297
FXUS66 KSEW 060341
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
841 PM PDT FRI JUN 5 2026
UPDATE
AS NIGHTFALL THE THREAT FOR THUNDERSTORMS WILL END THIS EVENING.
HOWEVER, SCATTERED SHOWERS ARE FAVORED TO REMAIN OVERNIGHT.
MINIMUM TEMPERATURES WILL RANGE BETWEEN THE LOWER TO UPPER 40S,
A BIT BELOW AVERAGE FOR EARLY JUNE. THE PREVIOUS DISCUSSION
REMAINS BELOW ALONG WITH AN UPDATED AVIATION SECTION.
SYNOPSIS
SHOWERS AND ISOLATED THUNDERSTORMS ARE PROGRESSING THROUGH
WESTERN WASHINGTON THIS AFTERNOON. LOW PRESSURE WILL MOVE
DIRECTLY OVERHEAD TOMORROW, LEADING TO AN INCREASE IN
THUNDERSTORM PROBABILITIES AREA-WIDE. PRIMARY THREATS WILL BE
LIGHTNING, GUSTY WINDS, AND BRIEF PERIODS OF HEAVY RAIN. THIS
THREAT WILL SUBSIDE IN THE EVENING. A WARMING AND DRYING TREND
TAKES HOLD LATE NEXT WEEK AND IS FORECAST TO CONTINUE INTO THE
MIDDLE OF THE MONTH.
SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/
A FEW LIGHTNING STRIKES HAVE BEEN OBSERVED ALONG THE CANADIAN
BORDER WITH WHATCOM COUNTY, WITH PULSE TYPE CELLS DEVELOPING IN
OTHER PORTIONS OF WESTERN WASHINGTON THIS AFTERNOON. THE THREAT
FOR THUNDERSTORMS IS STILL LARGELY FOCUSED ALONG THE COAST AND
IN THROUGH PORTIONS OF THE NORTH INTERIOR (15-20%) WITH LOWER
CHANCES FOR THUNDERSTORMS ELSEWHERE.
THE FOCUS THEN SHIFTS TO SATURDAY AS THE LOW PRESSURE MOVES
DIRECTLY OVERHEAD AND PROVIDES MORE ENHANCED DYNAMICS TO SUPPORT
AREA-WIDE THUNDERSTORMS. PROBABILITIES FOR THUNDERSTORMS HAVE
INCREASED IN THE LATEST MODEL GUIDANCE, UP TO AROUND 30 TO 35
PERCENT FOR MOST AREAS. THERE COULD BE LOCALLY HIGHER
PROBABILITIES UP TO 40 PERCENT IN AREAS FROM EVERETT SOUTH, BUT
MORE SO SOUTH OF OLYMPIA AND EAST TO SOUTH KING COUNTY. AGAIN,
PRIMARY THREATS INCLUDE LIGHTNING, GUSTY/ERRATIC WINDS AND
PERIODS OF HEAVIER RAIN. GIVEN THE FACT THAT THESE STORMS ARE
OCCURRING OVER THE WEEKEND AND THERE WILL BE AN INCREASE IN
OUTDOOR ACTIVITIES, PLEASE BE SURE TO REVIEW THE FORECAST AND
HAVE A PLAN TO HEAD INDOORS SHOULD LIGHTNING MOVE INTO YOUR
AREA. IN ADDITION TO THE THUNDERSTORM THREAT, SNOW LEVELS HOVER
AROUND 4000 FEET ON SATURDAY. STEVENS PASS WILL LIKELY SEE SOME
FLURRIES AND SHORT LIVED ACCUMULATIONS OF AN INCH OR LESS.
HIGHER ELEVATIONS OF THE CASCADES, INCLUDING PARADISE, COULD SEE
A QUICK HIT OF BETWEEN 3-5 INCHES OF SNOW. MAKE SURE TO CHECK
THE FORECAST IF PLANS INCLUDE MOUNTAINOUS RECREATION.
THE LOW PRESSURE SYSTEM BEGINS TO SHIFT OUT OF THE AREA LATE
SATURDAY INTO SUNDAY, BRINGING SOME MORE APPRECIABLE CLEARING
OVERNIGHT INTO SUNDAY MORNING. AS A RESULT, THERE IS POTENTIAL
FOR SOME FROST DEVELOPMENT IN EASTERN GRAYS HARBOR COUNTY AND
THE CASCADE VALLEYS AND FOOTHILLS ON SUNDAY MORNING.
TEMPERATURES WILL REBOUND INTO THE MID 60S BY SUNDAY AFTERNOON.
LONG TERM /MONDAY THROUGH FRIDAY/
UNSETTLED CONDITIONS LINGER INTO EARLY NEXT WEEK AS ANOTHER WEAK
LOW PRESSURE SYSTEM ARRIVES LATE SUNDAY INTO MONDAY MORNING.
