123
FXUS66 KSEW 240907
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
207 AM PDT TUE MAR 24 2026
SYNOPSIS
A STRONG STORM WILL BRING WIND, RAIN AND HIGH
ELEVATION SNOW TODAY. SHOWERS AND A CONVERGENCE ZONE WILL
FOLLOW ON WEDNESDAY. DRIER AND SLIGHTLY WARMER WEATHER WILL
PREVAIL INTO THE END OF THE WEEK. RAIN INCREASES BY MONDAY WITH
A TROUGH.
SHORT TERM /TODAY THROUGH THURSDAY/
A STRONG PACIFIC STORM
SYSTEM WILL SHIFT NORTH INTO B.C. TODAY, WITH ACTIVE WEATHER
ACROSS WESTERN WA. THIS SYSTEM IS TIED TO A DEEP, 990 MB, LOW
THAT WILL PASS OVER NORTHERN VANCOUVER ISLAND THIS AFTERNOON.
WITH THE PASSING OF THE LOW, WE WILL SEE TIGHTER PRESSURE
GRADIENTS OVER WESTERN WA WITH A PERIOD OF STRONGER SOUTH WINDS
THIS MORNING AND AFTERNOON. HIGHEST WINDS WILL BE ALONG THE
COAST AND OVER THE NORTH INTERIOR WHERE GUSTS TO 40-50 MPH WILL
OCCUR - A WIND ADVISORY IS IN EFFECT. EXPECT GUSTS TO 30-40 MPH
ELSEWHERE WITH WINDS EASING LATE THIS AFTERNOON AND EVENING. UP
IN THE MOUNTAINS, SNOW LEVELS WILL BE RISING THROUGH THE DAY
BUT WE MAY SEE A BRIEF PERIOD OF HEAVY SNOW AT MOUNT BAKER AND
THE NORTH CASCADES THIS MORNING. RAINFALL/QPF IS NOT TOO HEAVY
OTHERWISE. RIVERS MAY SEE SMALL RISES BUT ADDITIONAL FLOODING IS
NOT EXPECTED.
WE REMAIN UNDER MODERATE ONSHORE FLOW ON WEDNESDAY WITH HIGH
PRESSURE OFFSHORE AND LOW PRESSURE TO OUR NORTH. STILL PLENTY OF
MOISTURE OVER THE AREA WITH ADDITIONAL SHOWERS EXPECTED. SNOW
LEVELS WILL BE LOWER, AROUND 2500 FT, WITH SNOW IN THE CASCADES
AND PASSES. SHOWERS MAY BE ENHANCED WITH A PUGET SOUND
CONVERGENCE ZONE OVER SNOHOMISH COUNTY. THE AIR MASS WILL BE
SLIGHTLY UNSTABLE WITH A CHANCE OF THUNDERSTORMS TOO.
HIGH PRESSURE STARTS TO BUILD INLAND ON THURSDAY FOR A TREND
TOWARD DRIER WEATHER. 33
LONG TERM /THURSDAY NIGHT THROUGH MONDAY/
HIGH PRESSURE AND
OFFSHORE FLOW WILL LEAD TO A COUPLE OF DRY AND SLIGHTLY WARMER
DAYS MOVING INTO THE END OF THE WEEK AND WEEKEND. HIGHS ON
FRIDAY AND SATURDAY WILL BE IN THE 50S TO LOWER 60S. A TROUGH
KICKS THE RIDGE INLAND ON SUNDAY WITH INCREASING CLOUDS AND A
CHANCE OF SHOWERS OVER WESTERN WA. MONDAY IS WETTER (AND COOLER)
AS THE TROUGH SHIFTS INLAND AND OVER WA. 33
AVIATION
STRONG SOUTHWEST FLOW ALOFT WILL CONTINUE OVER
WESTERN WASHINGTON TODAY WITH A VIGOROUS FRONTAL SYSTEM EXPECTED
TO SWEEP ONSHORE EARLY THIS EVENING. MVFR CEILINGS IN RAIN WILL
DEVELOP ALONG THE COAST EARLY THIS MORNING THEN SPREAD TO
INTERIOR TERMINALS 15-18Z. CEILINGS ARE EXPECTED TO LIFT TO LOW
END VFR IN SCATTERED POST- FRONTAL SHOWERS BETWEEN 00Z AND 03Z
THIS EVENING. INCREASINGLY GUSTY SOUTH TO SOUTHEASTERLY SURFACE
WINDS ARE EXPECTED AHEAD OF THE FRONT BECOMING SOUTHWESTERLY
THIS EVENING AFTER FRONTAL PASSAGE.
