827
FXUS66 KPQR 222302 AAA
AFDPQR
AREA FORECAST DISCUSSION...UPDATE
NATIONAL WEATHER SERVICE PORTLAND OR
402 PM PDT THU OCT 22 2026
UPDATED AVIATION DISCUSSION.
SYNOPSIS
DRY WEATHER IS EXPECTED THROUGH MUCH OF SATURDAY,
BEFORE RAIN CHANCES INCREASE THROUGH THE LATTER HALF OF THE
WEEKEND. PERSISTENT SEASONABLE TEMPERATURES THROUGH THE PERIOD.
DISCUSSION...NOW THROUGH THURSDAY
A WEAK UPPER SHORTWAVE
PASSING OVERHEAD THIS AFTERNOON WILL REINFORCE ONSHORE FLOW,
ALLOWING FOR CONTINUED SEASONABLE TEMPERATURES THROUGH THE
COMING DAYS, BUT IS UNLIKELY TO PRODUCE RAINFALL. MEANWHILE, A
CUTOFF LOW OVER CALIFORNIA IS TRANSPORTING MOISTURE NORTHWARD
ON ITS EASTERN FLANK TOWARD EASTERN/CENTRAL OREGON, WHICH MAY
PRODUCE LIGHT RAIN SHOWERS THROUGH THIS EVENING IN THE NORTH AND
CENTRAL OREGON CASCADES. MUCH OF THE PRECIPITATION EVIDENT ON
AREA RADAR IS EVAPORATING BEFORE IT REACHES THE SURFACE, WITH
THE MAJORITY OF OBSERVED RAINFALL EAST OF THE CASCADE CREST
MEASURING 0.1 INCHES OR LESS. IF ANY RAIN DOES REACH THE GROUND
WEST OF THE CREST, IT WILL LIKELY ALSO ONLY MANAGE TO ADD UP TO
A FEW HUNDREDTHS OF AN INCH. AS SKIES CLEAR WEST OF THE CASCADES
TONIGHT, EFFICIENT RADIATIVE COOLING WILL ALLOW TEMPERATURES TO
FALL INTO THE LOW TO MID 30S AWAY FROM THE COAST AND FROM URBAN
AREAS, YIELDING WIDESPREAD CHANCES FOR FROST AND, WITHIN THE
SOUTHERN WILLAMETTE VALLEY AND SHELTERED COAST RANGE VALLEYS,
LOCAL AREA WHERE A FREEZE IS EXPECTED. FREEZE WARNINGS HAVE
THEREFORE BEEN ISSUED FROM 11 PM PDT THIS EVENING UNTIL 9 AM PDT
FRIDAY FOR PORTIONS OF LANE, BENTON, AND LINN COUNTIES WITHIN
THE WILLAMETTE VALLEY AS WELL AS INTERIOR VALLEYS OF THE
NORTHERN COAST RANGE INCLUDING NEAR VERNONIA AND GRAND RONDE.
FROST ADVISORIES ALSO REMAIN IN EFFECT FOR THE SAME TIMES
ELSEWHERE IN THE COAST RANGE, CENTRAL WILLAMETTE VALLEY, AND
INTERIOR SOUTH WASHINGTON LOWLANDS. THOSE WITH AGRICULTURAL
INTERESTS OR SENSITIVE OUTDOOR PLANTS SHOULD TAKE ACTION TO
PREVENT DAMAGE.
THERE IS THEN HIGH CONFIDENCE THAT DRY WEATHER RETURNS TONIGHT
THROUGH MUCH OF SATURDAY AS TRANSIENT UPPER RIDGING TRAVERSES
THE REGION. AS THE RIDGE AXIS SHIFTS INLAND ON FRIDAY NIGHT,
LIGHT OFFSHORE FLOW, PEAKING OVERNIGHT IN THE CASCADES AND COAST
RANGE, WILL SEE DAYTIME TEMPERATURES WARM SLIGHTLY ON SATURDAY,
BUT WILL GENERALLY REMAIN NEAR SEASONAL NORMS WITH AFTERNOON
HIGH TEMPERATURES IN THE 50S ON THE COAST AND IN TERRAIN, AND IN
THE LOW TO MID 60S WITHIN INLAND VALLEYS. OVERNIGHT TEMPERATURES
WILL AGAIN FALL INTO THE LOW TO MID 30S FOR MANY AWAY FROM THE
COAST ON FRIDAY NIGHT, WITH FREEZE WATCHES AND FROST ADVISORIES
REMAINING IN EFFECT; FREEZE WATCHES MAY BE UPGRADED TO FREEZE
WARNINGS IF CONFIDENCE INCREASES IN TEMPERATURES FALLING TO NEAR
OR BELOW FREEZING.
