113
FXUS66 KPQR 040525
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
925 PM PST TUE FEB 3 2026
UPDATED AVIATION DISCUSSION AND WATCHES/WARNINGS/ADVISORIES.
SYNOPSIS
HIGH PRESSURE BUILDS OVER THE PACIFIC NORTHWEST
AND PERSISTS THROUGH FRIDAY, RETURNING DRY AND MOSTLY SUNNY
WEATHER. LIGHT WINDS AND LIMITED AIR MOVEMENT WILL RESULT IN AIR
STAGNATION FOR PARTS OF THE WILLAMETTE VALLEY AND SOUTHWEST WA
LOWLANDS. EACH NIGHT THROUGH FRIDAY MORNING, CLEAR SKIES AND
CALM WINDS WILL RESULT IN POTENTIAL FROST OR FOG DEVELOPMENT. AN
EXCEPTION WOULD BE THE COLUMBIA RIVER GORGE AND EASTERN
PORTLAND/VANCOUVER METRO, WHERE EASTERLY WINDS WILL INCREASE
WITH GUSTS PEAKING WEDNESDAY NIGHT INTO THURSDAY.
DISCUSSION...TODAY THROUGH MONDAY
AN UPPER LEVEL RIDGE IS
BUILDING OVER THE PACIFIC NORTHWEST TODAY WHICH WILL PERSIST
THROUGH THE END OF THE WORK WEEK AND BRING DRY WEATHER THROUGH
FRIDAY. SATELLITE IMAGERY AS OF EARLY TUESDAY AFTERNOON DEPICTS
PATCHY AREAS OF LINGERING FOG AND LOW STRATUS ACROSS THE
WILLAMETTE VALLEY AND SOUTHWEST WASHINGTON LOWLANDS. FOG AND LOW
STRATUS WILL GRADUALLY DISSIPATE THROUGHOUT THE AFTERNOON AS
DAYTIME HEATING PROGRESSES. OTHERWISE, EXPECT MOSTLY SUNNY SKIES
ELSEWHERE. THERE WILL BE SOME LINGERING MID TO HIGH LEVEL
CLOUDS TODAY AS A SYSTEM IN THE NORTHEAST PACIFIC RIDES THE
NORTHWEST PERIPHERY OF THE RIDGE AND TREKS INTO WESTERN BRITISH
COLUMBIA, BUT SUNNIER DAYS ARE EXPECTED ON WEDNESDAY AND
THURSDAY. AFTERNOON HIGH TEMPERATURES ARE FORECAST TO PEAK IN
THE UPPER 50S TO LOW 60S FOR MOST INTERIOR LOWLAND VALLEYS THIS
WEEK, BUT SOME LOCATIONS AROUND 1000-2000 FEET ELEVATION MAY
EVEN REACH THE MID TO UPPER 60S DUE TO A STRENGTHENING INVERSION
FROM THE UPPER RIDGE. THESE TEMPERATURES ARE AROUND 10-15
DEGREES ABOVE NORMAL FOR THIS TIME OF YEAR.
WINDS THROUGHOUT THE DURATION OF THE UPPER LEVEL RIDGE WILL
GENERALLY BE LIGHT ACROSS MOST OF THE FORECAST AREA, EXCEPT IN
AND NEAR THE COLUMBIA RIVER GORGE AND EASTERN PORTLAND/VANCOUVER
METRO AREA. STRENGTHENING EAST-WEST PRESSURE GRADIENTS BETWEEN
TROUTDALE (KTTD) AND THE DALLES (KDLS) WILL LEAD TO BREEZY
EASTERLY GAP WINDS THROUGH THE GORGE, PARTICULARLY ON WEDNESDAY
AND THURSDAY. DETERMINISTIC AND ENSEMBLE GUIDANCE SUGGESTS WINDS
WILL PEAK SOMETIME WEDNESDAY NIGHT INTO THURSDAY MORNING.
GUIDANCE SHOWS PRESSURE GRADIENTS BETWEEN KTTD AND THE KDLS
AROUND -5 TO -6 MB ON WEDNESDAY AND INCREASING OVERNIGHT TO
AROUND -7 TO -8 MB BY THURSDAY MORNING. A FEW ECMWF ENSEMBLE
MEMBERS EVEN INDICATE GRADIENTS AS STRONG AS -9 MB THURSDAY
MORNING. BASED ON HIGH RESOLUTION GUIDANCE (REFS) AND NBM 5.0,
THERE IS A 30-50% CHANCE FOR PEAK WIND GUSTS UP TO 45 MPH ACROSS
THE EASTERN PORTLAND/VANCOUVER METRO, WITH A 50-70% CHANCE FOR
GUSTS UP TO 50 MPH FOR EXPOSED RIDGETOPS LIKE CROWN POINT OR
THREE CORNER ROCK. THERE ARE TIMES WHERE MODELS TEND OF
UNDERESTIMATE HOW TIGHT THE PRESSURE GRADIENT WILL BE, SO NBM
90TH WAS BLENDED INTO THE FORECAST TO INCREASE THESE EASTERLY
WINDS. WE'LL CONTINUE TO MONITOR THESE PRESSURE GRADIENTS
CLOSELY AND SEE IF A WIND ADVISORY IS WARRANTED. EITHER WAY,
CONDITIONS WILL BE BREEZY SO MAKE SURE TO SECURE ANY LOOSE
OUTDOOR ITEMS IF YOU'RE IN A EAST WIND-PRONE LOCATION. WINDS
APPEAR TO DECREASE ON FRIDAY AS PRESSURE GRADIENTS EASE.
