High Wind in Washington, January 10 to 11, 2014

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
900 PM PST FRI JAN 10 2014

.SYNOPSIS...A VIGOROUS PACIFIC STORM SYSTEM WILL MOVE THROUGH THE
PACIFIC NW TONIGHT THROUGH SAT NIGHT BRINGING WINDY CONDITIONS...
SNOW TO THE CASCADES...AND HIGH SURF TO THE COAST. THE SYSTEM WILL
CONSIST OF A WARM FRONT LIFTING N INTO WA THIS EVENING...A COLD
FRONT MOVING INLAND LATE TONIGHT...THEN FOLLOWED BY AN OCCLUDED
FRONT AND UPPER LEVEL TROUGH SAT. A WARM FRONT WILL FOLLOW LATE
SUN...THEN HIGH PRES WILL REBUILD OVER THE REGION EARLY NEXT WEEK.
&&

.EVENING UPDATE...THIS IS THE EARLIER EVENING UPDATE...ONLY CHANGES
IN THIS AFD ISSUANCE IS TO MARINE AND AVIATION...SEE BELOW.

MILD AND LIGHTLY BREEZY INLAND...WHILE WINDS ARE STARTING TO RAMP UP
ALONG THE SOUTH WASHINGTON AND NORTHERN COASTAL HEADLANDS AND
BEACHES WERE WINDS ARE SUSTAINED 35-45 IN SPOTS WITH GUSTS INTO THE
50S MPH. EXPECT THIS TREND TO CONTINUE THROUGH THE EVENING. MODELS
ARE TRACKING THE LOW PRETTY WELL...THE LOW DOWN TO 976 MB NEAR
50N/140W WITH AN OCCLUDED FRONT EXTENDING TO THE TRIPLE POINT AROUND
134W. THE COLD FRONT IS DRAPED SOUTH OF THERE AND HAS SINCE CLEARED
BUOY 36.

WINDS WILL PICK IN THE VALLEY QUITE A BIT OVERNIGHT...AND AGAIN ON
SATURDAY AFTER A LULL. SREF PLUMES FOR 10 M WINDSPEED DEPICT THESE
PEAKS REALLY WELL...RIGHT AROUND 4 AM IN THE VALLEY...AND AGAIN
AROUND 1 PM SATURDAY AFTERNOON. SUSTAINED 10 M WINDS (NOT GUSTS)
FROM THE SREF MEAN WHICH IS TRACKING WELL NOW FOR SALEM ARE 26 MPH
OVERNIGHT AND 29 MPH IN THE AFTERNOON. EXPECT ABOUT A 4 HOUR PERIOD
OF MODERATE TO HEAVY RAIN WHICH CLEARS THE VALLEY BY 7-8 AM.  THERE
MAY BE SOME CONVECTION ALONG THE FRONT BUT NO CLEAR SIGNAL AS TO
WHETHER CONVECTION WOULD BE STRONG ENOUGH TO ENHANCE WINDS GIVEN THE
INCREASING GRADIENT DRIVEN WINDS. MIXING WILL INCREASE ON SATURDAY
AND RESULT IN A WINDY AND SHOWERY DAY FOR EVERYONE.  ISOLATED
LIGHTNING STILL LOOKS POSSIBLE...AND IS INDICATED ON OFFSHORE
LIGHTNING STRIKE DENSITY PRODUCT NEAR THE CONVECTION WITH THE COLD
CORE TROUGH. SOUNDINGS STILL SUGGEST MOST OF THE SHOWERS WON'T BE
TALL ENOUGH FOR A TON OF LIGHTNING...BUT THESE LOOK TO BE POTENT
SMALL HAIL TYPE HEAVY SHOWERS. CURRENT FORECAST HAS A GOOD HANDLE ON
THIS FOR REASONS MENTIONED BELOW. /KMD

&&

.SHORT TERM...OVERALL...MODELS HAVE BEEN REMARKABLY CONSISTENT WITH
THE MAJOR FEATURES AFFECTING THE REGION THROUGHOUT THE NEXT FEW
DAYS...AND MOST NOTABLY WITH THE STORM SYSTEM ARRIVING TONIGHT AND
SAT. AS SUCH...FORECAST REQUIRED ONLY MINOR CHANGES TODAY.

