMPIC 
PENINSULA WHERE UP TO 1 INCH OF RAIN COULD FALL. MUCH LESS AMOUNTS 
EXPECTED ELSEWHERE WITH SNOW LEVELS EXPECTED TO RISE THROUGH THE 
DAY..RISING TO OVER 5000 FEET BY THIS EVENING. SNOW ACCUMULATIONS IN 
THE PASSES SHOULD REMAIN BELOW ADVISORY CRITERIA...MAYBE UP TO A FEW 
INCHES THIS EVENING BEFORE CHANGING TO RAIN. 

THE FRONT DISSIPATES OVER WRN WA UNDER A BUILDING UPPER RIDGE 
TONIGHT. THERE COULD BE SOME RESIDUAL LIGHT RAIN/DRIZZLE AND LOW 
CLOUDS HANGING IN THROUGH TUESDAY MORNING. COULD END UP BEING A 
RATHER MURKY DAY TUESDAY WITH SUBSIDENCE ALOFT AND RESIDUAL MOISTURE 
TRAPPED IN THE LOWER LEVELS. QPF WILL BE LIGHT WITH HIGHER SNOW 
LEVELS...THUS SNOW IN THE PASSES IS NOT EXPECTED.

HIGH PRESSURE BUILDS STRONGER OVER THE AREA TUESDAY NIGHT AND EARLY 
WEDNESDAY...THEN SHIFTS EWD WEDNESDAY AFTERNOON AS THE NEXT FRONTAL 
BAND APPROACHES. IT LOOKS LIKE PRECIP SHOULD HOLD OFF DURING THE DAY 
THE HEIGHTS AND RISING THICKNESS VALUES INDICATING WARMER AIR ALOFT. 
PRECIP ASSOCIATED THE THE FRONTAL BAND COULD START TO AFFECT THE 
OLYMPIC PENINSULA AND COAST BY LATE IN THE DAY. MERCER

.LONG TERM...PREVIOUS DISCUSSION FOLLOWS...THE MODELS DISAGREE ON 
HOW THE PATTERN WILL CHANGE IN THE LONGER RANGE. THE GFS SHOWS A 
MUCH DRIER SOLUTION WHILE THE EUROPEAN MODEL IS WETTER. SO 
CONFIDENCE IN THE EXTENDED FORECAST THANKSGIVING DAY THROUGH SUNDAY 
IS RATHER LOW AND THE APPROACH IS A BROAD BRUSH. IN A VERY GENERAL 
SENSE THEY AGREE THAT THANKSGIVING DAY THROUGH FRIDAY NIGHT WILL BE 
WETTER AS THE FRONTAL SYSTEM SITTING OFFSHORE WEDNESDAY MOVES 
THROUGH THE AREA. AND THEY AGREE THAT AN UPPER RIDGE WILL BUILD OVER 
THE AREA OVER THE WEEKEND ...REDUCING THE THREAT OF WET WEATHER TO A 
CHANCE. MCDONNAL

&&

.HYDROLOGY...THE SKOKOMISH RIVER REMAINS JUST ABOVE FLOOD STAGE 
EARLY THIS MORNING. THE CURRENT RIVER MODEL FORECAST SHOWS IT 
DROPPING BELOW FLOOD STAGE LATER TODAY...BUT THE ACTUAL RESULT WILL 
DEPEND HEAVILY UPON THE OPERATION OF CUSHMAN DAM #2 ON THE NORTH 
FORK OF THE RIVER. A PLANNED RELEASE OF WATER FROM THE DAM BEGAN 
EARLY SATURDAY AND CONTINUES EARLY THIS MORNING.

TWO FRONTAL SYSTEMS WILL MOVE THROUGH THE AREA THROUGH WEDNESDAY 
NIGHT...AND THE SNOW LEVEL WILL GRADUALLY CLIMB TO 7000-8000 FT. 
THESE SYSTEMS WILL NOT BRING ENOUGH PRECIPITATION FOR FLOODING 
CONCERNS ON ANY WESTERN WASHINGTON RIVERS...WITH THE POSSIBLE 
EXCEPTION OF THE SKOKOMISH RIVER.

