613
FXUS66 KSEW 171015
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
315 AM PDT WED JUN 17 2026
SYNOPSIS
DRY WEATHER FOR THE NEXT WEEK WITH UPPER LEVEL RIDGE CENTERED
OFFSHORE. VARYING DEGREES OF LOW LEVEL ONSHORE FLOW THROUGH THE
PERIOD. LOW LEVEL FLOW BECOMING LIGHT NORTHERLY ON THE WARMER
DAYS. RIDGE BUILDING AND DRIFTING CLOSER TO THE AREA THE FIRST
PART OF NEXT WEEK FOR A SMALL WARMING TREND.
SHORT TERM /TODAY THROUGH FRIDAY/
SATELLITE IMAGERY SHOWS STRATUS ALONG THE COAST, OVER THE
NORTHWEST INTERIOR AND DOWN THE CASCADE FOOTHILLS TO ABOUT I-90.
LOW LEVEL ONSHORE FLOW BRINGING MARINE AIR INTO THE INTERIOR
WITH TEMPERATURES AT 3 AM/10Z IN THE UPPER 40S TO MID 50S.
UPPER LEVEL RIDGE CENTERED WELL OFFSHORE WITH NORTHWESTERLY FLOW
ALOFT OVER WESTERN WASHINGTON THE NEXT COUPLE OF DAYS. LOW LEVEL
ONSHORE FLOW WILL WEAKEN LATER TODAY INTO TONIGHT WITH NORTHERLY
FLOW IN THE LOWER LEVELS THURSDAY. STRATUS OVER THE AREA THIS
MORNING WILL DISSIPATE BY 10 AM/17Z LEAVING SUNNY SKIES FOR THE
REMAINDER OF THE DAY. LESS STRATUS THURSDAY MORNING WITH THE LOW
LEVEL NORTHERLY FLOW. HIGHS TODAY IN THE MID AND UPPER 60S ALONG
THE COAST AND UPPER 60S TO MID 70S INLAND. A LITTLE WARMER
THURSDAY WITH HIGHS NEAR 70 COAST AND 70S TO LOWER 80S INLAND.
INCREASING NORTHERLY WINDS THURSDAY AFTERNOON. LOWS TONIGHT IN
THE UPPER 40S TO MID 50S.
A LITTLE BIT OF TROUGHINESS DEVELOPING OFFSHORE THURSDAY NIGHT
INTO FRIDAY SWITCHING THE FLOW ALOFT TO WEST SOUTHWESTERLY. THIS
WILL SEND SOME HIGH CLOUDS OUR WAY BUT THAT IS ABOUT IT. LIGHT
FLOW CONTINUING IN THE LOWER LEVELS. HIGHS FRIDAY NEAR 70 ALONG
THE COAST AND 70S TO MID 80S INLAND.
LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/
UPPER LEVEL RIDGE REMAINING OFFSHORE THROUGH THE WEEKEND WITH
VARYING DEGREES OF LOW LEVEL ONSHORE FLOW ( INCREASING ONSHORE
FLOW SATURDAY WEAKENING SUNDAY ). OFFSHORE RIDGE BUILDING AND
MOVING CLOSER TO THE AREA THE FIRST PART OF NEXT WEEK FOR A
COUPLE OF WARMER DAYS. HIGHS SATURDAY IN THE MID TO UPPER 60S
COAST AND 70S INLAND, SUNDAY NEAR 70 COAST AND 70S TO MID 80S
INLAND. A LITTLE WARMER MONDAY AND TUESDAY WITH THE COAST IN THE
LOWER TO MID 70S AND THE WARMER LOCATIONS OVER THE INTERIOR
GETTING CLOSE TO 90 DEGREES. NO RAIN IN SIGHT THE NEXT 7 DAYS.
WITH THE CONTINUATION OF THE ABOVE NORMAL TEMPERATURES SEATTLE
LOOKING AT A POSSIBLE TOP 10 AND MAYBE A TOP 5 WARMEST JUNE IF
THE TRENDS CONTINUE. THE FIRST HALF OF THE MONTH WAS THE 10TH
WARMEST IN SEATTLE AND ABOVE NORMAL TEMPERATURES WILL CONTINUE
FOR THE NEXT WEEK AT LEAST. FELTON
AVIATION
CURRENTLY VFR ACROSS ALL THE TERMINALS EARLY THIS MORNING, WITH THE
EXCEPTION OF THE COAST. LATEST SATELLITE IMAGERY SHOWS MARINE
STRATUS HUGGING THE COASTLINE AND BEGINNING TO DEVELOP OVER PORTIONS
OF THE INTERIOR. LATEST GUIDANCE IS STILL SUGGESTING THAT THE
SOUTHERN INTERIOR, KITSAP PENINSULA, AND COAST HAVE THE HIGHEST
CHANCES OF SEEING MVFR CIGS BETWEEN 11Z-20Z, WITH LATEST
PROBABILITIES BETWEEN 30-65% (HIGHEST CHANCES ALONG THE COAST).
