High Wind in Oregon, January 10 to 11, 2014

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
220 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.
&&

.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...MAINLY VFR EARLY THIS AFTERNOON...BUT AREAS OF
MVFR...IN THE WARM SECTOR. THE WARM FRONT WILL LIFT ACROSS THE
FORECAST AREA LATE THIS AFTERNOON. EXPECT FLIGHT CONDITIONS TO
DROP INTO IFR/MVFR ALONG THE COAST...BUT STILL SHOULD MAINTAIN
GENERALLY VFR OVER THE INLAND VALLEYS. THERE MAY BE SOME
IMPROVEMENT IN THE 00Z-06Z SAT TIME FRAME BETWEEN THE WARM FRONTAL
PASSAGE AND THE INCOMING COLD FRONT. THE COLD FRONT WILL REACH THE
COAST BETWEEN 09Z AND 12Z SAT WITH A BURST OF HEAVIER
PRECIPITATION. COASTAL SITES LIKELY TO BE MAINLY IFR AFTER 06Z
SAT...BUT SEE AN ABRUPT IMPROVEMENT TO VFR SHORTLY AFTER THE COLD
FRONTAL PASSAGE. INLAND LOWLAND AREAS IMPROVE TO VFR IN THE MID TO
LATE MORNING HOURS...THEN ENTER A PERIOD OF MIXED VFR AND MVFR.
MOUNTAIN WILL BE OBSCURED THROUGH MUCH OF THE 00Z FORECAST
PERIOD...ESPECIALLY AFTER 06Z SAT. INCLUDED LOW-LEVEL WIND SHEAR
AT THE COASTAL TAF SITES AS MODEL SOUNDINGS SUGGESTS 55-65 KT WIND
SPEEDS 1500 FT AGL.

KPDX AND APPROACHES...EXPECT PRIMARILY VFR AT THE TERMINAL THROUGH
EARLY EVENING. THERE IS A CHANCE OF BRIEF MVFR CIGS THROUGH THIS
EVENING AS A WARM FRONT LIFTS N INTO SW WA. A MIX OF VFR AND MVFR
WILL OCCUR FROM AROUND 03Z TO 09Z SAT...THEN PREDOMINANT MVFR.
COLD FRONT MOVES ACROSS THE TERMINAL AROUND 14Z SAT...WITH RAPID
IMPROVEMENT TO VFR MID TO LATE MORNING. WEISHAAR

&&

.MARINE...LATEST MODEL GUIDANCE SUGGESTS MINIMAL CHANGES TO THE
CURRENT FORECAST. THE MAIN STORY WILL BE STORM FORCE WIND GUSTS
AND DANGEROUS SEA CONDITIONS. LATEST MODEL DATA SUGGESTS STORM
FORCE GUSTS MAY NOT COMMENCE UNTIL EARLY EVENING...A LITTLE LATER
THAN THE CURRENT FORECAST...BUT WILL LEAVE THE CURRENT WARNING
TIMING AS IS. THE NEAR SHORE WATERS APPEAR TO BE THE BEST
LOCATION FOR THE STRONGEST WIND DUE TO THE PRESENCE OF A COASTAL
JET. COULD SEE GUSTS TO 60 KT WITHIN THIS COASTAL JET...IMPACTING
THE COLUMBIA RIVER BAR. THE WIND EASES A LITTLE LATE TONIGHT BUT
RAMPS UP AGAIN AS THE COLD FRONT MOVES INTO THE WATERS EARLY SAT
MORNING. WIND BEHIND THE COLD FRONT WILL LIKELY MAINTAIN GALE
FORCE GUSTS THROUGH SAT AFTERNOON OR EARLY EVENING BEFORE
SUBSIDING. THERE IS SOME POTENTIAL FOR STORM FORCE GUSTS SAT
AFTERNOON. FOR NOW...HAVE STORM FORCE GUSTS THROUGH 18Z SAT...AND
THEN JUST UNDER STORM FORCE IN THE EARLY AFTERNOON. MAY NEED TO
EXTEND THE STORM WARNING...BUT WILL LET THE NEXT SHIFT OR TWO
HANDLE THAT. ANOTHER SYSTEM MOVES ACROSS THE WATERS SUN FOR SMALL
CRAFT ADVISORY WIND SPEEDS...FOLLOWED BY SEVERAL DAYS OF QUIET
WIND CONDITIONS.

THE SEAS WILL BECOME EXTREMELY HAZARDOUS LATE TONIGHT THROUGH SAT
EVENING. SEAS STILL RUNNING ABOUT 1-2 FT HIGHER THAN GUIDANCE
EARLY THIS AFTERNOON. SEAS WILL BUILD TO NEAR 20 FT LATE TONIGHT
OR EARLY SAT MORNING...AND POSSIBLY A LITTLE SOONER THAN THE
CURRENT FORECAST INDICATES. STILL LOOKING AT MAXIMUM WAVE HEIGHTS
IN THE 30 TO 35 FT RANGE BEGINNING LATE SAT AFTERNOON OR EARLY
EVENING. 12Z GUIDANCE HAS SETTLED ON MAX SEAS AROUND 30 FT...A FEW
FEET LOWER THAN YESTERDAYS OUTPUT. 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. WEISHAAR

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...WINTER STORM WARNING FROM 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.