Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA

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000
FXUS66 KSEW 262142
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
245 PM PDT FRI SEP 26 2014

.SYNOPSIS...AN UPPER TROUGH WILL MOVE INLAND TONIGHT. WEAK HIGH
PRESSURE WILL BUILD OVER THE REGION THIS WEEKEND. A FRONT WILL BRING
SOME RAIN TO THE AREA MONDAY NIGHT. AN UPPER RIDGE MAY BUILD TOWARD
THE END OF NEXT WEEK.


&&

.SHORT TERM...SHOWERS WILL TAPER OFF THIS EVENING AS THE UPPER
TROUGH MOVES INLAND. THE SURFACE LOW PRESSURE TROUGH NEAR THE COAST
THIS MORNING FILLED AS IT MOVED ASHORE TODAY AND THERE IS WEAK
SURFACE HIGH PRESSURE BUILDING OVER THE REGION THIS AFTERNOON. THE
WEEKEND WILL BE DRY...MORNING CLOUDS AND PATCHY FOG SHOULD GIVE WAY
TO A DECENT AFTERNOON SATURDAY. SUNDAY OUGHT TO BE AN EVEN BETTER
DAY WEATHERWISE ALTHOUGH AREAS OF MORNING LOW CLOUDS AND FOG ARE A
GOOD BET. THE UPPER RIDGE BUILDING IN TO THE AREA IS NOT TOO
IMPRESSIVE...500MB HEIGHTS OUGHT TO PEAK AROUND 5780M SUNDAY AND MID
LEVEL TEMPS RISE ABOUT 6C BETWEEN TODAY AND SUNDAY.

.LONG TERM...A COLD FRONT WILL MOVE THROUGH WESTERN WA MONDAY NIGHT.
850MB TEMPS COOL OFF TO AROUND +4C AS THE UPPER TROUGH MOVES THROUGH
THE REGION MONDAY NIGHT. THE ECMWF HAS A SECOND UPPER SHORTWAVE
TROUGH INTO THE REGION WEDNESDAY WHILE THE GFS KEEPS IT NORTH OF THE
AREA. THE FORECAST IS A LITTLE UP IN THE AIR THROUGH THE MIDDLE OF
NEXT WEEK. TOWARD THE END OF THE WEEK THE GLOBAL MODELS ARE COMING
INTO AGREEMENT ON AN UPPER RIDGE BUILDING OVER THE PACNW.

&&

.AVIATION...A WEAK UPPER LEVEL TROUGH IS PRODUCING ISOLATED TO
SCATTERED SHOWERS ACROSS WESTERN WA THIS AFTERNOON. THESE SHOWERS
WILL TAPER DOWN THIS EVENING AS THE TROUGH EXITS. THE FLOW ALOFT IS
WESTERLY. EXPECT MOIST AND STABLE CONDITIONS OVERNIGHT WITH LOW
CLOUDS AND/OR FOG THROUGH SAT MORNING...EXPECT LIFR TO IFR
CONDITIONS IN THE INTERIOR. LOW CLOUDS WILL LIFT AND SCATTER SAT
AFTERNOON AS THE AIR MASS MIXES AND DRYS OUT. 33

KSEA...ISOLATED SHOWERS IN THE VICINITY THROUGH THIS EVENING.
SOUTHERLY WINDS WILL BECOME LIGHT AND VARIABLE OVERNIGHT. LOW CLOUDS
AND FOG POSSIBLE THROUGH SAT MORNING. 33

&&

.MARINE...WEAK SURFACE HIGH PRES WILL BRING GENERALLY LIGHT WINDS TO
WESTERN WA TONIGHT AND SAT. AN ONSHORE PUSH MAY BRING SMALL
CRAFT ADVISORY WINDS TO THE CENTRAL/EAST STRAIT OF JUAN DE FUCA SUN
NIGHT. THE NEXT COLD FRONT WILL CROSS WESTERN WA ON MON. ONSHORE
FLOW WILL THEN PREVAIL THROUGH MID WEEK. 33

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...NONE.

&&

$$

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





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