Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA

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000
FXUS66 KSEW 111702
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
900 AM PST THU FEB 11 2016

.SYNOPSIS...A WARM FRONT WILL SPREAD RAIN NORTH ACROSS THE AREA
TODAY. THE ASSOCIATED WEAK COLD FRONT WILL MOVE EAST ACROSS THE AREA
FRIDAY MORNING. AN UPPER LEVEL TROUGH WILL PRODUCE SHOWERS FRIDAY
AFTERNOON THROUGH SATURDAY MORNING. A PAIR OF WARM FRONTS WILL BRING
RAIN SATURDAY AFTERNOON THROUGH SUNDAY EVENING. WEST FLOW ALOFT WILL
MAINTAIN AN ACTIVE WEATHER PATTERN INTO EARLY NEXT WEEK.

&&

.SHORT TERM...LIKE YESTERDAY...RAIN HAS MOVED IN FASTER THAN MODELS
PREDICTED. RADAR IS LIT UP OVER SOUTHERN AREAS AND NEW MODEL RUNS
BRING RAIN NORTHEAST FASTER...GENERALLY TO THE SEATTLE AREA OR SO IN
THE AFTERNOON. HAVE ALREADY UPDATED THE GRIDS AND FORECASTS FOR
HIGHER POPS SOONER. ONLY THE NORTHERNMOST INTERIOR IS LIKELY TO
REMAIN DRY TODAY...THOUGH A SPRINKLE THERE IS NOT OUT OF THE
QUESTION. HIGHS TODAY WILL BE IN THE LOW TO MID 50S.

RAIN WILL CONTINUE TONIGHT AND ANY AREAS THAT STAY DRY TODAY WILL
GET WET TONIGHT. WARM FRONT MOVES NORTH THROUGH THE NIGHT...THEN BY
18Z FRIDAY A COLD FRONT IS ON THE COAST. IT MOVES EAST THROUGH
WESTERN WASHINGTON DURING THE DAY FRIDAY WITH SHOWERS IN ITS WAKE
LATE FRIDAY THROUGH SATURDAY MORNING. THIS IS ALSO A MINOR CHANGE
FROM EARLIER MODEL RUNS WHICH BROUGHT THE FRONT THROUGH FASTER. IF
CORRECT THEN SHOWERS WILL DEVELOP LATER AND MOST OF THE AREA WILL
SPEND THE DAY IN THE WARM SECTOR...GIVING HIGHS ON FRIDAY IN THE MID
50S. THE SNOW LEVEL WILL BE 6000 FEET OR HIGHER UNTIL THE COLD FRONT
PASSES.

AN UPPER TROUGH MOVES BY FRIDAY NIGHT GIVING SHOWERS. SATURDAY
MORNING LOOKS RELATIVELY DRY EXCEPT FOR MOUNTAIN SHOWERS. THE SNOW
LEVEL WILL DIP TO 3000-4000 FEET FRIDAY NIGHT AND SATURDAY. THE NEXT
SYSTEM WILL ARRIVE SATURDAY AFTERNOON ON THE COAST AND RAIN WILL
SPREAD INLAND AS THE SNOW LEVEL RISES BACK TO 6000 FEET OR SO
SATURDAY NIGHT. HIGHS SATURDAY WILL BE AROUND 50. BURKE

.LONG TERM...PREVIOUS DISCUSSION...WHILE GENERAL TREND FOR MONDAY
LINES UP WITH BOTH GFS AND ECMWF...THERE IS SOME DISAGREEMENT ON THE
DETAILS. GFS WANTS TO PUSH PRECIP UP AND OUT OF THE AREA WITH A WEAK
RIDGE IN PLACE. EURO ALSO HAS WEAK RIDGE IN PLACE...BUT KEEPS PRECIP
FURTHER SOUTH...IN THIS INSTANCE FROM THE SOUTHERN TIP OF THE SOUND
TO ALL POINTS NORTH. PRETTY DECENT LOW PRESSURE OVER THE PACIFIC MAY
PUMP UP MOISTURE INTO SAID WEAK RIDGE...KEEPING THE THREAT OF PRECIP
IN THE FORECAST AT LEAST INTO THE MIDDLE OF NEXT WEEK AND LIKELY
EVEN FURTHER.

