444
FXUS66 KSEW 130959
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
259 AM PDT TUE APR 13 2021
SYNOPSIS
UPPER LEVEL RIDGING WILL CONTINUE TO BUILD INTO
BRITISH COLOMBIA TODAY AND WEDNESDAY, WHILE AN UPPER LEVEL LOW
SINKS SOUTHWARD OVER THE GREAT BASIN. HIGH PRESSURE ALOFT WILL
INFLUENCE THE REGION THROUGH THE REMAINDER OF THE WEEK, FOR
CONTINUED DRY WEATHER AND A GRADUAL WARMING TREND.
SHORT TERM /TODAY THROUGH THURSDAY/
SATELLITE SHOWING CLEAR
SKIES ACROSS THE REGION THIS MORNING WHILE TEMPERATURES ARE
TRENDING 5-12 DEGREES WARMER THAN 24 HOURS AGO. MORNING LOWS WILL
BE A COUPLE DEGREES WARMER THAN THE LAST FEW DAYS-AND MAINLY IN
THE MID 30S TO LOW 40S ACROSS THE REGION.
AN UPPER LEVEL RIDGE WILL CONTINUE TO NUDGE INTO BRITISH COLUMBIA
TODAY AND WEDNESDAY AS AN UPPER LEVEL LOW, CURRENTLY SITUATED
ACROSS EASTERN WASHINGTON AND NORTHERN IDAHO, DROPS SOUTHWARD
TOWARDS THE GREAT BASIN. AT THE SURFACE, A THERMAL TROUGH ALONG
THE PACIFIC COAST WILL CONTINUE TO PROMOTE OFFSHORE FLOW IN THE
LOW LEVELS. THIS PATTERN WILL KEEP WESTERN WASHINGTON DRY AND
SUNNY. TEMPERATURES WILL CONTINUE TO WARM A FEW DEGREES EACH DAY,
WITH MANY LOWLAND LOCATIONS PUSHING THE MID 60S BY WEDNESDAY.
THE UPPER LEVEL LOW ACROSS THE GREAT BASIN WILL THEN START TO
PROGRESS EASTWARD TOWARDS THE ROCKIES ON THURSDAY, ALLOWING FOR
THE UPPER LEVEL HIGH TO STRENGTHEN ITS HOLD ACROSS WESTERN
WASHINGTON. AS A RESULT, UPPER LEVEL HEIGHTS WILL RISE AND
TEMPERATURES WILL CONTINUE TO WARM. THURSDAY COULD BE OUR FIRST
70 DEGREE DAY OF THE STRETCH FOR AREAS SEATTLE SOUTHWARD.
LONG TERM /FRIDAY THROUGH MONDAY/
WITH HIGH PRESSURE ALOFT,
WARM AND SUNNY WEATHER WILL CONTINUE INTO THE EXTENDED PERIOD.
TEMPERATURES WILL CONTINUE TO CLIMB, PEAKING OVER THE WEEKEND.
SATURDAY CURRENTLY LOOKS LIKE THE WARMEST DAY IN THE EXTENDED,
THOUGH SUNDAY COULD TRACK CLOSE. CURRENT FORECAST STILL CALLING
FOR MID 70S FOR SEATTLE, HOWEVER SOME GUIDANCE DOES STILL HINT
THAT TEMPERATURES COULD CLIMB A FEW DEGREES HIGHER. WILL NEED TO
KEEP AN EYE ON THE TREND AND SEE HOW THIS DEVELOPS THROUGHOUT THE
WEEK. ENSEMBLE AND DETERMINISTIC GUIDANCE THEN HINT AT A COOL DOWN
AND A POSSIBLE RETURN TO WETTER WEATHER EARLY NEXT WEEK AS HIGH
PRESSURE ALOFT WEAKENS ACROSS THE REGION AND OPENS THE DOOR FOR
WEAK SYSTEMS TO MOVE IN. 14
AVIATION
VFR CONDITIONS WITH CLEAR SKIES THROUGH THE PERIOD.
WINDS OUT OF THE N EARLY THIS MORNING 5-10KTS WILL PICK UP MID-LATE
MORNING, BECOMING BREEZY; SUSTAINED AT GENERALLY 10-15KTS WITH GUSTS
AROUND 25 KTS. GUSTS WILL DIMINISH AFTER SUNSET.
KSEA...CLEAR SKIES. N WIND 5-10KTS THROUGH SUNRISE, THEN PICKING UP
TO AROUND 15KTS LATE MORNING WITH GUSTS NEAR 25KTS THROUGH SUNSET.
KOVACIK
MARINE
OFFSHORE FLOW PATTERN CONTINUES EARLY THIS MORNING AS HIGH
PRESSURE REMAIN OVER THE INTERIOR OF THE PACIFIC NORTHWEST AND
WESTERN CANADA AND A TROUGH OF LOW PRESSURE RESIDES ALONG THE
WASHINGTON AND OREGON COASTS. WINDS HAVE RELAXED OVER THE WATERS
AFTER A BREEZY DAY YESTERDAY, AND THIS BREAK IS EXPECTED TO BE
RATHER SHORT-LIVED. SHORTLY AFTER SUNRISE THIS MORNING, SHOULD SEE
WINDS PICK BACK UP OUT OF THE NORTH, ESPECIALLY OVER THE NORTHERN
INLAND WATERS AND PUGET SOUND WHERE A SMALL CRAFT ADVISORY WILL GO
INTO EFFECT AT NOON. EVENTUALLY SMALL CRAFT ADVISORY LEVEL WINDS
WILL MAKE IT OVER THE COASTAL WATERS THIS AFTERNOON. ELSEWHERE,
WINDS WILL BE BREEZY OVER THE WATERS BUT SHOULD REMAIN 20KTS OR
BELOW.
WINDS WILL EASE AGAIN LATER THIS EVENING AND THROUGH THE OVERNIGHT
PERIOD INTO EARLY WEDNESDAY, BUT AGAIN EXPECT WINDS TO PICK UP OUT
OF THE N/NE AS OFFSHORE FLOW CONTINUES. A SMALL CRAFT ADVISORY WILL
LIKELY BE NEEDED FOR THE INNER COAST WATERS, WITH ALL OTHER WATERS
POTENTIALLY REMAINING JUST BELOW CRITERIA. ALTHOUGH
NORTHERLY/OFFSHORE FLOW WILL CONTINUE THURSDAY AND FRIDAY, WINDS
CURRENTLY LOOK LIGHT OVER ALL WATERS. THESE CONDITIONS APPEAR TO
CARRY THROUGH MUCH, IF NOT ALL, OF THE WEEKEND.
SWELLS WILL REMAIN BELOW 10 FT OVER THE NEXT 7 DAYS.
KOVACIK
HYDROLOGY
RIVER FLOODING NOT EXPECTED OVER THE NEXT 7 DAYS.
SEW WATCHES/WARNINGS/ADVISORIES
WA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 3 AM PDT EARLY THIS MORNING 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.
SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 11 PM PDT THIS
EVENING 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.
SMALL CRAFT ADVISORY FROM NOON TODAY TO 8 PM PDT THIS EVENING
FOR NORTHERN INLAND WATERS INCLUDING THE SAN JUAN ISLANDS-
PUGET SOUND AND HOOD CANAL.
WWW.WEATHER.GOV/SEATTLE
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