MODELS DIFFER ON THE THURSDAY SYSTEM. THE NAM IS LESS PROGRESSIVE 
AND HANGS THE FRONTAL BOUNDARY UP OVER THE OLYMPIC PENINSULA. 
RAINFALL RATES DO NOT LOOK INCREDIBLE BUT COULD BE ENOUGH FOR MINOR 
FLOODING CONCERNS ON THE SKOKOMISH RIVER. THE OTHER MODELS ARE 
WEAKER AND MUCH MORE PROGRESSIVE WITH THE FRONT AND WOULD NOT IMPLY 
ANY FLOOD THREAT.

NO FLOODING IS EXPECTED ON THE GREEN RIVER AT ANY TIME DURING THE 
FORECAST PERIOD.

&&

.AVIATION...AN UPPER LEVEL TROUGH CROSSING SOUTHERN BRITISH COLUMBIA 
WILL PUSH A WEAKENING COLD FRONT TO THE WA COAST AROUND 00Z. AIR 
MASS IS STABLE WITH GRADUALLY LOWERING CIGS IN RAIN EXPECTED AHEAD 
OF THE WEAK FRONT. THE FRONT WILL MOVE INLAND AFTER 00Z THEN 
EVENTUALLY DISSIPATE OVER SW WA 06Z-12Z. 

LATEST OBS SHOW CIGS GENERALLY BKN-0VC040-060 OVER THE INTERIOR WITH 
SOME SPOTTY MVFR STILL IN THE PROCESS OF DISSIPATING...WITH 
LOCALIZED LIGHT RAIN INTERFERING WITH THIS. WILL SHOW A MINOR BREAK 
IN THE RAIN AND KEEP CIGS UP THROUGH ABOUT 22Z BASED ON AN APPARENT 
BREAK IN THE HIGHER CLOUDS ON IR IMAGERY. SHOULD SEE CIGS LOWER WITH 
MORE WIDESPREAD RAIN TOWARD 00Z AS THE MAIN FRONT APPROACHES. 

KSEA...WILL KEEP CIGS BKN-OVC040-060 FOR MOST OF THE DAY THEN 
LOWERING TO BKN-OVC020-030 AFTER 03Z. NOT COMPLETELY CONFIDENT THAT 
THE CIGS WILL GET DOWN TO BKN020 WITH THE FRONT SO WEAK...BUT THE 
WINDS WILL WEAKEN TONIGHT AS WELL WHICH WOULD ALLOW CIGS TO LOWER A 
BIT MORE. EXPECT SURFACE WINDS TO REMAIN S THROUGH THIS EVENING. KAM

&&

.MARINE...THE WEAKENING COLD FRONT WAS UP AROUND 49N/128.5W AROUND 
16Z THIS MORNING. MODELS BRING IT TO THE N COAST LATE THIS 
AFTERNOON...12Z NAM A LITTLE FASTER THAN THE 12Z GFS. MODEL 
SOLUTIONS WEAKENING THIS FRONT AS IT MOVES INLAND SEEM ON TRACK 
SINCE WATER VAPOR IMAGERY SHOWS WHAT APPEARS TO BE THE LAST 
SHORTWAVE MOVING UP THE FRONT ALMOST TO QUEEN CHARLOTTE SOUND. MAIN 
QUESTION AT THIS POINT IS HOW STRONG THE WINDS WILL BE. SHOULD SEE A 
LITTLE STRENGTHENING IN THE WINDS THROUGH EARLY AFTERNOON...THEN 
WEAKENING. WILL LEAVE THE GALES COAST/WEST ENTRANCE UP AND SCA 
ELSEWHERE EXCEPT CENTRAL STRAIT. FORECAST ADVERTISES SCA W WINDS IN 
THE STRAIT BEHIND THE FRONT TONIGHT...BUT NEITHER THE GFS OR NAM 
SUPPORT THAT. WILL HOLD OFF ON THE ADVISORIES AND SEE WHAT THE 12Z 
WRF-GFS SHOWS. WINDS SHOULD BE BELOW ADVISORY LEVELS 
TUESDAY...EXCEPT FOR THE COAST. KAM

