700
FXUS66 KSEW 022250
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
250 PM PST TUE DEC 2 2025
SYNOPSIS
WEAK WARM FRONT WILL BRUSH THE NORTHWEST CORNER
WEDNESDAY. ANOTHER SYSTEM MOVING OVER THE TOP OF AN OFFSHORE RIDGE
MOVING THROUGH THURSDAY. A SERIES OF STRONGER AND WETTER
SYSTEMS WILL TAKE AIM AT WESTERN WASHINGTON BEGINNING FRIDAY AND
CONTINUING THROUGH THE MIDDLE OF NEXT WEEK.
SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/
THE SHORT TERM
PATTERN IS DOMINATED BY STRONG HIGH PRESSURE OFFSHORE, WITH
MOIST NW FLOW OVER WESTERN WA. WE'RE LOOKING FOR MAINLY DRY
WEATHER TONIGHT AND WEDNESDAY (THE DRIEST DAY OVER THE NEXT 7)
ALTHOUGH THE LOW LEVEL AIR MASS WILL REMAIN MOIST FOR LOW CLOUDS
AND FOG. THE FORECAST IS WETTER HEADING INTO THURSDAY AS THE
NEXT WAVE OF MOISTURE OVERRIDES THE RIDGE AND MOVES INTO THE
REGION. THIS MOISTURE TAP IS AIMED PARTICULARLY OVER THE CENTRAL
CASCADES FOR MOUNTAIN RAIN AND HIGH ELEVATION SNOW, POTENTIALLY
SENDING A FEW RIVERS IN KING AND SNOHOMISH COUNTIES INTO ACTION
STAGE. 33
LONG TERM /FRIDAY THROUGH TUESDAY/
THE PATTERN REMAINS ACTIVE
THROUGH THE EXTENDED PERIOD AS WAVE AFTER WAVE OF MOISTURE
STREAMS THROUGH WESTERN WA. THE MAIN CONCERN WILL BE FOCUSED
TOWARD RIVER LEVELS WITH POTENTIAL THREATS OF FLOODING AS WE
HEAD THROUGH EARLY NEXT WEEK. WITHOUT MUCH OF A BREAK, THE
LANDSLIDE THREAT WILL ALSO BE ELEVATED DUE TO SATURATED SOILS
AND ANTECEDENT CONDITIONS. THE AIR MASS WILL BE MILD WITH TEMPS
IN THE 40S AND 50S, AND HIGH SNOW LEVELS. STEVENS PASS MAY SEE
PERIODS OF LIGHT SNOW WITH ALL RAIN DOWN AT SNOQUALMIE PASS.
IN ADDITION, HIGH ASTRONOMICAL TIDES WILL BE OBSERVED THROUGH
THIS SAME PERIOD WITH POTENTIAL FOR MINOR COASTAL FLOODING (BOTH
COAST AND INTERIOR). 33
AVIATION
NORTHERLY FLOW ALOFT AS AN UPPER LEVEL RIDGE BEGINS
TO BUILD OFFSHORE. A MIXED BAG OF CEILINGS FROM EARLIER THIS
MORNING HAS CONTINUED TO LEAD TO MVFR/IFR CEILINGS THIS
AFTERNOON. SOME IMPROVEMENT IS LOOKING LIKELY LATER THIS EVENING
AS SOME TERMINALS REMAIN AROUND MVFR/LOW-END VFR. CONDITIONS
LOOK TO LOWER ONCE MORE OVERNIGHT AND INTO WEDNESDAY MORNING
WITH SOME PATCHY FOG POSSIBLE. WITH PATCHY FOG AND LOWERED
CEILINGS, WILL SEE A MIX OF MVFR/IFR CONDITIONS ACROSS MOST
INTERIOR TERMINALS GENERALLY AROUND 08-14Z. NORTHERLY WINDS THIS
AFTERNOON 6 TO 8 KNOTS WILL DECREASE GENERALLY AROUND 3 TO 6
KNOTS AND TURN MORE NE.
KSEA...MVFR CONDITIONS THIS AFTERNOON. CONDITIONS MAY IMPROVE
SLIGHTLY TO LOW END VFR LATER THIS EVENING AT TIMES, WITH
GUIDANCE SPLIT ON KEEPING MVFR THROUGH OVERNIGHT HOURS.
