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

Western Washington


269 
FXUS66 KSEW 211558
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
900 AM PM PDT TUE OCT 21 2014

.SYNOPSIS...A STRONG FRONTAL SYSTEM WILL BRING RAIN AND WIND TO THE 
COAST LATE THIS AFTERNOON AND TONIGHT AND TO THE INTERIOR OF WESTERN 
WASHINGTON TONIGHT INTO WEDNESDAY MORNING. VERY HEAVY RAINFALL IS 
POSSIBLE ALONG THE SOUTHWESTERN OLYMPIC MOUNTAINS. IT WILL REMAIN 
WET ON WEDNESDAY...ESPECIALLY IN THE CASCADES...AS SOUTHWEST FLOW 
ALOFT PERSISTS. UNSETTLED WEATHER WILL CONTINUE FOR THE REST OF THE 
WEEK AS A SERIES OF WEATHER SYSTEMS MOVE ONSHORE.

&&

.SHORT TERM...IT APPEARS THAT THE UPCOMING WEEK WILL BE QUITE ACTIVE 
WEATHERWISE AS A SERIES OF SYSTEMS CHARGE INTO THE PACIFIC 
NORTHWEST. THE JET ACROSS THE NORTH PACIFIC IS BECOMING RATHER 
STRONG AS COLD AIR DUMPS OUT OF THE BERING SEA INTO THE GULF OF 
ALASKA AND SUBTROPICAL AND TROPICAL MOISTURE AND ENERGY FROM SYSTEMS 
IN THE CENTRAL NORTH PACIFIC GETS ENTRAINED INTO THE FLOW.

FIRST FOR TODAY...A PASSING UPPER TROUGH IS CENTERED OVER NW 
WASHINGTON. AN OCCLUSION THAT IS ASSOCIATED WITH A VERTICALLY 
STACKED LOW NEAR 54N 141W EXTENDS SSW FROM NORTHERN VANCOUVER ISLAND 
INTO THE WASHINGTON AND OREGON OFFSHORE WATERS. THIS OCCLUSION HAS 
QUITE A BIT OF TSTM ACTIVITY ASSOCIATED WITH IT AS IT MOVES SLOWLY 
EAST TOWARD THE COASTAL WATERS. WILL ADD SCATTERED TSTMS TO THE 
OUTER COASTAL WATERS TODAY AS THE OCCLUSION NICKS THAT AREA. TSTM 
ACTIVITY SHOULD DECREASE AS THE FRONT MOVES EAST TOWARD THE COAST 
LATER THIS AFTERNOON AND THE MOST UNSTABLE AIR MOVES INTO VANCOUVER 
ISLAND.   

FOR TONIGHT...THE OCCLUSION STALLS OVER THE WESTERN OLYMPIC 
PENINSULA LATE THIS AFTERNOON AND EVENING. THEN A DEVELOPING WAVE 
NOW SEEN NEAR 43N 141W CHARGES EASTWARD INTO THE COASTAL WATERS THIS 
EVENING AND DEVELOPS TO AROUND A 992 MB LOW AS IT HITS SOUTH CENTRAL 
VANCOUVER ISLAND LATE TONIGHT. THIS LOW IS DEVELOPING IN THE LEFT 
EXIT REGION OF A 150 KT 300 MB JET THAT IS CHARGING EASTWARD ACROSS 
THE EAST CENTRAL NORTH PACIFIC AND HAS BEEN CHARGED WITH SUBTROPICAL 
MOISTURE FROM AN UPPER TROUGH NOW SEEN NEAR 35N 165E. TWO ISSUES ARE 
LIKELY WITH THIS LOW...WIND AND HEAVY RAINFALL. WIND IS LIKELY TO 
REACH THE HIGHER END OF THE ADVISORY LEVEL ALONG THE COAST TONIGHT 
AND THROUGH THE NORTH INTERIOR FROM ABOUT ADMIRALTY INLET NORTHWARD 
LATE TONIGHT INTO WEDNESDAY MORNING. THE ADVISORY WAS ISSUED LAST 
NIGHT AND WILL BE MAINTAINED. QPF FROM THE 12Z NAM12 AND THE 00Z 
WRFGFS MESOSCALE MODELS...ESPECIALLY IN THE RAIN FOREST AREAS OF THE 
SW OLYMPIC PENINSULA...IS QUITE IMPRESSIVE WITH 8 INCHES IN 12 HOURS 
FROM THE NAM12 AND 9-12 INCHES FROM THE WRFGFS IN A 12-15 HR PERIOD. 
WHILE THIS MAY BE OVERDONE IN THE MODELS...THIS IS HIGHER THAN WHAT 
IS TYPICALLY SEEN IN EVEN HEAVIER EVENTS ALONG THE SW OLYMPICS. THE 
FLOOD WATCH WILL BE EXTENDED FROM MASON COUNTY TO INCLUDE THE ENTIRE 
OLYMPIC PENINSULA TONIGHT INTO WEDNESDAY AFTERNOON.

