648
FXUS66 KSEW 071618
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
918 AM PDT THU MAY 7 2026
SYNOPSIS
AN UPPER LEVEL RIDGE WILL REMAIN SITUATED OVER THE REGION TODAY
WITH ONSHORE FLOW CONTINUING IN THE LOW LEVELS. A WEAK FRONTAL
SYSTEM WILL MOVE OVER THE AREA FRIDAY INTO SATURDAY, BRINGING A
SLIGHT CHANCE OF SHOWERS TO THE PACIFIC COAST. AN UPPER LEVEL
RIDGE WILL REBUILD OVER THE AREA THIS WEEKEND AND WILL INFLUENCE
THE AREA INTO EARLY NEXT WEEK, LEADING TO A GRADUAL WARM UP
ACROSS WESTERN WASHINGTON. SOME LIGHT SHOWERS WILL BE POSSIBLE
AROUND MIDWEEK AS SOME WEAK SYSTEMS APPROACH THE REGION.
SHORT TERM /TODAY THROUGH SATURDAY/
THE LATEST FORECAST REMAINS ON TRACK THIS MORNING WITH NO
UPDATES. AN UPPER LEVEL RIDGE WILL REMAIN SITUATED OVER THE
REGION TODAY WHILE ONSHORE FLOW CONTINUES IN THE LOW LEVELS.
ONSHORE FLOW WILL HELP KEEP STRATUS AROUND THROUGHOUT THE
MORNING HOURS, BUT GUIDANCE DOES INDICATE SOME SCATTERING IS
EXPECTED BY THIS AFTERNOON. AS A RESULT, EXPECT AFTERNOON HIGHS
TO BE A BIT WARMER THAN YESTERDAY, WITH AREAS ACROSS THE
INTERIOR TOPPING OUT IN THE MID 60S TO NEAR 70, WHILE AREAS
ALONG THE COAST LOOK TO REMAIN IN THE 50S TO LOW 60S. THE STATUS
OF THE STRATUS SCATTERING WILL BEAR WATCHING THOUGH, AS IT WILL
HAVE A DIRECT IMPACT ON THE DAY'S TEMPERATURES.
A WEAK, DISSIPATING FRONTAL SYSTEM WILL THEN APPROACH THE AREA
ON FRIDAY AS THE RIDGE AXIS PUSHES INLAND AND MAKES WAY FOR A
SHORTWAVE TROUGH. WHILE THE MAJORITY OF THE AREA LOOKS TO REMAIN
DRY, THIS SYSTEM MAY BRING SOME LIGHT SHOWER ACTIVITY TO THE
COAST BY FRIDAY EVENING. THE MORE NOTABLE IMPACT FROM THIS
SYSTEM WILL BE THE UPTICK IN ONSHORE FLOW AND THE INCREASED
CLOUDINESS ACROSS THE AREA. AFTERNOON HIGHS AS A RESULT WILL BE
IN THE 50S TO MID 60S.
AN UPPER LEVEL RIDGE WILL THEN REBUILD OVER THE REGION ON
SATURDAY, ALLOWING FOR THE GRADUAL WARM UP TO COMMENCE ACROSS
WESTERN WASHINGTON. HIGHS ON SATURDAY WILL WARM INTO THE LOW TO
MID 70S ACROSS THE INTERIOR AND INTO THE MID 60S ALONG THE
COAST. AREAS OF MINOR HEATRISK WILL EXPAND ACROSS WESTERN
WASHINGTON, BECOMING MORE WIDESPREAD.
LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/
ENSEMBLE GUIDANCE REMAINS IN GOOD AGREEMENT THAT THE UPPER
LEVEL RIDGE WILL REMAIN SITUATED OVER THE WESTERN US INTO EARLY
NEXT WEEK, BUT WILL GRADUALLY PUSH INLAND. AS THE RIDGE MOVES
EASTWARD, IT MAY OPEN THE DOOR TO SOME ADDITIONAL ROUNDS OF
LIGHT PRECIPITATION EARLY IN THE WEEK AS WEAK SYSTEMS BRUSH BY
TO THE NORTH. OVERALL, HOWEVER, EXPECT CONDITIONS TO REMAIN
LARGELY DRY AND WARM ACROSS THE AREA, WITH TEMPERATURES EXPECTED
TO CLIMB BACK UP INTO THE MID TO UPPER 70S BY TUESDAY. SOME
SPOTS MAY EVEN GET CLOSE TO 80 ACROSS THE SOUTHWEST INTERIOR.
ENSEMBLE SOLUTIONS START TO DIVERGE AGAIN CLOSER TO MIDWEEK, AS
THE RIDGE PUSHES FURTHER INLAND TOWARDS THE GREAT PLAINS AND AN
UPPER LEVEL TROUGH LOOKS TO SWING INTO BRITISH COLUMBIA.
TEMPERATURES LOOK TO REMAIN WARM, BUT THE UPPER TROUGH MAY START
TO REINTRODUCE SOME LIGHT PRECIPITATION CHANCES TO PORTIONS OF
THE AREA.
14
AVIATION
NORTHWESTERLY FLOW ALOFT AS UPPER LEVEL RIDGING REMAINS
OFFSHORE WESTERN WASHINGTON. A MIXED BAG OF CEILINGS EARLY
MORNING BETWEEN MVFR/VFR AS ONSHORE FLOW MAINTAINS STRATUS DECK
OVER THE AREA. WE'LL CONTINUE TO SEE SOME CEILINGS LOWER LOCALLY
TO IFR WITH MVFR CONTINUING THROUGHOUT THIS MORNING FOR MOST
AREAS. FLOW WILL START TO WEAKEN THIS AFTERNOON WHICH WILL HELP
LOW CLOUDS LIFT AND SCATTER (20Z-23Z) AND PROVIDE A GRADUAL
RETURN TO VFR FOR ALL TERMINALS.
KSEA...A MIX BETWEEN MVFR TO VFR THIS MORNING AS LOW CLOUDS
REMAIN AROUND THE TERMINAL. CONDITIONS WILL IMPROVE AFTER 20Z
WITH A RETURN TO VFR EXPECTED BY LATE AFTERNOON. WINDS REMAIN
S/SW UP TO 5 TO 10 KNOTS.
MARINE
SURFACE HIGH PRESSURE REMAINS OFFSHORE ALLOWING FOR LOW LEVEL
ONSHORE FLOW TO CONTINUE. WINDS WILL CONTINUE TO WEAKEN THIS
MORNING THROUGH THE STRAIT OF JUAN DE FUCA WITH ONSHORE FLOW
WEAKENING AS WELL.
A WEAK FRONT WILL CROSS OVER THE WATERS ON FRIDAY, WITH
GENERALLY BENIGN MARINE CONDITIONS. ONSHORE FLOW INCREASES OVER
THE WEEKEND ALLOWING FOR MORE STRONGER PUSHES DOWN THE STRAIT.
HYDROLOGY
THE DAILY HYDROLOGY DISCUSSION HAS ENDED UNTIL THE START OF THE NEXT
RAINY SEASON; IT WILL ONLY BE UPDATED DURING THIS TIME AS
NEEDED.
SEW WATCHES/WARNINGS/ADVISORIES
WA...NONE.
PZ...NONE.
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