CONDITIONS WILL LOWER AGAIN OVERNIGHT AND EARLY WEDNESDAY
MORNING WITH THE POSSIBILITY OF FOG NEAR THE TERMINAL, WHICH
COULD BRING IFR CONDITIONS (30% CHANCE) THROUGH 16Z. CONDITIONS
LOOK TO HOLD STEADY AT MVFR/VFR BY WEDS AFTERNOON. NORTHERLY
WINDS THIS AFTERNOON 7 TO 9 KNOTS WILL TURN NE AFTER 00Z AND
REMAIN AROUND 3 TO 6 KNOTS.
MAZURKIEWICZ
MARINE
SURFACE HIGH PRESSURE OFFSHORE WILL CONTINUE TO BRING
BENIGN CONDITIONS TO THE AREA WATERS THIS EVENING. WINDS AND
SEAS WILL START TO BECOME ELEVATED ON FRIDAY AS A SERIES OF
SYSTEMS WILL START TO APPROACH THE AREA WATERS, LIKELY BRINGING
SMALL CRAFT ADVISORY GUSTS TO THE COASTAL WATERS ALONG WITH A
PUSH DOWN THE STRAIT OF JUAN DE FUCA. ACTIVE WEATHER CONTINUES
THROUGHOUT THE WEEKEND AND INTO THE FIRST HALF OF NEXT WEEK WITH
ELEVATED WINDS AND SEAS.
COMBINED SEAS AROUND 8 TO 10 FEET THIS AFTERNOON LOWERING TO 4
TO 6 FEET OVERNIGHT. SEAS LOOK TO GET UP AROUND 10 FEET LATE
FRIDAY NIGHT, GENERALLY STAYING THAT WAY THROUGHOUT THE WEEKEND.
SEAS LOOK TO BUILD MORE RAPIDLY 10 TO 13 FEET BY MONDAY.
MAZURKIEWICZ
HYDROLOGY
THE SERIES OF WEATHER SYSTEMS FORECAST TO REACH
THE AREA WILL EVENTUALLY INCREASE THE THREAT OF RIVER FLOODING
IN THE COMING DAYS. WEST NORTHWESTERLY FLOW ALOFT WITH THE
SYSTEM FRIDAY PUTS THE AREA OF GREATEST PRECIPITATION IN THE
NORTH CENTRAL WASHINGTON CASCADES. SNOW LEVELS RISING OVER 6000
FEET. CURRENT FORECAST 18 HOUR PRECIPITATION AMOUNTS BETWEEN 06Z
FRIDAY AND 00Z SATURDAY HAVE AN AREA OF 2 INCH BULLSEYES
BETWEEN SNOQUALMIE PASS AND GLACIER PEAK. THIS WILL PUT PRESSURE
ON THE RIVERS FLOWING OUT OF THIS AREA INCLUDING BUT NOT
LIMITED TO THE SNOQUALMIE, SKYKOMISH, SNOHOMISH AND TOLT RIVERS.
AS THE FLOW ALOFT BECOMES MORE WEST SOUTHWESTERLY THE FLOOD
THREAT WILL SHIFT TO THE FLOOD PRONE SKOKOMISH RIVER LATER IN
THE WEEKEND.
PLENTY OF UNCERTAINTY ON HOW THE PATTERN WILL SET UP EARLY NEXT
WEEK BUT THERE IS A CHANCE FOR A WIDESPREAD RIVER FLOODING
EVENT.
THE LANDSLIDE THREAT IS MINIMAL THE NEXT FEW DAYS. THE SERIES
OF SYSTEMS WILL EVENTUALLY TAKE ITS TOLL WITH THE LANDSLIDE
THREAT INCREASING THIS WEEKEND INTO EARLY NEXT WEEK. FELTON
SEW WATCHES/WARNINGS/ADVISORIES
WA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 10 PM PST THIS EVENING FOR COASTAL
WATERS FROM CAPE FLATTERY TO JAMES ISLAND 10 TO 60 NM-
COASTAL WATERS FROM JAMES ISLAND TO POINT GRENVILLE 10 TO
60 NM-COASTAL WATERS FROM POINT GRENVILLE TO CAPE
SHOALWATER 10 TO 60 NM.
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