High Wind Warning 1, NWS Portland, OR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
237 AM PST FRI JAN 10 2014

.SYNOPSIS...AFTER A WEEK OF CLOUDS AND RAIN...IT APPEARS CURTAINS
WILL RISE ON THE FINALE. BREEZY AND MILD TODAY...WITH DECREASING RAIN
TODAY AND THIS EVENING AS WARM FRONT LIFTS NORTH...BUT RAIN AND
INCREASE WIND TONIGHT. WINDY AND WET ON SATURDAY...WITH SNOW LEVELS
PLUMMETING IN THE CASCADES. COOL AND SHOWERY INTO EARLY NEXT WEEK...
BUT APPEARS NEXT WEEK WILL BE MILD AND MORE TRANQUIL.
&&

.SHORT TERM...WARM FRONT STILL ON TARGET TO LIFT NORTH ACROSS THE
REGION TODAY AND THIS EVENING. THIS WILL PULL THE STEADY RAIN BACK TO
THE N...WITH MOST RAIN N OF THE COLUMBIA RIVER BY AFTERNOON. WOULD
NOT BE SURPRISE TO SEE RELATIVELY DRY AFTERNOON FROM SALEM
SOUTHWARD...THOUGH WILL BE PLENTY OF CLOUDS. IT WILL REMAIN BREEZY
TODAY AS SOUTHERLY GRADIENTS INCREASE.

ACT 1. ENTER THE WARM FRONT.
PROBLEM IS THAT WILL HAVE SEVERAL ROUNDS OF WIND. FIRST ROUND IS WITH
THE WARM FRONT. SHOULD SEE STRONG SOUTH WINDS BEHIND THE WARM FRONT
ON THE COAST LATE TODAY AND THIS EVENING...WITH GUSTS 60 TO 65 MPH
POSSIBLE. THOUGH BEST THREAT WILL BE ON THE HEADLANDS THIS
EVENING...IT WILL BE BREEZY OVER MUCH OF THE COASTAL AREA. HAVE
STARTED HIGH WIND WARNINGS FOR THE COASTAL AREAS AT 4 PM TODAY...AND
OVER COAST RANGE/WILLAPA HILLS AT MIDNIGHT. THESE WILL CONTINUE
TONIGHT THROUGH SAT EVENING.  SNOW LEVELS WILL BE RISING TODAY WITH
ONLY RAIN ON THE PASSES.

ACT 2. ENTER THE COLD FRONT.
IMPRESSIVE COLD FRONT NOW LIES NEAR LON 150W...OR ABOUT 1100 MILES
WEST OF THE COAST. AS THIS FRONT APPROACHES...PRES GRADIENTS
GRADUALLY INCREASE. ALL MODELS HAVE BEEN REMARKABLY CONSISTENT IN
SHOWING DECENT COASTAL JET OF 40 TO 55 KT DEVELOPING TONIGHT ALONG
THE HEADLANDS AFTER MIDNIGHT. OTHER LOW LEVEL MODELED DATA IS
SIMILAR...ALL POINTING TO GOOD POTENTIAL OF SOUTH WINDS 35 TO 45 MPH
WITH GUSTS ABOVE 65 MPH ON THE COAST. AFTER MIDNIGHT...SHOULD BE
ENOUGH GRADIENT INLAND THAT COAST RANGE WILL FEEL STRONG SOUTH
WINDS...WITH BREEZY CONDITIONS DEVELOPING THROUGHOUT THE I5 CORRIDOR
AND WILLAMETTE VALLEY. FOR MOST AREAS...STRONGEST WINDS WILL BE
BETWEEN 3 AND 7 AM SATURDAY. HAVE ISSUED WIND ADVISORY FOR INLAND
AREAS FOR LATER TONIGHT THROUGH SAT...FOR GUSTS 40 TO 50 MPH.

RAIN MAY BE HEAVY AT TIMES...AS TONGUE OF DECENT PRECIPITABLE WATER
OF 1.0 TO 1.5 INCHES LIES ALONG THE FRONTAL ZONE. GOOD POTENTIAL FOR
1 TO 3 INCHES OF RAIN ACROSS THE AREA...WITH MOST OVER THE COAST
MTNS. SAVING GRACE FOR RIVERS IS THAT THE HEAVIEST RAIN WILL REMAIN
FOCUSED TOO FAR TO THE N...UP OVER THE OLYMPICS AND NW WASHINGTON. SO
THOUGH RAIN IS HEAVY LATER TONIGHT...IT IS SHORT LIVED IN DURATION AS
THE FRONT IS MOVING ONSHORE RATHER QUICKLY. TIMING OF COLD FRONT TO
COAST IS ROUGHLY 6 TO 8 AM.

