625
FXUS66 KSEW 220300
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
800 PM PDT SAT MAR 21 2026
SYNOPSIS
CALMER WEATHER IS IN STORE FOR THE REST OF THIS WEEKEND, WITH
AREA RIVERS CONTINUING TO RECEDE INTO SUNDAY. A WEAK SYSTEM WILL
BRUSH THE NORTH COAST LATER TODAY, WITH DRY CONDITIONS ELSEWHERE.
MORE ACTIVE WEATHER RETURNS TO THE AREA BY THE MIDDLE OF THE
WEEK FOR MORE RAIN, HIGH ELEVATION SNOW AND GUSTY WINDS.
SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/
CLEARER SKIES AND DRIER WEATHER ARE FORECAST FOR MUCH OF THE
AREA OVER THE WEEKEND. A DECAYING SYSTEM WILL BRUSH THE NORTH
PACIFIC COAST TODAY, BUT THE BROADER REGION SHOULD STAY DRY.
TEMPERATURES WILL BE IN THE LOW 50S THIS WEEKEND, WITH LOWS IN
THE UPPER 20S IN THE CASCADE FOOTHILLS AND MID 30S IN THE
LOWLANDS. CONTINUED DRY WEATHER IS EXPECTED INTO MONDAY, BUT
THAT WILL LIKELY BE THE LAST CALM DAY FOR AT LEAST THE FIRST
HALF OF THE WEEK AS ANOTHER SYSTEM IS EXPECTED TO ARRIVE EARLY
TUESDAY MORNING AND LAST INTO WEDNESDAY.
LONG TERM /TUESDAY THROUGH SATURDAY/
A STRONG LOW PRESSURE SYSTEM IS FORECAST TO MOVE INTO THE
COASTAL WATERS EARLY TUESDAY MORNING AND BRING ABOUT ANOTHER
ROUND OF RAIN (ALTHOUGH LESS RAIN THAN THE SYSTEM FROM LAST
WEEK), HIGHER ELEVATION SNOW, AND MORE NOTABLY, THE POTENTIAL
FOR STRONGER WINDS ACROSS WESTERN WASHINGTON. SOME OF THE
FORTHCOMING DETAIL ON THIS SYSTEM IS VERY DEPENDENT ON THE TRACK
OF THE LOW PRESSURE SYSTEM. QPF FROM TUESDAY MORNING THROUGH
WEDNESDAY MORNING SEEMS TO BE ONLY ON THE ORDER OF AROUND A HALF
OF AN INCH FOR MOST LOWLAND LOCATIONS, AND UPWARD OF AN INCH OR
TWO IN THE MOUNTAINS. STRONGER SOUTHERLY WINDS ARE LIKELY TO
PICK UP ON TUESDAY MORNING, AND PEAK LATE THAT AFTERNOON. NBM
50TH PERCENTILE WINDS SHOW GUST POTENTIAL IN PUGET SOUND UP TO
35 MPH, WITH GUSTS TO 45-50 MPH ALONG THE COAST. THIS CAN AND
WILL CHANGE AS THE TRACK OF THE LOW EVOLVES, BUT CONFIDENCE IS
HIGHER ON ELEVATED WINDS FOR TUESDAY AFTERNOON AND EVENING.
WINDS GRADUALLY DECREASE INTO WEDNESDAY, WITH RAIN SHOWERS
LINGERING THROUGHOUT THE DAY. SHOWERS TAPER AND SCATTER BY
THURSDAY AND FRIDAY, BUT LOW PRESSURE LOOKS TO CONTINUE TO BE
THE DOMINANT FEATURE IN THE NE PACIFIC UNTIL HINTS OF RIDGING
EMERGE BY LATE IN THE WEEK AND NEXT WEEKEND.
21
AVIATION
WESTERLY FLOW ALOFT WILL PREVAIL TONIGHT AS AN EMBEDDED SHORTWAVE
MOVES THROUGH THE AREA LATE TONIGHT INTO EARLY SUNDAY. SURFACE WINDS
LARGELY SOUTH TO SOUTHWESTERLY ALTHOUGH SOME TERMINALS MAY SEE
PERIODS OF VARIABLE WIND DIRECTION. IMPACT WILL BE MINIMAL AS WIND
SPEEDS ARE EXPECTED TO REMAIN AT OR BELOW 5 KTS. CLM AND HQM WILL BE
EXCEPTIONS, WITH WESTERLY WINDS EXPECTED TO 6-12 KTS...ALTHOUGH CLM
MAY FALL PRONE TO OCCASIONAL LIGHT AND VARIABLE AS WELL AT TIMES
TONIGHT. FOR MOST TERMINALS, WINDS WILL SHIFT TO GENERALLY
NORTHWESTERLY BETWEEN 18-20Z SUNDAY.
