336
FXUS66 KSEW 011554
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
854 AM PDT SAT AUG 1 2026
SYNOPSIS
A WEAK FRONT WILL CONTINUE TO MOVE ACROSS THE AREA
INTO THIS AFTERNOON. UPPER LEVEL TROUGH ARRIVING SUNDAY MOVING
EAST LATE IN THE DAY. UPPER LEVEL RIDGE BUILDING OFFSHORE SUNDAY
NIGHT MOVING OVER WESTERN WASHINGTON MONDAY. TEMPERATURES
WARMING TUESDAY AND WEDNESDAY. RIDGE WEAKENING A LITTLE TOWARDS
THE END OF THE WEEK FOR SLIGHTLY COOLER TEMPERATURES.
SHORT TERM /TODAY THROUGH MONDAY/
A FRONT CONTINUES TO MOVE
ACROSS WESTERN WASHINGTON THIS MORNING, WITH LIGHT RAIN
CURRENTLY SLIDING INTO PORTIONS OF PUGET SOUND. THE FRONT WILL
CONTINUE TO WEAKEN AS IT PROGRESSES EASTWARDS. SKIES CLEARING
LATE IN THE AFTERNOON EXCEPT OVER SNOHOMISH COUNTY WHERE A PUGET
SOUND CONVERGENCE ZONE WILL FORM BEHIND THE FRONT. IN ADDITION
TO THE PRECIPITATION BREEZY CONDITIONS DEVELOPING WITH AND JUST
BEHIND THE FRONT WITH GUSTS AROUND 15 TO 30 MPH IN MOST
LOCATIONS. HIGHS IN THE 60S AND LOWER 70S.
WEAK UPPER LEVEL TROFINESS BEHIND THE FRONT TONIGHT WITH SHOWERS
BECOMING CONFINED TO THE CONVERGENCE ZONE BY LATE EVENING. IT'S
GOING TO BE A COOL EARLY AUGUST MORNING SUNDAY WITH THE COLDER
LOCATIONS DROPPING INTO THE 40S. FOR THE REMAINDER OF THE AREA
LOWS IN THE LOWER TO MID 50S.
UPPER LEVEL TROUGH MOVING INTO WESTERN WASHINGTON SUNDAY. TROUGH
COMING DOWN FROM THE NORTH SO NOT MUCH MOISTURE WITH IT. THE
LITTLE BIT OF LIFT IT WILL PROVIDE COULD GENERATE SOME SHOWERS
MOSTLY OVER THE NORTH CASCADES. CONVERGENCE ZONE OVER SNOHOMISH
COUNTY DISSIPATING LATE MORNING. ANOTHER COOL DAY UNDER MOSTLY
CLOUDY SKIES WITH HIGHS AGAIN IN THE 60S AND LOWER 70S.
UPPER LEVEL TROUGH MOVING EAST SUNDAY EVENING WITH AN UPPER
LEVEL RIDGE BUILDING OFFSHORE. RIDGE MOVING TOWARDS WESTERN
WASHINGTON OVERNIGHT. CLEARING SKIES PROVIDING ANOTHER COOL
MORNING WITH LOWS IN THE UPPER 40S TO MID 50S.
UPPER LEVEL RIDGE BUILDING MONDAY. HIGH TEMPERATURES WARMING BUT
STILL FALLING A COUPLE OF DEGREE SHORT OF NORMAL. HIGHS IN THE
70S.
FOR THE FIRST TIME SINCE 2012 SEATTLE HAD BELOW NORMAL
TEMPERATURES FOR THE MONTH OF JULY. THE AVERAGE TEMPERATURE FOR
THE MONTH WAS 66.9 DEGREES. NORMAL IS 67.1 DEGREES. THERE WERE
9 DAYS WITH HIGHS 80 DEGREES PLUS. FOR THE LAST 9 YEARS (
2017-2025 ) SEATTLE HAS AVERAGED 15 DAYS IN JULY WITH HIGHS 80
DEGREES PLUS. THE LAST YEAR THERE WAS LESS THAN 10 80 DEGREE
PLUS DAYS WAS 2016. IT WAS ALSO THE COLDEST JULY IN SEATTLE
SINCE 2016 WHERE THE AVERAGE TEMPERATURE WAS 66.8 DEGREES (
NORMAL TEMPERATURE FOR JULY IN 2016 WAS 65.7 DEGREES SO IT WAS
STILL AN ABOVE NORMAL MONTH TEMPERATURE WISE ). JD/FELTON
LONG TERM /MONDAY NIGHT THROUGH FRIDAY/
MODELS SHOWING GOOD
CONSISTENCY WITH A FLAT UPPER LEVEL RIDGE OVER WESTERN
WASHINGTON AT LEAST THROUGH WEDNESDAY. SOME SMALL DIFFERENCES
SHOWING UP IN THE MODELS BEGINNING THURSDAY WITH SOME OF THE
SOLUTIONS WEAKENING THE RIDGE WHILE OTHER SOLUTIONS KEEP THE
RIDGE IN THE MIDDLE TO UPPER 580 DMS. MUCH WARMER TUESDAY AND
WEDNESDAY AS THE LOW LEVEL FLOW TRIES TO TURN OFFSHORE. HIGHS IN
THE 70S ON THE COAST AND UPPER 70S TO NEAR 90 INLAND. WITH THE
STRONGER RIDGE SOLUTIONS JUST INTRODUCED THIS MODEL RUN WILL
STAY WITH THE PREVIOUS IDEA OF A LITTLE COOLER THURSDAY AND
FRIDAY WITH HIGHS NEAR 70 COAST AND LOWER 70S TO LOWER 80S
INLAND.