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...A FLOOD WARNING REMAINS IN EFFECT FOR THE SKOKOMISH RIVER       
     IN MASON COUNTY.    
PZ...GALE WARNING COAST AND WEST ENTRANCE.
     SMALL CRAFT ADVISORY ALL OTHER WATERS EXCEPT THE CENTRAL        
     STRAIT.
     SMALL CRAFT ADVISORY FOR ROUGH BAR CONDITIONS AT GRAYS HARBOR   
     ENTRANCE.

$$

WWW.WEATHER.GOV/SEATTLE

FOR AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION...PLEASE SEE 
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML.

Southwestern Washington and Western Oregon

312 
FXUS66 KPQR 231638
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
838 AM PST MON NOV 23 2009

.SYNOPSIS...A WEAK WARM FRONT OFF THE COAST WILL SHIFT NORTHEAST
TODAY...THEN A WEAK COLD FRONT WILL SAG SE INTO NW OREGON TONIGHT. 
THE FRONT WILL STALL LATE TONIGHT...THEN LIFT NE AS A WARM FRONT ON 
TUE. THE NEXT FRONTAL SYSTEM IS NOT EXPECTED TO MOVE IN UNTIL LATE 
THURSDAY.

&&

.SHORT TERM...THE MAIN THREAT FOR RAIN THOUGH TODAY SHOULD BE OVER
THE NW PART OF THE FORECAST AREA...WHERE ISENTROPIC LIFT IS BEST
AHEAD OF THE WARM FRONT OFFSHORE.

MODELS INDICATE A COLD FRONT SAGGING DOWN INTO THE REGION LATE TODAY
AND TONIGHT. WILL NEED TO INCLUDE POPS MOST AREAS BY TONIGHT AND
EARLY TUE WITH BAROCLINIC ZONE OVER THE AREA...BUT WITH WEAK DYNAMICS
POPS WILL BE LIMITED TO CHANCE TO LIKELY CATEGORY. FRONT LIFTS BACK
TO THE N LATE TUE AND TUE NIGHT WITH THE UPPER RIDGE
REBOUNDING...RESULTING IN DIMINISHING POPS BY TUE NIGHT...AND A DRY
DAY WED. WOLFE

.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...
MODELS IN SOME AGREEMENT ON BRINGING A FRONTAL SYSTEM AND ITS 
ASSOCIATED UPPER LEVEL TROF THROUGH THE REGION THU/THU NIGHT FOR A 
RETURN TO WET WEATHER. AFTER THIS SYSTEM MOVES THROUGH...THE WEAK 
HIGH PRES RIDGE REASSERTS ITSELF OVER THE FORECAST AREA...KEEPING 
MOST ENERGY NORTH OF FORECAST AREA. FOG MAY BE MORE OF A PROBLEM IN
THE EXTENDED.

&&

.AVIATION...MUCH MORE TRANQUIL TODAY. PRIMARILY VFR CONDITIONS 
ACROSS THE REGION. A WARM FRONT APPROACHING FROM THE WEST WILL 
SPREAD AREAS OF MVFR WITH OCCASIONAL RA ALONG THE COAST AROUND 20Z. 
MAY SEE SOME SPRINKLES INLAND AS THE WARM FRONT PASSES THROUGH...BUT 
REMAINING GENERALLY DRY WITH VFR THROUGH 02Z.

KPDX AND APPROACHES...NO ADVERSE WEATHER IMPACTS EXPECTED. VFR 
CONDITIONS TO REMAIN THROUGH 06Z TONIGHT. 