THE FRONT IS PROGRESSIVE AND WILL PUSH EASTWARD WED REACHING FROM 
THE N CASCADES TO THE NW OREGON COAST. THE NAM12 HINTS THAT RATHER 
HEAVY RAINFALL AMOUNTS ARE POSSIBLE OVER THE NORTH CASCADES WED 
MORNING. 

BREEZY AND SHOWERY WEATHER CAN BE EXPECTED WED AFTERNOON THROUGH THU 
IN STRONG SW FLOW ALOFT. 

FARTHER OUT...ALL OF THE LARGE SCALE MODELS...AS WELL AS THE LATEST 
12Z NAM12...ARE SHOWING GOOD SURFACE DEVELOPMENT OVER THE EASTERN 
PACIFIC THU NIGHT INTO FRI AS ENERGY DUMPING SOUTHWARD FROM THE 
BERING SEA INTO THE NORTH PACIFIC PHASES WITH THE REMAINS OF 
HURRICANE ANA THAT HAS RECENTLY IMPACTED WESTERN HAWAII. THIS LOW 
DEVELOPS OFFSHORE THEN POSSIBLY DECAYS SOMEWHAT AS IT MOVES INLAND 
OVER THE FIRST PART OF NEXT WEEKEND. THIS SYSTEM WILL NEED TO BE 
CAREFULLY MONITORED. ALBRECHT

.LONG TERM...FROM THE PREVIOUS LONG TERM DISCUSSION...ANOTHER 
VIGOROUS PACIFIC FRONTAL SYSTEM MAY IMPACT THE REGION ON SAT FOR 
ANOTHER ROUND OF WET AND WINDY WEATHER. MODELS ARE SHOWING HIGH WIND 
AS A SURFACE LOW TRACKS THROUGH WESTERN WA...BUT THE EXACT 
STRENGTH...TRACK AND TIMING OF THE SYSTEM IS STILL UNCLEAR. IT IS 
WORTH NOTING BUT NOT BITING ON ANY ONE SOLUTION JUST YET AS A LOT 
CAN CHANGE. THE FORECAST LOOKS COOL AND SHOWERY THROUGH THE REST OF 
THE WEEKEND WITH LONG WAVE TROUGHING ALONG THE WEST COAST. A RIDGE 
MAY BRING DRIER AND CALMER WEATHER ON MON. 33

&&

.HYDROLOGY...THE FLOOD WATCH FOR THE SKOKOMISH RIVER IN MASON COUNTY 
IS BEING EXPANDED TO INCLUDE THE ENTIRE OLYMPIC PENINSULA FOR 
TONIGHT INTO WEDNESDAY. MESOSCALE MODELS ARE QUITE AGGRESSIVE IN 
SHOWING RAINFALL RATES OF 0.70 TO 1.00 INCH PER HOUR FOR SEVERAL 
HOURS TONIGHT AS A FRONT STALLS THEN A LOW PRESSURE SYSTEM MOVES BY 
TO THE WEST OF THE AREA INTO VANCOUVER ISLAND. THE SKOKOMISH RIVER 
IS LIKELY TO FLOOD. WHILE RIVERS SUCH AS THE QUINAULT AND CLEARWATER 
CAN HANDLE A LOT OF WATER...THEY DONT TYPICALLY SEE 9-12 INCHES FALL 
IN A 12 TO 15 HOUR PERIOD. IT THAT OCCURS...FLOODING IS LIKELY ON 
PORTIONS OF THOSE RIVERS AND AN AREAL FLOOD WARNING WOULD BE ISSUED. 
THE BOGACHIEL AND OTHER RIVERS FLOWING OFF THE OLYMPICS WILL ALSO 
NEED TO BE WATCHED. 

MESOSCALE MODELS ALSO SHOW A PERIOD OF RATHER HEAVY RAINFALL IN THE 
NORTH CASCADES LATE TONIGHT INTO WEDNESDAY MORNING. WHILE MODELS DO 
NOT SHOW FLOODING IN THIS AREA AT THIS TIME...IF THE INCOMING WRFGFS 
4KM AND ECMWF SHOW VERY HEAVY RAINFALL IN THIS AREA...A FLOOD WATCH 
MAY ALSO NEED TO BE ISSUED FOR SOME RIVERS IN WHATCOM AND SKAGIT 
COUNTY LATER THIS AFTERNOON FOR THE WEDNESDAY AND WEDNESDAY NIGHT 
TIME PERIOD.

ANOTHER PERIOD OF HEAVY RAINFALL IS EXPECTED FRIDAY INTO THE 
WEEKEND...BUT AT THIS TIME FLOODING IS NOT EXPECTED ON WESTERN 
WASHINGTON RIVERS. ALBRECHT 

&&

.AVIATION...WESTERLY FLOW ALOFT BECOMING SOUTHWEST TONIGHT. A 
VIGOROUS FRONTAL SYSTEM WILL MOVE INTO THE AREA LATER TODAY AND 
TONIGHT...BRINGING RAIN AND WIND. AIR MASS MOIST AND STABLE.

CEILINGS MOSTLY 4000-7000 FEET TODAY WITH LOWER CEILING IN SCATTERED 
SHOWERS. CEILINGS EXPECTED TO GRADUALLY LOWER TONIGHT AS STEADY RAIN 
DEVELOPS.