LOW LEVEL FLOW TURNING A LITTLE NORTHERLY TUESDAY WHICH COULD
PULL SOME SMOKE FROM THE FIRES IN BRITISH COLUMBIA DOWN OVER THE
AREA. LOW LEVEL FLOW REMAINING NORTHERLY WEDNESDAY BEFORE
TURNING BACK TO A MORE WESTERLY DIRECTION THURSDAY. FELTON
AVIATION
SOUTHWESTERLY FLOW ALOFT WILL BECOME WESTERLY TONIGHT AS
AN UPPER TROUGH OFFSHORE MOVES ONSHORE INTO SOUTHERN BRITISH
COLUMBIA. WIDESPREAD MVFR AND POCKETS OF IFR CEILINGS THIS MORNING
WILL LIFT TO MOSTLY VFR THIS AFTERNOON EXCEPT IN AND AROUND
CONVERGENCE ZONE ACTIVITY EXPECTED TO DEVELOP THIS AFTERNOON INTO
THIS EVENING. CEILINGS ARE EXPECTED TO FALL BACK TO MVFR AREAWIDE
TONIGHT INTO SUNDAY MORNING. GUSTY POST-FRONTAL WEST TO
SOUTHWESTERLY SURFACE WINDS AT TIMES TODAY WILL EASE LATER THIS
EVENING.
KSEA...MVFR CEILINGS ARE EXPECTED TO LIFT TO LOW END VFR AROUND 19Z-
20Z THIS AFTERNOON THEN GRADUALLY FALL BACK TO HIGH END MVFR EARLY
SUNDAY MORNING. SURFACE WINDS S/SW RISING TO 15 GUSTING 20-25 KNOTS
THIS MORNING WILL EASE TO UNDER 10 KNOTS TOWARD 03Z THIS EVENING.
27
MARINE
A WEAK FRONTAL SYSTEM IS PUSHING ACROSS AREA WATERS TODAY.
INCREASING ONSHORE FLOW WILL LEAD TO SMALL CRAFT ADVISORY WESTERLY
WINDS IN THE CENTRAL/EAST STRAIT MUCH OF TODAY. ADDITIONALLY, POST-
FRONTAL ONSHORE FLOW WILL LEAD TO SMALL CRAFT ADVISORY
SOUTHWESTERLIES IN PUGET SOUND/HOOD CANAL DURING TODAY AS WELL. HIGH
PRESSURE WILL REBUILD OVER THE COASTAL WATERS SUNDAY AND REMAIN IN
PLACE INTO EARLY NEXT WEEK AS THERMALLY INDUCED LOW PRESSURE EXPANDS
NORTHWARD ACROSS THE INTERIOR WITH LIGHT FLOW.
41
FIRE WEATHER
A FRONTAL SYSTEM HAS BROUGHT WETTING RAINS TO
PORTIONS OF THE OLYMPIC PENINSULA THIS MORNING. RAIN WILL
CONTINUE TO PROGRESS EASTWARDS INTO THE CASCADES THIS AFTERNOON,
ESPECIALLY INTO THE NORTH CASCADES. THIS ALONG WITH COOLER
TEMPERATURES WILL HELP EASE FIRE WEATHER CONCERNS. THERE IS A
SLIGHT CHANCE OF THUNDERSTORMS IN THE NORTH CASCADES BUT IF ONE
DOES OCCUR IT WILL BE ACCOMPANIED BY RAIN. ANOTHER COOL DAY
SUNDAY WILL KEEP FIRE WEATHER CONCERNS AT A MINIMUM.
WARMING TEMPERATURES MONDAY WITH ELEVATED FIRE WEATHER CONCERNS
BEGINNING TUESDAY WITH ABOVE NORMAL TEMPERATURES AND LOW LEVEL
DRYING. MINIMUM RELATIVE HUMIDITY VALUES AGAIN DROPPING INTO
THE 20S LATE IN THE AFTERNOON OVER THE SOUTHERN PORTION OF THE
AREA AND THE CASCADE FOOTHILLS BOTH DAYS. ELEVATED FIRE WEATHER
CONCERNS COULD CONTINUE THROUGH THE END OF THE WEEK IF THE
SMALL COOL DOWN DOES NOT MATERIALIZE. FELTON
SEW WATCHES/WARNINGS/ADVISORIES
WA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 10 PM PDT THIS EVENING FOR CENTRAL
U.S. WATERS STRAIT OF JUAN DE FUCA-EAST ENTRANCE U.S.
WATERS STRAIT OF JUAN DE FUCA-PUGET SOUND AND HOOD CANAL.
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