&&

.MARINE...LOW PRESSURE IS MOVING INTO VANCOUVER ISLAND THIS 
MORNING...PUSHING A WARM FRONT INTO THE WA/OR COASTAL WATERS. 
ASSOCIATED COLD FRONT EXTENDS SW FROM LOW AND WILL NOT DIRECTLY MOVE 
THROUGH WATERS UNTIL MIDWEEK. WINDS JUST BEHIND WARM FRONT MAY 
APPROACH GALE IN A FEW GUSTS...BUT FOR NOW SCA FOR WINDS/SEAS APPEAR 
SUFFICIENT. SEAS WILL REMAIN IN THE 10-13 FT RANGE THROUGH TODAY... 
BUT MAY FALL BELOW 10 FEET FOR A TIME TONIGHT AND TUE. GENERALLY 
TRANQUIL WEATHER THEN EXPECTED INTO WED...THEN THE COLD FRONT WILL 
FINALLY SLIDE ACROSS THE COASTAL WATERS WED NIGHT/THU. SOME MODELS 
SHOW THE POSSIBILITY OF A STRONG LOW DEVELOPING ALONG THIS FRONT OFF 
THE OREGON COAST WED NIGHT OR EARLY THU...WILL NEED TO MONITOR THIS 
FOR POTENTIAL GALES DURING THAT TIME PERIOD.  WEAGLE

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
WA/OR...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS CAPE SHOALWATER TO   
	  FLORENCE OUT 0-60 NM THROUGH TUE.
	SMALL CRAFT ADVISORY FOR WINDS CAPE SHOALWATER TO CASCADE 
	  HEAD OUT 0-60 NM AND CASCADE HEAD TO FLORENCE OUT 20-60 
	  NM TODAY. 
	SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR THROUGH
	  THIS EVENING.
&&


$$

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


THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.

Southeastern Washington and Northeastern Oregon

794 
FXUS66 KPDT 231731 AAB
AFDPDT

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PENDLETON OR
930 AM PST MON NOV 23 2009

UPDATED AVIATION DISCUSSION

.SHORT TERM...HIGH PRESSURE THAT IS PROVIDING A MOSTLY SUNNY 
BEGINNING WILL GIVE WAY TO A DISTURBANCE MOVG INTO THE PACNW THIS 
AFTERNOON. THIS SHOULD SPREAD CLOUDS INTO PORTIONS OF THE AREA 
ESPECIALLY OVER THE WA CASCADES WHERE A FEW SHOWERS MAY DEVELOP LATE 
THIS AFTERNOON AND THEN SPREAD EAST LATER ON. OTHERWISE HIGH TEMPS 
SEEM TO BE IN THE BALLPARK AND THE SHORT TERM FORECAST APPEARS ON 
TRACK FOR NOW.

&&

.AVIATION DISCUSSION...18Z TAFS...VFR CONDITIONS WILL PREVAIL 
THROUGH THE DAY TODAY WITH INCREASING MID AND HIGH CLOUDS THIS 
AFTERNOON. ANOTHER WEATHER DISTURBANCE WILL MOVE INTO THE AREA 
OVERNIGHT TONIGHT WITH ANOTHER CHANCE OF RAIN AND MOUNTAIN SNOW.  
KRDM IN CENTRAL OREGON WILL LIKELY NOT SEE ANY PRECIPITATION FROM 
THIS SYSTEM. THERE MAY BE BRIEF PERIODS OF MVFR TONIGHT IN RAIN/SNOW 
SHOWERS...ESPECIALLY AT KDLS...KYKM AND KPSC...AND TO A LESSER 
DEGREE AT KPDT AND KALW. WINDS MAINLY LESS THAN 15 KTS...BUT PERHAPS 
15 TO 20 KTS AT TIMES NEAR SHOWERS.  76

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  47  34  48  33 /   0  20  20   0 
ALW  47  36  47  35 /   0  20  20   0 
PSC  48  34  47  32 /  10  20  10   0 
YKM  44  28  46  30 /  10  30  20   0 
HRI  49  32  48  31 /   0  20  10   0 
ELN  43  30  45  31 /  10  30  20  10 
RDM  46  26  50  25 /   0  10  10   0 
LGD  40  29  44  27 /   0  20  20   0 
GCD  43  27  47  27 /   0  10  10   0 
DLS  46  35  48  37 /  10  30  20   0 

