202
FXUS66 KPQR 200522 AAA
AFDPQR
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PORTLAND OR
922 PM PST MON JAN 19 2026
UPDATED AVIATION DISCUSSION.
SYNOPSIS
HIGH PRESSURE AND DRY WEATHER CONTINUES THROUGH AT
LEAST THE MIDDLE OF THE WEEK WITH BREEZY EASTERLY WINDS THROUGH
THE COLUMBIA RIVER GORGE AND EASTERN PORTLAND/VANCOUVER METRO AS
WELL. AS LONG AS HIGH PRESSURE PREVAILS, CLEAR SKIES AND LIGHT
WINDS AWAY FROM THE COLUMBIA GORGE WILL RESULT IN FROST AND/OR
FREEZING FOG FORMATION ACROSS MOST INTERIOR LOWLAND VALLEYS.
NEAR/BELOW FREEZING TEMPERATURES IN COMBINATION WITH ANY FOG MAY
LEAD TO LOCALLY SLICK ROAD CONDITIONS. LOWER CONFIDENCE FOR
FOG/FROST FOR LOCATIONS THAT REMAIN WINDY AND/OR HAVE PERSISTENT
STRATUS. CHANCES FOR PRECIPITATION RETURN LATE WEEK BUT DETAILS
ON THE EXACT TIMING AND IMPACTS REMAIN NEBULOUS.
DISCUSSION...NOW THROUGH SUNDAY
SIMILAR TO THE LAST SEVERAL
DAYS A STRONG RIDGE OF HIGH PRESSURE REMAINS SITUATED OVER THE
WEST COAST LIKELY HOLDING IN PLACE INTO WEDNESDAY LEADING TO
DRY WEATHER AND MOSTLY CLEAR SKIES ACROSS NW OREGON AND SW
WASHINGTON. THE ONLY EXCEPTION IS THE CENTRAL/EASTERN COLUMBIA
RIVER GORGE AND HOOD RIVER VALLEY WHERE STRATUS HAS REMAINED
SOCKED IN FOR DAYS, AS WELL AS PORTIONS OF COWLITZ COUNTY AND THE
SOUTHERN WILLAMETTE VALLEY AROUND AND SOUTH OF EUGENE WHERE
DIURNAL LOW STRATUS AND FOG DEVELOP CONTINUES TO TAKE PLACE.
BREEZY EASTERLY WINDS ARE STILL IN PLACE THROUGH THE COLUMBIA
RIVER GORGE, SURROUNDING TERRAIN, AND EASTERN PORTLAND METRO
THIS AFTERNOON DUE TO A STRONG PRESSURE GRADIENT ACROSS THE
CASCADES DUE IN-PART TO OUR CURRENT WEATHER PATTERN. THE
PRESSURE GRADIENT FROM KPDX TO KDLS HAS PEAKED AROUND -9.5MB
THIS AFTERNOON LEADING TO OBSERVED WIND GUSTS OF 20-35 MPH
THROUGH THE PORTLAND METRO AREA, 30-45 MPH ACROSS THE EASTERN
PORTLAND METRO AREA AROUND AND EAST OF GRESHAM/TROUTDALE, AND
55-75 MPH AT THE KNOWN WINDY LOCATIONS EAST OF TROUTDALE,
INCLUDING CROWN POINT, AND CORBETT. GRADIENTS ARE EXPECTED TO
SLOWLY DECREASE TONIGHT BEFORE LARGELY LEVELING OFF THROUGH
WEDNESDAY. PEAK WIND GUSTS WILL RESPOND BE LOWERING AS WELL BUT
STILL REMAIN BREEZY/GUSTY, ESPECIALLY IN THE LATE AFTERNOON
THROUGH OVERNIGHT HOURS.
CLEAR SKIES AND LIGHT WINDS AWAY FROM THE WINDS FROM THE
COLUMBIA RIVER GORGE WILL LEAD TO EFFICIENT RADIATIONAL
COOLING ACROSS THE AREA EACH NIGHT THROUGH THE END OF THE WEEK,
DROPPING OVERNIGHT LOWS TO NEAR OR BELOW FREEZING ACROSS THE
WILLAMETTE VALLEY, SOUTHWEST WASHINGTON LOWLANDS, AND UPPER HOOD
RIVER VALLEY. HIGH CONFIDENCE IN FAVORABLE CONDITIONS FOR
WIDESPREAD FROST DEVELOPMENT, ESPECIALLY OVER GRASSES AND METAL
SURFACES. FREEZING FOG MAY ALSO DEVELOP IN SOME LOCATIONS,
PARTICULARLY ACROSS THE SOUTHERN WILLAMETTE VALLEY AND LOWER
ELEVATIONS OF COWLITZ COUNTY WHERE SURFACE CONDITIONS ARE MORE
MOIST AND PROTECTED FROM THE DRY AIR FILTERING THROUGH THE
CASCADE GAPS. ANY FREEZING FOG THAT DEVELOPS COULD LEAD TO
LOCALLY SLICK ROAD CONDITIONS. MEANWHILE, HIGHER ELEVATIONS
ABOVE 1500-2000 FT BUT BELOW 5000 FT WILL REMAIN MUCH WARMER
THAN THE LOWLAND VALLEYS DUE TO A STRONG SUBSIDENCE INVERSION.
