141
FXUS66 KSEW 220951
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
251 AM PDT TUE APR 22 2025
SYNOPSIS
DRY AND WARMING CONDITIONS ARE EXPECTED THROUGH THURSDAY
AS HIGH PRESSURE MOVES INTO THE REGION. COOLER CONDITIONS AND
PRECIPITATION CHANCES WILL RETURN TO THE FORECAST FRIDAY INTO THE
WEEKEND.
SHORT TERM /TODAY THROUGH THURSDAY/
CLOUD COVER WILL CONTINUE
TO DECREASE EARLY THIS MORNING AS A DRY SHORTWAVE TROUGH DIGS
SOUTHWARD INTO THE PACIFIC NORTHWEST AND HIGH PRESSURE BUILDS
OFFSHORE. CLEARING SKIES WILL ALLOW TEMPERATURES TO DIP INTO THE
30S FOR MOST AREAS THIS MORNING WITH PATCHES OF FOG AND FROST
POSSIBLE, ESPECIALLY FOR AREAS SOUTH OF THE PUGET SOUND.
A RIDGE OF HIGH PRESSURE WILL MOVE INLAND LATER TODAY THROUGH
THURSDAY, BRINGING IN A GRADUAL WARMING TREND ALONGSIDE DRY AND
SUNNY CONDITIONS. TEMPERATURES WILL RISE TO WELL ABOVE NORMAL BY
THURSDAY, WITH MOST LOWLAND AREAS EAST AND SOUTH OF THE PUGET
SOUND SEEING HIGHS IN THE 70S. CLOUDS WILL SLOWLY START TO MOVE
BACK INTO THE REGION LATER ON THURSDAY AS A TROUGH SLOWLY
APPROACHES THE COAST AND THE UPPER RIDGE AXIS SHIFTS TO THE EAST
OF THE CASCADES.
LONG TERM /FRIDAY THROUGH MONDAY/
A CUTOFF LOW IS ON TRACK TO
MOVE INLAND OVER NORTHERN CALIFORNIA ON FRIDAY, ADVECTING MOISTURE
NORTHWARD TOWARDS WESTERN WASHINGTON. PRECIPITATION WILL BE
HIGHLY DEPENDENT ON THE TRACK OF THE LOW PRESSURE SYSTEM, WITH
ENSEMBLES MAINTAINING A CHANCE OF SHOWERS ACROSS THE AREA ON
FRIDAY. CHANCES FOR LIGHT PRECIPITATION ALONGSIDE COOLER
TEMPERATURES CONTINUE THROUGH THE WEEKEND, WITH ENSEMBLES
MAINTAINING TROUGHING OVER THE REGION THROUGH SUNDAY. RIDGING IS
FAVORED TO RETURN BY EARLY NEXT WEEK, ALTHOUGH FORECAST MODELS
SHOW DIFFERENCES OVER THE TIMING AND STRENGTH OF THE NEXT INCOMING
SYSTEM TO START OFF NEXT WEEK.
15
AVIATION
A TRANSIENT RIDGE WILL BEGIN TO BUILD NORTHWEST OF THE
TERMINALS TODAY UP IN B.C., CONTINUING THE NORTHWEST FLOW ALOFT. VFR
CONDITIONS ARE CURRENTLY PRESENT ACROSS ALL TERMINALS THIS MORNING
(EXCEPT FOR KPAE WITH A PATCHY BKN010 DUE TO A VERY WEAK CONVERGENCE
BAND OF SPRINKLES/SHOWERS FROM THERE UP TO KBLI - THESE LOWER CIGS
WILL BE BRIEF). CLOUD COVERAGE WILL CONTINUE TO DISSIPATE OVERNIGHT.
THERE IS A SLIGHT POTENTIAL FOR SOME PATCHY FOG (OR FROST) IN SOME
LOW LYING AREAS THIS MORNING, BUT THE POTENTIAL IS TOO LOW TO
INCLUDE IN THE TAFS AT THIS TIME). LIGHT AND VARIABLE NORTHWEST
WINDS THIS MORNING WILL PICK UP TO 5 TO 10 KT (COUPLE HIGHER GUSTS
TO 15 KT POSSIBLE FOR TERMINALS ALONG WATERS).
KSEA...VFR CONDITIONS IN THE TAF PERIOD. FEW BROKEN CLOUDS AT 5,000
FT WILL INCREASE AND SCATTER OUT THROUGH THE MORNING. EXPECT NORTH
WINDS TO PICKUP THROUGHOUT THE DAY UP TO 5 TO 10 KT.
HPR
MARINE
HIGH PRESSURE WILL BUILD OFFSHORE, WITH LOW PRESSURE
INLAND, CREATING AN ONSHORE FLOW PATTERN THROUGH MUCH OF THE WEEK
WITH NORTHWEST WINDS OVER THE WATERS. THERE COULD BE A FEW GUSTS TO
20 KT IN THE OUTER COASTAL WATERS THROUGH WEDNESDAY MORNING, BUT THE
PROBABILITY WAS TOO LOW TO CONSIDER A SMALL CRAFT ADVISORY WITH A
DIMINISHING WIND THREAT. THE WINDS WILL BE SIGNIFICANTLY LIGHTER IN
ALL REMAINING WATERS, AND THE NEXT SYSTEM AT THE END OF THE WEEK
DOES NOT APPEAR THAT IT WILL PRODUCE ANY HAZARDOUS GUSTY WINDS AT
THIS TIME.
SEAS 5-7 FEET TODAY, DECREASING TO 4 TO 6 FEET WEDNESDAY THROUGH THE
END OF THE WEEK.
HPR
HYDROLOGY
NO RIVER FLOODING IS EXPECTED OVER THE NEXT 7 DAYS.
SEW WATCHES/WARNINGS/ADVISORIES
WA...NONE.
PZ...NONE.
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