299
FXUS66 KSEW 141803
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
1103 AM PDT FRI AUG 14 2026
SYNOPSIS
UPPER LEVEL TROUGH OVER THE AREA TODAY WILL DISSIPATE TONIGHT.
WEAK UPPER LEVEL RIDGE BUILDING IN FROM THE SOUTHEAST OVER THE
WEEKEND. ANOTHER UPPER LEVEL TROUGH WILL ARRIVE MONDAY AND
REMAIN OVER WESTERN WASHINGTON FOR MOST OF NEXT WEEK.
SHORT TERM /TODAY THROUGH SUNDAY/
SATELLITE IMAGERY THIS MORNING SHOWS STRATUS HAS PUSHED INLAND
ACROSS MUCH OF THE INTERIOR LOWLANDS THIS MORNING. SMOKY SKIES
ARE ALSO PRESENT OVER THE REMAINDER OF THE AREA. WEAK UPPER
LEVEL TROUGH REMAINING OVER THE AREA TODAY WITH LIGHT LOW LEVEL
ONSHORE FLOW. MARINE LAYER WILL RETREAT BACK TO THE COAST IN THE
AFTERNOON. LIKE THE PREVIOUS TWO DAYS AIR MASS BECOMING
UNSTABLE OVER THE HIGHER TERRAIN IN THE AFTERNOON CREATING A
CHANCE FOR CONVECTION OVER THE OLYMPICS AND CASCADES. THERE IS A
GOOD CHANCE THAT THESE STORMS WILL NOT PRODUCE WETTING RAINS.
GIVEN THE CURRENT VERY DRY CONDITIONS HAVE UPGRADED THE FIRE
WEATHER WATCH TO A RED FLAG WARNING THIS AFTERNOON INTO THE
EVENING HOURS FOR THE OLYMPICS AND CASCADES. ANY STORM THAT DOES
DEVELOP COULD PRODUCE GUSTY AND ERRATIC OUTFLOW WINDS IN
ADDITION TO THE LIGHTNING OUTPUT. HIGHS IN THE 70S AND LOWER 80S
INLAND AND MID TO UPPER 60S COAST.
UPPER LEVEL TROUGH DISSIPATING TONIGHT. CONVECTION THREAT OVER THE
MOUNTAINS COMING TO AN END QUICKLY THIS EVENING. LOW LEVEL FLOW
REMAINING LIGHT ONSHORE WITH THE MARINE LAYER MOVING INLAND AGAIN
LATE TONIGHT INTO THE EARLY MORNING HOURS. THE LAYER WILL MOST
LIKELY NOT GET TO THE PUGET SOUND BY 12Z. LOWS IN THE 50S.
WEAK UPPER LEVEL RIDGE BUILDING IN FROM THE SOUTHEAST SATURDAY WITH
THE FLOW ALOFT BECOMING SOUTH SOUTHWESTERLY. THIS WILL BEGIN TO PUSH
THE SMOKE OUT OF THE AREA. IN THE LOWER LEVELS LIGHT ONSHORE FLOW
CONTINUING WITH THE MARINE LAYER GETTING EAST OF PUGET SOUND AROUND
SUNRISE. THE MARINE LAYER WILL DISSIPATE OVER THE INTERIOR BY MIDDAY
LEAVING STRATUS JUST ALONG THE COASTLINE. AIR MASS BECOMING SLIGHTLY
UNSTABLE OVER THE HIGHER TERRAIN IN THE AFTERNOON. WITH THE SOUTH
SOUTHWESTERLY FLOW ALOFT BEST CHANCE FOR A THUNDERSTORM WILL BE NEAR
THE CASCADE CREST. THUNDERSTORM CHANCES WILL BE LESS THAN TODAY.
HIGHS IN THE 70S AND LOWER 80S FOR THE INTERIOR AND MID TO UPPER 60S
COAST.