ADDITIONALLY, STAGNANT AIR WILL BE A CONTINUED CONCERN UNDER
THIS SUBSIDENCE INVERSION AS THE WINDS DECREASE, LEADING TO AIR
QUALITY CONCERNS THROUGH AT LEAST MID-WEEK. MIXING HEIGHTS WILL
REMAIN LOW AND TRANSPORT WINDS WILL BE WEAK. THEREFORE, AN AIR
STAGNATION ADVISORY REMAINS IN EFFECT FOR MOST OF THE WILLAMETTE
VALLEY DUE TO THIS CONCERN THROUGH 4 PM WEDNESDAY. THE PORTLAND
METRO AREA FROM THE WEST HILLS EASTWARD WERE NOT INCLUDED IN
THIS ADVISORY DUE TO STRONGER WINDS FROM THE GORGE MAINTAINING A
MORE MIXED ATMOSPHERE.
LOOKING AHEAD, THE GEFS, ECMWF, GEPS AND THEIR RESPECTIVE
DETERMINISTIC MODELS CONTINUE TO INDICATE HIGH PRESSURE COULD
REMAIN IN PLACE OVER THE EASTERN PACIFIC AND PACIFIC NW ON
WEDNESDAY INTO THURSDAY AND POSSIBLY INTO THE WEEKEND. THE
MAJORITY OF ENSEMBLE MEMBERS INDICATE A TROUGH MOVING THROUGH
THE CENTRAL PACIFIC THAT WILL PINCH OFF INTO A CUTOFF LOW AND
MOVE TOWARDS CALIFORNIA, UNDERCUTTING THE RIDGE OF HIGH PRESSURE
INSTEAD OF BREAKING IT DOWN COMPLETELY, THUS LEAVING US IN A
DRIER REX BLOCK PATTERN. THERE REMAINS A 15-25% CHANCE OF
PRECIPITATION RETURNING LATE THURSDAY THROUGH FRIDAY, MAINLY
FOR THE COAST AND HIGHER TERRAIN FEATURES, WITH ONLY A 5-10%
CHANCE FOR PRECIPITATION ACROSS THE INLAND VALLEYS - ALL IN ALL
DRY WEATHER IS FAVORED TO PERSIST. THIS WEEKEND, THE LATEST
ENSEMBLE 500 MB CLUSTER ANALYSIS INDICATE ABOUT A 25% CHANCE OF
A SHORTWAVE PUSHING SOUTHWEST THROUGH THE GREAT BASIN AND INTO
THE PACNW AND A 30% CHANCE OF A WEAK WEATHER SYSTEM MOVING IN
FROM THE PACIFIC AND BREAKING DOWN THE RIDGE. BOTH SOLUTIONS
PRODUCE AN INCREASED CHANCE FOR PRECIPITATION SATURDAY INTO
SUNDAY. HOWEVER, THAT STILL LEAVES ~45% OF ENSEMBLE SOLUTIONS
CONTINUING AT LEAST WEAK RIDGING THROUGH THE WEEKEND WITH
MOSTLY DRY WEATHER. AT ANY RATE, RIDGING THAT CONTINUES
WEDNESDAY AND BEYOND WOULD BE WEAKER THAN EARLIER IN THE WEEK,
WHICH COULD LEAD TO A MODERATING OF DAYTIME TEMPERATURES AND A
POTENTIAL BREAKDOWN OF THE STRONG SUBSIDENCE INVERSION.
ADDITIONALLY, ABOUT 15% OF ENSEMBLE MEMBERS SUGGEST THAT
OVERNIGHT/EARLY MORNING TEMPERATURES WILL REMAIN COLD ENOUGH TO
RESULT IN WET, NON-IMPACTFUL SNOW OR RAIN/SNOW MIX FALLING DOWN
TO THE VALLEY FLOOR WHEN PRECIPITATION RETURNS. IF THIS OCCURS,
IMPACTS WOULD BE MINIMAL GIVEN AIR TEMPERATURES WILL BE
MARGINALLY FREEZING DUE TO ONSHORE FLOW AND ROADS WOULD BE TOO
WARM TO ACCUMULATE SNOW.
