706
FXUS66 KPQR 290456 AAA
AFDPQR
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PORTLAND OR
956 PM PDT MON SEP 28 2026
UPDATED AVIATION DISCUSSION.
SYNOPSIS
DRY WEATHER CONTINUES THROUGH THIS EVENING, BUT
EXPECT SUNNY SKIES TO GIVE WAY TO INCREASING CLOUDS AS A FRONTAL
SYSTEM APPROACHES FROM THE NORTH. ON TUESDAY, THIS DECAYING
FRONTAL SYSTEM DROPS SOUTH ACROSS NORTHERN PORTIONS OF THE AREA
BRINGING CHANCES FOR RAIN THROUGH LATE TUE NIGHT, WITH THE
HIGHEST PROBABILITIES ALONG THE WASHINGTON AND NORTH OREGON
COAST AND COAST RANGE. DRY WEATHER IS FAVORED AGAIN BY WEDNESDAY
WITH TEMPERATURES TRENDING WARMER THIS WEEKEND.
DISCUSSION...NOW THROUGH MONDAY
SATELLITE IMAGERY SHOWS MOSTLY
CLEAR SKIES OVER THE FORECAST AREA EARLY THIS AFTERNOON. BUT, MID TO
HIGH LEVEL CLOUDS ARE EXPECTED TO INCREASE THROUGH TONIGHT AS A
WEATHER SYSTEM TO THE NORTH GRADUALLY SHIFTS SOUTHWARD. THE WEAK
RIDGE OF HIGH PRESSURE OVER THE AREA WILL BE REPLACED BY ZONAL FLOW
OVER THE REGION. WITH INCREASING CLOUD COVER, DO NOT EXPECT
OVERNIGHT TEMPERATURES TO COOL AS MUCH AS THIS MORNING'S LOWS.
A DECENT PLUME OF MOISTURE ASSOCIATED WITH THE FRONTAL SYSTEM IS
CURRENTLY IMPACTING VANCOUVER ISLAND, BUT IS EXPECTED TO WEAKEN AS
IT DROPS SOUTH INTO WESTERN WASHINGTON AS UPPER LEVEL SUPPORT
QUICKLY MOVES EASTWARD ACROSS CANADA. BUT, THERE APPEARS TO BE
ENOUGH LINGERING MOISTURE TO BRING SOME RAIN TO THE NORTH OREGON
COAST AND POSSIBLY INTO THE PORTLAND METRO AREA AND LOCATIONS
NORTHWARD. LATEST GUIDANCE SUGGESTS THERE IS AROUND A 40-60% CHANCE
FOR 0.25 INCH OF RAINFALL FROM TILLAMOOK NORTHWARD, WITH ABOUT A 50%
CHANCE FOR A HALF INCH OF RAIN IN THE WILLAPA HILLS. RAIN WILL
LIKELY BE MORE SPOTTY WITH LIGHT AMOUNTS EXPECTED ACROSS PORTIONS OF
SOUTHWEST WA AND THE PORTLAND METRO, GENERALLY LESS THAN 25% CHANCE
FOR EXCEEDING 0.10 INCH, WHILE CONDITIONS SALEM SOUTHWARD REMAINING
DRY.
WIDESPREAD DRY CONDITIONS RETURN BY WEDNESDAY MORNING, AND LIKELY
CONTINUING THROUGH THE REMAINDER OF THE WEEK INTO THE WEEKEND. THE
ONE CAVEAT INCLUDES A WEAK WEATHER SYSTEM POTENTIALLY CLIPPING
NORTHERN PORTIONS OF OUR FORECAST AREA AGAIN THURSDAY INTO FRIDAY.
BUT, MOST ENSEMBLE MEMBERS ARE PUSHING THE SYSTEM FARTHER NORTH,
WITH ONLY 10% OR LESS SHOWING RAIN. TEMPERATURES REMAIN FAIRLY
SEASONABLE THROUGH THE END OF SEPTEMBER.
