202
FXUS66 KPQR 180459 AAA
AFDPQR
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PORTLAND OR
859 PM PST TUE DEC 17 2024
SYNOPSIS
A STRONG FRONTAL SYSTEM WILL MAINTAIN ACTIVE
WEATHER THROUGH WEDNESDAY MORNING. MODERATE TO HEAVY RAIN HAS
TAPERED OFF SOUTH OF SALEM BUT CONTINUES TO THE NORTH. A COLD
FRONT ARRIVES TONIGHT WHICH WILL BRING ANOTHER ROUND OF RAIN
THOUGH IT WILL BE SHOWERY. THE FRONT WILL ALSO BRING STRONG
SOUTH WINDS, WITH GUSTS TO 60 MPH AT THE IMMEDIATE COAST AND AS
HIGH AS 45 MPH FOR THE INLAND VALLEYS THROUGH EARLY WEDNESDAY
MORNING. DRIER CONDITIONS LIKELY LATER WEDNESDAY THROUGH FRIDAY,
ALTHOUGH WEATHER REMAINS ACTIVE OVER THE PACIFIC AND NEAR THE
COAST. RAIN RETURNS FOR THE WEEKEND INTO EARLY NEXT WEEK AS
SEVERAL FRONTAL SYSTEMS PUSH INLAND.
SHORT TERM...NOW THROUGH FRIDAY NIGHT
THE UPPER LEVEL
PATTERN THIS AFTERNOON IS CHARACTERIZED BY SOUTHWEST FLOW ALOFT
ON THE PERIPHERY OF AN UPPER LEVEL RIDGE CENTERED EAST OF THE
CASCADES. AT THE SURFACE, A MATURE 985 MB LOW IS CENTERED WEST
OF HAIDA GWAII, WITH AN OCCLUDED FRONT EXTENDING SOUTHEAST TO A
TRIPLE POINT OFF THE WASHINGTON COAST. THE WARM FRONT AND WEAK
ATMOSPHERIC RIVER FROM THIS MORNING HAS WEAKENED AND SHIFTED
NORTHWARD. THE IMPACTS FROM THAT SYSTEM THOUGH ARE STILL BEING
FELT WITH MINOR FLOODING OCCURRING ALONG THE GRAYS RIVER AND
PONDING IN POOR DRAINAGE AREAS. RADAR SHOWS MOST OF THE RAIN TO
THE NORTH WITH THE LINGERING SHOWERS OVER PACIFIC COUNTY.
ANOTHER ROUND OF HEAVIER PRECIPITATION ARRIVES WITH THE TRAILING
COLD FRONT AROUND MIDNIGHT.
THE COLD FRONT WILL ALSO BE ACCOMPANIED BY STRONG WINDS AS IT
REACHES THE COAST LATER THIS EVENING AND THEN PUSHES INLAND
OVERNIGHT, WITH BUOY OBSERVATIONS OVERT THE COASTAL WATERS
ALREADY REPORTING 50 MPH GUSTS THIS AFTERNOON AHEAD OF THE
FRONT. A HIGH WIND WARNING REMAINS IN EFFECT FOR BEACHES AND
HEADLANDS, WHERE A FEW GUSTS TO 60 MPH ARE EXPECTED LATE THIS
EVENING INTO EARLY WEDNESDAY MORNING. INLAND COASTAL COMMUNITIES
SUCH AS ASTORIA AND TILLAMOOK WILL LIKELY SEE GUSTS TO AROUND
45 MPH, WITH A 20-30% CHANCE FOR GUSTS AS HIGH AS 60 MPH. ALSO
OPTED TO ISSUE A WIND ADVISORY FOR THE WILLAMETTE VALLEY AND THE
INTERIOR LOWLANDS OF SW WA FROM 8 PM THIS EVENING UNTIL 4 AM
WEDNESDAY AS HREF PROBS FOR 45 MPH GUSTS HAVE INCREASED TO
50-60% ACROSS THE INTERIOR VALLEYS. A STABLE LAYER ABOVE THE
SURFACE WILL INITIALLY INHIBIT THE STRONGER GUSTS FROM REACHING
THE VALLEY FLOOR, BUT EXPECT AT LEAST SOME WIND TO START TO MIX
DOWN LATER IN THE EVENING AS THE COLD FRONT MOVES INTO THE AREA.
THE MOST LIKELY TIME FOR STRONGER GUSTS WILL BE FROM 10 PM TO 2
AM, WITH THE BEST CHANCES FROM SALEM TO PORTLAND AND INTO
SOUTHWEST WASHINGTON. CHANCES WILL BE LOWER ACROSS THE SOUTH
WILLAMETTE VALLEY, WITH AROUND A 20% CHANCE TO SEE 45 MPH GUSTS
IN THE EUGENE AREA.