ACT 3.	ENTER THE COLD POST-FRONTAL AIR...AND SNOW.
THE SURFACE LOW WILL PUSH INTO VANCOUVER ISLAND SAT AM...LEAVING
STRONG PRES GRADIENT OVER THE PAC NW. THIS WILL MAINTAIN GUSTY WINDS
ACROSS THE REGION...THOUGH WINDS WILL GRADUALLY TURN MORE WESTERLY AS
THE DAY PROGRESSES. WITH COLD AIR ALOFT OVER REGION...WILL SEE AIR
MASS BECOMING INCREASINGLY MORE UNSTABLE. WILL KEEP ISOLATED
THUNDERSTORM THREAT WITH SMALL HAIL FOR SAT INTO SAT EVENING.
AS GRADIENTS RELAX SAT EVENING...WITH WINDS EASING AT THAT TIME.

MAIN STORY ON SATURDAY WILL BE RAPID DROP IN THE SNOW LEVELS BEHIND
THE COLD FRONT. SNOW LEVELS WILL START NEAR 6000 FEET AROUND 6 AM
SAT...BUT DROP DOWN TO 2500 TO 3000 FT BY SAT AFTERNOON. WITH STRONG
ONSHORE...WITH MOIST COOL AIR...WILL HAVE IDEAL CONDITIONS FOR
SIGNIFICANT OROGRAPHIC SNOWFALL. LOOKS GOOD FOR 12 TO 18 INCHES OF
SNOW AT THE PASSES...WITH UPWARDS OF 2 FT OF SNOW HIGH UP TOWARDS THE
SKI RESORTS. TO MAKE WORST...INCREASING PRES GRADIENTS OVER THE
CASCADES IN THE AFTERNOON AND EVENING WILL RESULT IN STRONG WINDS
OVER THE CASCADES...WITH GUSTS 45 TO 60 MPH. THIS WINDS WILL COMBINE
WITH SNOW TO PRODUCE BLIZZARD CONDITIONS ON THE PASSES LATE SAT
AFTERNOON AND SAT NIGHT...WITH WIDESPREAD BLOWING SNOW AND WHITE OUT
CONDITIONS. THIS WOULD NOT BE THE TIME FOR TRAVELING OVER THE
CASCADES. CURRENT WINTER STORM WATCH LIKELY WILL BE UPGRADED TO A
WARNING BY LATER SHIFTS AS CLARITY IN TIMING AND DETAILS INCREASES.

SHOWERY AIR MASS REMAINS IN PLACE SAT NIGHT AND SUNDAY...THROUGH
SHOWERS DECREASING ON SUN. WINDS WILL BE EASING OVER MOST AREAS SAT
NIGHT...BUT REMAIN BREEZY OVER THE CASCADES INTO SUN AM. ANOTHER WEAK
UPPER LEVEL DISTURBANCE ARRIVES SUN...MAINTAINING SNOW SHOWERS OVER
THE CASCADES.					       ROCKEY.

.LONG TERM...MODELS AGREE MUCH OF NEXT WEEK IS LIKELY TO BE
DOMINATED BY AN UPPER LEVEL RIDGE OFF THE COAST. BEFORE THE RIDGE
REBUILDS THOUGH...WILL NEED TO KEEP A CHANCE FOR SOME LIGHT RAIN
LINGERING INTO MON AS MODELS SHOW WEAK WARM AIR ADVECTION UNDER THE
BUILDING RIDGE. ANOTHER SYSTEM...LIKELY WEAKER GIVEN THE STRENGTH OF
THE RIDGE BEFOREHAND...SLIPS DOWN THE E SIDE OF THE RIDGE WED.
OPERATIONAL RUN OF THE ECMWF IS CONSIDERABLY STRONGER WITH THIS
SYSTEM THAN THE GFS...BUT NOT WELL SUPPORTED BY ENSEMBLES...SO FOR
NOW PREFER TO PUT IN JUST A SLIGHT CHANCE FOR SHOWERS IN THE N.
OTHERWISE THE REST OF THE WEEK LOOKS PRIMED FOR MORE VALLEY FOG AND
CLOUDS WITH A STRONG RIDGE ALOFT...THOUGH NORTH VALLEY LOCATIONS MAY
BE SPARED LATER IN THE WEEK WITH OFFSHORE FLOW.
&&

.AVIATION...THE AREA WILL BE IN THE TAIL END OF A LULL BEFORE THE
NEXT STORM AFFECTS THE AREA. A WARM FRONT OFFSHORE WILL MOVE INTO
THE AREA TODAY. FLIGHT CONDITIONS SHOULD LOWER TO MVFR WITH LOCAL
IFR...ESPECIALLY AT THE COAST. FLIGHT CONDITIONS MAY TREND TOWARD VFR
FRIDAY EVENING ONCE THE WARM FRONT LIFTS TO THE NORTH OF THE
AREA. WINDS AT THE SURFACE AND ALOFT WILL INCREASE THROUGH THE DAY
AND IS EXPECTED TO PEAK TONIGHT. WINDS WILL REMAIN QUITE STRONG AT
TIMES THROUGH SAT BUT WILL EASE SATURDAY EVENING.

