378
FXUS66 KPQR 222200
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
300 PM PDT THU OCT 22 2026
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 18Z FRIDAY
A WEAK SOUTHWEST-NORTHEAST
ORIENTED COLD FRONT WAS APPROACHING THE NORTH COAST AS OF 17Z
THURSDAY, BRINGING MVFR CEILINGS TO KAST. EXPECT CONDITIONS TO
IMPROVE BACK TO VFR BEHIND THE FRONT LATER THIS AFTERNOON. THIS
FRONT WILL EVENTUALLY REACH THE CENTRAL OREGON COAST AROUND 20-21Z
THURSDAY, BRINGING A 50-60% CHANCE FOR MVFR CEILINGS BELOW 3000
FEET AT KONP FOR A 2-3 HOUR PERIOD OF TIME BEFORE CONDITIONS
LIKELY IMPROVE BACK TO VFR. THIS FRONT WILL ALSO BRING GUSTY NORTH
TO NORTHWEST WINDS TO KAST AND KONP WITH GUSTS UP TO 20-25 KT.
WINDS WILL DECREASE THIS EVENING BEHIND THE FRONT.
PREDOMINATELY VFR FLIGHT CONDITIONS ARE EXPECTED FOR INLAND TAF
SITES THROUGH THIS EVENING WITH SCATTERED TO BROKEN HIGH CLOUDS
ABOVE 15-20 KFT. NORTHWEST WINDS WILL DEVELOP THIS AFTERNOON FOR
INLAND TAF SITES, BUT SHOULD GENERALLY STAY UNDER 10 KT THE VAST
MAJORITY OF THE TIME. HEADING INTO TONIGHT, CLEARING SKIES AND
DECREASING WINDS WILL SUPPORT AT LEAST SOME PATCHY FOG DEVELOPMENT
WITHIN THE WILLAMETTE VALLEY, PARTICULARLY FROM KSLE TO KEUG.
THAT SAID, SURFACE VISIBILITIES SHOULD STAY ABOVE 6 SM AT BOTH TAF
SITES THE MAJORITY OF THE TAF PERIOD, IF NOT THE ENTIRE TAF
PERIOD. PROBABILITIES FOR VISIBILITIES BELOW 1 SM ARE LESS THAN
5-10%. THEREFORE, HAVE DECIDED NOT TO INCLUDE VISIBILITY
RESTRICTIONS IN THE TAFS, BUT WILL ACKNOWLEDGE THERE IS A NON-ZERO
CHANCE FOR BRIEF VISIBILITY REDUCTIONS TOWARDS 12Z FRIDAY.
KPDX AND APPROACHES...HIGH PRESSURE OVER THE REGION WILL LEAD TO
LIGHT NORTHWEST WINDS AROUND 5-10 KT AND VFR CONDITIONS. WINDS
BECOME LIGHT AND VARIABLE LESS THAN 5 KT TONIGHT. -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.
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