Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA

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000
FXUS66 KSEW 282247
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
300 PM PST WED JAN 28 2015

.SYNOPSIS...A WEAK UPPER LEVEL DISTURBANCE WILL MOVE INLAND TONIGHT
FOR ISOLATED LIGHT SHOWERS. AN UPPER LEVEL RIDGE WILL PROVIDE DRY
AND MILD WEATHER THURSDAY THROUGH SATURDAY. A FRONT WILL BRING RAIN
BACK TO THE AREA SUNDAY AND EARLY NEXT WEEK.

&&

.SHORT TERM...A WEAK UPPER LEVEL TROUGH IS PASSING NORTH OFF THE
COAST THIS AFTERNOON WHICH MAY BRING ISOLATED LIGHT SHOWERS TO
WESTERN WA...MAINLY COAST AND SOUTH PART TONIGHT. SO FAR ACTIVITY IS
PRETTY WEAK ON KLGX BUT THE IR DOES SHOW A LITTLE ENHANCEMENT. POPS
ARE LOW AT 20 PERCENT WITH JUST A TRACE OF PRECIP TO A COUPLE
HUNDREDTHS IF ANYTHING.

AN UPPER LEVEL RIDGE WILL STRENGTHEN OVER THE AREA THU AND FRI FOR
MORE DRY AND STABLE WEATHER. EXPECT PATCHY LOW CLOUDS AND FOG DURING
THE MORNING HOURS...THEN PARTLY TO MOSTLY SUNNY SKIES IN THE
AFTERNOON. TEMPS WILL REMAIN ABOVE NORMAL WITH HIGHS IN THE LOW TO
MID 50S. THE RIDGE AXIS WILL CROSS WESTERN WA ON SATURDAY AND WE
COULD SEE LOW 60S ONCE AGAIN. A WARM FRONT WILL MOVE INTO B.C.
DURING THE AFTERNOON WHICH MAY BRING SOME HIGH CLOUDS TO THE AREA. 33

.LONG TERM...A WARM FRONT WILL BRING SOME RAIN TO THE AREA ON SUNDAY
AS IT MOVES INLAND. BUT THIS SYSTEM IS LOOKING SLOWER AND WEAKER
WITH EACH NEW MODEL SOLUTION. A WETTER PACIFIC FRONTAL SYSTEM WILL
THEN REACH THE AREA ON MON FOR ANOTHER SHOT OF RAIN. SNOW LEVEL ARE
A LITTLE LOWER WITH THIS SYSTEM AROUND 4000-5000 FT. THE GFS TRIES
TO BUILD ANOTHER RIDGE OVER THE REGION TUE AND WED. THE ECMWF
HOWEVER STEERS SOME MOISTURE OUR WAY FOR WETTER WEATHER PATTERN.
CONFIDENCE REMAINS LOW AT THIS POINT. 33

&&

.HYDROLOGY...FLOODING IS NOT EXPECTED FOR THE NEXT 7 DAYS.

&&

.AVIATION...A WEAK UPPER LEVEL RIDGE WILL REMAIN OVER WESTERN
WASHINGTON TONIGHT AND THURSDAY. AT THE SURFACE WEAK OFFSHORE FLOW
WILL CONTINUE. MOST AREAS HAVE CLEARED THIS AFTERNOON BUT THERE IS A
WEAK DISTURBANCE OVER SOUTHERN AREAS THAT ARE KEEPING SKIES MOSTLY
CLOUDY THERE. THE AIR MASS IS MOIST AND STABLE.

MOST AREAS HAVE NO CEILINGS. OVER SOUTHERN AREAS THE CEILINGS ARE
MVFR AROUND 2K FT. THE DISTURBANCE IS FORECAST TO MOVE NORTH ALONG
THE COAST TONIGHT AND THE MVFR CEILINGS SHOULD FOLLOW THAT TRACK.
SOME DRIZZLE IS LIKELY TO BE SQUEEZED OUT OF THE MOIST AIR MASS BY
WEAK UPLIFT. AREAS EAST OF THE OLYMPIC MOUNTAINS MAY REMAIN FREE OF
CEILINGS THOUGH PATCHY STRATUS AND FOG IS LIKELY IN CLEAR AREAS LATE
TONIGHT AND THURSDAY MORNING. SKIES WILL BE MOSTLY SUNNY THURSDAY
AFTERNOON.

KSEA...SHOULD BE VFR TONIGHT AND THURSDAY EXCEPT FOR A CHANCE OF IFR
STRATUS AND FOG FOR A FEW HOURS LATE TONIGHT AND EARLY THURSDAY
MORNING. MAY OPT TO LEAVE IFR CONDITIONS OUT OF THE TAF. WINDS WILL
BE NORTHERLY 3-6 KT. CHB

&&

.MARINE...A WEAK SURFACE RIDGE CENTERED OVER EASTERN WASHINGTON WILL
MAINTAIN WEAK OFFSHORE FLOW THROUGH SATURDAY. PRESSURE GRADIENTS
ACROSS WESTERN WASHINGTON WILL REMAIN WEAK WITH NORTHERLY AND
OFFSHORE WINDS OF MOSTLY LESS THAN 20 KT. THE EXCEPTION IS THE WEST
ENTRANCE WHERE EASTERLY WINDS WILL GET INTO THE 15-25 KT RANGE AT
TIMES TONIGHT AND THURSDAY MORNING...AND POSSIBLY SOME OTHER DAYS AS
WELL.

MODELS BRING A WEAK FRONT THROUGH THE AREA SUNDAY. LATEST RUNS SHOW
WINDS MOSTLY STAYING BELOW SMALL CRAFT ADVISORY LEVELS WITH THIS
FRONT. A STRONGER SYSTEM WILL FOLLOW ON MONDAY AND THE SMALL CRAFT
ADVISORY WINDS APPEAR TO BE ASSOCIATED MORE WITH THIS SYSTEM. CHB

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY WEST ENTRANCE.

&&

$$

WWW.WEATHER.GOV/SEATTLE

YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML




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