KPDX AND APPROACHES...VFR TRENDING TOWARD MVFR THIS AFTERNOON WITH
OCCASIONAL VISIBILITY RESTRICTIONS IN MODERATE RAIN AND MIST.
SUSTAINED SOUTH WINDS AROUND 20 KT WITH GUSTS TO 30 KT ARE
POSSIBLE TONIGHT AND CONTINUE AT TIMES SAT.
&&

.MARINE...A VERY POTENT SYSTEM WILL BRING INCREASING WINDS AND
SEAS TODAY INTO SATURDAY. IT APPEARS STORM FORCE GUSTS WILL HIT
THE WATERS AS THE WARM FRONT NEARS THE COAST THIS AFTERNOON. THE
NEAR SHORE WATERS APPEAR TO BE THE BEST LOCATIONS FOR THE
STRONGEST WINDS AS A COASTAL JET SETS UP. GUSTS COULD APPROACH 60
KT. WINDS EASE A LITTLE LATE TONIGHT BUT RAMP UP AGAIN AS THE COLD
FRONT NEARS SAT MORNING. WINDS BEHIND THE COLD FRONT WILL LIKELY
SUSTAIN GALE FORCE GUSTS THROUGH SAT AFTERNOON OR EARLY EVENING
BEFORE SUBSIDING. LESS STORMY CONDITIONS START NEXT WEEK WITH
WEAKER FRONTS OCCASIONALLY MOVING THROUGH THE WATERS WITH WINDS
GENERALLY IN THE SMALL CRAFT ADVISORY CATEGORY.

BESIDES THE WINDS...THE SEAS WILL BE EXTREMELY HAZARDOUS. SEAS
WILL BUILD TO ABOVE 20 FT SATURDAY MORNING...THEN UP TO AROUND 30
FEET SATURDAY EVENING. THE MODELS SHOW A SWATH OF HIGH
WINDS...AROUND 50 KT MOVING AROUND 4 DEGREES LONGITUDE PER 6 HOURS
ALONG THE GREAT CIRCLE ROUTE TOWARDS THE WATERS. THIS SUGGESTS
THAT THERE MAY BE A DYNAMIC FETCH WITH THIS SWELL AND THAT THE
MODELS MAY BE TOO QUICK TO DECAY THE OFFSHORE SEAS. NEW MODEL
GUIDANCE IS A LITTLE LOWER SO HAVE ADJUSTED FORECAST AS WELL...BUT
REMAIN SLIGHTLY ABOVE GUIDANCE.

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...WINTER STORM WATCH FOR SATURDAY THROUGH SATURDAY NIGHT
	  FOR CASCADES OF NORTHERN OREGON AND LANE COUNTY.
     WIND ADVISORY FROM MIDNIGHT TONIGHT TO 10 PM SATURDAY
	  ALL OF THE WILLAMETTE VALLEY.
     HIGH WIND WARNING FROM 6 PM THIS EVENING TO 10 PM SATURDAY
	  FOR THE NORTH AND CENTRAL OREGON COAST.
     HIGH WIND WARNING FROM MIDNIGHT TONIGHT TO 10 PM SATURDAY
	  FOR CENTRAL COAST RANGE OF WESTERN OREGON
	  AND COAST RANGE OF NORTHWEST OREGON.
     HIGH SURF WARNING FROM 4 PM SATURDAY TO 10 AM SUNDAY FOR
	  NORTH AND CENTRAL OREGON COAST.

WA...WINTER STORM WATCH FOR SATURDAY THROUGH SATURDAY NIGHT
	  FOR SOUTH WASHINGTON CASCADES.
     WIND ADVISORY FROM MIDNIGHT TONIGHT TO 10 PM SATURDAY
	  FOR CLARK COUNTY AND GREATER VANCOUVER AREA
	  AND I-5 CORRIDOR IN COWLITZ COUNTY.
     HIGH WIND WARNING FROM 6 PM THIS EVENING TO 10 PM SATURDAY
	  FOR SOUTH WASHINGTON COAST.
     HIGH WIND WARNING FROM MIDNIGHT TONIGHT TO 10 PM SATURDAY
	  FOR WILLAPA HILLS.
     HIGH SURF WARNING FROM 4 PM SATURDAY TO 10 AM SUNDAY FOR
	 SOUTH WASHINGTON COAST.

PZ...STORM WARNING FROM 4 PM THIS AFTERNOON TO 10 AM SATURDAY
	 FOR ALL COASTAL WATERS.
     SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL
	 1 AM 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.