323  
FXUS66 KSEW 091010  
AFDSEW  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SEATTLE WA  
310 AM PDT SAT AUG 9 2025  
   
SYNOPSIS  
A HIGH PRESSURE RIDGE WILL BUILD OVER WESTERN  
WASHINGTON INTO EARLY NEXT WEEK, BRINGING WARMER AND DRIER  
CONDITIONS. MODERATE HEATRISK IS FORECAST FOR MOST LOWLAND AREAS  
SUNDAY AND MONDAY, WITH HIGHS REACHING THE 80S TO LOW 90S. UPPER  
LEVEL TROUGHING WILL BRING COOLER TEMPERATURES WITH INCREASED  
CHANCES FOR RAIN LATER IN THE WEEK.  
 
 
   
SHORT TERM /TODAY THROUGH MONDAY/  
A RIDGE OF HIGH PRESSURE  
CENTERED OVER THE PACIFIC WILL CONTINUE TO BUILD INTO WESTERN  
WASHINGTON THROUGH THE SHORT-TERM, BRINGING A WARMING AND DRYING  
TREND INTO EARLY NEXT WEEK. PASSING HIGH CLOUDS WILL LIKELY LIMIT  
THE DEVELOPMENT OF MARINE STRATUS TO THE PACIFIC COAST EARLY THIS  
MORNING, SCATTERING OUT BY THE LATE MORNING AS SKIES CLEAR  
ELSEWHERE. HIGHS ARE ON TRACK TO PEAK TODAY IN THE UPPER 70S TO  
LOWER 80S FOR MOST INLAND AREAS, WITH HIGHS NEAR 70 DEGREES ALONG  
THE COAST. WHILE ONLY A FEW DEGREES ABOVE NORMAL FOR EARLY AUGUST,  
THIS WILL RESULT IN WIDESPREAD MINOR (YELLOW) HEATRISK ACROSS  
WESTERN WASHINGTON TO START THE WEEKEND.  
 
WARMING WILL CONTINUE INTO SUNDAY AS THE HIGH PRESSURE RIDGE  
OVERHEAD AMPLIFIES, WITH HIGHS INCREASING SEVERAL DEGREES ACROSS  
WESTERN WASHINGTON. AREAS ALONG THE COAST WILL SEE ANOTHER MORNING  
OF LOW STRATUS WHILE CLEAR SKIES WILL PREVAIL INLAND. TEMPERATURES  
WILL PEAK IN THE MID TO UPPER 80S FOR MOST AREAS, WITH SOME  
LOWLAND AREAS WEST AND SOUTH OF THE PUGET SOUND REACHING 90  
DEGREES. THIS WILL RESULT IN WIDESPREAD MODERATE (ORANGE) HEATRISK  
ACROSS MUCH OF WESTERN WASHINGTON. OVERNIGHT TEMPERATURES WILL  
REMAIN ELEVATED IN THE LOW TO MID 60S FOR MUCH OF THE LOWLANDS,  
PROVIDING LITTLE RELIEF TO THE ELEVATED DAYTIME TEMPERATURES.  
 
MONDAY WILL BE A SIMILAR STORY, WITH A FEW DEGREES OF CONTINUED  
WARMING. MODERATE HEATRISK WILL EXPAND SLIGHTLY ACROSS WESTERN  
WASHINGTON, WITH A FEW ISOLATED POCKETS OF MAJOR (RED) HEATRISK  
POSSIBLE IN SOME OF THE MOUNTAIN VALLEYS. AREAS ACROSS THE  
CHEHALIS RIVER BASIN AND ALONG THE I-5 CORRIDOR SOUTH OF OLYMPIA  
WILL SEE THE WARMEST TEMPERATURES, PEAKING IN THE LOWER 90S. WHILE  
DETERMINISTIC ENSEMBLE FORECASTS SHOW HIGHS IN THE UPPER 80S EAST  
OF THE PUGET SOUND ON MONDAY, AREAS ALONG THE CASCADE FOOTHILLS  
WILL SEE A MODERATE CHANCE (50% TO 70%) OF REACHING 90 DEGREES AS  
WELL. WHILE TEMPERATURES WILL BE HOT, NO DAILY RECORDS IN WESTERN  
WASHINGTON ARE CURRENTLY FORECAST TO BE BROKEN.  
   