KSEA...GENERALLY MID LEVEL CLOUDS TODAY BUT LOWER CEILINGS AT TIMES 
IN SHOWERS. CEILINGS SHOULD GRADUALLY LOWER TONIGHT AS RAIN 
DEVELOPS. SOUTH WIND 10 TO 15 KNOTS...INCREASING TO 10 TO 20 KNOTS 
WEDNESDAY MORNING. SCHNEIDER

&&

.MARINE...A VIGOROUS FRONTAL SYSTEM WILL BRING GALE FORCE WINDS TO 
MOST WATERS LATE THIS AFTERNOON AND TONIGHT WITH SMALL CRAFT 
ADVISORY WINDS ALL OTHER WATERS. 

THERE WILL BE A RELATIVE LULL IN THE STORMY WEATHER IN THE MIDDLE OF 
THE WEEK...THEN ANOTHER STRONG WEATHER SYSTEM WILL AFFECT THE WATERS 
FRIDAY AND SATURDAY. A DEEP SURFACE LOW IS EXPECTED TO TRACK THROUGH 
THE WATERS DURING THIS TIME BUT THERE IS STILL A LOT OF UNCERTAINTY 
WITH HOW STRONG THE LOW WILL BE AND WHERE IT WILL GO. SCHNEIDER

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...FLOOD WATCH MASON...CLALLAM...JEFFERSON...AND GRAYS HARBOR
      COUNTIES TONIGHT INTO WEDNESDAY AFTERNOON.
     WIND ADVISORY COAST...ADMIRALTY INLET...SAN JUANS...WESTERN
       WHATCOM...WESTERN SKAGIT.

PZ...GALE WARNING COASTAL WATERS...ENTRANCES TO THE STRAIT OF
      JUAN DE FUCA...NORTHERN INLAND WATERS...AND ADMIRALTY INLET 
      LATE THIS AFTERNOON THROUGH TONIGHT.
     SMALL CRAFT ADVISORY COASTAL WATERS...ENTRANCES TO THE 
      STRAIT  OF JUAN DE FUCA...NORTHERN INLAND WATERS...AND
      ADMIRALTY INLET TODAY.
     SMALL CRAFT ADVISORY CENTRAL STRAIT OF JUAN DE FUCA AND PUGET
      SOUND AND HOOD CANAL.
     SMALL CRAFT ADVISORY GRAY HARBOR BAR FOR ROUGH BAR.
     
&&

$$

WWW.WEATHER.GOV/SEATTLE

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS 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


324 
FXUS66 KPQR 211644
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
944 AM PDT TUE OCT 21 2014

.SYNOPSIS...EXPECT A VERY WET AND OCCASIONALLY WINDY WEEK AHEAD AS 
AN ACTIVE FALL WEATHER PATTERN DOMINATES SOUTHWEST WASHINGTON AND 
NORTHWEST OREGON. THE SYSTEM WHICH BROUGHT SHOWERS AND A COUPLE 
CLAPS OF THUNDER MONDAY HAS MOVED INTO EASTERN OREGON AND THE GREAT 
BASIN. ENOUGH MOISTURE AND INSTABILITY REMAINS LEFT BEHIND FOR 
SCATTERED SHOWERS THIS MORNING. MEANWHILE A STRONG FRONTAL SYSTEM IS 
TAKING SHAPE OFFSHORE. THIS SYSTEM WILL BE A SLOW MOVER...SPREADING 
LOCALLY HEAVY RAIN SOUTH AND EAST ACROSS THE FORECAST AREA TONIGHT 
THROUGH EARLY THURSDAY. THIS FRONT WILL PRODUCE STRONG COASTAL WINDS 
AS WAVES OF LOW PRESSURE DEVELOP ALONG IT AND PASS BY. ANOTHER WET 
AND POTENTIALLY WINDY FRONT IS EXPECTED BY THE WEEKEND.

&&

.UPDATE...MODELS HAVE CHANGED LITTLE THUS FAR WITH THE 12Z OUTPUT. 
THE WARM FRONT IS CURRENTLY SPREADING ACROSS THE AREA WITH THE 
TRAILING COLD FRONT STILL WELL OFFSHORE. THE OCCLUSION IS SITUATED 
JUST OFFSHORE THE NORTH TIP OF VANCOUVER ISLAND. THIS SETUP PLACES 
OUR REGION SQUARELY IN THE WARMING SECTOR OF THE FRONTAL SYSTEM. 
CONDITIONS ARE STILL VERY FAVORABLE TO SEE A COASTAL JET DEVELOP 
WITH NAM12 AND RAP INDICATED PEAK SPEEDS AROUND 67 MPH CENTERED 
AROUND 900 MB. THUS FEEL MOST GUSTS ALONG THE COAST WILL PEAK OUT 
AROUND 60 MPH GIVEN BROAD ISENTROPIC LIFT AHEAD OF THE COLD FRONT 
AND WINDS AT THAT LEVEL VEERING MORE SW THAN THE SOUTH WINDS TRAPPED 
ALONG THE TERRAIN. WILL STILL CARRY THE HIGHER SPEEDS TONIGHT IN THE 
PRODUCTS FOR NOW AS THE EXPOSED HIGHER HEADLANDS SUCH AS CAPE 
FOULWEATHER...CAPE LOOKOUT...AND CAPE DISAPPOINTMENT CERTAINLY COULD 
FULLY REALIZE THOSE HIGHER SPEEDS. RAIN AMOUNTS REMAIN ON TRACK AS 
EXPECTED FROM OVER THE LAST COUPLE DAYS. /JBONK
 
