427
FXUS66 KPQR 191621 AAA
AFDPQR
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PORTLAND OR
ISSUED BY NATIONAL WEATHER SERVICE SEATTLE WA
921 AM PDT MON MAY 19 2025
UPDATED AVIATION DISCUSSION...
SYNOPSIS
A FRONT IS CURRENTLY MOVING INTO THE REGION THE REST OF
TONIGHT INTO MONDAY, BRINGING ANOTHER ROUND OF WIDESPREAD SHOWERS
THROUGH MONDAY MORNING. EXPECT TEMPERATURES TO REMAIN SLIGHTLY BELOW
AVERAGE THROUGH MIDWEEK. TEMPERATURES ARE TRENDING WARMER TOWARDS THE
UPPER 60S TO NEAR 70 FOR THE SECOND HALF OF NEXT WEEK WITH THE
POTENTIAL FOR WEAK ACTIVE WEATHER TO CONTINUE.
SHORT TERM...MONDAY THROUGH WEDNESDAY
A LOW IS CURRENTLY IN THE
PROCESS OF MOVING ASHORE, WITH RAIN SHOWERS JUST BEGINNING ALONG THE
SOUTHERN WASHINGTON COAST AS OF 2:30AM MONDAY. RAIN CONTINUES TO FILL
IN THROUGHOUT THE AREA GOING INTO MONDAY, BUT THE INITIAL FRONTAL
BAND MOVES THROUGH THE AREA BY AROUND 2-4PM MONDAY. THIS INITIAL WAVE
OF RAIN ONLY SEES AROUND A 10% CHANCE OF EXCEEDING 0.25 INCHES IN THE
WILLAMETTE VALLEY, AND AROUND A 50-60% CHANCE OF EXCEEDING 0.25
INCHES IN THE CASCADES AND COAST RANGE. THIS WILL BE ACCOMPANIED BY A
SHIFT TO WESTERLY WINDS WITH GUSTS UP TO 20-25 MPH POSSIBLE
THROUGHOUT MOST OF THE REGION. AFTERWARDS, THROUGHOUT THE REST OF
MONDAY NIGHT AND TUESDAY AM HOURS, RAIN SHOWERS CONTINUE DUE TO
GENERALLY UNSETTLED AIR; SOME WEAK COASTAL THUNDERSTORMS MAY BE
POSSIBLE (10-15% CHANCE) MONDAY EVENING. DURING THIS TIME, THE
AFTERNOON HIGH ON MONDAY AND TUESDAY LOOKS TO BE AROUND THE LOW TO
MID 60S FOR THE WILLAMETTE VALLEY, CLOSER TO THE MID TO UPPER 50S AT
THE COAST.
WEDNESDAY LOOKS TO BE WARMER, WITH GOOD AGREEMENT IN BRIEF RIDGING
BUILDING INTO THE AREA. THIS WILL ALLOW TEMPERATURES TO RISE INTO THE
UPPER 60S/NEAR 70 IN THE WILLAMETTE VALLEY, WITH A 30-40% CHANCE OF
EXCEEDING 70 DEGREES IN THE WILLAMETTE VALLEY ON WEDNESDAY AFTERNOON.
THE NEXT SYSTEM WILL BE WEDNESDAY EVENING/NIGHT, BUT PRECIPITATION
ACCUMULATION LOOKS MINIMAL WITH THIS SYSTEM.
LONG TERM...THURSDAY THROUGH SUNDAY
CONDITIONS REMAIN SOMEWHAT
UNCERTAIN THURSDAY AND BEYOND. AROUND 50% OF WPC CLUSTERS SHOW WEAK
TROUGH ENTERING THE AREA FROM THE NORTHEASTERN PACIFIC, WHILE THE
OTHER 50% SHOW RELATIVELY ZONAL FLOW THROUGH FRIDAY. SLIGHTLY BETTER
AGREEMENT IN RIDGING BUILDING IN OVER THE WEEKEND, WITH AROUND 60%
AGREEMENT IN STRONG RIDGING BUILDING ON BY SUNDAY, ALLOWING FOR
WARMER TEMPERATURES INTO THE 70S. /JLIU
AVIATION
AS OF 16Z MONDAY, MOSTLY MVFR CONDITIONS WITH A FEW
TERMINALS EXPERIENCING IFR (KSLE) AND LIFR CONDITIONS (KONP). LOOKS
LIKE SOME TERMINALS MAY BOUNCE BETWEEN MVFR AND VFR CONDITIONS
THROUGH THE MORNING. RAIN SHOULD BEGIN TO DISSIPATE AND INLAND
TERMINAL CONDITIONS SHOULD IMPROVE TO VFR BY 20-21Z MONDAY. MVFR
CONDITIONS ALONG THE COAST WILL LIKELY PERSIST UNTIL 06Z TUESDAY. AS
FOR WINDS, SOUTHERLY TO SOUTHWESTERLY WINDS WILL REMAIN INCREASED
AND GUSTY UNTIL 00Z TUESDAY FOR INLAND TERMINALS AND 06Z TUESDAY FOR
COASTAL TERMINALS. EXPECT GUSTS UP TO 20 KT FOR MOST TERMINALS
DURING THE AFOREMENTIONED TIME.
