354  
FXUS66 KSEW 171700  
AFDSEW  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SEATTLE WA  
1000 AM PDT THU JUL 17 2025  
   
SYNOPSIS  
WESTERN WASHINGTON IS POISED FOR A PATTERN SHIFT,  
USHERING IN COOLER TEMPERATURES ALONG WITH NIGHT AND MORNING  
CLOUDS. AN UPPER LEVEL LOW WILL BRING A CHANCE OF SHOWERS OVER  
THE CASCADES MONDAY AND TUESDAY.  
 
 
   
SHORT TERM /TODAY THROUGH SATURDAY/  
THE TRANSITION TO COOLER  
CONDITIONS BEGINS TODAY. THE MARINE LAYER WILL SPREAD PARTIALLY  
INLAND THIS MORNING BEFORE BURNING BACK TOWARD THE COAST.  
ON FRIDAY, A WEAK UPPER LEVEL TROUGH IS EXPECTED TO SWING THROUGH  
THE REGION, FURTHER REINFORCING THE COOLING TREND. THE WEEKEND  
WILL START WITH CONTINUED COOL AND MOSTLY CLOUDY CONDITIONS WITH  
SOME PARTIAL CLEARING SATURDAY AFTERNOON.  
   
LONG TERM /SUNDAY THROUGH WEDNESDAY/  
SUNDAY WILL SEE A SIMILAR  
PATTERN OF MORNING CLOUDS FOLLOWED BY SOME AFTERNOON SUN. PERSISTENT  
ONSHORE FLOW WILL KEEP TEMPERATURES A LITTLE BELOW AVERAGE FOR  
THIS TIME OF YEAR. AN UPPER TROUGH ON MONDAY WILL LEAD TO A MIX OF  
CLOUDS AND SUN WITH A CHANCE OF SHOWERS OVER THE CASCADES. A  
WARMING TREND MAY BEGIN TO TAKE SHAPE BY THE MIDDLE OF NEXT WEEK  
AS THE UPPER LEVEL LOW SHIFTS EASTWARD AND A RIDGE BUILDS  
OFFSHORE.  
 
 
 
   
AVIATION  
VFR CONDITIONS AT THE MAJORITY OF THE TERMINALS THIS  
MORNING. LATEST SATELLITE IMAGERY SHOWS THE MARINE LAYER WELL  
SITUATED ALONG THE COAST THIS MORNING, AND EVEN MANAGED TO PUSH AS  
FAR EAST AS THE KITSAP PENINSULA AND SOUTHERN INTERIOR (KOLM). THE  
MARINE LAYER IS SLOWLY STARTING TO RETREAT THIS MORNING, SO NOT  
EXPECTING IT TO MAKE IT MAKE IT FULLY INTO KSEA AND KBFI.  
IMPROVEMENT INTO VFR IS EXPECTED AFTER 18Z-20Z. CLEAR SKIES FOR THE  
REMAINDER OF THE DAY.  
 
GENERALLY SW WINDS THIS MORNING TURNING WESTERLY THIS AFTERNOON,  
BEFORE BECOMING NW THIS EVENING.  
 
KSEA...VFR CONDITIONS EXPECTED TODAY, WITH CLEAR SKIES EXPECTED  
THROUGH EARLY FRIDAY MORNING. STRATUS APPROACHING THE TERMINAL AFTER  
12Z FRIDAY. SW WIND THIS MORNING BECOMING WESTERLY (250-280 DEGREES)  
AROUND 19Z-20Z. NW WINDS THIS EVENING AROUND 5-8 KT AROUND 23Z-0Z  
AND THEN BACK SW AFTER 8Z-9Z. FELTON/29  
 
 
   
MARINE  
HIGHER PRESSURE OVER THE COASTAL WATERS WITH LOWER  
PRESSURE INLAND WILL RESULT IN ONSHORE FLOW FOR THE FIRST PART OF  
NEXT WEEK.  
 
SMALL CRAFT ADVISORY WESTERLY WINDS IN THE CENTRAL AND EASTERN  
STRAIT TONIGHT AND FRIDAY NIGHT WITH POSSIBLE EVENING SMALL CRAFT  
ADVISORY WESTERLIES OVER THE WEEKEND.  
 
CHOPPY SEAS IN THE OUTER COASTAL WATERS THROUGH FRIDAY AND OVER THE  
INNER COASTAL WATERS TODAY WITH SEAS AROUND 8 FEET AND PERIODS  
AROUND 9 SECONDS. FELTON/29  
 
 
   
FIRE WEATHER  
THIS MORNING'S MARINE PUSH WAS ABLE TO BRING  
GOOD RH RECOVERIES ALONG THE COAST, AND INTO PARTS OF THE THE  
INTERIOR. THERE REMAINS ELEVATED FIRE WEATHER CONCERNS TODAY FOR  
DRY, HOT AND UNSTABLE AIR (PARTICULARLY FOR THE CASCADES AS MIN  
RH'S ARE EXPECTED TO DROP TO 25-40%). INCREASING NORTHWEST  
WINDS 5-10 MPH TODAY INTO FRIDAY WILL BRING MORE COOL/MOIST AIR  
INTO THESE AREAS. A FEW GUSTS TO 20 MPH ARE POSSIBLE FRIDAY  
AFTERNOON IN PORTIONS OF THE SOUTH INTERIOR. A CHANCE OF  
ISOLATED THUNDERSTORMS IN THE NORTH CASCADES NEXT MONDAY/TUESDAY  
MAY BRING ELEVATED FIRE WEATHER CONCERNS (DUE TO LIGHTNING).  
 
HPR  
 
 
   
SEW WATCHES/WARNINGS/ADVISORIES  
 
WA...HEAT ADVISORY UNTIL 8 PM PDT THIS EVENING FOR CITY OF SEATTLE-  
DOWNTOWN EVERETT / MARYSVILLE AREA-EASTSIDE-FOOTHILLS AND  
VALLEYS OF CENTRAL KING COUNTY-FOOTHILLS AND VALLEYS OF  
PIERCE AND SOUTHERN KING COUNTIES-FOOTHILLS AND VALLEYS  
OF SNOHOMISH AND NORTHERN KING COUNTIES-FOOTHILLS AND  
VALLEYS OF THE NORTH CASCADES-LOWLANDS OF PIERCE AND  
SOUTHERN KING COUNTIES-LOWLANDS OF WESTERN SKAGIT AND  
NORTHWESTERN SNOHOMISH COUNTIES-LOWLANDS OF WESTERN  
WHATCOM COUNTY-SHORELINE / LYNNWOOD / SOUTH EVERETT AREA.  
PZ...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 5 AM PDT FRIDAY  
FOR CENTRAL U.S. WATERS STRAIT OF JUAN DE FUCA-EAST  
ENTRANCE U.S. WATERS STRAIT OF JUAN DE FUCA.  
 
 
 
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.
The Nexlab WA Page
Main Text Page