ONE LOCATION WE NEED TO KEEP A CLOSER EYE ON WHEN PRECIPITATION
EVENTUALLY RETURNS IS CENTRAL COLUMBIA RIVER GORGE AND UPPER
HOOD RIVER VALLEY. IF EASTERLY WINDS CONTINUE, THEN COLDER AIR
MAY LINGER LONGER FOR THESE AREAS. THIS COULD RESULT IN WINTERY
PRECIPITATION, ESPECIALLY IF THE INCOMING MOISTURE OVERLAPS AT
THE SAME TIME AS THE FREEZING AIR NEAR THE SURFACE. THESE AREAS
CAN REMAIN MUCH COLDER THAN OTHER INTERIOR VALLEYS LIKE THE
WILLAMETTE VALLEY AND SOUTHWEST WA LOWLANDS, AND MODEL GUIDANCE
IS GENERALLY TOO QUICK SCOURING OUT THE COLD AIR. SPECIFIC
DETAILS WILL BECOME MORE CLEAR AS WE GET CLOSER TO PRECIPITATION
RETURNING. -99/03
AVIATION
A PERSISTENT UPPER LEVEL RIDGE OVER THE REGION WILL
CONTINUE TO YIELD WIDESPREAD VFR CONDITIONS FOR MOST TERMINALS
THROUGH THE PERIOD. POCKETS OF IFR/LIFR CONDITIONS WITHIN LOW
STRATUS/FOG MAY REDEVELOP IN SHELTERED PORTIONS OF THE SOUTHERN
WILLAMETTE AND COWLITZ VALLEYS LATE THIS EVENING INTO TONIGHT, AS
WELL AS MVFR CIGS IN VALLEYS EAST OF THE CASCADE CREST INCLUDING
AT K4S2. AN OFFSHORE PRESSURE GRADIENT CONTINUES TO SUPPORT
EASTERLY WINDS AT PORTLAND-AREA AND COASTAL TERMINALS, AND LIGHT
NORTHERLY WINDS ALONG THE WILLAMETTE VALLEY. STRONGER EASTERLY
GUSTS OF 30-40 KT WILL CONTINUE AT KTTD INTO TONIGHT, WITH GUSTS
UP TO 45-60 KT EAST OF KTTD AT THE WESTERN END OF THE COLUMBIA
RIVER GORGE. WINDS WILL EASE FOR A TIME OVERNIGHT BUT GUSTS TO
20-25 KT WILL REMAIN POSSIBLE AT KTTD. LOCALLY STRONGER GUSTS TO
25 KT ARE ALSO POSSIBLE DOWNWIND OF GAPS IN THE COASTAL TERRAIN,
INCLUDING AT KONP. THE PRESSURE GRADIENT IS EXPECTED TO EASE
TONIGHT, REDUCING WINDS ACROSS THE REGION BEFORE INCREASING AGAIN
TUESDAY MORNING.
KPDX AND APPROACHES...VFR FLYING CONDITIONS EXPECTED THROUGH THE
PERIOD. DIURNAL EAST-SOUTHEAST WINDS AT 10-15 KT WILL EASE TO
AROUND 5 KT AFTER 8-10Z TUESDAY BEFORE INCREASING AGAIN BY 18-20Z.
-19/36
MARINE
STRONG RIDGING ALOFT CONTINUES TO FAVOR PERSISTENT
OFFSHORE EASTERLY FLOW THROUGH MIDWEEK. WHILE WINDS ARE LARGELY
AT 10 KT OR LESS, AREAS DOWNWIND OF GAPS IN THE COASTAL TERRAIN
MAY SEE STRONGER FLOW WITH GUSTS UP TO 15-20 KT, MAINLY WEST OF
THE MOUTH OF THE COLUMBIA RIVER. SEAS REMAIN BELOW 10 FT AT
10-13 SECONDS THROUGH THE MIDDLE OF THE WEEK. -03/36
PQR WATCHES/WARNINGS/ADVISORIES
OR...AIR STAGNATION ADVISORY UNTIL 4 PM PST WEDNESDAY FOR ORZ109-
114>118.
WA...NONE.
PZ...NONE.
WWW.WEATHER.GOV/PORTLAND
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSPORTLAND
X.COM/NWSPORTLAND
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