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

Western Washington


115 
FXUS66 KSEW 301559 CCA
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
900 AM PDT TUE SEP 30 2014

.SYNOPSIS...MOIST ONSHORE FLOW WILL BRING SOME SHOWERS TO WESTERN 
WASHINGTON TODAY...ESPECIALLY IN THE MOUNTAINS. A WEAK SYSTEM MOVING 
THROUGH WESTERN CANADA WILL BRUSH THE AREA ON WEDNESDAY FOR SPOTTY 
LIGHT SHOWERS IN THE NORTH PART. THURSDAY SHOULD BE DRY AND PARTLY 
SUNNY BUT A FRONT WILL SAG SOUTH INTO THE REGION ON FRIDAY. AN UPPER 
RIDGE WILL HELP LIMIT RAIN TO THE COAST AND MOUNTAINS THIS WEEKEND.

&&

.SHORT TERM...MOIST NW FLOW WILL PREVAIL TODAY AS AN UPPER TROUGH 
OVER THE REGION SHIFTS EWD. RADAR SHOWS SOME SCATTERED SHOWERS 
AROUND THE AREA AND ESPECIALLY ALONG THE COAST AND MOUNTAINS. WITH 
CONTINUED FLOW THROUGH THE STRAIT AND SOUTHWESTERLIES THROUGH THE 
SOUND THE CONVERGENCE ZONE COULD REDEVELOP TODAY. THE 00Z WRF-GFS 
WAS INDICATING THIS TO OCCUR N OF THE KING/SNOHOMISH COUNTY LINE 
EARLY THIS MORNING BUT THERE IS LITTLE OR NO SIGNATURE ON RADAR YET. 
THE NEW 12Z NAM HAS A COUPLE AREAS OF CONVERGING WINDS. ONE IS OVER 
KING COUNTY AND ANOTHER FURTHER N OVER SNOHOMISH/SKAGIT COUNTIES. 
QPF FIELDS ARE LESS CLEAR BUT IMPLY SOME ENHANCED PRECIPITATION OVER 
THESE AREAS TODAY. GIVEN THE LATEST TRENDS...CONVERGENCE ZONE 
FORMATION COULD GO EITHER WAY TODAY. CHANCE POPS IN THE LOWLANDS AND 
LIKELY POPS IN THE MOUNTAINS SEEM REASONABLE.

THE REGION REMAINS UNDER CYCLONIC FLOW THROUGH THE EVENING SO THERE 
IS STILL SOME THREAT OF SHOWERS. AS HIGHER PRESSURE OFFSHORE STARTS 
TO BUILD IN LATER TONIGHT THE CHANCE OF SHOWERS WILL DECREASE. A 
SHORT WAVE RIDGE IS OVER THE AREA WEDNESDAY SO IT SHOULD BE MOSTLY 
DRY WITH SOME MORNING LOW CLOUDS AND FOG AROUND. MODELS STILL SHOW 
SPOTTY LIGHT QPF IN THE MOUNTAINS SO A FEW RESIDUAL SHOWERS ARE 
STILL POSSIBLE. HIGHS WILL REMAIN COOL IN THE LOWER 60S. 

UPPER HEIGHTS BUILD ON THURSDAY WITH LIGHT SURFACE FLOW. AREAS OF 
MORNING FOG STILL SEEM LIKELY UNLESS HIGH CLOUDS FROM AN OFFSHORE 
SYSTEM INTERFERE WITH RADIATIONAL COOLING OVERNIGHT. MOST MODELS 
MAINTAIN DRY WEATHER ON THURSDAY BUT THE 06Z GFS SHOWS WARM FRONTAL 
PRECIPITATION OVER WRN WA JUST N OF PUGET SOUND. HOPEFULLY THE NEW 
12Z GFS/ECMWF COME INTO BETTER AGREEMENT FOR THE THURSDAY PERIOD AND 
BEYOND. THE FORECAST FOR THURSDAY REMAINS DRY.  MERCER

