919
FXUS66 KPQR 180609 AAA
AFDPQR
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PORTLAND OR
1009 PM PST SAT JAN 17 2026
UPDATED AVIATION DISCUSSION.
SYNOPSIS
DRY WEATHER PREVAILS AS HIGH PRESSURE CONTINUES
THROUGH THE MIDDLE OF THE NEXT WEEK. BREEZY EASTERLY WINDS
CONTINUE THROUGH THE COLUMBIA RIVER GORGE AND EASTERN
PORTLAND/VANCOUVER METRO THROUGH THE REMAINDER OF THE WEEKEND.
TONIGHT AND FOR THE NEXT SEVERAL NIGHTS, CLEAR SKIES AND LIGHT
WINDS WILL RESULT IN FROST 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.
DISCUSSION...NOW THROUGH FRIDAY NIGHT
SUNNY SKIES PREVAIL
ACROSS THE MAJORITY OF NORTHWEST OREGON AND SOUTHWEST WASHINGTON
AS STRONG HIGH PRESSURE SITS OVER THE PACIFIC NORTHWEST. AN
EXCEPTION WOULD BE THE CENTRAL COLUMBIA RIVER GORGE AND UPPER
HOOD RIVER VALLEY, WHERE LOW STRATUS HAS BEEN PERSISTENT WITH
LITTLE TO NO CLEARING. EASTERLY WINDS THROUGH THE GORGE AND
EASTERN PORTLAND METRO CONTINUES WITH GUSTS UP TO 35-40 MPH.
WILL LET THE WIND ADVISORY DROP OFF AT 3 PM TODAY AS PRESSURE
GRADIENTS GRADUALLY WEAKEN THIS EVENING. KTTD-KDLS PRESSURE
GRADIENTS AROUND -9 TO
-10 MB THIS AFTERNOON ARE FORECAST TO FALL TO AROUND -6 TO -7 MB
TONIGHT. EASTERLY WINDS WILL REMAIN BREEZY THROUGH THE
REMAINDER OF THE WEEKEND, HOWEVER IT DOES NOT APPEAR THAT WE'LL
HAVE FREQUENT WIND GUSTS OF 45+ MPH ACROSS THE MAJORITY OF THE
EASTERN PORTLAND METRO TO WARRANT A CONTINUATION OF THE WIND
ADVISORY. BASED ON HIGH RESOLUTION GUIDANCE, CHANCES FOR WIND
GUSTS 45 MPH OR GREATER FALL BELOW 5% THIS AFTERNOON IN THIS
AREA, BUT CAN'T RULE OUT SOME BRIEF, ISOLATED GUSTS OF 45-50 MPH
CLOSER TO THE MOUTH OF THE GORGE. FOR HIGHER TERRAIN
SURROUNDING THE GORGE AND EXPOSED RIDGETOPS LIKE CROWN POINT OR
THREE CORNER ROCK, WIND GUSTS UP TO 50-60 MPH CONTINUE THROUGH
THIS EVENING.
TONIGHT, CLEAR SKIES AND LIGHT WINDS WILL LEAD TO EFFICIENT
RADIATIONAL COOLING ACROSS THE AREA, DROPPING OVERNIGHT LOWS TO
NEAR OR BELOW FREEZING ACROSS THE WILLAMETTE VALLEY AND
SOUTHWEST WA LOWLANDS. HIGH CONFIDENCE THAT THIS WOULD FAVOR
WIDESPREAD FROST DEVELOPMENT AND/OR FREEZING FOG, ESPECIALLY
OVER GRASSES AND METAL SURFACES. FREEZING FOG COULD LEAD TO
LOCALLY SLICK ROAD CONDITIONS. MEANWHILE, THERE IS MODERATE
CONFIDENCE FOR FROST DEVELOPMENT IN THE UPPER HOOD RIVER VALLEY
DUE TO TODAY'S PERSISTENT CLOUD COVER. IF CLOUDS CONTINUE
OVERNIGHT, IT MAY BE MORE DIFFICULT FOR FROST TO DEVELOP.