LITTLE CHANGE IN THE PATTERN SATURDAY NIGHT AND SUNDAY WITH THE
WEAK, 500 MB HEIGHTS IN THE LOWER 580 DMS, UPPER LEVEL RIDGE OVER
THE AREA AND SOUTH SOUTHWESTERLY FLOW ALOFT. GOOD CHANCE UPPER LEVEL
SMOKE GETTING OUT OF THE AREA BY SUNDAY. LOW LEVEL ONSHORE FLOW WILL
PUSH THE MARINE LAYER INLAND FROM THE COAST AGAIN EARLY SUNDAY
MORNING. STRATUS DISSIPATING BACK TO THE COAST BY MIDDAY. SOME HIGH
CLOUDS EMBEDDED IN THE FLOW ALOFT MOVING THROUGH DURING THE DAY
SUNDAY WILL HAVE LITTLE EFFECT ON THE TEMPERATURES. HIGHS, YOU
GUESSED IT, IN THE 70S AND LOWER 80S INLAND, MID TO UPPER 60S COAST.
LOWS IN THE 50S.
LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/
UPPER LEVEL RIDGE FLATTENING OUT SUNDAY NIGHT WITH ANOTHER WEAK
UPPER LEVEL TROUGH DIGGING DOWN FROM THE NORTH ARRIVING MONDAY.
TROUGH REMAINING OVER THE AREA TUESDAY. VERY LITTLE MOISTURE WITH
THE TROUGH. THE FLOW ALOFT WILL TURN NORTHERLY BRINGING UPPER LEVEL
SMOKE BACK INTO THE AREA. IN THE LOWER LEVELS ONSHORE FLOW
CONTINUING BRINGING STRATUS INLAND EACH LATE NIGHT AND EARLY
MORNING. HIGHS IN THE 70S INLAND AND MID 60S COAST.
LOWS IN THE 50S.
DIFFERENCES IN THE MODELS SHOW UP WEDNESDAY AND THURSDAY. SOME OF
THE SOLUTIONS PRODUCE THE SAME SCENARIO AS THIS WEEKEND WITH A WEAK
UPPER LEVEL RIDGE BUILDING BACK INTO THE AREA FROM THE SOUTHEAST.
THE OTHER GROUPING OF SOLUTIONS KEEPS THE UPPER LEVEL TROUGH OVER
THE AREA. IN EITHER SOLUTION THE LOW LEVEL FLOW REMAINS ONSHORE.
WILL GO WITH A CLIMATOLOGY FORECAST FOR THE MIDDLE OF NEXT WEEK,
MORNING CLOUDS AFTERNOON SUN FOR THE INTERIOR WITH HIGHS STAYING IN
THE 70S. CLOUDS HANGING TOUGH MOST OF THE DAY ON THE COAST WITH
HIGHS ONLY IN THE MID 60S. LOWS BOTH DAYS IN THE 50S. FELTON
AVIATION
THE STRATUS IS LOW TO THE GROUND ONCE AGAIN, WITH LIFR CEILINGS
AND IMPACTS TO VISIBILITY DUE TO FOG. WITH SLIGHTLY STRONGER
ONSHORE FLOW FORECAST FOR TODAY, LOW STRATUS AND FOG WILL LIKELY
BE A BIT SLOWER TO RETREAT LATE THIS MORNING, AND LIKELY NOT
CLEAR OUT ALONG THE COAST. THIS WILL ALSO PROMOTE A SLIGHTLY
EARLIER RETURN OF THE STRATUS LATE TONIGHT INTO SATURDAY
MORNING.
WEST TO SOUTHWESTERLY WINDS WILL CONTINUE THROUGH THE MORNING,
THOUGH WILL BEGIN TO SWITCH TO NORTHWESTERLY THROUGH THE CENTRAL
PUGET SOUND TERMINALS FROM AROUND 23Z THROUGH 03Z SAT AND EASE
LATE TONIGHT.