&&

.PREV DISC... /ISSUED 351 AM PDT TUE OCT 21 2014/ 

SHORT TERM...TODAY THROUGH THURSDAY...THE MAIN FEATURE OF THE SHORT 
TERM FORECAST PERIOD WILL BE OUR STRONGEST FRONTAL SYSTEM SO FAR 
THIS SEASON...PRODUCING STRONG COASTAL WINDS LATER TODAY THROUGH 
WEDNESDAY. THIS FRONT WILL ALSO HAVE A STRONG TAP TO SUBTROPICAL 
MOISTURE...SPREADING LOCALLY HEAVY RAIN SOUTHWARD ACROSS SOUTHWEST 
WASHINGTON AND NORTHWEST OREGON TONIGHT THROUGH THURSDAY MORNING. 
CONDITIONS ARE RIPE FOR CYCLOGENESIS ALONG THE FRONT...AND MULTIPLE 
WAVES OF LOW PRESSURE ARE EXPECTED TO DEVELOP AND RIDE NE ALONG THE 
FRONT AS IT PASSES SLOWLY SOUTHWARD ACROSS WESTERN WA/OR. 

FIRST THINGS FIRST...SCATTERED SHOWERS CONTINUE THIS MORNING IN THE
RESIDUAL MOISTURE AND CONDITIONAL INSTABILITY LEFT BEHIND THE FRONT
WHICH MOVED THROUGH THE FORECAST AREA MONDAY. THESE SHOULD GRADUALLY
TAPER OFF THIS MORNING AS THE AIR MASS WARMS ALOFT...HOWEVER THE WARM
ADVECTION ALOFT WILL ALSO PRODUCE ISENTROPIC LIFT. THIS SHOULD RESULT
IN RAINY DAY FOR THE COAST AND PERHAPS OUR NORTHERN ZONES AS A WARM
FRONT LIFTS THROUGH NW OREGON AND SW WASHINGTON.

BEHIND THE WARM FRONT...THE DOOR WILL BE OPENED FOR A STRENGTHENING
COASTAL JET AHEAD OF AN APPROACHING COLD FRONT. THOUGH DETAILS
VARY...MODEL RUNS HAVE BEEN FAIRLY CONSISTENT IN SUGGESTING A 55 TO
65 KT SOUTHERLY JET DEVELOPING ALONG THE COAST AT 950 MB. THIS SHOULD
BE AMPLE FOR 55-70 MPH GUSTS AT TIMES ALONG THE BEACHES AND HEADLANDS
FROM THE S WA COAST DOWN TO THE LINCOLN AND POSSIBLY LANE COUNTY
COAST. THEREFORE WILL BE UPGRADING THE HIGH WIND WATCH TO A WARNING
FOR THESE AREAS. TIMING WILL REMAIN THE SAME FOR THE S WA/N OR
COAST...THIS AFTERNOON INTO WEDNESDAY MORNING. WILL EXTEND THE TIMING
FOR THE CENTRAL COAST INTO MIDDAY WEDNESDAY TO GIVE THE FRONT SOME
TIME TO PUSH SOUTH OF THE LANE/DOUGLAS COUNTY BORDER.

AS MENTIONED ABOVE...MULTIPLE WAVES OF LOW PRESSURE ARE EXPECTED TO
DEVELOP ALONG THE FRONT...WHICH WILL SLOW DOWN ITS SOUTHWARD
PROGRESS. THESE WAVES OF LOW PRESSURE WILL LIKELY EACH PRODUCE A
BURST OF COASTAL WIND TO ITS SOUTH AND EAST ALONG THE FRONT. SO WINDS
MAY BE STRONG FOR A FEW HOURS...LET UP A BIT...THEN PICK BACK UP
AGAIN UNTIL THE FRONT PUSHES SOUTH OF COASTAL LOCATIONS. THERE IS
STILL A GOOD DEAL OF UNCERTAINTY AS TO HOW DEEP THESE LOWS WILL
GET...WHICH OF COURSE WOULD IMPACT THE EXPECTED WIND SPEEDS. 