OTHER TERMINALS HAVE A VERY SMALL CHANCE OF 10-20%. OTHERWISE, VFR
EXPECTED FOR ALL TERMINALS THIS AFTERNOON. LIGHT TO CALM WINDS FOR
THE INTERIOR TERMINALS EARLY THIS MORNING. W/NW WINDS WILL INCREASE
THIS AFTERNOON TO 5-10 KT. BREEZY WINDS EXPECTED ALONG THE COAST
THIS AFTERNOON, WITH GUSTS TO 20 KT.
KSEA...VFR CONDITIONS THROUGH THE TAF PERIOD. LIGHT VARIABLE WINDS
OVERNIGHT WILL BECOME W/NW IN THE AFTERNOON AND INCREASE TO 5-8 KT.
WINDS SHIFT NE AFTER 04Z-06Z AT 5-7 KT.
MARINE
BROAD HIGH PRESSURE OVER THE NE PACIFIC WILL KEEP WEAK HIGH PRESSURE
OVER WASHINGTON'S WATERS. HIGH PRESSURE OVER THE WATERS WILL THEN
BEGIN TO WEAKEN LATE THURSDAY AS A LOW PRESSURE SYSTEM SLOWLY MOVES
ACROSS BRITISH COLUMBIA THROUGH SATURDAY. AS THE LOW PRESSURE SYSTEM
PUSHES TO THE EAST, BROAD HIGH PRESSURE OVER THE NE WILL BEGIN TO
BUILD EAST INTO AREA WATERS AND WILL STRENGTHEN INTO EARLY NEXT
WEEK.
ELEVATED NORTHWESTERLY WINDS AND SEAS ARE EXPECTED ACROSS THE
COASTAL WATERS THROUGHOUT THE WEEK. GUIDANCE SUGGESTS A 70% CHANCE
OR HIGHER OF 21 KT WINDS ACROSS THE COASTAL WATERS, ESPECIALLY THE
OUTER COASTAL WATERS. WESTERLY PUSHES ARE EXPECTED THROUGH THE
STRAIT OF JUAN DE FUCA THIS WEEKEND. HOWEVER, AT THIS TIME WINDS
LOOK TO REMAIN BELOW SMALL CRAFT THRESHOLDS, AS THE LATEST
PROBABILITIES ARE AROUND 20-35%.
FIRE WEATHER
THE RETURN OF LOW LEVEL ONSHORE FLOW HAS EASED FIRE WEATHER
CONCERNS FOR THE NEXT COUPLE OF DAYS. ELEVATED FIRE WEATHER
CONCERNS RETURN FRIDAY AND THE FIRST PART OF NEXT WEEK WITH A
FEW WARMER AND DRIER DAYS. MINIMUM RELATIVE HUMIDITY VALUES ARE
FORECAST TO DROP TO AROUND 30 PERCENT FRIDAY AND DURING THE
FIRST PART OF NEXT WEEK. BREEZY CONDITIONS IN THE AFTERNOON AND
EVENING HOURS COMBINED WITH THE LOWER RELATIVE HUMIDITY VALUES
COULD BE PROBLEMATIC ESPECIALLY WITH THE FUELS CONTINUING TO DRY
OUT IN THE NEXT WEEK. FELTON
SEW WATCHES/WARNINGS/ADVISORIES
WA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 11 PM PDT THURSDAY FOR COASTAL
WATERS FROM CAPE FLATTERY TO JAMES ISLAND 10 TO 60 NM-
COASTAL WATERS FROM CAPE FLATTERY TO JAMES ISLAND OUT 10
NM-COASTAL WATERS FROM JAMES ISLAND TO POINT GRENVILLE 10
TO 60 NM-COASTAL WATERS FROM JAMES ISLAND TO POINT
GRENVILLE OUT 10 NM-COASTAL WATERS FROM POINT GRENVILLE
TO CAPE SHOALWATER 10 TO 60 NM-COASTAL WATERS FROM POINT
GRENVILLE TO CAPE SHOALWATER OUT 10 NM.
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