UPPER LOW WAS SEEN IN WATER VAPOR PICTURES NEAR 48N 148W EARLY THIS
AFTERNOON...WITH A LARGE SWATH OF SUBTROPICAL MOISTURE PULLED UP
AHEAD OF THE TROUGH. THE TROUGH IS EXPECTED TO MOVE RAPIDLY
E...MOVING INLAND OVER THE PACIFIC NW LATE SAT. A SURFACE LOW
ASSOCIATED WITH THE UPPER TROUGH IS EXPECTED BY MODELS TO TRACK E...
MOVING INLAND AROUND VANCOUVER ISLAND LATE SAT. THE LOW IS
CHARACTIZED BY A STRONG AND LARGE WIND FIELD AROUND IT...THAT
COUPLED WITH SEVERAL KEY FEATURE WILL BRING AN EXTENDED CHANCE FOR
HIGH WINDS TO THE COAST AND COASTAL WATERS TONIGHT AND SAT. THE
INITIAL THREAT FOR HIGH WINDS COMES WITH THE ARRIVAL OF THE WARM
FRONT TO THE COAST THIS EVENING AS THE SURFACE LOW BECOMES MORE
SOUTHERLY AND A COASTAL JET DEVELOPS. A COLD FRONT ARRIVING ON THE
COAST WILL PROVIDE A BETTER FOCUS FOR HIGH WINDS LATE TONIGHT...AND
ALSO BRING SOME GUSTY WINDS TO INLAND AREAS AS IT MOVES INLAND.
FINALLY...THE OCCLUSION WRAPPING AROUND THE LOW IS EXPECTED TO
ARRIVE DUIRNG THE DAY SAT...AND WHILE THE WESTERLY WINDS ARE NOT
CONDUCIVE TO MAINTAINING A COASTAL JET...GRADIENT WINDS STILL
SUGGEST THE POSSIBLITY FOR HIGH WINDS ALONG THE COAST INTO THE
AFTERNOON HOURS. PEAK WINDS IN THE VALLEY...WHILE NOT QUITE AS
STRONG...WILL COME WITH THE ARRIVAL OF THE COLD FRONT LATE
TONIGHT...THEN AGAIN SAT WITH THE OCCLUDED FRONT AND N TO S SURFACE
PRES GRADIENTS ON THE ORDER OF 6 TO 8 MB DOWN THE VALLEY.

WITH ORIGINS IN THE N PACIFIC...THE POST FRONTAL AIR WILL BE COOL
ENOUGH TO DROP SNOW LEVELS BELOW THE PASSES SAT AFTERNOON. A STRONG
WESTERLY 850 MB FLOW ON THE ORDER OF 50 KT SHOULD GENERATE STRONG
OROGRAPHIC LIFT WHICH COUPLED WITH INITIALLY DEEP MOISTURE SHOULD
GENERATE A PERIOD OF RATHER HEAVY SNOW FOR THE CASCADES SAT
AFTERNOON AND EVENING. THE FLOW BEGINS THE WEAKEN OVERNIGHT SAT
NIGHT. WILL UPGRADE THE WINTER STORM WATCH TO A WARNING FOR SAT AND
SAT NIGHT.

WITH THE UPPER RIDGE BEGINNING TO REBUILD OFFSHORE SUN...A WARM
FRONT APPROACHES THE COAST. MOISTURE OVERRUNNING THE FRONT WILL KEEP
A THREAT OF RAIN GOING SUN FOR MOST OF THE AREA...ESP ACROSS THE N.
WILL SEE POPS DROP OFF FROM SW TO NE SUN NIGHT AND MON AS THE FRONT
PUSHES INLAND.

.LONG TERM...MONDAY NIGHT THROUGH FRIDAY.
KEPT A SLIGHT CHANCE FOR SOME LINGERING SHOWERS LATE MONDAY ACROSS
THE NORTHERN ZONES. AFTER THIS...MODELS ARE IN GOOD AGREEMENT THAT
AN UPPER LEVEL RIDGE WILL DEVELOP OVER THE REGION AND DOMINATE THE
PATTERN UNTIL NEXT WEEKEND. AS A RESULT...NO PRECIP IS EXPECTED
THROUGH FRIDAY EXCEPT FOR PERHAPS A LITTLE LIGHT RAIN IN SW
WASHINGTON ZONES EARLY WEDNESDAY IN ASSOCIATION WITH A SHORTWAVE
DISTURBANCE PROGGED TO MOVE ACROSS NORTHERN WASHINGTON. OTHERWISE
EXPECT DAILY FOG TO DEVELOP ACROSS THE VALLEY LOCATIONS. THE UPPER
LEVEL RIDGE WILL AMPLIFY BY THURSDAY AND OFFSHORE FLOW WILL DEVELOP
INTO FRIDAY. FORECAST MODELS INDICATE THAT THE NEXT FRONTAL SYSTEM
WILL ARRIVE ACROSS THE PACIFIC NORTHWEST FOR NEXT WEEKEND.
TEMPERATURES WILL BE NEAR SEASONAL NORMS...WITH HIGHS GENERALLY IN
THE UPPER 40S AND LOWS IN THE MID 30S THROUGH THE EXTENDED PERIOD.
CULLEN
&&