KSEA...CEILINGS ARE EXPECTED TO LOWER TO MVFR IN RAIN BETWEEN 15Z
AND 18Z THIS MORNING. THESE CONDITIONS WILL PERSIST INTO THE
AFTERNOON AND ARE THEN EXPECTED TO LIFT TO LOW END VFR IN SCATTERED
SHOWERS AFTER AROUND 01Z. E/SE SURFACE WINDS OF 7 TO 10 KNOTS WILL
SHIFT S/SW AND INCREASE ABRUPTLY TO 15 TO 25 KNOTS BETWEEN 21Z AND
00Z WITH OCCASIONAL GUSTS OF 30 TO 35 KNOTS. WINDS WILL GRADUALLY
EASE LATE THIS EVENING, BUT WILL LIKELY REMAIN GUSTY THROUGH 08Z.
27
MARINE
A VIGOROUS FRONTAL SYSTEM ASSOCIATED WITH A SUB 990
MILLIBAR SURFACE LOW CURLING NORTHEASTWARD OFFSHORE TOWARD NORTH
VANCOUVER ISLAND WILL SWEEP ACROSS ACROSS THE WATERS LATE THIS
AFTERNOON INTO THIS EVENING. A STRONG ONSHORE PUSH IS EXPECTED
BEHIND IT. GALES ARE EXPECTED ALL WATERS WITH COASTAL SEAS
BUILDING WELL INTO THE DOUBLE DIGITS THIS AFTERNOON AND TONIGHT
AND PERSISTING INTO WEDNESDAY. SURFACE RIDGING WILL BEGIN TO
REBUILD ACROSS THE WATERS ON THURSDAY AND REMAIN IN PLACE INTO
FRIDAY BEFORE ANOTHER FRONT APPROACHES OVER THE WEEKEND. SEAS
WILL SLOWLY SUBSIDE TO 6-8 FEET THURSDAY AND 5-7 FEET TOWARD THE
WEEKEND.
27
HYDROLOGY
RIVER FLOODING IN NOT EXPECTED OVER THE NEXT 7
DAYS.
SEW WATCHES/WARNINGS/ADVISORIES
WA...WIND ADVISORY FROM 11 AM THIS MORNING TO 6 PM PDT THIS EVENING
FOR ISLAND COUNTY-LOWLANDS OF WESTERN SKAGIT AND
NORTHWESTERN SNOHOMISH COUNTIES-LOWLANDS OF WESTERN
WHATCOM COUNTY-PORT TOWNSEND AREA-SAN JUAN COUNTY.
WIND ADVISORY FROM 9 AM THIS MORNING TO 3 PM PDT WEDNESDAY FOR
GRAYS HARBOR COUNTY COAST-NORTHERN WASHINGTON COAST.
PZ...SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 5 AM PDT
WEDNESDAY FOR GRAYS HARBOR BAR.
GALE WARNING FROM 5 AM EARLY THIS MORNING TO 11 PM PDT THIS
EVENING 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.
GALE WARNING FROM 10 AM THIS MORNING TO 11 PM PDT THIS EVENING
FOR CENTRAL U.S. WATERS STRAIT OF JUAN DE FUCA.
GALE WARNING FROM 8 AM THIS MORNING TO 9 PM PDT THIS EVENING
FOR ADMIRALTY INLET-EAST ENTRANCE U.S. WATERS STRAIT OF
JUAN DE FUCA-NORTHERN INLAND WATERS INCLUDING THE SAN
JUAN ISLANDS.
GALE WARNING FROM 8 AM THIS MORNING TO 11 PM PDT THIS EVENING
FOR PUGET SOUND AND HOOD CANAL.
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