Small Craft Advisory 59, NWS Seattle, WA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
230 PM PST WED MAR 9 2016

.SYNOPSIS...A VERY STRONG FRONTAL SYSTEM ASSOCIATED WITH A RAPIDLY
DEEPENING LOW PRESSURE SYSTEM WILL BRING RAIN AND WINDY CONDITIONS
TO THE AREA TONIGHT INTO THURSDAY MORNING. THE STRONGEST WIND WILL
BE ON THE COAST. THE WEATHER WILL BE WET AT TIMES INTO THE WEEKEND
AS A SERIES OF FRONTAL SYSTEMS MOVE ACROSS THE REGION.

&&

.SHORT TERM...RAIN AND WINDY WEATHER IS ON TAP FOR WESTERN WA TNGT.
IT WILL SNOW HEAVILY IN THE CASCADES INTO THE EVENING...THEN THE
SNOW LEVEL WILL RISE ABOVE THE PASSES AS THE WARM FRONT MOVES THRU
SO THE MOUNTAIN SNOW IS ABOUT THE LEAST INTERESTING THING ABOUT THIS
STRONG FRONTAL SYSTEM MOVING ASHORE THIS AFTERNOON.

THE SYSTEM HAS TWO LOW PRESSURE CENTERS AND IF STRONG DAMAGING WINDS
DO NOT OCCUR ON THE COAST WITH THE INCREASING PRESSURE GRADIENT
TONIGHT THERE IS A VERY GOOD CHANCE THAT THE BENT BACK TROUGH...THE
SECOND LOW...WILL DO THE TRICK BY DAYBREAK. THIS SYSTEM HAS FORMED
JUST AS THE MODELS SHOWED IT WOULD AND THERE IS VERY GOOD AGREEMENT
THAT A STRONG SE SUCKER PATTERN WITH VERY WINDY CONDITIONS WILL
OCCUR IN THE NORTH INTERIOR AS WELL. THE AREAS THAT HAD WIND ADVISORIES
ARE NOW UPGRADED TO HIGH WIND WARNINGS...AND A WIND ADVISORY WAS
ADDED TO THE EVERETT AREA ZONE. THIS IS MORE SPECULATIVE...BUT THE
STRONGEST WINDS COULD OCCUR ON WHIDBEY ISLAND AND THE ADMIRALTY INLET
AREA AND THE QUIMPER PENINSULA DUE TO MESOSCALE LOW PRESSURE FORMING
AROUND THE EAST ENTRANCE TO THE STRAIT...AS STRONG WINDS ALOFT INTERACT
WITH THE OLYMPICS AND A MESOLOW FORMS.

THIS FRONT WILL GIVE THE OLYMPICS HEAVY OROGRAPHIC RAINFALL TONIGHT AND
THE SKOKOMISH RIVER SHOULD GET OVER THE NEW FLOOD STAGE OF 17 FEET.
THE RAIN WILL TURN TO SHOWERS WITH THE FRONTAL PASSAGE AROUND 4AM.

WINDS WILL SETTLE DOWN RAPIDLY BY MIDDAY THURSDAY AS THE LOW FILLS OVER
SOUTHWEST BRITISH COLUMBIA. SEE THE ADDITIONAL DISCUSSIONS BELOW AND
ESPECIALLY THE MARINE DISCUSSION FOR TIDAL OVERFLOW AND HEAVY SURF.

.LONG TERM...THE WEATHER PATTERN WILL REMAIN ACTIVE WITH WEATHER
SYSTEMS GIVING PERIODS OF RAIN ABOUT EVERY OTHER DAY THROUGH THE
EXTENDED PERIOD...WITH SOME SHOWERY PERIODS AND SUNBREAKS BETWEEN
THE SYSTEMS.

&&

.HYDROLOGY...HEAVY RAIN TONIGHT IN THE OLYMPICS WILL LIKELY DRIVE
THE SKOKOMISH RIVER ABOVE ITS NEW FLOOD STAGE ON THURSDAY AND A
FLOOD WATCH REMAINS UP FOR MASON COUNTY. THIS FRONT GIVES THE
OLYMPIC PENINSULA ABOUT 12 TO 18 HOURS OF HEAVY RAIN AND THEN THERE
IS A FRONTAL PASSAGE BY DAYBREAK THURSDAY. RIVER FLOODING IS NOT
LIKELY EXCEPT FOR FOR THE SKOKOMISH RIVER IN MASON COUNTY.

&&

.AVIATION...A STRONG FRONTAL SYSTEM WILL MOVE THROUGH THE AREA
TONIGHT WITH WEST TO SOUTHWEST FLOW ALOFT. AN ASSOCIATED DEEP
SURFACE LOW WILL MOVE NORTH ALONG 130W. DECREASING ONSHORE FLOW
WILL PREVAIL BEHIND THE FRONT THURSDAY. THE AIR MASS IS MOIST AND
STABLE...BECOMING UNSTABLE BEHIND THE FRONT THURSDAY MORNING.