WIDESPREAD VFR CONDITIONS THIS EVENING AND EXPECTED TO PERSIST
TONIGHT. CEILINGS WILL THEN GRADUALLY LOWER LATER TONIGHT INTO EARLY
SUNDAY MORNING AS A DISSIPATING COLD FRONT MOVES ACROSS THE AREA.
WHILE MOST SPOTS WILL REMAIN VFR, A FEW COULD SEE BRIEFLY SEE CIGS
DIP DOWN TO MVFR. LIGHT SHOWERS WILL BE POSSIBLE AS THE SYSTEM MAKES
ITS WAY THROUGH THE AREA, ESPECIALLY FOR TERMINALS ALONG THE COAST
AND ACROSS THE NORTH INTERIOR (KHQM, KCLM, KBLI), BUT EXPECT MANY
SPOTS TO REMAIN DRY.
KSEA...VFR CONDITIONS AT THE TERMINAL ARE EXPECTED TO PERSIST
THROUGH THE TAF PERIOD. CIGS WILL GRADUALLY LOWER OVERNIGHT AS A
WEAK FRONT APPROACHES THE AREA, BUT WILL LIKELY REMAIN VFR, WITH
SHOWERS NOT LIKELY TO MAKE IT INTO THE TERMINAL. WINDS WILL PERSIST
OUT OF THE SOUTH/SOUTHWEST AT 4-7 KTS BEFORE TURNING MORE
NORTHWESTERLY BY 20Z SUNDAY AFTERNOON.
14/18
MARINE
A DISSIPATING FRONTAL SYSTEM WILL MOVE ACROSS THE AREA WATERS
TONIGHT INTO EARLY SUNDAY. WIND GUSTS ACROSS THE NORTHWESTERN
PORTION OF THE COASTAL WATERS MAY BRIEFLY INCREASE TO NEAR SMALL
CRAFT ADVISORY CRITERIA IN THE VICINITY OF THE FRONT, BUT DO
NOT EXPECT GUSTS TO BE WIDESPREAD OR FREQUENT ENOUGH TO WARRANT
ANY PRODUCT ISSUANCE AT THIS TIME. SEAS WILL PERSIST BETWEEN
6-9 FT TONIGHT INTO SUNDAY.
HIGH PRESSURE WILL THEN BUILD IN THE WAKE OF THE FRONTAL SYSTEM
ON SUNDAY AND REMAIN SITUATED ACROSS THE AREA WATERS THROUGH
MONDAY. A STRONGER, DEEPENING LOW PRESSURE SYSTEM WILL MOVE
INTO THE NORTHEASTERN PACIFIC ON TUESDAY AND SWING A FRONTAL
SYSTEM ACROSS THE AREA WATERS. WHILE UNCERTAINTY REMAINS IN
REGARDS TO THE EXACT TRACK OF THE SYSTEM, IT HAS THE POTENTIAL
TO BRING STRONG WINDS AND BUILDING SEAS TO THE WASHINGTON
WATERS. AT THIS TIME, THE MOST LIKELY SOLUTION HAS WINDS
REACHING GALE-FORCE ACROSS THE COASTAL WATERS AND THE EASTERN
STRAIT OF JUAN DE FUCA ON TUESDAY. SEAS WILL BUILD TOWARDS 17-20
FT ACROSS THE COASTAL WATERS, WITH THE LATEST GEFS GUIDANCE
INDICATING ROUGHLY A 40-50% CHANCE OF SEAS BUILDING TO GREATER
THAN 20 FT OVER PORTIONS OF THE COASTAL WATERS BY TUESDAY
NIGHT.
14
HYDROLOGY
RIVERS CONTINUE TO GRADUALLY RECEDE ACROSS THE REGION AND WILL
CONTINUE TO DO SO INTO SUNDAY. RELEASES FROM CHESTER MORSE WILL
MAINTAIN THE CEDAR RIVER NEAR RENTON AT MINOR FLOOD INTO SUNDAY.
ELSEWHERE, TRENDS REMAIN ON TRACK THIS EVENING. ADDITIONAL
RIVER FLOODING IS NOT EXPECTED THROUGH THE REMAINDER OF THE WEEK
AHEAD, THOUGH SOME RIVERS WILL SEE MODEST INCREASES AROUND
MIDWEEK WITH THE NEXT WEATHER SYSTEM.
SEW WATCHES/WARNINGS/ADVISORIES
WA...NONE.
PZ...NONE.
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