THERE REMAINS GOOD CONSENSUS AMONG LONG-RANGE ENSEMBLES THAT
ANOTHER CUTOFF LOW WILL DEVELOP OVER THE GULF OF ALASKA ON
SATURDAY AND TRACK TO THE SOUTHEAST OFFSHORE OF VANCOUVER
ISLAND. BY SUNDAY, THERE IS LESS AGREEMENT ON HOW THE LOW WILL
EVOLVE AS IT NEARS THE PACIFIC NORTHWEST. FOR NOW, THERE ARE
MODEST CHANCES, NEAR 50%, FOR RAIN ON SUNDAY ACROSS THE REGION,
DECREASING THROUGH THE FIRST HALF OF NEXT WEEK AS TROUGHING MAY
LINGER OVERHEAD. COOL AIR ALOFT WILL ALSO LIKELY CONTINUE TO
SUPPORT SEASONABLE TEMPERATURES FOR LATE OCTOBER. -36
AVIATION...THROUGH 00Z FRIDAY
A WEAK SOUTHWEST-NORTHEAST
ORIENTED COLD FRONT WAS DRAPED OVER THE WILLAMETTE VALLEY AS OF
23Z THURSDAY. BEHIND THE FRONT, COASTAL TERMINALS HAVE IMPROVED TO
VFR AS EXPECTED AS CLOUDS SCATTER OUT. INLAND TAF SITES ARE
OBSERVING INCREASING MID-LEVEL CLOUDS WITH THE PASSING FRONT,
HOWEVER CEILINGS HAVE REMAINED PREDOMINATELY VFR. EXPECT THIS
TREND TO CONTINUE THE REST OF TODAY AND INTO TONIGHT, WITH
WIDESPREAD VFR FLIGHT CONDITIONS EXPECTED.
THIS FRONT HAS ALSO RESULTED IN GUSTY NORTH TO NORTHWEST WINDS AT
KAST AND KONP WITH GUSTS UP TO 20-25 KT. WINDS FOR INLAND TAF
SITES ARE GENERALLY TOPPING OUT BETWEEN 6-15 KT, HOWEVER A FEW
BRIEF GUSTS AS HIGH AS 20 KT ARE POSSIBLE WITH THE FRONTAL
PASSAGE. WINDS WILL DECREASE THIS EVENING BEHIND THE FRONT, BUT IT
APPEARS WINDS WILL REMAIN JUST STRONG ENOUGH MOST OF TONIGHT TO
PREVENT FOG DEVELOPMENT. CHANCES FOR SURFACE VISIBILITIES AT ALL
TAF SITES REMAIN LESS THAN 10% TONIGHT THROUGH TOMORROW MORNING.
KPDX AND APPROACHES...A COLD FRONT WAS MOVING OVER THE TERMINAL AS
OF 23Z THURSDAY, BRINGING A SLIGHT UPTICK IN NORTHWEST WINDS TO
10-15 KT. WINDS WILL GRADUALLY DECREASE THIS EVENING INTO TONIGHT,
EVENTUALLY BECOMING LIGHT AND VARIABLE BY 08-10Z FRIDAY. VFR
CEILINGS ARE EXPECTED TO CONTINUE THROUGHOUT THE TAF PERIOD. -23
MARINE
BUOY OBSERVATIONS FROM 2 PM PDT THURSDAY SHOWED
NORTHERLY WINDS INCREASING BEHIND A COLD FRONTAL PASSAGE, WITH
SUSTAINED WINDS BETWEEN 15 AND 25 KT AND GUSTS UP TO 30 KT. SEAS
WERE BEGINNING TO GRADUALLY INCREASE AS A NORTHWEST SWELL
CONTINUES TO BUILD OVER THE WATERS. SEAS ARE EXPECTED TO CONTINUE
BUILDING THIS EVENING, BECOMING STEEP AND HAZARDOUS SHORTLY AFTER
SUNSET. SEAS WILL THEN REMAIN STEEP AND HAZARDOUS THROUGH EARLY
FRIDAY MORNING WITH SIGNIFICANT WAVE HEIGHTS RANGING BETWEEN 8 AND
12 FT AND WAVE PERIODS BETWEEN 8 AND 10 SECONDS. SMALL CRAFT
ADVISORIES REMAIN IN PLACE FOR ALL MARINE ZONES UNTIL 8 PM PDT
THURSDAY, BEFORE RAMPING UP TO A HAZARDOUS SEAS WARNING LASTING
FROM 8 AM PDT THURSDAY UNTIL 8 AM PDT FRIDAY FOR ALL MARINE
ZONES, EXCEPT THE MAIN CHANNEL OF THE COLUMBIA RIVER BAR WHERE A
SMALL CRAFT ADVISORY IS IN EFFECT NOW THROUGH 8 AM PDT FRIDAY.