EXPECT A PERIOD OF QUIETER WEATHER THROUGH THE END OF THE WORK
WEEK AS THE FRONT CLEARS THE AREA WEDNESDAY MORNING, WITH MODELS
IN GOOD AGREEMENT ON UPPER LEVEL RIDGING PREVAILING OVER THE
PACIFIC NORTHWEST WEDNESDAY THROUGH FRIDAY. ANOTHER SYSTEM MAY
CLIP THE WASHINGTON COAST LATE THURSDAY, BUT PRECIPITATION
CHANCES SHOULD MAINLY STAY CONFINED TO THE COASTAL AREAS, WITH
THE MAJORITY OF GLOBAL ENSEMBLE MEMBERS KEEPING INLAND LOCATIONS
DRY THROUGH THE PERIOD. EXPECT TEMPS TO REMAIN ABOVE SEASONAL
NORMALS WITH DAYTIME HIGHS IN THE 50S AND OVERNIGHT LOWS MAINLY
IN THE 40S THROUGH THE REST OF THE WEEK. -CB/MUESSLE
LONG TERM...SATURDAY THROUGH TUESDAY
CLUSTERS ARE IN GOOD
AGREEMENT THAT THE UPPER LEVEL RIDGE SHIFTS EAST BY THE WEEKEND,
ALLOWING FOR FRONTAL SYSTEMS TO PUSH BACK INLAND. THERE IS HIGH
CONFIDENCE THAT WET WEATHER OVER THE WEEKEND CONTINUES INTO
NEXT WEEK. SNOW LEVELS APPEAR TO STAY RELATIVELY HIGH ABOVE
5000-6000 FT INTO EARLY NEXT WEEK. -DH
AVIATION
VFR CONDITIONS THIS EVENING AS THE AREA IS IN BETWEEN
FRONTS. A COLD FRONT WILL BRING ANOTHER ROUND OF RAIN, WINDS, AND
MVFR CONDITIONS TO THE COAST BY WED 9Z AND INLAND (WILLAMETTE
VALLEY AND CASCADE FOOTHILLS) BY WED 12Z. LOW LEVEL WIND SHEAR IN
THE FORM OF SPEED SHEAR IS LIKELY UNTIL 15Z. SOUTH WINDS CAN GUST
UP TO 35-40 KTS AHEAD OF AND ALONG THE FRONTS, WITH SIMILAR
STRENGTH SOUTHWEST WINDS JUST BEHIND THE FRONT. WEST WIND 8-12 KT
WITH VFR CONDITIONS IS EXPECTED BY WED 18Z.
PDX AND APPROACHES...COLD FRONT WILL BRING A RETURN OF RAIN AND
MVFR CONDITIONS AFTER WED 9Z. LOW LEVEL WIND SHEAR IN THE FORM OF
SPEED SHEAR THROUGH WED 15Z. SOUTH WINDS WILL INCREASE AHEAD OF
THE FRONT AFTER 5Z WITH GUSTS OF 30-35 KT THROUGH 12Z. LIGHTER
WEST WINDS EXPECTED BEHIND THE FRONT AFTER 15Z WED.-TJ
MARINE
ACTIVE WEATHER CONTINUES THROUGH THE MAJORITY OF THE
WEEK AS A SERIES OF SYSTEMS MOVE THROUGH THE REGION. EACH SYSTEM
WILL BRING INCREASING WINDS AND SEAS ACROSS ALL WATERS. THE FIRST
SYSTEM CURRENTLY CONTINUES TO BRING LOW-END STORM FORCE GUSTS UP
TO 50 KT THROUGH AT LEAST WEDNESDAY MORNING. HOWEVER, MORE SYSTEMS
ARE READY TO TAKE A SHOT AT THE REGION THROUGH THE REMAINDER OF
THE WEEK AND INTO THE START OF NEXT WEEK.
GALES FRIDAY AND SATURDAY (60-80% PROBABILITY) WITH STORM FORCE
(50-75% PROBABILITY) SUNDAY/MONDAY. SEAS BUILD TOWARDS 20 FT ON
FRIDAY AND SATURDAY AND WILL LIKELY TOP OUT AROUND 20-23 FT ON
SUNDAY/MONDAY.
CURRENTLY, THERE IS A 60% PROBABILITY THAT THE OUTER COASTAL
WATERS WILL EXCEED 20 FT FOR SATURDAY AND A 50% PROBABILITY OF
SEAS GREATER THAN 20 FT ON SUNDAY AND MONDAY. -42
PQR WATCHES/WARNINGS/ADVISORIES
OR...HIGH WIND WARNING UNTIL 4 AM PST WEDNESDAY FOR ORZ101>103.
WIND ADVISORY UNTIL 4 AM PST WEDNESDAY FOR ORZ108>118.
WA...HIGH WIND WARNING UNTIL 4 AM PST WEDNESDAY FOR WAZ201.
WIND ADVISORY UNTIL 4 AM PST WEDNESDAY FOR WAZ204>207.
PZ...STORM WARNING UNTIL 1 AM PST WEDNESDAY FOR PZZ210-251>253-
271>273.
GALE WARNING FROM 1 AM TO 4 AM PST WEDNESDAY FOR PZZ210-
251>253-271>273.
HAZARDOUS SEAS WARNING FROM 4 AM TO 1 PM PST WEDNESDAY FOR
PZZ210-251>253-271>273.
WWW.WEATHER.GOV/PORTLAND
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSPORTLAND
X.COM/NWSPORTLAND
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