TEMPERATURES RIGHT NOW ARE ALREADY IN THE MID TO UPPER 30S
ACROSS THE UPPER HOOD RIVER VALLEY, SO IF ANY CLEARING OCCURS,
IT WON'T TAKE LONGER FOR TEMPERATURES TO FALL BELOW FREEZING AND
LEAD TO FROST. WIDESPREAD FROST REMAINS IN THE FORECAST FOR THE
NEXT SEVERAL NIGHTS THROUGH THURSDAY MORNING AS CLEAR SKIES AND
LIGHT WINDS PROMOTE LOW TEMPS IN THE LOW TO MID 30S FOR MANY
INTERIOR LOWLAND VALLEYS. MEANWHILE, HIGHER ELEVATIONS ABOVE
1500-2000 FT BUT BELOW 5000 FT REMAIN MUCH WARMER THAN THE
LOWLAND VALLEYS DUE TO A STRONG SUBSIDENCE INVERSION.
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 20-40% CHANCE OF
PRECIPITATION RETURNING SOMETIME THURSDAY, MAINLY OVER THE COAST
AND TERRAIN. PRECIPITATION CHANCES INCREASE FRIDAY TO 40-60%
CHANCE FOR THE INTERIOR LOWLANDS AND 60-70% FOR THE COAST AND
TERRAIN. ONSHORE FLOW APPEARS TO RETURN ON FRIDAY AS WELL,
BRINGING MORE MILD AIR. HOWEVER, IF EASTERLY WINDS CONTINUE
THROUGH THE COLUMBIA RIVER GORGE, COLD AIR MAY LINGER LONGER
ACROSS THE CENTRAL GORGE AND UPPER HOOD RIVER VALLEY. THIS WOULD
RESULT IN WINTERY PRECIPITATION FOR THESE AREAS, ESPECIALLY IF
THE INCOMING MOISTURE OVERLAPS THE SAME TIME AS THE FREEZING
AIR. SPECIFIC DETAILS WILL BECOME MORE CLEAR AS WE GET CLOSER
TO PRECIPITATION RETURNING. -10/03
AVIATION
A PERSISTENT UPPER LEVEL RIDGE OVER THE REGION WILL
CONTINUE TO YIELD WIDESPREAD VFR CONDITIONS FOR MOST TERMINALS
THROUGH THE PERIOD. GUIDANCE IS VARIED ON WHETHER FOG/LOW STRATUS
DEVELOPS AGAIN THROUGH PORTIONS OF THE WILLAMETTE VALLEY AND THE
LOWER COWLITZ. GIVEN SIMILAR CONDITIONS TO LAST NIGHT, KEUG WILL
HAVE THE BEST SHOT AT SEEING SUB-VFR CONDITIONS. HAVE ADDED A
PERIOD OF MVFR VIS FOR THE TERMINAL TONIGHT BUT CANT RULE OUT
LOWER VIS REDUCTIONS COMPLETELY BASED ON GUIDANCE. OFFSHORE
PRESSURE GRADIENT REMAINS IN PLACE BUT IS SLOWLY BEGINNING TO
WEAKEN BUT GUSTS AROUND 25-30 KT ARE EXPECTED AT KTTD THROUGH THE
NIGHT.
KPDX AND APPROACHES...VFR FLYING CONDITIONS WITH LARGELY CLEAR
SKIES EXPECTED. EAST TO SOUTHEAST WINDS AROUND 10 KTS EXPECTED.
-19
MARINE
STRONG RIDGING ALOFT CONTINUES THROUGH THE WEEKEND
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 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, HOWEVER EASING GUSTS HAVE RESULTED THE
CANCELLATION OF THE SMALL CRAFT ADVISORY EARLY THIS AFTERNOON.
WHILE OFFSHORE PRESSURE GRADIENTS WILL WEAKEN SLIGHTLY AND THESE
STRONGEST EAST WINDS WILL CONTINUE TO EASE THROUGH TONIGHT,
LIGHTER OFFSHORE FLOW WILL OTHERWISE PERSIST INTO EARLY NEXT
WEEK, GENERALLY AT 10 KT OR LESS. SEAS REMAIN BELOW 10 FT AROUND
10-13 SECONDS THROUGH THE MIDDLE OF NEXT WEEK. -03/36
PQR WATCHES/WARNINGS/ADVISORIES
OR...AIR STAGNATION ADVISORY UNTIL 10 AM PST TUESDAY 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
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page