732  
FXUS66 KSEW 240230  
AFDSEW  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SEATTLE WA  
730 PM PDT WED APR 23 2025  
   
SYNOPSIS  
HIGH PRESSURE WILL BUILD OVER THE REGION THROUGH  
THURSDAY, WITH DRY AND WARMING CONDITIONS. COOLER AND WETTER  
WEATHER WILL MOVE IN LATER THIS WEEKEND, WITH A RETURN OF DRIER  
AND WARMER WEATHER POSSIBLE TOWARDS THE LATTER HALF OF NEXT WEEK.  
 
 
   
SHORT TERM /TONIGHT THROUGH SATURDAY/  
ANOTHER EVENING UNDER THE  
RIDGE WITH CLEAR SKIES IN PLACE OVER W WA. SOME LOW 60S STILL IN  
PLACE OVER THE SOUTH SOUND AND SW INTERIOR AT THE TIME OF THIS  
WRITING, WHILE REMAINING OBS FIND THEMSELVES IN THE MID TO UPPER  
50S. INHERITED FORECAST REMAINS ON TRACK WITH NO NEED FOR EVENING  
UPDATES. FOR ADDITIONAL FORECAST DETAILS, PLEASE REFER TO THE  
PREVIOUS DISCUSSION SECTION BELOW.  
 
18  
 
FROM PREVIOUS DISCUSSION...UPPER LEVEL RIDGING WILL CONTINUE TO  
BUILD OVER THE REGION THROUGH THURSDAY FOR DRY AND WARM CONDITIONS.  
TEMPERATURES THIS AFTERNOON HAVE BEEN WARMING STEADILY INTO THE MID  
TO UPPER 60S, WITH SOME LOCALIZED SPOTS IN 70S. TEMPERATURES WILL  
WARM A TOUCH MORE ON THURSDAY, WITH MOST OF THE INTERIOR LOCATIONS  
SEEING TEMPERATURES IN THE LOWER 70S - AREAS ALONG THE WATER WILL  
SEE HIGHS CLOSE TO THE MID 60S.  
 
A WEAK TROUGH OFFSHORE WILL START TO INCREASE CLOUD COVER SLIGHTLY  
HEADING INTO FRIDAY, AS A CUTOFF LOW CONTINUES TO MOVE SOUTHWARD  
INTO CALIFORNIA. LATEST ENSEMBLE GUIDANCE HAS CONTINUED THIS TRACK  
OF A SOUTHWARD PROGRESSION, WHICH WOULD DECREASE PRECIPITATION  
CHANCES FOR WESTERN WASHINGTON. HIGH TEMPERATURES ON FRIDAY WILL  
CONTINUE TO BE THE UPPER 60S/LOWER 70S.  
 
A SPLIT FLOW REGIME LOOKS TO SET UP HEADING INTO THE WEEKEND, WITH  
SATURDAY LOOKING TO BE MAINLY DRY AND TEMPERATURES IN THE LOW TO  
MID 60S.  
   
LONG TERM /SUNDAY THROUGH WEDNESDAY/  
SPLIT FLOW WILL SLIGHTLY  
DIFFER AS A UPPER TROUGH OPENS WAY FOR PRECIPITATION CHANCES ON  
SUNDAY. ENSEMBLES ARE HAVING A DIFFICULT TIME GRASPING ON THE  
STRENGTH AND SPREAD OF PRECIPITATION AS IT SEEMS WEAK, BUT  
OVERALL, IT LOOKS GENERALLY LIGHT, IF ANY PRECIP, ON SUNDAY.  
SHOWERS MAY LINGER THROUGH MIDWEEK BEFORE DRIER WEATHER RETURNS.  
 
MAZURKIEWICZ  
 
 
   
AVIATION  
AN UPPER LEVEL RIDGE AXIS OVER THE COASTAL WATERS WILL  
SHIFT ONSHORE TONIGHT WITH NORTH TO NORTHWEST FLOW ALOFT BECOMING  
LIGHT SOUTHERLY OVERNIGHT. THE LOW LEVEL FLOW REMAINS NORTHERLY. THE  
AIR MASS IS DRY AND STABLE. MOSTLY CLEAR SKIES EXPECTED THROUGH THE  
PERIOD EXCEPT FOR SOME PATCHY STRATUS ALONG THE COAST AND LOCALLY IN  
THE CHEHALIS GAP ON THURSDAY MORNING.  
 
KSEA...VFR. SURFACE WINDS NORTH/NORTHWESTERLY 5 TO 8 KNOTS BECOMING  
LIGHT NORTHEASTERLY TONIGHT THEN NORTH/NORTHWESTERLY 7 TO 10 KNOTS  
ONCE AGAIN THURSDAY AFTERNOON. 27  
 
 
   
MARINE  
A SURFACE RIDGE CENTERED OFFSHORE WILL WEAKEN THROUGH  
TOMORROW. A BROAD AREA OF WEAK SURFACE LOW PRESSURE WILL DEVELOP  
LATE IN THE WEEK OVER THE PACIFIC NORTHWEST WHILE HIGH PRESSURE  
REMAINS CENTERED WELL OFFSHORE. THIS WILL LEAD TO AN OVERALL  
INCREASE IN ONSHORE FLOW LEADING INTO THE UPCOMING WEEKEND. THE END  
RESULT WILL LIKELY BE A PERIOD OF SMALL CRAFT ADVISORY WINDS ACROSS  
THE COASTAL WATERS AS WELL AS THE CENTRAL/EAST PORTIONS OF THE  
STRAIT. 27  
 
 
   
HYDROLOGY  
NO RIVER FLOODING IS EXPECTED OVER THE NEXT 7 DAYS.  
 
 
   
SEW WATCHES/WARNINGS/ADVISORIES  
 
WA...NONE.  
PZ...NONE.  
 
 
 
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