.LONG TERM...NO CHANGES TO PREVIOUS DISCUSSION...THE WARM FRONT 
DISCUSSED ABOVE AND ITS TRAILING COLD FRONT SHOULD WEAKEN AND SAG 
SOUTH INTO WESTERN WASHINGTON ON FRIDAY. MODEL SOLUTIONS DIFFER 
CONSIDERABLY FOR THE WEEKEND AND EARLY NEXT WEEK. THE EUROPEAN MODEL 
KEEPS A STRONGER RIDGE OVER THE REGION... WITH THE FRONTAL SYSTEM 
REMAINING MOSTLY TO OUR NORTH. IN THE GFS SOLUTION THE UPPER RIDGE 
WEAKENS AND SHIFTS EAST OF THE CASCADES... ALLOWING THE FRONTAL BAND 
TO MOVE INTO WESTERN WASHINGTON UNIMPEDED. AND THE GFS KEEPS SOME 
PRECIPITATION OVER THE REGION AS ANOTHER SHORTWAVE WITH ANOTHER 
SHORTWAVE ARRIVING MONDAY. FOR NOW I WILL RESIST THE TEMPTATION TO 
UPDATE THE SATURDAY THROUGH MONDAY PERIOD...BUT IT DOES LOOK A BIT 
OPTIMISTIC BASED ON THE LATEST MODEL RUNS.   MCDONNAL 

&&

.AVIATION...AN UPPER TROF OVER THE PACNW WILL BE REPLACED BY A WEAK 
UPPER RIDGE TONIGHT. ANOTHER UPPER TROUGH WILL MOVE THROUGH B.C. AND 
ALBERTA WED NITE AND THU...THIS WILL KEEP WNW FLOW ALOFT OVER WA. 
THE LOW LEVEL FLOW WILL REMAIN WLY AND THE AIR OVER WRN WA WILL 
REMAIN FAIRLY MOIST WITH SCATTERED SHOWERS...ESPECIALLY OVER THE 
CASCADES AND IN THE PSCZ AT TIMES.

KSEA...SCATTERED SHOWERS AND SOME CLEARING PERIODS. A LIGHT SW 
BREEZE...BUT IF THE RADAR SHOWS A PSCZ DEVELOP AGAIN AND MOVE TOWARD 
SEATTLE THE WIND WOULD BECOME VARIABLE. THERE IS A CHANCE OF THAT 
HAPPENING LATER THIS AFTERNOON AND EVENING.

&&

.MARINE...SURFACE HIGH PRESSURE OFFSHORE WITH LOWER PRESSURE INLAND 
WILL RESULT IN WESTERLY FLOW THROUGH WED. A 1023MB HIGH WILL WORK 
EAST OVER THE AREA WED NITE AND THU GIVING LIGHT GRADIENTS. 

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY CENTRAL AND EASTERN STRAIT OF JUAN DE FUCA.

&&

$$

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


558 
FXUS66 KPQR 300932
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
230 AM PDT TUE SEP 30 2014

.SYNOPSIS...AN UPPER LEVEL TROUGH OF LOW PRES OVER THE PACIFIC NW 
WILL KEEP A COOL SHOWERY AIR MASS OVER THE REGION TODAY. HIGH PRES 
WILL BUILD IN OFF THE PACIFIC TONIGHT AND WED...AND LAST THROUGH 
MOST OF THE WEEK BRINGING A RETURN TO DRIER WEATHER. 
&&

.SHORT TERM DISCUSSION...RADAR SHOWED SHOWERS CONTINUING TO MOVE IN 
OFF THE PACIFIC OVER THE FORECAST AREA EARLY THIS MORNING IN A NW 
FLOW. MESOWEST PRECIPITATION TOTALS OVER THE PAST FEW HOURS INDICATE 
MOST OF THE SHOWERS WERE OVER THE UPWIND SIDE OF THE TERRAIN...WITH 
A BIT OF A RAIN SHADOW EFFECT TO THE LEE SIDE. WATER VAPOR PICTURES 
SHOWED THE MAIN TROUGH AXIS ALONG THE CASCADES THIS MORNING MOVING 
E. A SECONDARY TROUGH COMING DOWN THE BC COAST THOUGH IS EXPECTED TO 
MOVE THROUGH THE REGION LATER IN THE MORNING. THIS WILL KEEP A 
THREAT OF SHOWERS IN THE FORECAST TODAY...BUT WITH THE HIGHEST POPS 
CONTINUING OVER THE UPWIND SLOPES. MODELS INDICATE THE NW FLOW 
WEAKENING TONIGHT. MODELS SOUNDINGS SHOW STRONG SUBSIDENCE FROM 
UPPER LEVEL RIDGING WILL SHRINK THE LOW LEVEL UNSTABLE LAYER FROM 
THE TOP DOWN TONIGHT...EFFECTIVELY BRINGING AN END TO ANY THREAT OF 
SHOWERS BY WED MORNING. COOL TEMPS WILL REMAIN AS THE TROUGH MOVES 
ACROSS TODAY AND AFTERNOON H8 TEMPS DROP AS LOW AS 6 DEG C. 