.AVIATION...WILL SEE LIGHT RAIN CONFINED MAINLY TO NORTHERN PORTIONS
OF THE FCST AREA OVER THE NEXT FEW HOURS AS WE REMAIN THE WARM
SECTOR OF A VERY STRONG FRONTAL SYSTEM. EXPECT MAINLY MVFR
CONDITIONS AT THE COAST AND MAINLY VFR INLAND WITH A BIT OF HIGH END
MVFR MIXED IN AT TIMES. THE COLD FRONT WILL BEGIN TO PUSH ONSHORE
AROUND 09Z AND WILL MOVE FAIRLY QUICKLY THROUGH THE REGION DURING
THE MORNING HOURS. EXPECT MODERATE TO HEAVY RAIN FOR A 4 TO 6 HR
PERIOD WITH THE FRONT...ALONG WITH IFR CONDITIONS AT THE COAST AND
MAINLY MVFR INLAND. EXPECT CONDITIONS TO IMPROVE TO VFR BEHIND THE
FRONT IN THE MID TO LATE MORNING. HOWEVER...THERE WILL BE PLENTY OF
SHOWERS AROUND THROUGH THE REST OF THE DAY INTO TOMORROW EVENING.
EXPECT PERIODS OF MVFR TO DEVELOP IN SOME OF THESE SHOWERS. THE
MOUNTAINS WILL BE OBSCURED THROUGH MUCH OF THE 00Z FORECAST PERIOD.

THE BIGGEST IMPACT FROM THIS FRONTAL SYSTEM WILL LIKELY BE VERY
GUSTY WINDS THAT WILL PICK UP OVER THE NEXT FEW HOURS AS THE FRONT
APPROACHES. WIND SHEAR WILL LIKELY BE A CONCERN FOR MANY SITES AS A
LOW LEVEL JET OF 60+ KT IS BEING ADVERTISED BY THE FCST MODELS
BETWEEN 1500 AND 2000 FT. EXPECT THE GUSTY WINDS TO CONTINUE WELL
INTO THE AFTERNOON.

KPDX AND APPROACHES...A MIX OF VFR AND MVFR WILL OCCUR FROM AROUND
03Z TO 09Z IN THE WARM SECTOR. THEN RAIN WILL PICK UP AFTER THIS AS
A COLD FRONT MOVES THROUGH. EXPECT THE FRONT TO MOVE ACROSS THE
TERMINAL AROUND 13Z TO 14Z SAT...WITH RAPID IMPROVEMENT TO VFR MID
TO LATE MORNING. EXPECT PLENTY OF SHOWERS AROUND THROUGH THE
REMAINDER OF THE DAY...WITH PERIODS OF MVFR DEVELOPING DURING
SHOWERS. ALSO...LOOK FOR VERY GUSTY S/SW WINDS TO DEVELOP AFTER
MIDNIGHT AND CONTINUE THROUGH MUCH OF TOMORROW. PYLE

&&

.MARINE...NOT A LOT HAS CHANGED WITH THE LATEST FCST MODEL RUNS. THE
COASTAL WATERS CURRENTLY SIT IN THE WARM SECTOR OF A STRONG FRONTAL
SYSTEM. SOUTHERLY WINDS ARE COMING UP A BIT MORE SLOWLY THAN THE
FCST MODELS HAD BEEN INDICATING...BUT THEY HAVE CERTAINLY BEEN
RISING OVER THE PAST COUPLE OF HRS. EXPECT WINDS TO PICK UP EVEN
MORE THROUGH THE REST OF THE EVENING...WITH STORM FORCE WINDS STILL
LOOKING LIKELY. THE STRONGEST WINDS WILL LIKELY BE RIGHT ALONG THE S
WA AND N OR COAST AND THE NEAR SHORE WATERS AS CONDITIONS LOOK
FAVORABLE FOR COASTAL JET ENHANCEMENT. COULD SEE GUSTS TO 60 KT
WITHIN THIS COASTAL JET...IMPACTING THE COLUMBIA RIVER BAR.

