324
FXUS66 KSEW 121556
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
856 AM PDT FRI JUN 12 2026
SYNOPSIS
UPPER LEVEL RIDGE OFFSHORE MOVING EAST OVER WESTERN WASHINGTON
SATURDAY. THE RIDGE WILL REMAIN IN PLACE THROUGH MONDAY THEN
WEAKEN THROUGH THE MIDDLE OF NEXT WEEK. LOW LEVEL ONSHORE FLOW
TODAY WILL BECOME LIGHT SATURDAY. LOW LEVEL FLOW TURNING
OFFSHORE SATURDAY NIGHT WITH THERMALLY INDUCED SURFACE TROUGH
ALONG THE COAST. THERMAL TROUGH SHIFTING INLAND MONDAY AND EAST
OF THE CASCADES MONDAY NIGHT. LOW LEVEL ONSHORE FLOW INCREASING
TUESDAY INTO WEDNESDAY WITH A COOLING TREND. TEMPERATURES
PEAKING SUNDAY AND MONDAY WITH RECORD HIGHS LIKELY.
SHORT TERM /TODAY THROUGH SUNDAY/
SATELLITE IMAGERY SHOWS A LITTLE BIT OF STRATUS ALONG THE NORTH
COAST, NEAR GRAYS HARBOR AND IN THE NORTH AND CENTRAL CASCADES.
MOSTLY CLEAR SKIES OVER THE REMAINDER OF THE AREA. TEMPERATURES
AT 3 AM/10Z WERE IN THE UPPER 40S TO MID 50S.
UPPER LEVEL RIDGE BUILDING WELL OFFSHORE TODAY WITH THE RIDGE
AXIS NEAR 135W. SURFACE HIGH PRESSURE ALSO CENTERED WELL
OFFSHORE WITH NORTHWESTERLY ONSHORE SURFACE GRADIENTS. SUNNY
SKIES ACROSS THE AREA WITH WHAT LITTLE STRATUS THERE IS OUT
THERE NOT LASTING VERY LONG. HIGHS IN THE UPPER 60S AND 70S.
UPPER LEVEL RIDGE OFFSHORE MOVING EAST TONIGHT AND SATURDAY WITH
THE RIDGE AXIS INSIDE 130W SATURDAY AFTERNOON. TEMPERATURES
ALOFT WARMING. THERMALLY INDUCED SURFACE TROUGH MOVING UP THE
OREGON COAST DURING THE DAY WITH WEAKENING NORTHWESTERLY
ONSHORE GRADIENTS. UNDER MOSTLY CLEAR SKIES HIGH TEMPERATURES
WARMING INTO THE UPPER 70S AND 80S. LOWS TONIGHT UPPER 40S TO
MID 50S.
THERMALLY INDUCED SURFACE TROUGH MOVING UP THE WASHINGTON COAST
SATURDAY NIGHT AND REMAINING ALONG THE COAST THROUGH SUNDAY.
UPPER LEVEL RIDGE AXIS MOVING OVER WESTERN WASHINGTON.
TEMPERATURES ALOFT CONTINUING TO WARM. THIS COMBINED WITH THE
LOW LEVEL OFFSHORE FLOW WILL PRODUCE RECORD HIGH TEMPERATURES IN
MANY LOCATIONS SUNDAY. HIGHS IN THE 80S COMMON WITH LOWER 90S
IN THE WARMER LOCATIONS LIKE THE SOUTHWEST INTERIOR.
A HEAT ADVISORY WILL GO INTO EFFECT BEGINNING AT 11 AM/18Z
SUNDAY WITH WIDESPREAD MODERATE HEATRISK ACROSS THE AREA AND A
SLIGHT CHANCE OF MAJOR HEATRISK OVER THE SOUTHWEST INTERIOR AND
LOWER CHEHALIS VALLEY. FELTON
LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/
MODELS CONSISTENT WITH HIGH TEMPERATURES PEAKING MONDAY AS THE
THERMALLY INDUCED SURFACE TROUGH MOVES INLAND. THE EXCEPTION TO
THIS WILL BE THE COAST WHERE AFTERNOON SEABREEZES WILL CAP HIGHS
IN THE 70S. FOR THE INTERIOR HIGHS IN THE 80S TO MID 90S.