SEAS WILL BE RELATIVELY LESS STEEP OVER THE COLUMBIA RIVER BAR
WITH SIGNIFICANT WAVE HEIGHTS OF 7 TO 9 FT AT 8 TO 10 SECONDS, BUT
WILL STILL BE HAZARDOUS TO SMALL CRAFT, ESPECIALLY DURING EBB
CURRENTS. IT IS ALSO WORTH NOTING THAT BRIEF AND ISOLATED WIND
GUSTS AS HIGH AS 35 KT ARE POSSIBLE THROUGH 10 PM PDT THURSDAY
OVER THE COLUMBIA RIVER BAR, BUT WIND GUSTS OF THIS MAGNITUDE ARE
NOT EXPECTED TO BE FREQUENT ENOUGH TO JUSTIFY THE ISSUANCE OF A
GALE WARNING.
NORTH WINDS WEAKEN LATE FRIDAY MORNING INTO THE AFTERNOON WITH A
CONTINUED NORTHWEST SWELL AND SEAS BECOMING LESS STEEP. NORTH
WINDS WILL THEN PERSIST THROUGH AT LEAST SATURDAY AFTERNOON AS AN
APPROACHING LOW STALLS WEST OF THE COASTAL WATERS. THERE IS STILL
UNCERTAINTY ON THE EXACT STRENGTH AND TRACK OF THIS LOW HEADING
INTO SATURDAY NIGHT AND SUNDAY. DESPITE THIS UNCERTAINTY, CONFIDENCE
IS HIGH WIND SPEEDS WILL STAY BELOW GALE-FORCE, AS PROBABILITIES
FOR WIND GUSTS OF 34 KT OR STRONGER ARE NOW LESS THAN 10% THIS
WEEKEND. PROBABILITIES FOR SEAS OVER 10 FT REACH 10-20% SUNDAY
MORNING AND AFTERNOON. -23
PQR WATCHES/WARNINGS/ADVISORIES
OR...FROST ADVISORY FROM 11 PM FRIDAY TO 9 AM PDT SATURDAY FOR
ORZ101>103-105-107>109-111>113-119-123.
FREEZE WARNING FROM 11 PM THIS EVENING TO 9 AM PDT FRIDAY FOR
ORZ104-116>118.
FREEZE WATCH FROM FRIDAY EVENING THROUGH SATURDAY MORNING FOR
ORZ104-106-114>118-124-125.
FROST ADVISORY FROM 11 PM THIS EVENING TO 9 AM PDT FRIDAY FOR
ORZ105>107-109-114-115-124-125.
WA...FROST ADVISORY FROM 11 PM FRIDAY TO 9 AM PDT SATURDAY FOR
WAZ203>208.
FROST ADVISORY FROM 11 PM THIS EVENING TO 9 AM PDT FRIDAY FOR
WAZ203>205-208.
PZ...SMALL CRAFT ADVISORY UNTIL 8 AM PDT FRIDAY FOR PZZ210.
SMALL CRAFT ADVISORY UNTIL 8 PM PDT THIS EVENING FOR PZZ251>253-
271>273.
HAZARDOUS SEAS WARNING FROM 8 PM THIS EVENING TO 8 AM PDT FRIDAY
FOR PZZ251>253-271>273.
WWW.WEATHER.GOV/PORTLAND
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