High Wind in Washington, December 10, 2015

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
942 PM PST WED DEC 9 2015

.SYNOPSIS...STRONG FRONTS WILL MOVE THROUGH WESTERN WASHINGTON
THURSDAY AND AGAIN SATURDAY. IT WILL BE WINDY AT TIMES...WITH
PERIODS OF SNOW IN THE MOUNTAINS. A COOLER DRIER WEATHER PATTERN
WILL DEVELOP NEXT WEEK.

&&

.SHORT TERM...A DEEP 969 MB LOW CENTER WITH A NICE SATELLITE
PRESENTATION IS CURRENTLY CENTERED NEAR 47N 135W. A STRONG
OCCLUDED FRONT EXTENDS SE FROM THE LOW CENTER AND IS LIFTING N-NE.
THE OCCLUDED FRONT WILL CROSS WRN WA OVER THE COURSE OF THU MRNG.
THE FRONT WILL BRING A FEW HOURS OF MODERATE PRECIP. RAIN WILL
SPREAD INTO GRAYS HARBOR AROUND MIDNIGHT...THEN MOVE NE TO THE
BELLINGHAM AREA AROUND 5 AM THU. SNOW LEVELS WILL BE AROUND
3000-3500 FEET DURING THIS EVENT...WITH SNOW ACCUMULATION OF ABOUT
5 TO 10 INCHES OR MORE EXPECTED IN THE MOUNTAINS.

IN TERMS OF WIND...EASTERLY GRADIENTS WILL PICK UP IN ADVANCE OF
THE FRONT EARLY THU...THEN S-SE GRADIENTS WILL FOLLOW THE FRONT.
MOST OF WRN WA WILL GET WINDY...BUT ZEROING IN ON EAST- AND
SOUTHEAST-WIND PRONE LOCATIONS FOR THE STRONGER WIND. THOSE ARE
THE VERY LOCATIONS WHERE WIND ADVISORIES ARE IN EFFECT...
SPECIFICALLY FOR THE COAST AND NORTH INTERIOR. EVEN OUTSIDE THE
WIND ADVISORY AREA...STRONG GUSTS ARE FORECAST...INCLUDING A
FORECAST OF 40 MPH GUSTS IN THE SEATTLE AREA AROUND MID-DAY THU
IN THE WAKE OF THE FRONT.

THE DEEP SURFACE LOW WILL REACH 50N 131W LATE THU...THEN MOVE SE
ON THU NGT AND FRI WHILE QUICKLY FILLING AND WEAKENING. SHOULD
EVENTUALLY REACH THE FAR NORTH OREGON COAST ON FRI AFTN AS A
992-997 MB LOW...WHICH IS MUCH WEAKER THAN IT IS NOW. THE MAIN
IMPACT WILL BE TO SPREAD RAIN AND MOUNTAIN SNOW ACROSS THE
SOUTHERN HALF OF THE FORECAST AREA...BUT WE MAY ESCAPE WITHOUT ANY
IMPACTFUL WINDS OVER LAND AREAS.

ANOTHER LOW CENTER WILL IMPACT WRN WA ON SAT. DESPITE THE
POTENTIAL FOR A BRIEF PERIOD OF HEAVY PRECIP...THE QUICK MOVEMENT
OF THE LOW AND SHORT DURATION OF THE PRECIP...ALONG WITH SNOW
LEVELS AROUND 3000 FEET...WILL PRECLUDE FLOODING. SHOULD BE
WINDIER WITH SATURDAY'S LOW. AT THIS POINT...DOUBT WE WILL ESCAPE
WITHOUT ANOTHER ROUND OF WIND ADVISORIES ON SAT OR SAT NGT.
HANER

.LONG TERM...FROM PREVIOUS DISCUSSION...A COOLER WEATHER PATTERN
SHOULD DEVELOP AND A COUPLE OF DRY DAYS NEXT WEEK IS LOOKING
INCREASINGLY LIKELY. THERE IS A WEAK SYSTEM THAT WILL PROBABLY
BRING SOME PRECIP WITH A FAIRLY LOW SNOW LEVEL TO THE AREA
MIDWEEK...BUT PRECIP SHOULD BE LIGHT. ANOTHER SYSTEM IS STRONGER
BUT STAYS OFFSHORE LATE IN THE WEEK. THE DETAILS ARE UP IN THE AIR
BUT A SWITCH FROM STORMY WEATHER TO A BENIGN WEATHER PATTERN IS
LIKELY FOR NEXT WEEK.