RIGHT NOW THERE IS A 10-15% CHANCE OF THUNDER INDICATED FOR THE
OLYMPIC PENINSULA AND SOUTHWEST INTERIOR. LINGERING PERIODS OF
SHOWERS ARE POSSIBLE THROUGH WEDNESDAY AS A TROUGH LINGERS OVER
THE INTERMOUNTAIN WEST. HIGH PRESSURE BEGINS TO DEVELOP LATE IN
THE WEEK. A LOT IS YET TO BE DETERMINED, HOWEVER THE WEEK 2
OUTLOOK FROM THE CPC, INCLUDING THE ASSOCIATED PROBABILISTIC
HAZARDS IN THIS TIME FRAME DOES INDICATE A SLIGHT RISK, 20-40%
CHANCE OF HAZARDOUS TEMPERATURES IN THE JUNE 13-19 PERIOD.
MONITOR THE TEMPERATURE FORECAST OVER THE NEXT SEVERAL DAYS IF
YOU NEED TO MAKE ADVANCED PREPARATIONS FOR POTENTIAL HEAT.
21
AVIATION
SHOWERS WILL PERSIST THIS EVENING WITH THE ISOLATED THUNDERSTORM
THREAT COMING TO AN END. THERE IS STILL NOT ENOUGH CONFIDENCE
TO INCLUDE THUNDERSTORMS IN THE TAFS, BUT WILL BE ADDED IF
CONDITIONS WARRANT IT. SURFACE WINDS HAVE BEEN GUSTY OUT OF THE
SSW AT 15 TO 20 KTS. CIGS HAVE BEEN VFR AND WILL CONTINUE UNTIL
TOMORROW MORNING AROUND 12Z, WHERE A DIP TO MVFR IS POSSIBLE.
THUNDERSTORMS BECOME INCREASINGLY LIKELY TOMORROW FOR PUGET
SOUND TERMINALS AND ENHANCED MONITORING WILL BE IN PLACE AS IT
COMES TO INCLUSION OF TS IN THE TAFS.
KSEA...GUSTY SW WINDS CONTINUE AT THE TERMINAL WITH SHOWERS IN
THE VICINITY. THE ISOLATED THUNDERSTORM THREAT WILL DIMINISH
THIS EVENING THROUGH LOSS OF DIURNAL HEATING. EXPECT MORE
THUNDERSTORMS TOMORROW AT AND AROUND THE TERMINAL, GENERALLY
BETWEEN 19Z-01Z. PRIMARY HAZARDS INCLUDE LIGHTNING, HEAVY RAIN
AND GUSTY/ERRATIC WINDS.
21/41
MARINE
AS LOW PRESSURE MOVES OVER AREA WATERS, EXPECT HEIGHTENED WINDS
OVER THE NEXT SEVERAL DAYS. THIS EVENING, A WESTERLY PUSH
THROUGH THE STRAIT OF JUAN DE FUCA IS EXPECTED, BUT ARE NOT
LIKELY TO REACH SCA CRITERIA. THROUGHOUT THE NEXT SEVERAL DAYS,
OFFSHORE SEAS WILL BE BETWEEN 6-8 FEET. AS THE LOW PRESSURE
SYSTEM MOVES OVERHEAD TOMORROW, THERE IS AROUND A 70 TO 80%
CHANCE OF SCA WINDS THROUGH THE STRAIT OF JUAN DE FUCA ON
SATURDAY, AND PUGET SOUND WILL HAVE TO BE MONITORED. WINDS WILL
BE STRONGER IN AND AROUND ANY THUNDERSTORMS THAT HAPPEN TO
DEVELOP OVER THE WATERS. OFFSHORE WINDS INCREASE MONDAY INTO
WEDNESDAY AS UNSETTLED WEATHER CONTINUES. CONDITIONS SHOULD EASE
AS HIGH PRESSURE BUILDS LATER IN THE WEEK.
21
FIRE WEATHER
ERCS WILL RESPOND TO THE INCREASE IN MOISTURE OVER THE NEXT
SEVERAL DAYS, ESPECIALLY IN THE FINE FUELS. TODAY AND MORE SO
SATURDAY WILL FEATURE AREA WIDE CHANCES FOR THUNDERSTORMS. THE
STORMS THAT ARE MOST LIKELY TO CONTAIN A WETTING RAIN WILL BE IN
THE OROGRAPHICALLY ENHANCED REGIONS OF THE CASCADE FOOTHILLS,
WITH LESSER AMOUNTS ELSEWHERE. THE THREAT FOR IMPACTS FROM
STRIKES ON DRIER FINE FUELS CANNOT BE FULLY RULED OUT. FUELS
WILL CONTINUE TO BE MONITORED AS HIGH PRESSURE BUILDS IN LATE
NEXT WEEK AND TEMPERATURES BEGIN TO CLIMB INTO THE WEEK 2 TIME
PERIOD.
21
SEW WATCHES/WARNINGS/ADVISORIES
WA...NONE.
PZ...NONE.
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