421
FXUS66 KPQR 171706
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
906 AM PST SAT JAN 17 2026
UPDATED AVIATION DISCUSSION AND WATCHES/WARNINGS/ADVISORIES.
SYNOPSIS
HIGH PRESSURE SITS ACROSS THE REGION INTO AT LEAST
THE MIDDLE OF NEXT WEEK WITH DRY WEATHER PREVAILING. GUSTY
EASTERLY WINDS CONTINUE THROUGH THE CASCADE AND COAST RANGE
GAPS, AND ALONG THE COLUMBIA RIVER GORGE INTO PORTIONS OF THE
PORTLAND METRO THIS WEEKEND AS WELL, STRONGEST TODAY. EXPECT
OVERNIGHT/MORNING LOW STRATUS AND FOG TO REMAIN LIMITED TO
VALLEY AREAS MORE PROTECTED FROM EAST WINDS LIKE THE SOUTHERN
WILLAMETTE VALLEY THIS MORNING BEFORE COVERAGE GRADUALLY
INCREASES DAY TO DAY GOING FORWARD DUE TO A DECREASE IN OFFSHORE
WINDS. OVERNIGHT LOWS NEAR/BELOW FREEZING IN COMBINATION WITH
ANY FOG MAY LEAD TO LOCALLY SLICK ROAD CONDITIONS - SOMETHING TO
KEEP IN MIND.
UPDATE
AS OF 0900 AM PST, AREAS OF DENSE FOG IN THE SOUTHERN
WILLAMETTE VALLEY HAVE BEGUN TO ERODE AS WINDS AND INSOLATION
INCREASE THIS MORNING. WHILE THE MOST SHELTERED VALLEYS,
INCLUDING ALONG I-5 IN THE CRESWELL/COTTAGE GROVE AREA, MAY
CONTINUE TO SEE RESTRICTED VISIBILITY IN THE COMING FEW HOURS,
THE DENSE FOG ADVISORY HAS BEEN CANCELLED AS THE MAJORITY OF THE
REGION HAS SEEN VISIBILITIES RISE ABOVE 1/4 MILE. -36
DISCUSSION...SATURDAY MORNING THROUGH FRIDAY
SATELLITE
IMAGERY EARLY AROUND 2 AM PST SATURDAY MORNING INDICATES MOSTLY
CLEAR SKIES OVER NW OREGON AND SW WASHINGTON EXCEPT FOR POCKETS
OF FOG AND LOW STRATUS IN THE LANE COUNTY LOWLANDS, SW
WASHINGTON LOWLANDS (I-5 CORRIDOR), AND THE UPPER HOOD RIVER
VALLEY. NOT EXPECTING MUCH MORE OF AN EXPANSION OF FOG/STRATUS
OVER THE MORNING HOURS AS CURRENT DEW POINT DEPRESSIONS ACROSS
MUCH OF THE WILLAMETTE VALLEY ARE TOO WIDE DUE TO DRYING
NORTHERLY WINDS. STRONG HIGH PRESSURE CONTINUES OVER THE REGION
THROUGH AT LEAST TUESDAY, PROMOTING A STRONG SUBSIDENCE
INVERSION AND RADIATIONAL COOLING IN THE LOWLANDS. DAYTIME
TEMPERATURE FORECASTS REMAIN ABOVE NORMAL FOR JANUARY, PEAKING
IN THE UPPER 40S TO LOW 50S ACROSS THE WILLAMETTE VALLEY AND
UPPER 50S TO 60S ALONG THE COAST AND WESTERN FOOTHILLS OF THE
COAST RANGE AND CASCADES. ADDITIONALLY, MORNING LOW TEMPERATURES
WILL BE NEAR OR BELOW FREEZING ACROSS LOW LYING AREAS THAT ARE
AWAY FROM EASTERLY WINDS FROM THE GORGE, LEADING TO THE
PROMOTION OF WIDESPREAD FROST IN THESE AREAS. HOWEVER,
ELEVATIONS AROUND ~1000-5000 FT WILL SEE MUCH WARMER THAN NORMAL
LOW TEMPERATURES DUE TO THE STRONG SUBSIDENCE INVERSION.