THE TRAILING COLD FRONT WILL BEGIN TO MOVE ONSHORE AFTER ROUGHLY 09Z
UP NORTH AND 12Z FURTHER SOUTH. EXPECT A BIT OF A LULL IN THE
STRONGER WINDS BEHIND THE FRONT. HOWEVER...EXPECT WE WILL MAINTAIN
GALES OR AT LEAST HIGH END SMALL CRAFT WINDS THROUGH THE DAY. THERE
IS SOME POTENTIAL FOR MORE STORM FORCE GUSTS LATE DURING THE LATE
MORNING AND AFTERNOON. FOR NOW...THE STORM WARNING RUNS THROUGH
18Z...BUT IT MAY NEED TO BE EXTENDED EVENTUALLY. WE WAIT UNTIL WE
SEE IF THE FIRST ROUND OF STORM FORCE WINDS DEVELOP BEFORE DECIDING
ON THIS. WINDS THEN SUBSIDE SOMEWHAT LATER TOMORROW AFTERNOON AND
EVENING. BUT ANOTHER SYSTEM MOVES ACROSS THE WATERS SUN FOR
CONTINUED SMALL CRAFT ADVISORY WINDS...FOLLOWED BY SEVERAL DAYS OF
QUIET WIND CONDITIONS.

THE SEAS WILL BECOME EXTREMELY HAZARDOUS OVERNIGHT THROUGH SAT
EVENING. SEAS WERE RUNNING A BIT ABOVE GUIDANCE EARLIER TODAY...BUT
THE ENP SEEMS TO BE DOING A PRETTY GOOD JOB AT THIS POINT. SEAS WILL
BUILD TO NEAR 20 FT EARLY SAT MORNING. STILL LOOKING AT MAXIMUM WAVE
HEIGHTS IN THE 30 TO 35 FT RANGE BEGINNING LATE SAT AFTERNOON OR
EARLY EVENING. 00Z GUIDANCE CONTINUES THE 12Z AND 18Z TREND OF
KEEPING MAX SEAS AROUND 30 FT. THIS LOOKS TO BE A DYNAMIC FETCH
SITUATION AND THE MODELS MAY BE TOO QUICK TO DECAY THE OFFSHORE
SEAS. MODELS ALSO TEND TO BE TOO SLOW BUILDING THE SEAS IN THESE
SITUATIONS. WENT A LITTLE HIGHER ON THE MAX SEAS THAN ENP OR GWW AND
DECAYED THEM A BIT MORE SLOWLY. PYLE/WEISHAAR

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...WINTER STORM WARNING FROM 6  6 AM SATURDAY TO 4 AM PST SUNDAY
     FOR CASCADES IN LANE COUNTY-NORTHERN OREGON CASCADES.

     WIND ADVISORY FROM MIDNIGHT TONIGHT TO 10 PM PST SATURDAY FOR
     CENTRAL WILLAMETTE VALLEY-GREATER PORTLAND METRO AREA-LOWER
     COLUMBIA-SOUTH WILLAMETTE VALLEY.

     HIGH WIND WARNING UNTIL 10 PM PST SATURDAY FOR CENTRAL OREGON
     COAST-NORTH OREGON COAST.

     HIGH SURF WARNING FROM 4 PM SATURDAY TO 10 AM PST SUNDAY FOR
     CENTRAL OREGON COAST-NORTH OREGON COAST.

     HIGH WIND WARNING FROM MIDNIGHT TONIGHT TO 10 PM PST SATURDAY
     FOR CENTRAL COAST RANGE OF WESTERN OREGON-COAST RANGE OF
     NORTHWEST OREGON.

WA...WINTER STORM WARNING FROM 6 AM SATURDAY TO 4 AM PST SUNDAY FOR
     SOUTH WASHINGTON CASCADES.

     WIND ADVISORY FROM MIDNIGHT TONIGHT TO 10 PM PST SATURDAY FOR
     GREATER VANCOUVER AREA-I-5 CORRIDOR IN COWLITZ COUNTY.

     HIGH WIND WARNING UNTIL 10 PM PST SATURDAY FOR SOUTH WASHINGTON
     COAST.

     HIGH SURF WARNING FROM 4 PM SATURDAY TO 10 AM PST SUNDAY FOR
     SOUTH WASHINGTON COAST.

     HIGH WIND WARNING FROM MIDNIGHT TONIGHT TO 10 PM PST SATURDAY
     FOR WILLAPA HILLS.

PZ...STORM WARNING UNTIL 10 AM PST SATURDAY FOR COASTAL WATERS
     FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 60 NM.

     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 4 PM
     PST SATURDAY.

&&

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.