THE 06Z NAM IS DEVELOPING A 990 MB LOW ALONG THE FRONT BY 09Z WED...
PUSHING IT INTO VANCOUVER ISLAND WED MORNING. THE FIRST SIGNS OF THIS
DEVELOPING LOW ARE ALREADY SHOWING UP ON INFRARED/WATER VAPOR IMAGERY
WITH A BAROCLINIC LEAF TAKING SHAPE ALONG THE FRONT NEAR 150W. A
SECONDARY LOW WILL LIKELY DEVELOP ALONG THE TRIPLE POINT OF THE
RESULTING OCCLUDING FRONT OFF THE NORTHERN OREGON COAST...AND PERHAPS
A TERTIARY LOW THEREAFTER. THESE WAVES OF LOW PRESSURE WILL SLOW THE
SOUTHWARD PROGRESS...EACH PRODUCING A BURST OF COASTAL WIND TO ITS
SOUTH AND EAST ALONG THE FRONT. SO WINDS MAY BE STRONG FOR A FEW
HOURS...LET UP A BIT...THEN PICK BACK UP AGAIN UNTIL THE FRONT PUSHES
SOUTH OF COASTAL LOCATIONS. THERE IS STILL A GOOD DEAL OF UNCERTAINTY
AS TO HOW DEEP THESE LOWS WILL GET...WHICH OF COURSE WOULD IMPACT THE
EXPECTED WIND SPEEDS.

ALSO THE 06Z NAM IS BEGINNING TO SHOW SOME POTENTIAL FOR GUSTY WINDS
IN THE WILLAMETTE VALLEY...AS ITS SECONDARY LOW MOVES ONSHORE NEAR
ASTORIA WED MORNING. THIS TRACK COULD OPEN UP ENOUGH SOUTHERLY
GRADIENT FOR 30-40 MPH WIND GUSTS IN THE WILLAMETTE VALLEY AND
STRONGER WIND GUSTS IN THE COASTAL COMMUNITIES. FOR NOW IT APPEARS
WINDS WILL REMAIN SUB-ADVISORY CRITERIA INLAND...BUT WILL NEED TO
MONITOR CLOSELY.

NOT TO GET LOST IN ALL THE DISCUSSION ABOUT OUR FIRST COASTAL HIGH
WIND EVENT...IS THE POTENTIAL FOR RATHER IMPRESSIVE RAINFALL TOTALS
AS THIS SLOW MOVING...WAVY FRONT MOVES SLOWLY SOUTH ACROSS OUR
FORECAST AREA. THIS SYSTEM IS TAPPING INTO A DECENT ATMOSPHERIC RIVER
WHICH EXTENDS ALL THE WAY BACK BEYOND THE DATELINE. MADE ONLY MINOR
CHANGES TO THE QPF FORECAST...WITH 2 INCHES OF RAIN EXPECTED FOR THE
INLAND VALLEYS...2-4 INCHES ALONG THE COAST...AND 3-6 INCHES IN THE
HIGHER TERRAIN BY THURSDAY. IT WILL BE A CLOSE CALL WHETHER OR NOT
THIS WILL BE ENOUGH TO CAUSE PROBLEMS ON FLASHIER RIVERS LIKE THE
GRAYS RIVER IN THE WILLAPA HILLS...AS WELL AS THE BURN SCAR AREAS
FROM THE 36 PIT AND DECEPTION FIRES. IMPACTS ON THESE AREAS WILL NEED
TO BE MONITORED CLOSELY OVER THE COMING DAYS.

DUE TO THIS SYSTEMS SUBTROPICAL ORIGINS SNOW LEVELS WILL REMAIN
RATHER HIGH THROUGHOUT THIS EVENT...SO ONLY THE HIGHEST VOLCANO PEAKS
ABOVE 6000-7000 FEET WILL RECEIVE SIGNIFICANT SNOWFALL.

THE FRONT WILL FINALLY PUSH SOUTH AND EAST OF OUR FORECAST AREA
SOMETIME LATE WED NIGHT OR THU MORNING. SHOWERS WILL LINGER IN THE
COOL UNSETTLED AIR MASS BEHIND THE FRONT THURSDAY.  WEAGLE

LONG TERM...FRIDAY THROUGH MONDAY...MEDIUM RANGE GUIDANCE CONTINUES 
TO STRUGGLE WITH HOW TO HANDLE THE LATE WEEK AND WEEKEND PERIOD. 
THERE IS INCREASING AGREEMENT THAT ANOTHER POTENT LOW PRESSURE/ 
FRONTAL SYSTEM WILL DEVELOP OFFSHORE...PERHAPS BRINGING ANOTHER 
PERIOD OF HEAVY RAIN AND GUSTY WINDS FRIDAY AND/OR SATURDAY. AS FOR 
THE LONGWAVE PATTERN...THE LATEST 00Z RUNS ARE TRYING TO KEEP THE 
MEAN RIDGE POSITION OVER THE WESTERN HALF OF THE UNITED STATES. THIS 
IS NOT SURPRISING CONSIDERING THE LARGE POOL OF ABOVE NORMAL SEA 
SURFACE TEMPS OVER THE NE PACIFIC. THE PACIFIC NORTHWEST MAY REMAIN 
IN THE TRANSITION ZONE BETWEEN LONGWAVE RIDGING AND TROUGHING WELL 
INTO NEXT WEEK...WHICH IS OF COURSE WHERE THE STORM TRACK TENDS TO 
BE. THEREFORE ACTIVE AND WET WEATHER AT TIMES IS EXPECTED TO 
CONTINUE INTO NEXT WEEK.  WEAGLE

&&

.AVIATION...SHOWERS CONTINUE THIS MORNING AS A WARM FRONT
APPROACHES THE REGION. EXPECT PRIMARILY VFR CONDITIONS TODAY AND
TONIGHT WITH BRIEF MVFR CIGS FORMING FROM TIME TO TIME. GUSTY
SOUTHERLY WINDS WILL PICK UP TODAY AND ESPECIALLY THIS EVENING.
COASTAL SITES MAY SEE WIND GUSTS TO 45 KT AT TIMES TONIGHT THROUGH
WED MORNING. A HIGH WIND WARNING IS NOW IN EFFECT FOR THE COASTAL
SITES. A COLD FRONT WILL SPREAD HEAVIER RAIN ONTO THE COAST
OVERNIGHT NIGHT AND INLAND TOMORROW MORNING.