LONG TERM /TUESDAY THROUGH FRIDAY/  
CONFIDENCE OVER THE  
TEMPERATURE FORECAST DECREASES INTO TUESDAY, AS FORECAST MODELS  
CONTINUE TO SHOW DIFFERENCES OVER HOW THE UPPER LEVEL RIDGE WILL  
START TO BREAK DOWN. A SERIES OF WEAK TROUGHS WILL MOVE ALONG THE  
PERIPHERY OF THE RIDGE MID-WEEK, BRINGING A COOL DOWN AND CAUSING  
TEMPERATURES TO FALL BELOW NORMAL BY WEDNESDAY. TEMPERATURES WILL  
PEAK IN THE MID 60S TO LOWER 70S THROUGH THE REMAINDER OF THE  
WEEK, WITH A RETURN OF MORE CLOUDY CONDITIONS ACROSS WESTERN  
WASHINGTON. CHANCES FOR RAIN SHOWERS INCREASE ON THURSDAY AND  
FRIDAY, BUT THE COVERAGE AND INTENSITY OF INCOMING PRECIPITATION  
REMAINS UNCERTAIN AT THIS TIME.  
 
15  
 
 
   
AVIATION  
UPPER LEVEL RIDGE CENTERED OFFSHORE WITH  
NORTHWESTERLY FLOW ALOFT. LIGHT NORTHWESTERLY ONSHORE FLOW IN THE  
LOWER LEVELS.  
 
THE COMBINATION OF WEAK ONSHORE FLOW AND HIGH CLOUDS OVER THE AREA  
HAS KEPT STRATUS DEVELOPMENT TO A MINIMUM OVER THE AREA THIS  
MORNING. THE LOCATION REPORTING STRATUS BRIEFLY WAS THE NORTH  
COAST. STRATUS CONFINED TO THE COAST THIS MORNING. HIGH CLOUDS AT  
TIMES OVER THE REMAINDER OF THE AREA INTO SUNDAY MORNING.  
 
KSEA...HIGH CLOUDS AT TIMES. NORTHEAST WIND 4 TO 8 KNOTS BECOMING  
NORTHWESTERLY THIS AFTERNOON. WIND SWITCHING BACK TO NORTHEASTERLY  
OVERNIGHT.  
 
FELTON  
 
 
   
MARINE  
HIGH PRESSURE WILL REMAIN OVER THE COASTAL WATERS THROUGH  
EARLY THE MIDDLE OF NEXT WEEK. A WEAK THERMALLY INDUCED SURFACE  
TROUGH WILL MOVE UP THE COASTLINE SUNDAY NIGHT THEN SHIFT INLAND  
MONDAY.  
 
SEAS BUILDING TODAY INTO SUNDAY WITH 10 OR 11 FOOT SEAS OVER THE  
OUTER COASTAL WATERS SUNDAY NIGHT THROUGH TUESDAY NIGHT. SEAS OVER  
THE INNER COASTAL WATERS WILL BE JUST UNDER 10 FEET.  
 
POSSIBLE SMALL CRAFT ADVISORY WESTERLY WINDS IN THE CENTRAL AND  
EASTERN STRAIT OF JUAN DE FUCA TUESDAY NIGHT.  
 
FELTON  
 
 
   
FIRE WEATHER  
THE NEXT ELEVATED FIRE WEATHER CONCERN WILL BE  
THE HOT AND DRY PATTERN EXPECTED TO DEVELOP LATER THIS WEEKEND  
INTO EARLY NEXT WEEK AS RIDGING BUILDS IN OVER THE AREA FROM THE  
PACIFIC. WARMING TEMPERATURES, WITH HIGHS IN THE 80S TO LOW 90S  
AND MINIMUM RELATIVE HUMIDITIES DIPPING DOWN INTO THE 20S AND 30S  
BY EARLY NEXT WEEK, WILL BRING ELEVATED FIRE WEATHER CONCERNS  
ACROSS PORTIONS OF THE INTERIOR AND IN THE CASCADE FOOTHILLS.  
ENSEMBLES THEN SUGGEST TROUGHING REDEVELOPING ACROSS THE REGION  
AGAIN BY MIDWEEK, WHICH WOULD HELP MODERATE TEMPERATURES AND  
INCREASE ONSHORE FLOW.  
 
 
   
SEW WATCHES/WARNINGS/ADVISORIES  
 
WA...NONE.  
PZ...NONE.  
 
 
 
 
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