&&

.AVIATION...MODERATE SW FLOW ALOFT BECOMING STRONG SOUTH TO
SOUTHWEST FLOW ALOFT THURSDAY. AT THE SURFACE SOUTHEASTERLY WIND
WILL INCREASE LATE TONIGHT...ESPECIALLY AT THE COAST AND OVER THE
NORTH. THE AIR MASS IS SLIGHTLY UNSTABLE WITH SCATTERED
SHOWERS...THEN RAIN AT TIMES THURSDAY WITH AREA OF MVFR.

KSEA...SE WINDS WILL INCREASE AFTER MIDNIGHT AND REACH 10-13 KT W/
GUSTS 25 KT BY THURSDAY MORNING. MOSTLY VFR CIGS FILLING IN LATER
TONIGHT WITH INCREASING RAIN THURSDAY. MVFR CIGS AT TIMES BY LATE
MORNING AND AFTERNOON.

&&

.MARINE...A VERY DEEP 967 MB SURFACE LOW WILL REACH 130 W LATER
TONIGHT THEN LIFT NORTHWARD ON THURSDAY. THE LEADING FRONT WILL
BRING ON ROUND OF WIND LATER TONIGHT AND EARLY THURSDAY WITH POST
FRONTAL WINDS LATER TODAY AND THIS EVENING. ANOTHER STRONG SYSTEM
WILL FOLLOW THURSDAY NIGHT AND FRIDAY...MAINLY BRUSHING THE
COASTAL WATERS. GALE WARNINGS ARE UP FOR MOST WATERS EXCEPT SMALL
CRAFT FOR PUGET SOUND. A GALE WATCH IS UP FOR THE OUTER WATERS
FRIDAY AS THE NEXT SYSTEM SKIRTS THE COASTAL WATERS AS IT TRACKS
SOUTHEAST INTO OREGON.

COASTAL FLOODING IS LIKELY ON THE COAST THURSDAY AND THURSDAY NIGHT.
IT WILL COME IN TWO WAYS...HIGH TIDE PLUS ANOMALIES AND ALSO VERY
LARGE WAVES. THE TIDAL ANOMALIES HAVE BEEN RUNNING AT 2-2.5 FT
RECENTLY. THROW IN SOME WIND AND EVEN LOWER PRESSURE AND SOME
COASTAL FLOODING SHOULD OCCUR IN LOW LYING AREAS AROUND GRAYS
HARBOR. THE BIG WAVES...25-30 FT COMBINED SEAS...WILL ARRIVE
THURSDAY EVENING AND WILL LIKELY DAMAGE SOME LEVEES AND OTHER
PROTECTIVE STRUCTURES. DETAILS ARE IN THE CFW PRODUCT. DTM/CHB

&&

.HYDROLOGY...THE THREAT OF ADDITIONAL SIGNIFICANT RAINFALL HAS
ENDED. RIVERS HAVE CRESTED WITH THE EXCEPTION OF THE SKOOKUMCHUCK
NEAR CENTRALIA...WHICH IS CRESTING THIS EVENING...AND THE CHEHALIS
FROM ABOUT CENTRALIA DOWNSTREAM TO GRAYS HARBOR. THE FLOOD CREST ON
THE CHEHALIS WILL NOT REACH GRAYS HARBOR UNTIL EARLY SATURDAY MORNING.
A MAJORITY OF THE RIVERS WITH WARNING IN EFFECT WILL RECEDE BELOW
FLOOD STAGE ON THURSDAY.

SNOW LEVELS ARE ANTICIPATED TO BE MAINLY AT OR BELOW 3500 FEET
THROUGH THE MIDDLE OF NEXT WEEK...WHICH MEANS THAT PRECIPITATION
WILL FALL AS SNOW IN THE MOUNTAINS. CONSEQUENTLY...NO ADDITIONAL
RIVER FLOODING IS EXPECTED THROUGH NEXT WEDNESDAY. FELTON

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...FLOOD WATCHES AND NUMEROUS FLOOD WARNINGS ARE IN EFFECT.
     WINTER WEATHER ADVISORY IN EFFECT FOR THE CASCADES THU.
     COASTAL FLOOD WARNING COAST.
     COASTAL FLOOD ADVISORY INLAND WATERS.
     WIND ADVISORY COAST AND NORTH PORTIONS OF WRN WA THU.

PZ...GALE WARNING ALL WATERS EXCEPT PUGET SOUND.
     SMALL CRAFT ADVISORY PUGET SOUND.
     GALE WATCH OUTER COASTAL WATERS FRIDAY.
  	 SMALL CRAFT ADVISORY FOR ROUGH GRAYS HARBOR BAR.

&&

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