KSEA...LOW CLOUDS AND RAIN WILL PREVAIL TONIGHT...CHANGING TO
SHOWERS EARLY THURSDAY MORNING. CEILING SHOULD IMPROVE A BIT
BEHIND THE FRONT THURSDAY. EASTERLY WIND 5-10 KNOTS WILL BECOME
SOUTHERLY 10-20 KNOTS WITH GUSTS TO 30 KNOTS LATE TONIGHT.
SCHNEIDER

&&

.MARINE...A STRONG FRONTAL SYSTEM WILL BRING GALE FORCE WINDS TO
MOST WATERS TONIGHT WITH STORM FORCE WINDS POSSIBLE FOR THE
COASTAL WATERS AS A DEEP SURFACE LOW TRACK NORTH ALONG 130W. SEAS
OVER THE COASTAL WATERS WILL BUILD TO 20 TO 30 FEET TONIGHT AND
THURSDAY MORNING...THEN SUBSIDE BELOW 20 FEET BY THURSDAY NIGHT.

HIGH ASTRONOMICAL TIDES...UNUSUALLY LOW SURFACE PRESSURE...AND
LARGE WAVES WILL BRING THE THREAT OF COASTAL FLOODING TO THE
CENTRAL COAST TONIGHT AROUND THE TIME OF HIGH TIDE. MINOR TIDAL
OVERFLOW IS ALSO LIKELY AROUND THE TIME OF HIGH TIDE TONIGHT FOR
THE AREAS ADJACENT TO THE INLAND WATERS.

DECREASING ONSHORE FLOW WILL PREVAIL BEHIND THE FRONTAL SYSTEM ON
THURSDAY. OFFSHORE FLOW WILL DEVELOP FRIDAY AS A SURFACE LOW
TRACKS TOWARDS THE OREGON COAST. A FRONTAL SYSTEM WILL REACH THE
AREA FRIDAY NIGHT AND SATURDAY...FOLLOWED BY ANOTHER SYSTEM
SATURDAY NIGHT OR SUNDAY. SCHNEIDER

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...COASTAL FLOOD ADVISORY FROM 2 AM TO 8 AM PST THURSDAY FOR
     ADMIRALTY INLET AREA-BREMERTON AND VICINITY-EASTERN STRAIT
     OF JUAN DE FUCA-EVERETT AND VICINITY-HOOD CANAL AREA-SAN
     JUAN COUNTY-SEATTLE AND VICINITY-SOUTHWEST INTERIOR-TACOMA
     AREA-WESTERN SKAGIT COUNTY-WESTERN STRAIT OF JUAN DE FUCA-
     WESTERN WHATCOM COUNTY.

     FLOOD WATCH FROM 6 PM PST THIS EVENING THROUGH THURSDAY
     AFTERNOON FOR HOOD CANAL AREA-LOWER CHEHALIS VALLEY AREA-
     OLYMPICS.

     HIGH WIND WARNING UNTIL 9 AM PST THURSDAY FOR ADMIRALTY INLET
     AREA-SAN JUAN COUNTY-WESTERN SKAGIT COUNTY-WESTERN WHATCOM
     COUNTY.

     HIGH WIND WARNING UNTIL 9 AM PST THURSDAY FOR CENTRAL COAST-
     NORTH COAST.

     COASTAL FLOOD WARNING FROM 11 PM THIS EVENING TO 5 AM PST
     THURSDAY FOR CENTRAL COAST.

     HIGH SURF ADVISORY FROM 10 PM THIS EVENING TO 4 PM PST THURSDAY
     FOR CENTRAL COAST-NORTH COAST.

     COASTAL FLOOD ADVISORY UNTIL 3 PM PST THIS AFTERNOON FOR CENTRAL
     COAST.

     WIND ADVISORY UNTIL 9 AM PST THURSDAY FOR EVERETT AND VICINITY.

	 WINTER WEATHER ADVISORY FOR THE CASCADES TIL 10 PM.

PZ...SMALL CRAFT ADVISORY FOR ROUGH BAR UNTIL 4 AM PST THURSDAY FOR
     GRAYS HARBOR BAR.

     STORM WARNING UNTIL 9 AM PST THURSDAY FOR COASTAL WATERS FROM
     CAPE FLATTERY TO JAMES ISLAND 10 TO 60 NM-COASTAL WATERS
     FROM CAPE FLATTERY TO JAMES ISLAND OUT 10 NM-COASTAL WATERS
     FROM JAMES ISLAND TO POINT GRENVILLE 10 TO 60 NM-COASTAL
     WATERS FROM JAMES ISLAND TO POINT GRENVILLE OUT 10 NM-
     COASTAL WATERS FROM POINT GRENVILLE TO CAPE SHOALWATER 10
     TO 60 NM-COASTAL WATERS FROM POINT GRENVILLE TO CAPE
     SHOALWATER OUT 10 NM-WEST ENTRANCE U.S. WATERS STRAIT OF
     JUAN DE FUCA.

     GALE WARNING UNTIL 4 PM PST THURSDAY FOR EAST ENTRANCE U.S.
     WATERS STRAIT OF JUAN DE FUCA-NORTHERN INLAND WATERS
     INCLUDING THE SAN JUAN ISLANDS.

     GALE WARNING UNTIL 6 AM PST THURSDAY FOR CENTRAL U.S. WATERS
     STRAIT OF JUAN DE FUCA.

     GALE WARNING FROM 6 PM THIS EVENING TO 1 PM PST THURSDAY FOR
     PUGET SOUND AND HOOD CANAL.

&&

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