670
FXUS66 KPQR 191530 AAA
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
830 AM PDT MON MAY 19 2025
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 WEAKACTIVE 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
OBSERVATIONS FROM AROUND THE REGION SHOW CEILINGS
LOWERING TO MVFR ALONG THE COAST AS OF 09Z MON AHEAD OF A FRONT
MOVING THROUGH THE WA/OR COASTAL WATERS EARLY THIS MORNING. VFR
CONDITIONS ARE HOLDING ON FOR NOW ACROSS THE INLAND TERMINALS BUT
WILL TREND DOWN TO MVFR BY 12-13Z AS THE FRONT AND ASSOCIATED
RAIN SHOWERS BEGIN TO PUSH ONSHORE. THE FRONT WILL BRING RAIN,
MVFR CIGS, AND 10-15 KT SOUTHERLY WINDS TO MOST TERMINALS AS IT
MOVES ACROSS THE AREA THROUGH ROUGHLY 21Z MON, WITH CONDITIONS
THEN IMPROVING BACK TOWARDS VFR AT MOST SITES THIS AFTERNOON.
WINDS WILL SHIFT OUT OF THE WEST-SOUTHWEST AT AROUND 10 KT BEHIND
THE FRONT, PERHAPS WITH SOME GUSTS AS HIGH AS 20 KT AT TIMES
THOUGH 03-06Z TUE. GUIDANCE SHOWS AN UPTICK IN SHOWER COVERAGE
AGAIN AFTER 06Z TUE 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...VFR CONDITIONS TREND DOWN TO MVFR 12-13Z MON
AS RAIN SPREADS INLAND AHEAD OF AN APPROACHING FRONT. EXPECT
THESE CONDITIONS TO LAST THROUGH AROUND 21Z MON, WITH SOUTH WINDS
AROUND 10 KT. CONDITIONS IMPROVE BACK TO VFR AFTER 21Z MON IN THE
WAKE OF THE FRONT, WITH WINDS SHIFTING W-SW AROUND 10 KT. MAINLY
VFR IN SCATTERED SHOWERS FOR THE REMAINDER OF THE TAF PERIOD, WITH
A 20-30% CHANCE FOR INTERMITTENT MVFR CONDITIONS AFTER 06Z TUE.
/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.
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