KPDX AND APPROACHES...VFR PREVAILING THROUGH TONIGHT...ALTHOUGH A
BRIEF MVFR CIG MAY FORM THROUGH ABOUT 21Z IN SHOWERS. BREEZY
SOUTHERLY WINDS ARE EXPECTED THIS EVENING AND OVERNIGHT. A COLD
FRONT TO SPREAD STEADY RAIN IN AFTER 12Z TOMORROW. PYLE

&&

.MARINE...S/SW WINDS CONTINUE AROUND 10 TO 20 KT WITH GUSTS TO 25
KT THIS MORNING. WINDS WILL GRADUALLY INCREASE TODAY...REACHING
GALE FORCE BY MID AFTERNOON. THE STRONGEST WINDS ARE EXPECTED THIS
EVENING AND OVERNIGHT AHEAD OF AN APPROACHING COLD FRONT...WITH
GUSTS TO 40 TO 45 KT EXPECTED. SOME COASTAL JET ENHANCEMENT MAY
BRING A FEW 50 TO 55 KT GUSTS TO THE NEAR SHORE WATERS.
 
A WESTERLY SWELL ON THE ORDER OF 10 FT WILL CONTINUE FOR THE NEXT 
FEW DAYS...BUT SEAS WILL INCREASE SIGNIFICANTLY TONIGHT AS THE
SOUTHERLY WINDS PICK UP. BASED ON THE LATEST MODEL GUIDANCE...SEAS
MAY APPROACH 20 KT LATER THIS EVENING AND OVERNIGHT.

WINDS AND SEAS ARE EXPECTED TO DROP OFF DURING THE DAY WEDNESDAY.
ADDITIONAL SYSTEMS ARE EXPECTED LATER THIS WEEK...BUT THE TONIGHT
INTO WEDNESDAY IS EXPECTED TO BE THE STRONGEST. PYLE

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...HIGH WIND WARNING FROM 3 PM THIS AFTERNOON TO 9 AM PDT WEDNESDAY 
     FOR NORTH OREGON COAST.

     HIGH WIND WARNING FROM 3 PM THIS AFTERNOON TO NOON PDT WEDNESDAY 
     FOR CENTRAL OREGON COAST.

WA...HIGH WIND WARNING FROM 3 PM THIS AFTERNOON TO 9 AM PDT WEDNESDAY 
     FOR SOUTH WASHINGTON COAST.

PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL 1 PM PDT THIS AFTERNOON FOR 
     COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 60 NM.

     GALE WARNING FROM 1 PM THIS AFTERNOON TO 11 AM PDT WEDNESDAY FOR 
     COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 1 PM PDT THIS 
     AFTERNOON FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE 
     OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 9 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


390 
FXUS66 KPDT 211733 AAA
AFDPDT

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PENDLETON OR
1033 AM PDT TUE OCT 21 2014

UPDATED AVIATION DISCUSSION

.SHORT TERM...STRONG UPPER LEVEL TROUGH MOVING INTO IDAHO THIS 
MORNING. SOME LINGERING LIGHT RAIN OVER THE BLUES AND WALLOWA COUNTY 
FOR A FEW MORE HOURS. A MUCH WEAKER SHORT WAVE IS MOVING ACROSS THE 
PACIFIC NORTHWEST TODAY. THIS WILL RESULT IN PARTLY TO MOSTLY CLOUDY 
SKIES. SCATTERED SHOWERS MAINLY OVER THE CASCADES. COOLER AIRMASS 
OVER THE REGION TODAY WITH HIGHS IN THE 50S AND 60S. 12Z MODELS 
CONTINUE TO SHOW RAIN LIKELY WEDNESDAY INTO WEDNESDAY NIGHT. 94

&&

.AVIATION...18Z TAFS...VFR CONDITIONS SHOULD PREVAIL NEXT 24 
HOURS...BUT MID AND HIGH CLOUDS CAN BE EXPECTED. CLOUDS WILL THICKEN 
AND LOWER OVERNIGHT WITH NEXT WEATHER SYSTEM. RAIN COULD ARRIVE AT 
KBDN...KDLS AND KYKM BY WEDNESDAY MORNING. WINDS WILL GENERALLY 
REMAIN BELOW 12 KTS...EXCEPT FOR GUSTY SOUTH WINDS AT KBDN.  82 