A SURFACE RIDGE OF HIGH PRES BUILDING INTO WA AND OREGON WED AND THU 
TURN THE LOW LEVEL FLOW NORTHERLY DRYING THE AIR MASS. THE STRONG 
UPPER LEVEL RIDGE THAT DEVELOPS OVER THE E PACIFIC THOUGH IS 
EXPECTED TO FLATTEN SOME AS IT SHIFTS TOWARDS THE COAST. THIS WILL 
OPEN THE DOOR FOR HIGH LEVEL CLOUDS...BUT ANY THREAT FOR WARM 
FRONTAL TYPE PRECIPITATION APPEARS TO BE RESTRICTED N OF THE AREA. 
TEMPS WILL MODERATE SOME WED AND THU AS H8 TEMPS CLIMB BACK TO 
AROUND 12 DEG C. 

.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS. NOT MUCH 
CHANCE MADE TO THE EXTENDED FCST TODAY. AN UPPER LEVEL RIDGE IS 
FORECAST TO REMAIN ENTRENCHED OVER THE WEST COAST...WITH FLAT 
RIDGING OVER THE PAC NW. THIS IS CURRENTLY EXPECTED TO KEEPING 
CONDITIONS MOSTLY DRY ACROSS OUR FCST AREA WITH TEMPS SLIGHTLY ABOVE 
NORMAL. HOWEVER...A SIGNIFICANT ATMOSPHERIC RIVER EVENT APPEARS 
LIKELY TO BRING HEAVY RAINS TO OUR NORTH ALONG THE BRITISH COLUMBIA 
COAST. THERE IS A SLIGHT CHANCE THAT THE RIDGE WILL WEAKEN ENOUGH TO 
ALLOW SOME LIGHT RAIN TO BRUSH THE NORTHERNMOST PORTIONS OF OUR FCST 
AREA FROM TIME TO TIME OVER THE WEEKEND OR EARLY NEXT WEEK. PYLE

&&

.AVIATION...VARIABLE VFR CIGS ACROSS MOST OF THE REGION EARLY THIS
MORNING IN THE WAKE OF A COLD FRONT THAT HAS PUSHED EAST OF THE
CASCADES. SCATTERED SHOWERS CONTINUE TO PUSH ONSHORE AND ANY
HEAVIER SHOWERS MAY CREATE BRIEF MVFR REDUCTIONS. WITH ABUNDANT
MOISTURE...ANY AREAS WITH BREAKS IN CLOUD COVER AND CALM WINDS MAY
DEVELOP SHALLOW RADIATION FOG THROUGH DAYBREAK...PARTICULARLY IN
THE INTERIOR VALLEYS. AS UPPER LOW PRES SLIDES INLAND...EXPECT
CHANCE FOR SHOWERS THROUGH THIS AFTERNOON. WITH CALMING WINDS AND
CLEARING SKIES...BETTER CHANCES FOR FOG DEVELOPMENT TUE NIGHT.

KPDX AND APPROACHES...VARIABLE CLOUD LAYERS GENERALLY ABOVE 4000
FT WITH VFR CIGS DEVELOPING AT TIMES. ABOUT A 25 PERCENT CHANCE OF
MVFR CIGS DEVELOPING 12Z-17Z THIS MORNING. THEREAFTER...SHOWERS
CONTINUE MOVING ONSHORE THROUGH TUE AFTERNOON BUT EXPECT VFR WITH
PERHAPS BRIEF MVFR REDUCTIONS IN ANY HEAVIER SHOWERS. CULLEN

&&

.MARINE...HIGH PRES WILL BUILD OVER THE NE PAC TODAY AND REMAIN
THROUGH AT LEAST THU BRINGING A RETURN TO NORTHERLY WINDS OVER THE
WATERS. A THERMAL LOW PRES MAY BUILD INTO THE S OREGON COAST BY
WED OR THU TO INCREASE WINDS OVER THE CENTRAL OREGON WATERS...BUT
EXPECT WINDS 20 KT OR LESS THROUGH THE WEEK. ANOTHER FRONT WILL
APPROACH FROM THE NORTH LATE IN THE WEEK. SEAS REMAIN AROUND 7-8
FT THROUGH WED...BEFORE EASING LATER IN THE WEEK. ANOTHER W SWELL
WILL RETURN SEAS TO AROUND 8 FT AT THE END OF THE WEEK. CULLEN

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR FROM 7 PM 
     TO 11 PM PDT THIS EVENING.

