Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA

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000
FXUS66 KSEW 270358
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
900 PM PDT TUE MAY 26 2015

.SYNOPSIS...LOW LEVEL ONSHORE FLOW WILL WEAKEN OVER THE NEXT FEW
DAYS WITH WARMER AND SUNNIER WEATHER AS THE WEEK PROGRESSES. AN
UPPER TROUGH COULD BRING SOME SHOWERS AND COOLING EARLY NEXT WEEK.

&&

.SHORT TERM...AN UPPER LEVEL LOW IS SPINNING ALONG THE WA/ID BORDER
THIS EVENING. MOISTURE WRAPPING AROUND THE LOW IS MAINLY AFFECTING
EASTERN WA ALTHOUGH A FEW SHOWERS ARE POSSIBLE OVER THE CASCADES.
THE UPPER LOW WILL WEAKEN ON WEDNESDAY AS IT SHIFTS SE INTO CENTRAL
ID. MEANWHILE...WESTERN WA IS STILL UNDER THE INFLUENCE OF LOW LEVEL
ONSHORE FLOW WITH STRATUS CLOUDS ACROSS THE LOWLANDS. HOWEVER...IT
LOOKS LIKE WE WILL SEE MORE SUNBREAKS WEDNESDAY AFTERNOON AS A RIDGE
MOVES IN FROM THE WEST. TEMPS WILL BE A FEW DEGREES WARMER IN THE
INTERIOR WITH HIGHS IN THE LOWER TO MID 70S. MODELS CONTINUE TO SHOW
SOME MOISTURE AND INSTABILITY OVER THE CASCADES FOR ISOLATED
AFTERNOON AND EVENING SHOWERS...WITH A CHANCE OF THUNDERSTORMS NEAR
THE CREST. ONSHORE FLOW WILL BE WEAKER THURSDAY AND FRIDAY FOR LESS
CLOUD COVER AND WARMER WEATHER. 33

.LONG TERM...PREVIOUS DISCUSSION...UPPER HEIGHTS WILL SLOWLY LOWER
OVER THE AREA SATURDAY AND SUNDAY WITH A BIT OF AN INCREASE IN LOW
LEVEL ONSHORE FLOW. THIS WILL CAUSE HIGHS TO COOL SLIGHTLY BUT
TEMPERATURES WILL REMAIN ABOVE NORMAL.

AN UPPER LOW OFFSHORE NORTHERN CALIFORNIA WILL MOVE TO THE WEST
COAST MONDAY. NOT SURPRISINGLY...THE MODELS ARE NOT IN VERY GOOD
AGREEMENT WITH HOW THIS WILL UNFOLD. THE GENERAL IDEA IS THAT
MOISTURE COMING UP FROM THE SOUTH WILL START TO IMPACT WESTERN
WASHINGTON MONDAY AS THE UPPER LOW NEARS FOR A CHANCE OF SHOWERS.
THE UPPER LOW WILL REMAIN IN THE VICINITY FOR A CONTINUED CHANCE OF
SHOWERS TUESDAY. HIGHS WILL COOL TO NEAR NORMAL BY TUESDAY AS CLOUDS
AND ONSHORE FLOW INCREASE. SCHNEIDER

&&

.AVIATION...AN UPPER LEVEL LOW WILL MOVE SLOWLY SOUTHEAST THROUGH
EASTERN WASHINGTON TONIGHT AND WEDNESDAY WITH NORTHERLY FLOW ALOFT
OVER WESTERN WASHINGTON. MODERATE ONSHORE FLOW AT THE SURFACE WILL
EASE OVERNIGHT. AIR MASS IS MOIST WITH MAINLY MID LEVEL MOISTURE AND
IS SLIGHTLY UNSTABLE. MARINE STRATUS IS LIKELY TO RETURN TO AT LEAST
SOME AREAS BY MORNING WITH MVFR CEILINGS. A CLEARING TREND WILL
BEGIN WEDNESDAY AFTERNOON.

KSEA...DISCUSSION ABOVE APPLIES. CEILINGS 6-9K FT WILL PERSIST THIS
EVENING. ONSHORE FLOW DOES NOT SEEM STRONG ENOUGH TO BRING STRATUS
INLAND TO THE TERMINAL FROM THE COAST. BEST GUESS IS CONTINUED VFR
WITH CEILINGS PERHAPS GETTING AS LOW AS 4K FT. LIGHT NORTHWEST WIND
WILL BECOME SOUTHERLY OVERNIGHT. CHB

&&

.MARINE...HIGH PRESSURE WILL REMAIN OFFSHORE WITH LOWER PRESSURE
INLAND THROUGH THE WEEK. SMALL CRAFT ADVISORY STRENGTH WEST WINDS OF
15 TO 25 KT WILL CONTINUE TONIGHT THEN EASE BY MORNING. CURRENTLY
MODELS KEEP WINDS BELOW 20 KT FOR THE REST OF THE WEEK IN THE
STRAIT. CHB

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY CENTRAL AND EAST STRAIT.

&&

$$

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YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
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