THE MAIN HAZARD OF CONCERNS REMAINS THE EAST WINDS THROUGH THE
WESTERN COLUMBIA RIVER GORGE. A THERMALLY INDUCED TROUGH AT THE
SURFACE REMAINS SITUATED JUST OVER THE OREGON AND WASHINGTON
COAST, LEADING TO A STRONG SURFACE PRESSURE GRADIENT OVER THE
CASCADES. CURRENT OBSERVATIONS SHOW A -9 TO -10 MB PRESSURE
GRADIENT BETWEEN KPDX AND KDLS, WHICH IS EXPECTED TO CONTINUE
THROUGH MUCH OF TODAY. THIS IS RESULTING IN PEAK WIND GUSTS
UP TO 40-55 MPH INTO THE TROUTDALE AREA, 25-45 MPH IN THE
EASTERN PORTLAND METRO, AND 55-70 MPH FOR OUR CLIMATOLOGICALLY
WINDIEST SPOTS LIKE CORBETT, CROWN POINT, THREE CORNER ROCK,
ETC. A WIND ADVISORY REMAINS IN EFFECT THROUGH THIS AFTERNOON
FOR THE EASTERN PORTLAND METRO AREA. BREEZIER EAST WINDS WITH
PEAK GUSTS UP TO 35-45 MPH ARE ALSO EXPECTED THROUGH SOME COAST
RANGE GAPS AND PEAKS OF THE COAST RANGE AND CASCADES. MOST
ENSEMBLE GUIDANCE INDICATES THE PRESSURE GRADIENT BEGINS TO
SLOWLY WEAKEN TONIGHT INTO SUNDAY AS THE RIDGE WEAKENS SLIGHTLY
CAUSING THE THERMAL TROUGH NEAR THE SURFACE TO ALSO WEAKEN.
BREEZY WINDS ARE STILL EXPECTED INTO SUNDAY AND EARLY NEXT WEEK,
JUST NOT AS STRONG AS YESTERDAY AND TODAY. ELEVATED EAST WINDS
ARE LIKELY TO CONTINUE IN THE GORGE INTO AT LEAST WEDNESDAY,
BUT NOT EXPECTING MUCH MORE THAN PEAK GUSTS UP TO 25-30 MPH
MAKING IT FARTHER WEST THAN THE TROUTDALE AREA BEYOND SUNDAY.
AS THE THERMAL TROUGH WEAKENS AND STRONG EASTERLY WINDS DIMINISH
OUTSIDE OF THE GORGE, FOG CHANCES INCREASE EACH NIGHT AND
MORNING, BECOMING MORE WIDESPREAD ACROSS THE INTERIOR LOWLANDS.
OVERNIGHT LOWS NEAR OR BELOW FREEZING IN COMBINATION WITH ANY
FOG MAY LEAD TO LOCALLY SLICK ROAD CONDITIONS. ADDITIONALLY,
STAGNANT AIR IS INCREASINGLY A CONCERN UNDER THIS SUBSIDENCE
INVERSION AS THE WINDS DECREASE, LEADING TO AIR QUALITY CONCERNS
TODAY INTO AT LEAST TUESDAY. AN AIR STAGNATION ADVISORY IS IN
EFFECT FOR MOST OF THE WILLAMETTE VALLEY DUE TO THIS CONCERN.
BEYOND TUESDAY, ENSEMBLE GUIDANCE INDICATES THE STRONG HIGH
PRESSURE WILL BEGIN BREAKING DOWN WITH ~75% OF THE GFS, EURO,
AND CANADIAN ENSEMBLE MEMBERS INDICATING LOWERING 500MB HEIGHTS
OVER OREGON AND WASHINGTON ON WEDNESDAY. HOWEVER, THE MAGNITUDE
OF LOWERING HEIGHTS IS NOT AS STRONG AS PREVIOUS GUIDANCE, AND
THE PRECIPITATION CHANCES HAVE BEEN MAINLY ELIMINATED ON
WEDNESDAY. THE MAIN IMPACT FROM THE BREAKDOWN OF THE HIGH
PRESSURE IS THE SUBSIDENCE INVERSION BEGINNING TO BREAK DOWN
ALONG WITH TEMPERATURES BEGINNING A RETURN TO NEAR NORMAL FOR
JANUARY. BY THURSDAY, NEARLY ALL ENSEMBLE MEMBERS ARE ON BOARD
WITH THE BREAKDOWN OF THE HIGH PRESSURE, THOUGH NOT WITH THE
RETURN OF PRECIPITATION. THERE'S AROUND A 15-30% CHANCE OF
PRECIPITATION RETURNING SOMETIME THURSDAY, MAINLY OVER THE COAST
AND TERRAIN. PRECIPITATION CHANCES INCREASE FRIDAY TO 20-40%
CHANCE FOR THE INTERIOR LOWLANDS AND 30-55% FOR THE COAST AND
TERRAIN. ONE THING TO NOTE IS OVERNIGHT TEMPERATURES WILL