&&

$$

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


284 
FXUS66 KPDT 301733 AAA
AFDPDT

AREA FORECAST DISCUSSION...UPDATE
NATIONAL WEATHER SERVICE PENDLETON OR
1032 AM PDT TUE SEP 30 2014

UPDATED AVIATION DISCUSSION

.SHORT TERM...COLD FRONT HAS MOVED WELL EAST OF THE REGION HOWEVER 
UPPER LEVEL TROUGH WITH COOL CYCLONIC FLOW WILL REMAIN OVER THE 
REGION TODAY. NORTHWEST UPSLOPE FLOW WILL KEEP SKIES MOSTLY CLOUDY 
OVER THE CASCADES AND BLUES WITH ISOLATED SHOWERS THROUGH EVENING. 
REMAINDER OF THE FORECAST AREA MOSTLY CLEAR NOW BUT EXPECT SOME 
CUMULUS TO DEVELOP WITH THE COOLER AIR ALOFT. BREEZY TO LOCALLY 
WINDY CONDITIONS THROUGH THE DAY. STRONGEST WINDS IN THE GORGE AND 
KITTITAS VALLEY. DIMINISHING CLOUDS AND WINDS TONIGHT WITH COOL 
TEMPERATURES. SOME LOCATIONS WILL DROP BELOW FREEZING...ESPECIALLY 
CENTRAL AND NORTHEAST OREGON. 94

.AVIATION...18Z TAFS...VFR CONDITIONS EXPECTED AT ALL TAF SITES 
THROUGH THE PERIOD. MAIN CONCERN TODAY WILL BE GUSTY WEST TO 
NORTHWEST WINDS BEHIND AN EXITING COLD FRONT. WINDS WILL BE BTWN 15 
TO 30 KTS THRU 01/03Z BEFORE DIMINISHING TO AOB 10 KTS OVERNIGHT.  
MVFR HAZE AND/OR AREAS OF BLOWING DUST INVOF OF KPDT IS POSSIBLE 
THRU 01/03Z...BUT WILL NOT INCLUDE IN TAFS DUE TO UNCERTAINTY. 
VICINITY SHOWERS NEAR KPDT AND KALW DUE TO PASSING SHORTWAVE BTWN 
01/00Z TO 01/04Z. MURPHY/BIEDA

&&

.PREV DISC... /ISSUED 109 AM PDT TUE SEP 30 2014/ 

SHORT TERM...TODAY THROUGH THURSDAY...A COLD FRONT WHICH MOVED 
ACROSS THE CWA LAST EVENING BROUGHT SOME RAIN SHOWERS TO THE EASTERN 
CWA. THESE HAVE MOVED OFF TO THE EAST. WINDS HAVE PICKED UP WITH AND 
BEHIND THE FRONT TO LOCALLY BREEZY TO WINDY. THE WINDS ARE EXPECTED 
TO INCREASE FURTHER TODAY. WINDS IN THE KITTITAS VALLEY ARE EXPECTED 
TO REACH WIND ADVISORY SPEEDS AROUND 15-16Z THIS MORNING. WILL BE 
ISSUING A WIND ADVISORY FROM 15Z-00Z TODAY FOR THE KITTITAS VALLEY 
AS A RESULT. THE STRONGEST WINDS WILL OCCUR DURING TIMES OF MAXIMUM 
MIXING THIS AFTERNOON. AFTER THAT TIME THE WINDS ARE EXPECTED TO 
DIMINISH QUICKLY TONIGHT AS PRESSURE GRADIENTS RELAX AND DUE TO 
NIGHT TIME STABILIZATION OF THE ATMOSPHERE. THE NEXT CONCERN WILL BE 
COLD TEMPERATURES TONIGHT AND WEDNESDAY NIGHT. TEMPERATURES TONIGHT 
IN CENTRAL OREGON (MADRAS...REDMOND AND BEND) ARE ALL EXPECTED TO 
DROP TO OR BELOW FREEZING. WILL BE ISSUING A FREEZE WARNING THERE 
FOR TONIGHT. ON WEDNESDAY NIGHT TEMPERATURES WILL NOT BE AS COLD. ON 
WEDNESDAY COOL TEMPERATURE WILL CONTINUE IN A NORTHWEST FLOW ALOFT. 
AFTER THAT AN UPPER RIDGE WILL BEGIN TO BUILD BACK OVER THE REGION 
BEGINNING ON THURSDAY WITH A WARMING TREND. 88

LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...A RIDGE OF HIGH 
PRESSURE WILL BUILD OVER WESTERN NORTH AMERICA THROUGH THE FORECAST 
PERIOD. THIS WILL PLACE THE FORECAST AREA IN FAST WESTERLY FLOW 
ALOFT RESULTING IN SOME CLOUD COVER BUT LITTLE IN THE WAY OF 
PRECIPITATION. IT WILL BE WARM WITH TEMPERATURES ABOVE NORMAL FOR 
THIS TIME OF YEAR. ON SATURDAY...A WEAK DISTURBANCE WILL FLATTEN THE 
RIDGE AND PERHAPS PUSH A WEAK COOL FRONT ACROSS THE REGION FROM THE 
NORTH. THE MODELS ARE SHOWING LIMITED MOISTURE WITH THIS FEATURE SO 
FOR NOW HAVE CONFINED POPS TO THE WASHINGTON CASCADE CREST. ANY 
MOISTURE OVER THE AREA WILL BE SHORT LIVED...WITH A RETURN TO DRY 
CONDITIONS FOR EARLY NEXT WEEK. 78

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  65  39  66  40 /  10  10   0   0 
ALW  66  42  66  44 /  10  10   0   0 
PSC  71  39  69  41 /  10   0   0   0 
YKM  66  35  67  41 /  10   0   0   0 
HRI  69  37  68  40 /  10   0   0   0 
ELN  62  39  63  38 /  10   0   0   0 
RDM  61  27  63  31 /   0   0   0   0 
LGD  58  35  62  36 /  20  10   0   0 
GCD  58  29  63  34 /  10  10   0   0 
DLS  67  43  68  44 /  10  10   0   0 

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...FREEZE WARNING FROM 10 PM THIS EVENING TO 9 AM PDT WEDNESDAY 
     ORZ511.

WA...WIND ADVISORY UNTIL 5 PM PDT THIS AFTERNOON WAZ026.

&&

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

$$

94/77/98




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

Northeastern Washington and Northern Idaho


039 
FXUS66 KOTX 301740
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
1040 AM PDT TUE SEP 30 2014

.SYNOPSIS...
Cooler temperatures will arrive today courtesy of a passing cold
front. The front will also deliver breezy winds and scattered
showers. Dry weather will return on Wednesday. Look for a warming
trend and a continuation of mainly dry conditions Thursday into
the weekend.

&&

.DISCUSSION...
Made a few tweaks to the forecast. With upper trough over the
region, the cold front and first of the shortwaves is rolling
across extreme eastern Washington into north Idaho. Scattered
showers with embedded thunderstorms developed with this front and
should continue over north Idaho through late morning. A second
shortwave with the upper trough axis will move through across the
Cascades this afternoon and bring another round of convection to
the Inland NW. Given the daytime heating and surface based
instability up to 200 j/kg, could see showers with embedded
thunderstorms develop across the northeast quarter of the forecast
area. Rainfall amounts for the most part will be light, but could
see some isolated heavy downpours with heavier showers.
Temperatures will reflect more fall like conditions today. /rfox.

&&

.AVIATION...
18Z TAFS: A cold front moved through eastern Washington and north
Idaho overnight. This afternoon, the Idaho Panhandle will be
squarely under the 500mb cold pool. Look for diurnally driven
showers to increase around 20z and persist until 02z. Some of the
strongest cells may produce a couple of lightning strikes and
brief heavy downpours. Thunderstorms will be handled on a
"nowcast" basis as we monitor radar trends this afternoon. The
Spokane, Coeur D'Alene, and Pullman TAFs may require an amendment
to add a short-lived thunderstorm. As the sun sets, skies should
clear quickly with the loss of afternoon heating. /GKoch

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        63  40  61  39  64  45 /  30  10   0   0   0  10 
Coeur d'Alene  62  40  62  40  63  43 /  50  20   0   0   0  10 
Pullman        62  38  62  37  65  42 /  20  10   0   0   0   0 
Lewiston       68  45  68  45  71  47 /  10  10   0   0   0   0 
Colville       67  36  66  38  67  43 /  20  10   0   0   0  10 
Sandpoint      60  39  60  36  61  39 /  70  30   0  10   0  10 
Kellogg        56  37  56  40  59  43 /  60  30  10  10   0  10 
Moses Lake     71  40  69  41  68  45 /  10   0   0   0   0   0 
Wenatchee      69  46  68  45  69  49 /   0   0   0   0   0  10 
Omak           69  38  66  39  66  46 /  20  10   0   0   0  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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