KSEA...STRATUS CONTINUES TO SLOWLY LIFT AND ERODE THIS MORNING,
WITH CONDITIONS EXPECTED TO TREND TO IFR BY 1830Z, THEN SCATTER
OUT BY 20Z, WITH VFR THROUGH THE REMAINDER OF THE DAY. WINDS
PREDOMINANTLY FROM THE SOUTHWEST THIS MORNING, BECOMING
WEST/NORTHWEST (BUT 5 KT OR LESS) THIS EVENING AROUND 02Z. A
RETURN TO LIGHT SOUTHWEST WINDS THEN FOLLOWS OVERNIGHT, AND LOW
STRATUS LIKELY RETURNS AROUND 12Z TONIGHT WITH IFR/LIFR
CONDITIONS INTO THE MORNING TOMORROW.
MARINE
HIGH PRESSURE WILL REMAIN WELL TO THE SOUTH AND WEST, OFF THE
COAST OF CALIFORNIA, ALLOWING WINDS OVER THE COASTAL WATERS TO
REMAIN LIGHT THROUGH SATURDAY. HIGH PRESSURE LOOKS TO REBUILD
OFFSHORE OF CANADA AND MOVE SOUTHWARD ON SUNDAY AND INTO NEXT
WEEK, BRINGING BACK NORTHWESTERLY WINDS OVER THE COASTAL WATERS.
DIURNALLY DRIVEN WESTERLY PUSHES DOWN THE STRAIT OF JUAN DE FUCA
REMAINS THE ONLY AREA OF CONCERN THIS WEEKEND INTO NEXT WEEK,
WITH WINDS LIKELY REACHING SMALL CRAFT ADVISORY THRESHOLDS EACH
EVENING.
SEAS REMAIN 3 TO 6 FT THROUGH THE NEXT SEVEN DAYS. 62
FIRE WEATHER
A RED FLAG WARNING REMAINS IN EFFECT FOR THE OLYMPICS AND CASCADES
THIS AFTERNOON AND EVENING FOR THE POTENTIAL OF ANOTHER ROUND OF
CONVECTION. SIMILARLY TO THURSDAY, MOST OF THE STORMS ARE NOT
EXPECTED TO PRODUCE WETTING RAINS. GIVEN THE DRY CONDITIONS, ANY
STORMS THAT DO DEVELOP COULD HAVE GUSTY AND ERRATIC OUTFLOW WINDS,
WHICH COMBINED WITH THE LIGHTNING AND THE DRY CONDITIONS PRESENT,
COULD PRODUCE NEW FIRE STARTS. THERE IS A SMALL CHANCE THE STORMS
COULD REMAIN STATIONARY OVER A BURN SCAR. IF THAT IS THE CASE, FLASH
FLOODING CAN NOT TOTALLY BE RULED OUT.
CHANCES OF THUNDERSTORMS WILL BE POSSIBLE ALONG THE CASCADE CREST ON
SATURDAY AFTERNOON AND EVENING, BUT OVERALL CHANCES FOR CONVECTION
WILL DECREASE THROUGH THE WEEKEND WITH AN UPPER LEVEL RIDGE BUILDING
INTO THE AREA. YET ANOTHER UPPER LEVEL TROUGH ARRIVING ON MONDAY
WILL INCREASE FIRE WEATHER CONCERNS AGAIN NEXT WEEK. FELTON/14
SEW WATCHES/WARNINGS/ADVISORIES
WA...RED FLAG WARNING UNTIL 9 PM PDT THIS EVENING FOR EAST PORTION
OF THE OLYMPIC MOUNTAINS-WEST PORTION OF THE OLYMPIC
MOUNTAINS-WEST SLOPES OF THE CENTRAL CASCADES GENERALLY
ABOVE 1500 FEET-WEST SLOPES OF THE NORTH CASCADES
GENERALLY ABOVE 1500 FEET.
PZ...SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 5 AM PDT
SATURDAY 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.
Main Text Page