REMAIN ON THE COLD SIDE ACROSS MOST OF THE AREA, AND A COLDER
AIRMASS WILL REMAIN IN PLACE NEAR THE SURFACE AROUND HOOD RIVER
VALLEY AND SURROUNDING AREAS. THIS ALONG THE LINGERING EASTERLY
FLOW THROUGH THE CASCADE GAPS COULD LEAD TO A PERIOD OF WINTRY
PRECIPITATION AS PRECIPITATION BEGINS FOR LOWER ELEVATIONS,
MAINLY IN THE COLUMBIA RIVER GORGE, HOOD RIVER VALLEY, AND
SURROUNDING LOCATIONS. SPECIFIC DETAILS WILL BECOME MORE CLEAR
AS WE GET CLOSER TO PRECIPITATION RETURNING. -03
AVIATION
A PERSISTENT UPPER LEVEL RIDGE OVER THE REGION WILL
CONTINUE TO YIELD WIDESPREAD VFR CONDITIONS FOR MOST TERMINALS
THROUGH THE PERIOD. FOG OR LOW STRATUS WILL CONTINUE IN SHELTERED
PORTIONS OF THE COWLITZ AND SOUTHERN WILLAMETTE VALLEYS THROUGH
20-21Z SAT, ALTHOUGH MAJOR TERMINALS INCLUDING KEUG HAVE ALREADY
CLEARED OUT THIS MORNING. ONGOING OFFSHORE FLOW WILL MAINTAIN
EAST WINDS IN THE PORTLAND AREA AS WELL AS ALONG THE COAST, WITH
NORTHERLY FLOW EXPECTED THROUGH THE WILLAMETTE VALLEY. THE
GUSTIEST EAST WINDS WILL BE CONSTRAINED TO THE WESTERN COLUMBIA
RIVER GORGE INCLUDING NEAR KTTD WHERE GUSTS OF 35-45 KT ARE LIKELY
TO CONTINUE THROUGH THE PERIOD, UP TO 50-55 KTS EAST OF KTTD. GAP
FLOWS THROUGH THE COAST RANGE WILL ALSO YIELD AREAS OF GUSTY EAST
WINDS AT FAVORED LOCATIONS ALONG THE COAST, INCLUDING NEAR KONP.
WHERE SURFACE WINDS ARE SHELTERED FROM STRONGER EASTERLIES TO THE
WEST OF THE COLUMBIA RIVER GORGE, LOW-LEVEL WIND SHEAR OF 35-40
KT IN THE LOWEST 2 KFT WILL CONTINUE.
KPDX AND APPROACHES...VFR FLYING CONDITIONS WITH LARGELY CLEAR
SKIES THROUGH THE PERIOD. EAST-SOUTHEAST WINDS WILL INCREASE TO
10-15 KT WITH GUSTS UP TO 25 KT BY 20-21Z SAT, THEN EASING AGAIN
TO AROUND 10 KT OR LESS AFTER 00-03Z SUN. -36
MARINE
STRONG UPPER LEVEL HIGH PRESSURE CONTINUES INTO THE
WEEKEND WITH A THERMALLY-INDUCED SURFACE TROUGH ALONG THE COAST
FAVORING PERSISTENT EASTERLY OFFSHORE FLOW. WHILE WINDS ARE
LARGELY AT 10 KT OR LESS, AREAS DOWNWIND OF GAPS IN THE COASTAL
TERRAIN MAY SEE STRONGER FLOW WITH GUSTS AS HIGH AS 20-25 KT.
THE MOST WIDESPREAD AREA OF THESE STRONGER GUSTS CONTINUES WEST
OF THE MOUTH OF THE COLUMBIA RIVER, BETWEEN CAPE FOULWEATHER AND
CAPE FALCON BEYOND 10 NM, WHERE A SMALL CRAFT ADVISORY HAS BEEN
EXTENDED THROUGH 10 AM THIS MORNING. EAST WINDS OTHERWISE
PERSIST THROUGH THE WEEKEND, GENERALLY LESS THAN 15-20 KT. SEAS
REMAIN BELOW 10 FT AROUND 10-13 SECONDS THROUGH EARLY NEXT WEEK.
-03/36
PQR WATCHES/WARNINGS/ADVISORIES
OR...AIR STAGNATION ADVISORY FROM 7 PM THIS EVENING TO 10 AM PST
TUESDAY FOR ORZ109-114>118.
WIND ADVISORY UNTIL 3 PM PST THIS AFTERNOON FOR ORZ112.
WA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 10 AM PST THIS MORNING FOR PZZ271.
WWW.WEATHER.GOV/PORTLAND
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSPORTLAND
X.COM/NWSPORTLAND
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