Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA

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924
FXUS66 KSEW 301611
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
911 AM PDT SAT APR 30 2016

.SYNOPSIS...HIGH PRESSURE ALOFT WILL BRING DRY AND WARMER WEATHER
THROUGH MONDAY. SOUTHERLY FLOW ALOFT AND LOW LEVEL ONSHORE FLOW
WILL RETURN TUESDAY AND PERSIST FOR MOST OF THE REST OF THE WEEK
FOR A CHANCE OF SHOWERS AND COOLER TEMPERATURES.

&&

.SHORT TERM...AN UPPER RIDGE WILL BUILD OVER THE AREA TODAY FOR
MOSTLY SUNNY AND WARMER WEATHER. HIGHS WILL BE MAINLY IN THE 60S.
THE RIDGE WILL SHIFT A BIT INLAND SUNDAY WITH LOW LEVEL OFFSHORE
FLOW DEVELOPING. HIGHS WILL JUMP 10-15 DEGREES WITH 70S COMMON AND
LOWER 80S POSSIBLE IN A FEW SPOTS.

HIGH PRESSURE ALOFT WILL SHIFT FURTHER INLAND MONDAY WITH
INCREASING SOUTHERLY FLOW ALOFT FOR WESTERN WASHINGTON. LOW LEVEL
OFFSHORE FLOW WILL DECREASE A BIT BUT A WEAK TROUGH WILL REMAIN
JUST OFFSHORE. THIS SHOULD BE THE WARMEST DAY FOR THE INTERIOR...A
FEW DEGREES WARMER THAN SUNDAY. THE COAST WILL REMAIN WELL ABOVE
NORMAL BUT PROBABLY SEE A FEW DEGREES OF COOLING AS SOUTHERLY
WINDS DEVELOP IN THE AFTERNOON. SCHNEIDER

.LONG TERM...PREVIOUS DISCUSSION...THE WEATHER PATTERN OVER THE
AREA TUESDAY THROUGH FRIDAY OF THE UPCOMING WEEK WILL BE SOMEWHAT
UNSETTLED. AN OMEGA BLOCK WILL BE OVER THE USA...WITH UPPER LEVEL
TROFS OVER THE WEST AND EAST COASTS. IT APPEARED THAT MUCH OF THE
ENERGY WITH THE WEST COAST TROF WILL IMPACT THE SOUTHWEST USA BUT
THERE WILL STILL BE A THREAT OF SHOWERS OVER THE FORECAST AREA.
OTHERWISE...EXPECT ONSHORE FLOW ACROSS WESTERN WA DURING THIS
PERIOD...WITH TEMPS RETURNING TO NEAR NORMAL.

&&

.AVIATION...UPPER LEVEL RIDGE OFFSHORE WILL BUILD INTO SOUTHERN
BRITISH COLUMBIA LATER TODAY AND TONIGHT. NORTHERLY FLOW ALOFT WILL
BECOME NORTHEASTERLY TONIGHT. LOW LEVEL NORTHWESTERLY ONSHORE FLOW
IS EXPECTED TO PERSIST TODAY.

SATELLITE IMAGERY SHOWS A LITTLE BIT OF SC OVER WESTERN WASHINGTON
THIS MORNING. SOME ISOLATED CEILINGS NEAR 4000 FEET. FOR THE MOST
PART THE SC DECK IS SCATTERED. THE FEW LOCATIONS WHERE THE SC DECK
IS BROKEN THIS MORNING THE SC DECK WILL BECOME SCATTERED BY NOON.
SKIES CLEARING OUT TONIGHT.

KSEA...TEMPORARY CEILINGS NEAR 4000 FEET THIS MORNING OTHERWISE
SCATTERED SC DECK WITH HIGH CLOUDS. SKIES CLEARING OUT TONIGHT.
LIGHT WIND BECOMING NORTHWESTERLY 5 TO 10 KNOTS MID
AFTERNOON. FELTON

&&

.MARINE...LOW LEVEL ONSHORE FLOW PATTERN CONTINUING TODAY
WITH SMALL CRAFT ADVISORIES PERSISTING OVER COASTAL WATERS THROUGH
TONIGHT. SMALL CRAFT WINDS WILL RETURN TO THE ENTIRE STRAIT LATE
THIS AFTERNOON AND INTO TONIGHT BEFORE DIMINISHING ONCE MORE.
NORTHWESTERLY ONSHORE FLOW TODAY AS HIGH PRESSURE BUILDS INTO
SOUTHERN BRITISH COLUMBIA. LOW LEVEL FLOW TURNING OFFSHORE ON SUNDAY
WITH THERMALLY INDUCED TROUGH ALONG THE COAST. A RETURN TO LOW LEVEL
ONSHORE FLOW WILL OCCUR LATER MONDAY INTO TUESDAY. FELTON

&&

.CLIMATE...APRIL 2016 WILL BE THE WARMEST APRIL ON RECORD IN
SEATTLE. WHAT DOES A WARM APRIL MEAN FOR MAY TEMPERATURES? LOOKING
AT THE PREVIOUS TOP 10 WARMEST APRILS AT SEA-TAC AIRPORT...THE
FOLLOWING MAY WAS WARMER THAN NORMAL 7 TIMES AND COOLER THAN
NORMAL 3 TIMES. THREE OF THE FOLLOWING MAYS ARE IN THE TOP 10
WARMEST MAYS FOR SEA-TAC. RECORDS STARTED AT SEA-TAC AIRPORT IN
1945. FELTON

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 5 AM PDT SUNDAY 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.

     SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO 2 AM PDT SUNDAY
     FOR CENTRAL U.S. WATERS STRAIT OF JUAN DE FUCA-EAST
     ENTRANCE U.S. WATERS STRAIT OF JUAN DE FUCA-WEST ENTRANCE
     U.S. WATERS STRAIT OF JUAN DE FUCA.

&&

$$

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