&&

.PREV DISC... /ISSUED 445 AM PDT TUE OCT 21 2014/ 

SHORT TERM...TODAY THROUGH THURSDAY...A COLD FRONT IS MOVING ACROSS 
UNION AND WALLOWA COUNTY AT THIS TIME. THE FRONT WILL SLOWLY MOVE 
EASTWARD AND EXIT THE AREA EARLY TODAY. RAIN WILL SHIFT EASTWARD 
WITH THE FRONT. WITH THE FRONT EXITING THIS MORNING WILL SEE 
SHOWERS ON THE DECREASE OVER FAR EASTERN OREGON TO JUST A SLIGHT 
CHANCE BY AFTERNOON. REST OF THE FORECAST AREA WILL BE PARTLY CLOUDY 
AND COOL FOLLOWING THE FRONTAL PASSAGE. RAIN WILL BE SLOW TO SPREAD 
EASTWARD...AS THE UPPER LEVEL FLOW IS PARALLEL TO THE FRONT. 
PRECIPITATION WILL EVENTUALLY DEVELOP OVER ALL AREAS BY WEDNESDAY 
NIGHT. A COLD FRONT WITH THE SYSTEM WILL LOWER SNOW LEVELS DOWN TO 
5500-6500 FEET ALONG THE CASCADES THURSDAY. RAIN SHADOWING WILL 
DEVELOP IN THE COLUMBIA BASIN, AND YAKIMA AND KITTITAS VALLEYS 
THURSDAY BEHIND THE FRONT. COONFIELD 

LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...MOIST SOUTHWEST FLOW 
AHEAD OF PACIFIC TROF WILL BRING PERIODS OF RAIN TO MAINLY THE 
MOUNTAIN AREAS THURSDAY NIGHT THROUGH SATURDAY.  THE RAIN WILL 
DECREASE SUNDAY AND MONDAY.  EC-GFS IN GOOD AGREEMENT UNTIL SUNDAY 
WHEN EC DEVELOPS A RIDGE AND GFS STAYS WITH WEAK TROF AND FLAT 
WESTERLY FLOW.  WITH THIS SLIGHT UNCERTAINTY WILL LEAVE A SMALL 
CHANCE FOR PRECIPITATION IN THE MOUNTAINS FOR MONDAY AND TUESDAY. 
BREEZY TO WINDY CONDITIONS WILL ACCOMPANY A FRONTAL PASSAGE ON 
SUNDAY. NO SIGNIFICANT TEMPERATURE EXTREMES EXPECTED.

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  65  45  69  53 /  10  10  40  70 
ALW  65  48  68  53 /  10  10  40  70 
PSC  67  49  67  53 /  10  10  50  60 
YKM  63  44  59  45 /  10  30  70  70 
HRI  67  43  66  51 /  10  10  50  70 
ELN  63  45  60  45 /  10  60  80  80 
RDM  60  40  66  46 /  10  10  50  80 
LGD  60  41  64  50 /  40  10  20  50 
GCD  60  40  64  48 /  20  10  20  50 
DLS  65  48  62  52 /  10  30  70  80 

&&

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

&&

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

$$

94/82




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

Northeastern Washington and Northern Idaho


191 
FXUS66 KOTX 211811
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
1111 AM PDT TUE OCT 21 2014

.SYNOPSIS...

A cold front is very slowly moving through the Inland Northwest
which will bring precipitation to much of the area and an end to
the above average temperatures. The active pattern will continue
through the weekend with the potential for heavy rain continuing
as moisture associated with former typhoons makes its way toward
the Pacific Northwest early next week.

&&

.DISCUSSION...

.Today and tonight...Deep upper level trough and associated cold 
front will continue to make a slow eastward crawl through the Inland 
NW this morning. As of 200 am...the front was located along a
line from Colville to the Blue Mountains with widespread
precipitation immediately ahead of the boundary. This shield of
precipitation will be the main feature of the weather today over
the region. North of I-90...the precipitation will be somewhat hit
or miss with lesser amounts of available moisture and deep ascent.
Meanwhile...south of I-90...the precipitation will begin to
blossom as the base of the aforementioned shortwave trough tracks
northeast...moving into SW Montana by afternoon. Various model
guidance is all consistent on producing a MISSPEND of heavier
precipitation across the southern Panhandle. The NAM is the most
aggressive solution and produces a broad swath of precipitation
amounts from 0.20-0.40 inches this morning. Some of this
intersects southern Shoshone County...impacting the towns of Avery
and Clarkia. The other solutions are insistent the heaviest
precipitation band will remain over the Clearwater Mountains and
points to the south. This scenario leaves most of the Inland NW
free of moderate to heavy precipitation for this morning.

The base of the trough is forecast to move into SW Montana by late 
afternoon/evening which allows shortwave ridging to rebuild over
most of the area. This should bring a brief drying trend to the
region...however residual moisture and instability will keep a
threat of showers going along the ID/MT border as well as near the
Canadian border.

The shortwave ridge is expected to shift from the Cascades this
evening and into NW Montana by daybreak on Wednesday. This
transition will mark an increasing threat of precipitation once
again beginning near the Cascades and spreading into the Okanogan
Highlands and Wenatchee overnight. This round of precipitation
should be wetter than what the current front is delivering. These
differences are related to higher amounts of precipitable water
and much stronger isentropic ascent. The precipitation will also
be aided weak to moderate orograhpic ascent from south-southeast
winds in the mid-atmosphere. The threat of precipitation will
persist through most of Wednesday and Wednesday night. fx

Wednesday through Saturday...