WARM NIGHT MONDAY NIGHT OVER THE INTERIOR WITH THE THERMALLY
INDUCED TROUGH IN THE AREA. LOWS IN THE SEATTLE METRO AREA WILL
BE ABOVE 60 DEGREES WITH OTHER INLAND LOCATIONS NEAR 60. THE
HEAT ADVISORY WILL REMAIN IN EFFECT THROUGH 5 AM/12Z TUESDAY
MORNING.
UPPER LEVEL RIDGE WEAKENING TUESDAY. ONSHORE FLOW IN THE LOWER
LEVELS KICKING IN WITH THE THERMALLY INDUCED SURFACE TROUGH EAST
OF THE CASCADES. HIGH CONFIDENCE THAT TUESDAY WILL BE COOLER.
HOW MUCH COOLER IS ANOTHER STORY. MODELS HAVE BEEN OSCILLATING
BETWEEN A WEAKER MARINE PUSH, HIGH TEMPERATURES DROPPING 5
DEGREES OR SO, VERSUS A STRONGER PUSH THAT WOULD DROP HIGH
TEMPERATURES 10 TO 15 DEGREES. MODELS NOW LEANING TOWARDS THE
STRONGER PUSH SCENARIO. MODEL SURFACE PROGS SHOWING THE SURFACE
RIDGE AXIS TO THE SOUTH. THIS IS A GOOD INDICATOR OF A STRONGER
PUSH. WILL GO WITH THAT IDEA FOR THIS FORECAST PACKAGE PUTTING
HIGHS IN THE 70S FOR THE INTERIOR AND MID 60S FOR THE COAST.
UPPER LEVEL RIDGE CONTINUING TO SLOWLY WEAKEN WEDNESDAY AND
THURSDAY. 500 MB HEIGHTS STILL NEAR 580 DMS THURSDAY AFTERNOON.
INCREASING LOW LEVEL ONSHORE FLOW WILL DEEPEN THE MARINE LAYER
OVER THE INTERIOR COOLING HIGHS A FEW MORE DEGREES BUT AT THIS
POINT THE MARINE LAYER DOES NOT LOOK DEEP ENOUGH TO STICK AROUND
IN THE AFTERNOON. HIGHS WEDNESDAY AND THURSDAY NEAR NORMAL,
UPPER 60S TO MID 70S INLAND AND MID 60S ALONG THE COAST. FELTON
AVIATION
VFR CONDITIONS WILL REMAIN IN PLACE AT ALL TERMINALS
TODAY AS MOSTLY CLEAR SKIES CONTINUE ACROSS THE REGION. CALM
WINDS THIS MORNING WILL GIVE WAY TO INCREASING NORTH TO
NORTHWEST WINDS IN THE AFTERNOON, PEAKING BETWEEN 5-12 KT.
CLEAR SKIES AND VFR CONDITIONS ARE EXPECTED TO CONTINUE OVER
THE AREA TONIGHT THROUGH 18Z SATURDAY. CHANCES FOR CEILINGS
BELOW 3000 FT ALONG THE COAST ONLY PEAK BETWEEN 5-10% BETWEEN
12-16Z SATURDAY. WINDS WILL BECOME CALM AGAIN TONIGHT.
KSEA...VFR CONDITIONS WILL PREVAIL TODAY THROUGH 18Z SATURDAY
WITH MOSTLY CLEAR SKIES. LIGHT NE WINDS LESS THAN 5 KT SHOULD
SHIFT TO THE NORTH/NORTHWEST AT SPEEDS OF 5-10 KT AFTER 17-18Z
FRIDAY. -23
MARINE
BROAD HIGH PRESSURE CONTINUES TO BUILD OVER THE NE PACIFIC AND WILL
ALSO START TO SETTLE OVER AREA WATERS TODAY. HIGH PRESSURE IS
EXPECTED TO STRENGTHEN OVER THE WATERS THIS WEEKEND THROUGH
MONDAY ESTABLISHING NORTHERLY FLOW OVER THE WATERS. ON TUESDAY,
HIGH PRESSURE WILL THEN WEAKEN OVER THE REGION AS THE BROAD AREA
OF HIGH PRESSURE RETREATS BACK INTO THE OPEN WATERS OF THE
PACIFIC IN THE WAKE OF AN INCOMING FRONTAL SYSTEM. ONSHORE FLOW
ALSO RETURNS TUESDAY. THERE IS INCREASING CONFIDENCE (70% CHANCE
OR GREATER) FOR GALES THROUGH THE STRAIT OF JUAN DE FUCA ON
TUESDAY. SEAS WILL ALSO BUILD ON TUESDAY, WITH GUIDANCE
SUGGESTING SEAS BUILDING ABOVE 10 FEET.