GUIDANCE SHOWS AN UPTICK IN SHOWER COVERAGE AGAIN AFTER 06Z TUESDAY
AS A TRAILING UPPER LEVEL DISTURBANCE CROSSES THE REGION. MAINLY
EXPECT VFR CONDITIONS WITH SOME INTERMITTENT BOUTS OF MVFR IN
PASSING SHOWERS THROUGH THE END OF THE PERIOD.
PDX AND APPROACHES...MVFR CONDITIONS PERSIST, EXPECTED TO LAST UNTIL
AROUND 21Z MONDAY, WITH SOUTHWESTERLY WINDS AROUND 10 KT, WITH
INFREQUENT GUSTS UP TO 20 KT. MAINLY VFR IN SCATTERED SHOWERS FOR
THE REMAINDER OF THE TAF PERIOD, WITH A 10-20% CHANCE FOR
INTERMITTENT MVFR CONDITIONS AFTER 06Z TUESDAY.
~HALL/CB
MARINE
LATEST SURFACE ANALYSIS PLACES A FRONT OVER THE
WASHINGTON AND OREGON COASTAL WATERS AS OF 2 AM MONDAY, WITH SOUTH
WINDS GUSTING TO 25-30 KT PER RECENT BUOY OBSERVATIONS. EXPECT
THESE WINDS TO CONTINUE OVER THE NEARSHORE WATERS THROUGH 7-8 AM,
WITH WINDS THEN SHIFTING RATHER ABRUPTLY OUT OF THE WEST AS THE
FRONT PUSHES ONSHORE BY MID MORNING. WEST WIND WILL REMAIN RATHER
GUSTY INTO THE AFTERNOON IN THE WAKE OF THE FRONT, MOST COMMONLY
IN THE 15-20 KT RANGE BUT WITH OCCASIONAL GUSTS AS HIGH AS 25 KT.
SEAS WILL ALSO REMAIN LOCALLY STEEP AND CHAOTIC IN THE 6-8 FT
RANGE DUE TO LINGERING SHORT PERIOD WAVE ENERGY AND A PERSISTENT
WESTERLY SWELL. WILL THEREFORE LEAVE SMALL CRAFT HEADLINES IN
EFFECT THROUGH EARLY AFTERNOON TO ACCOUNT FOR CONDITIONS
CONTINUING TO MARGINALLY MEET CRITERIA. EXPECT SOMEWHAT OF A LULL
IN CONDITIONS THIS EVENING AS WINDS AND SHORT PERIOD SEAS GRADUALLY
DIMINISH, BUT THE BREAK WILL BE SHORT LIVED AS A FRESH ARRIVING
MID PERIOD WESTERLY SWELL BUILDS TO AROUND 10 FT LATE TONIGHT
THROUGH TUESDAY, POSSIBLY WARRANTING ANOTHER ROUND OF SMALL CRAFT
ADVISORIES. WILL HOLD OFF ON THAT DECISION UNTIL ISSUANCE OF THE
AFTERNOON FORECAST PACKAGE.
SEAS SUBSIDE BACK TO 5-7 FEET ON WEDNESDAY, USHERING A PERIOD OF
RELATIVELY CALMER CONDITIONS THROUGH THE END OF THE WEEK. WEAK
HIGH PRESSURE LOOKS TO BRING A ROUND OF LIGHT TO MODERATE
NORTHERLY BREEZES TO THE WATERS WEDNESDAY AND THURSDAY, WITH
BENIGN ONSHORE FLOW THEN TAKING OVER FRIDAY INTO NEXT WEEKEND. /CB
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 2 PM PDT THIS AFTERNOON FOR PZZ210-
251>253-271>273.
WWW.WEATHER.GOV/PORTLAND
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