BY THE WEEKEND, MODELS AND THEIR ENSEMBLES ARE IN FAIRLY GOOD
AGREEMENT OF A MORE PRONOUNCED RIDGE OF HIGH PRESSURE BUILDING OVER
THE REGION. THIS WOULD MAINTAIN DRY WEATHER AND POTENTIALLY TREND
AFTERNOON TEMPERATURES AROUND 5-10 DEGREES ABOVE NORMAL FOR EARLY
OCTOBER. CLUSTERS HINT AT MORE UNCERTAINTY THOUGH HEADING INTO EARLY
NEXT WEEK. /DH
AVIATION...THROUGH 06Z WEDNESDAY
VFR CONDITIONS HANG ON FOR A
BIT LONGER FOR ALL TERMINALS BEFORE CHANCES FOR SUB-VFR CONDITIONS
INCREASES TONIGHT. MID LEVEL CLOUDS CONTINUE TO INCREASE OVER THE
AREA AHEAD OF A SHORTWAVE TROUGH THAT WILL SKIRT NORTH OF SW WA
AND NW OR LATE TONIGHT INTO TUESDAY. PROBABILITIES FOR MVFR CIGS
INCREASE TO GREATER THAN 80% ALONG THE COAST BETWEEN 07-11Z AND
SPREAD INLAND AFTER 12-14Z. PROBABILITIES FOR INLAND TERMINALS ARE
HIGHEST AROUND THE PORTLAND METRO AT 50-70% BETWEEN 16-20Z. LOW
CLOUDS ARE LIKELY MORE SCT TO BKN THROUGHOUT THE WILLAMETTE VALLEY
WITH MVFR CHANCES AT 20-40% ANY GIVEN HOUR BETWEEN 14-20Z.
GENERALLY LIGHT SOUTHERLY WINDS WILL GRADUALLY INCREASE TO 5-10
KT AS A COLD FRONT ASSOCIATED WITH THE TROUGH MOVES THROUGH THE
REGION. HIGHER SPEEDS AT KAST UP TO 15 KT WITH GUSTS UP TO 25 KT
EXPECTED.
KPDX AND APPROACHES...VFR CONDITIONS PREVAIL WITH MID LEVEL CLOUD
COVER INCREASING. EXPECT MVFR CIGS TO ENTER THE METRO BETWEEN
12-14Z WITH THE GREATEST PROBABILITIES AFTER 14Z. WINDS LIGHT
OVERNIGHT, INCREASING TO AROUND 5 KT FROM THE SOUTH AFTER 18Z.
-19
MARINE
HIGH PRESSURE WILL CONTINUE TO WEAKEN AS A FRONTAL
BOUNDARY APPROACHES THE COASTAL WATERS TONIGHT. SOUTHERLY WINDS
ARE EXPECTED TO INCREASE OVERNIGHT INTO TUESDAY MORNING WITH GUSTS
MOST LIKELY PEAKING AROUND 25-30 KT, STRONGEST ACROSS THE INNER
WATERS NORTH OF CAPE FALCON. A SMALL CRAFT ADVISORY IS IN EFFECT
FOR COASTAL WATERS NORTH OF CAPE FOULWEATHER, INCLUDING THE
COLUMBIA RIVER BAR WHERE A STRONG EBB CURRENT IS EXPECTED THIS
EVENING. WINDS ARE EXPECTED TO ABRUPTLY SHIFT TO THE NORTHWEST
BEHIND THE COLD FRONT AS IS MOVES ACROSS THE WATERS LATER TUE
AFTERNOON AND EVENING. ONCE THE FRONT PASSES, NORTHERLY WINDS
RETURN TUESDAY NIGHT THROUGH THE MIDDLE OF THE WEEK. ANOTHER WEAK
SYSTEM MAY APPROACH THE NORTHERN WATERS FROM THE WEST ON THURSDAY,
BUT LIKELY REMAINS NORTH AS IT MOVES TOWARD THE WASHINGTON COAST.
A MID-PERIOD WEST-NORTHWESTERLY SWELL OF 6 TO 8 FT AT 13-15
SECONDS WILL MOVE THROUGH THE COASTAL WATERS TODAY THROUGH TUE
NIGHT, INCREASING SIGNIFICANT WAVE HEIGHTS INTO THE 8 TO 10 FT
RANGE. SEAS THEN GRADUALLY SUBSIDE TO AROUND 4 TO 6 FT LATER IN
THE WEEK. /DH
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 5 PM PDT TUESDAY FOR PZZ210-251-271.
SMALL CRAFT ADVISORY FROM 5 AM TO 5 PM PDT TUESDAY FOR PZZ252-
272.
WWW.WEATHER.GOV/PORTLAND
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSPORTLAND
X.COM/NWSPORTLAND
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