29
FIRE WEATHER
DRYING TREND OVER THE AREA THE NEXT FEW DAYS WITH ELEVATED FIRE
WEATHER CONCERNS BEGINNING SATURDAY AND LASTING INTO TUESDAY.
UPPER LEVEL RIDGE BUILDING THIS WEEKEND WITH THE LOW LEVEL FLOW
TURNING OFFSHORE SATURDAY NIGHT. HIGHS WARMING INTO THE 80S
SATURDAY, 80S TO LOWER 90S SUNDAY AND FOR THE INTERIOR 80S TO
MID 90S MONDAY. RELATIVE HUMIDITY VALUES LOWERING IN THE DRIER
LOCATIONS, LIKE THE SOUTHWEST INTERIOR, INTO THE TEENS BOTH
SUNDAY AND MONDAY AFTERNOON. EVEN THOUGH FINE FUELS HAVE NOT
REACHED CRITICAL THRESHOLDS, THIS RAPID DRYING WILL CREATE
ELEVATED FIRE CONCERNS ESPECIALLY FOR DRY GRASSY/SHRUBBY AREAS,
AS WELL AS PILES OF DEAD FUELS. OFFSHORE FLOW SUNDAY INTO MONDAY
WILL PREVENT GOOD RELATIVE HUMIDITY RECOVERIES OVERNIGHT.
RELATIVE HUMIDITIES WILL IMPROVE WITH THE RETURN OF ONSHORE FLOW
TUESDAY. WINDS WILL BECOME PARTICULARLY GUSTY, WITH PORTIONS OF
THE COAST/MOUNTAINS/SOUTH INTERIOR SEEING WEST TO NORTHWEST
WIND GUSTS UP TO 20 TO 30 MPH. LOW LEVEL ONSHORE FLOW AND
COOLER TEMPERATURES WEDNESDAY AND THURSDAY WILL EASE FIRE
WEATHER CONCERNS THE MIDDLE OF NEXT WEEK. FELTON/HPR
SEW WATCHES/WARNINGS/ADVISORIES
WA...HEAT ADVISORY FROM 11 AM SUNDAY TO 5 AM PDT TUESDAY FOR CITY
OF SEATTLE-DOWNTOWN EVERETT / MARYSVILLE AREA-EASTERN
KITSAP COUNTY-EASTERN STRAIT OF JUAN DE FUCA-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 THURSTON AND LEWIS
COUNTIES-FOOTHILLS AND VALLEYS OF THE NORTH CASCADES-
FOOTHILLS OF THE WESTERN AND SOUTHERN OLYMPIC PENINSULA-
ISLAND COUNTY-LAKE CRESCENT AREA INCLUDING US 101-LOWER
CHEHALIS RIVER VALLEY-LOWLANDS OF LEWIS AND SOUTHERN
THURSTON COUNTIES-LOWLANDS OF PIERCE AND SOUTHERN KING
COUNTIES-LOWLANDS OF WESTERN SKAGIT AND NORTHWESTERN
SNOHOMISH COUNTIES-LOWLANDS OF WESTERN WHATCOM COUNTY-
MIDDLE CHEHALIS RIVER VALLEY-NORTHERN HOOD CANAL-OLYMPIA
AND SOUTHERN PUGET SOUND-PORT TOWNSEND AREA-SAN JUAN
COUNTY-SHORELINE / LYNNWOOD / SOUTH EVERETT AREA-SOUTHERN
HOOD CANAL-WILLAPA AND BLACK HILLS.
PZ...NONE.
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