...SUBTROPICAL MOISTURE FETCH TO BRING HEAVY RAIN TO THE CASCADES
WEDNESDAY...

Wednesday...Forecast models continue to show an atmospheric river
containing subtropical moisture getting picked up by a deep closed
low off the Central BC coast...with moisture slamming into the
Cascades on Wednesday...with rain also spilling into North Central
and Northeast Washington through the afternoon. 850mb winds out of
the south-southeast may result in significant spill over from the
crest into the valleys with 1-2 inches of rain not out of the
question with up to 3 inches along the Cascade crest. This long
duration rain may be enough to cause small debris flows over the
burn scar areas. With rivers and streams at their climatologically
lowest stages these rain amounts are not expected to cause
flooding. Elsewhere timing of when the moisture plume sags
southeast has slowed a bit with the 00z model runs with the
exception of the ECMWF. Thus POP's were lowered east of a line
from Ritzville to Spokane to Sandpoint as rain in these areas may
hold off until Wednesday evening. 850mb winds out of the south-
southwest over the northern mountains will provide strong upslope
flow where around an inch of rain is possible. These same winds
will downslope off the Blue and Wallowa Mountains with the
Lewiston area getting the least amount of rain with this system.

Thursday...The atmospheric river shifts south across Oregon
possibly clipping far southeast Washington. Central and Eastern
Washington and North Idaho will be on the cool side of a 140kt
upper level jet supporting more of a showery scenario. With 850mb
winds out of the southwest at 30 kts and lack of isentropic
lift...a more pronounced rain shadow east of the Cascades is
expected. POP's were lowered for much of the Columbia Basin
extending to Spokane and the Palouse on Thursday. Afternoon sun
breaks in combination with stronger winds aloft should result in
breezy conditions over the Upper Columbia Basin, Spokane area, and
Palouse.

Friday and Saturday...GFS and ECMWF models show the development of
a 990mb surface low off the Oregon coast tracking north to off the
Washington Coast. The GFS shows the low closer to the coast and
shows more precipitation and wind potential compared to the ECMWF.
However both models indicate a warm front lifting north into
Washington and North Idaho late Friday afternoon into Friday night
with easterly flow favoring the East Slopes of the Cascades and
adjacent valleys and POP's were increased to likely over a broader
area with chance POP's elsewhere. Then the cold front passage
Saturday will keep precip chances alive especially in the
mountains. Snow levels look to remain high through the period with
the only the higher peaks being cold enough for snow.  JW

Saturday night through Tuesday night: An active weather pattern
remains over the Inland Northwest, with additional chances for
precipitation into early next week. The trough will finally move
inland on Sunday, which may be followed by somewhat of a break in
the wet weather over the lowlands. However, the approach of
another storm system in the Monday night/Tuesday time frame will
bring additional chances for rainfall and high mountain snowfall.
This system looks to ride on another deep moisture fetch, which
could bring heavier rainfall to at least the Cascades.

Another thing to watch, although it doesn't look like it will be
too much of an issue at this point, are snow levels. Snow levels
may fall low enough that some of the mountain passes could be
affected. Something to watch in the coming days. Otherwise,
temperatures should finally fall back to near normal late October
values, at least during the afternoons. Low temperatures may be a
bit above normal. ty

&&

.AVIATION...
18Z TAFS: Low stratus will linger around the northern and eastern
basin, as well as, into the ID Panhandle through this afternoon.
This will impact the KGEG, KSFF, KCOE and KPUW TAF locations. The stratus
deck is expected to lift into a stratocumulus deck through the
afternoon with VFR cigs possible by the late afternoon hours. Low
level flow will back to out of the southeast overnight as a moist
Pacific storm system approaches the region. Strong warm air
advection should clear out the low clouds tonight with rainfall
forming northwest of a line from KMWH to KCQV by Wednesday
morning. KEAT will likely see light rain developing after 12Z with
cigs lowering to MVFR category. Low level wind shear will become a
concern as well with winds increasing significantly off the
surface and veering to out of the southwest; however, low level
wind shear is not mentioned in the TAFs as it does not look to be
strong enough. /SVH

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        57  43  59  47  59  44 /  20  10  50  90  50  20 
Coeur d'Alene  56  40  57  45  58  43 /  40  10  40  90  60  20 
Pullman        56  42  62  47  58  46 /  30   0  20  80  60  40 
Lewiston       63  43  66  50  62  49 /  40   0  10  20  60  50 
Colville       58  43  54  46  58  44 /  30  30  90 100  70  40 
Sandpoint      55  40  55  44  55  40 /  50  10  50 100  90  40 
Kellogg        51  39  57  44  52  42 /  80  10  20  90  80  50 
Moses Lake     65  46  59  49  64  45 /   0  20  80  70  20  10 
Wenatchee      63  48  55  46  61  45 /   0  70  80  80  20  20 
Omak           61  45  52  45  60  43 /  10  70 100  80  50  10 

&&

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

$$


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