&&

.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

$$

97

Northeastern Washington and Northern Idaho

471 
FXUS66 KOTX 231834
AFDOTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
1034 AM PST MON NOV 23 2009

.SYNOPSIS...
WEAK HIGH PRESSURE OVER THE REGION WILL PROMOTE DRY BUT MOSTLY
CLOUDY CONDITIONS TODAY. A WEAK PACIFIC WARM FRONT WILL BRING A
POSSIBILITY OF VERY LIGHT PRECIPITATION TONIGHT...WITH GENERALLY
DRY BUT CLOUDY WEATHER RETURNING TUESDAY AND THROUGH THANKSGIVING.
ON FRIDAY A COLD FRONT WILL PASS THROUGH WITH ANOTHER REASONABLE
CHANCE OF MOUNTAIN SNOW AND VALLEY RAIN OR SNOW. CONDITIONS WILL
REMAIN CLOUDY AND UNSETTLED INTO NEXT WEEKEND.


&&

.DISCUSSION...
A SHORTWAVE RIDGE WILL BUILD OVER THE REGION TODAY FOR MAINLY DRY
CONDITIONS ACROSS THE INLAND NORTHWEST. SATELLITE WATER VAPOR
IMAGERY SHOWS THE MOISTURE ASSOCIATED WITH A WEAK WARM FRONT
APPROACHING VANCOUVER ISLAND THIS MORNING. SOME LIGHT RETURNS ARE
SHOWING UP ON REGIONAL RADAR MOSAIC BUT SURFACE OBSERVATIONS
INDICATE THAT THIS IS JUST THE MID LEVEL CLOUD DECK MOVING IN FROM
THE WEST. CLOUDS WILL BE ON THE INCREASE THIS AFTERNOON BUT ONLY
VERY LIGHT PRECIPITATION EXPECTED ACROSS THE CASCADE CREST AND 
NORTHERN TIER AS MOIST ISENTROPIC UPGLIDE SPREADS ACROSS THE
CASCADES TO THE NORTHERN MTS THIS EVENING. ONLY MINOR UPDATES MADE
TO THE FORECAST THIS MORNING. POPS WERE REDUCED A BIT AND TEMPS
AND SKY COVER ADJUSTED TO ACCOUNT FOR TRENDS IN OBSERVATIONS.
/KELCH

&&

.AVIATION...
A SHORTWAVE RIDGE WILL MOVE OVERHEAD TODAY RESULTING IN LARGELY
VFR CONDITIONS AREA WIDE. A WEAK WARM FRONT WILL MOVE INTO
NORTHERN WA AND THE ID PANHANDLE TONIGHT RESULTING IN RAIN AND
SNOW SHOWERS. HOWEVER...SOME UNCERTAINTY EXISTS ON WHETHER OR NOT
PRECIP...AND SUBSEQUENT MVFR CIGS...WILL REACH THE KGEG-KCOE
CORRIDOR LATE TONIGHT. LIGHT UPSLOPE WINDS MAY ALLOW LOW STRATUS
TO DEVELOP IN THE KGEG-KCOE AREA AFTER 10Z TUESDAY. /EK




&&

.PRELIMINARY POINT TEMPS/POPS...
SPOKANE        38  33  39  31  41  31 /   0  50  10  10   0   0 
COEUR D'ALENE  39  33  39  31  41  31 /   0  50  10  10   0   0 
PULLMAN        39  34  41  29  43  32 /  10  50  30   0   0   0 
LEWISTON       45  34  45  34  45  34 /  10  30  20   0   0   0 
COLVILLE       40  34  40  29  40  27 /  20  70  10  20  20  10 
SANDPOINT      37  30  35  27  36  26 /  10  60  10  20  20  10 
KELLOGG        35  28  37  28  40  29 /  20  60  30  10  10   0 
MOSES LAKE     43  28  44  31  44  30 /   0  10  10   0   0   0 
WENATCHEE      42  31  43  32  43  32 /  10  20  10  10  10   0 
OMAK           40  27  43  29  43  29 /  40  60  10  20  10  10 

&&

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

$$