MONDAY PROBABLY SEES THE WARMEST TEMPS OF THE FORECAST PERIOD...WITH
WIDESPREAD MID-50S IN THE LOWLANDS...BEFORE TEMPERATURES START TO
FALL AGAIN...ALTHOUGH LOWLAND TEMPS WILL REMAIN IN THE 50S UNTIL THE
SECOND HALF OF NEXT WEEK. SMR

&&

.HYDROLOGY...RIVER FLOODING IS UNLIKELY THROUGH SATURDAY. THERE IS
SOME POTENTIAL FOR HEAVY RAIN OVER THE OLYMPICS BEGINNING SATURDAY
NIGHT WHICH COULD CAUSE THE SKOKOMISH RIVER TO FLOOD EARLY NEXT WEEK.

&&

.AVIATION...SW FLOW ALOFT. THE AIR MASS IS STABLE AND MOIST. A
WARM FRONT SITTING FROM THE CENTRAL COAST OF OREGON TO A 988 MB LOW
CENTERED NEAR 48N 141W WILL LIFT NE ACROSS THE REGION THIS
EVENING...THE THE ASSOCIATED COLD FRONT ASSOCIATED WITH THIS SYSTEM
WILL MOVE EAST ACROSS THE AREA FRI MORNING.

OFFSHORE FLOW ASSOCIATED WITH THE APPROACHING WARM FRONT WILL GIVE
MAINLY VFR CEILINGS TO THE INTERIOR AND TO THE COASTAL STRIP TODAY
EVEN WITH RAINFALL INCREASING DURING THE DAY. THE NORTH AND EAST
SLOPES OF THE OLYMPICS WILL SEE IFR CONDITIONS WITH LOW STRATUS AND
LIGHT RAIN. CONDITIONS WILL DETERIORATE SOMEWHAT WITH LOWERING CIGS
FRI MORNING AS OFFSHORE PRES GRADIENTS DECREASE AHEAD OF THE
APPROACHING COLD FRONT. ALBRECHT

KSEA...P6SM BKN-OVC080 WILL LOWER TO OVC040 THIS AFTERNOON AND
TONIGHT.  OCCASIONAL SPRINKLES WILL INCREASE TO A STEADY LIGHT RAIN
ABOUT 22Z. CEILINGS WILL LIKELY LOWER TO OVC025-030 ABOUT 12Z FRI.
WINDS NE 4-6 KT BECOMING SELY 5-7 KT AT 06Z AND SLY 8-12 KT 14Z.
ALBRECHT

&&

.MARINE...A WARM FRONT EXTENDING FROM THE CENTRAL OREGON COAST TO A
988 MB LOW NEAR 48N 141W WILL LIFT NE THROUGH THE WATERS LATE THIS
AFTERNOON AND THIS EVENING. A TRAILING COLD FRONT WILL MOVE EAST
ACROSS THE WATERS FRIDAY MORNING. SMALL CRAFT ADVISORIES ARE IN
EFFECT FOR THE COAST AND THE WEST ENTRANCE TO THE STRAIT. SMALL
CRAFT ADVISORIES HAVE ALSO BEEN ISSUED FOR LATE THIS AFTERNOON
THROUGH FRIDAY MORNING FOR THE EAST ENTRANCE TO THE STRAIT AND
ADMIRALTY INLET...AND LATE TONIGHT INTO FRIDAY MORNING FOR ADMIRALTY
INLET.

THE FRONTAL SYSTEM WILL MOVE INLAND FRIDAY MORNING AND THEN ONSHORE
FLOW WILL FOLLOW FRI AFTERNOON OR EVENING INTO SAT MORNING. SMALL
CRAFT ADVISORY SOUTH FLOW IS LIKELY OVER PUGET SOUND AND HOOD CANAL
FRIDAY NIGHT AND SATURDAY MORNING AS FLOW ALOFT INTERACTS WITH THE
OLYMPICS AND A MESO LOW FORMS OVER THE NE OLYMPIC PENINSULA.

A SERIES OF FRONTAL SYSTEMS WILL GIVE SMALL CRAFT ADVISORY
CONDITIONS TO MOST OF THE WATERS SAT NIGHT THROUGH EARLY NEXT WEEK.
ALBRECHT

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 9 AM PST FRIDAY 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.

     SMALL CRAFT ADVISORY FOR ROUGH BAR UNTIL 9 AM PST FRIDAY FOR
     GRAYS HARBOR BAR.

     SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 9 AM PST FRIDAY
     FOR EAST ENTRANCE U.S. WATERS STRAIT OF JUAN DE FUCA-
     NORTHERN INLAND WATERS INCLUDING THE SAN JUAN ISLANDS.

     SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 9 AM PST FRIDAY
     FOR ADMIRALTY INLET.

&&

$$

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