FOR LOCATIONS AWAY FROM THE INFLUENCE OF EASTERLY WINDS, THERE
ARE TWO MAIN CONCERNS: FOG/FROST POTENTIAL AND AIR STAGNATION.
FIRST, CLEAR SKIES AND CALM WINDS WILL MAINTAIN A FAVORABLE SET-
UP FOR FOG AND FROST FORMATION ACROSS INTERIOR LOWLAND VALLEYS.
THE HIGHEST THREAT FOR FROST WILL BE THURSDAY AND FRIDAY
MORNINGS, WHERE CHANCES FOR TEMPERATURES FALLING BELOW 36
DEGREES ARE AROUND 40-60% FOR THE CENTRAL/SOUTHERN WILLAMETTE
VALLEY, 20-40% FOR THE NORTHERN WILLAMETTE VALLEY AND SOUTHWEST
WA LOWLANDS (EXCLUDING THE PORTLAND METRO), AND GREATER THAN 80%
FOR THE UPPER HOOD RIVER VALLEY. FROST WOULD MOST LIKELY BE
SEEN OVER GRASSES AND METAL SURFACES.
WHEN IT COMES TO AIR STAGNATION, LIGHT WINDS AND LIMITED AIR
MOVEMENT DUE TO THE INVERSION FROM THE RIDGE WILL LEAD TO A
PERIOD OF STAGNANT AIR CONDITIONS, WHICH MAY LEAD TO
DETERIORATING AIR QUALITY. THE AIR STAGNATION ADVISORY HAS BEEN
REMAINS IN EFFECT THROUGH 4 PM FRIDAY ACROSS THE SOUTHERN
WILLAMETTE VALLEY, EAST CENTRAL WILLAMETTE VALLEY, NORTH AND
CENTRAL OREGON CASCADE FOOTHILLS, NORTH CLARK COUNTY LOWLANDS,
AND THE LOWER COLUMBIA RIVER/COWLITZ RIVER VALLEYS. BASED ON
SOUNDINGS AND MODEL GUIDANCE, MIXING HEIGHTS IN THESE LOCATIONS
ARE FORECAST BELOW 2000 FEET WITH TRANSPORT WINDS AROUND 5 KT OR
LESS. THE PORTLAND/VANCOUVER METRO AREA AND WEST-CENTRAL
WILLAMETTE VALLEY REMAINS EXCLUDED FROM THE ADVISORY AS THESE
AREAS WILL REMAIN BETTER MIXED FROM THE INCREASING EASTERLY
WINDS THIS WEEK (THESE WINDS TURN MORE NORTHERLY AS IT GETS INTO
WEST-CENTRAL VALLEY).
A PATTERN CHANGE RETURNS THIS WEEKEND AS THE MAJORITY OF
ENSEMBLE MEMBERS SHOW AN UPPER LEVEL TROUGH APPROACHING THE
PACIFIC NORTHWEST AND SHIFTING THE UPPER RIDGE EASTWARD. THERE
IS HIGH CONFIDENCE THAT WE'LL TURN COOLER AND WETTER, HOWEVER,
THERE IS STILL UNCERTAINTY WITH THE EXACT TIMING OF WHEN
PRECIPITATION WILL ARRIVE AND EXACTLY HOW MUCH WE'LL GET. ON
SATURDAY, 55% OF MEMBERS SHOW PRECIPITATION JUST CLIPPING THE
FAR NORTHWEST OREGON AND SOUTHWEST WASHINGTON COAST, WHILE 35%
OF MEMBERS SHOW A SOAKER ACROSS MUCH OF THE AREA, AND 15% OF
MEMBERS SHOW CONDITIONS REMAINING COMPLETELY DRY. BY SUNDAY, THE
MAJORITY OF ENSEMBLE MEMBERS RETURN WIDESPREAD PRECIPITATION TO
THE AREA. COOLER TEMPERATURES WILL ALSO BRING SNOW LEVELS DOWN
TO 3000-4000 FEET, WHICH WOULD RETURN SOME MUCH NEEDED SNOW TO
THE CASCADES. -10
AVIATION
VFR FLYING CONDITIONS CONTINUE ACROSS THE REGION AS
HIGH PRESSURE BUILDS OVER MUCH OF THE WEST. BKN HIGH-LEVEL CLOUDS
AND LARGELY CALM WINDS WILL AGAIN ALLOW FOR AREAS OF VALLEY FOG
TO DEVELOP INLAND OVERNIGHT. THE HIGHEST CONFIDENCE IN LIFR VIS
WITHIN FOG REMAINS ACROSS THE SOUTHERN WILLAMETTE VALLEY (KEUG,
KCVO), WITH LESSER BUT STILL MODERATE CONFIDENCE (40-60% CHANCE
OF IFR VIS) THROUGHOUT THE REST OF THE WILLAMETTE VALLEY (KSLE
NORTH TO KHIO). IN THE PORTLAND AREA, EAST WINDS WILL LESSEN THE
CHANCES FOR FOG, BUT THERE IS A 10-15% CHANCE FOR LIGHT NORTH
WINDS AT KPDX OVERNIGHT, WHICH WOULD FAVOR MORE WIDESPREAD FOG.
ANY VIS RESTRICTIONS WILL IMPROVE BY 19-20Z WED AS FOG MIXES OUT
AND CONDITIONS RETURN TO VFR BENEATH LARGELY CLEAR SKIES. ALONG
THE COAST, VFR CONDITIONS ARE EXPECTED TO PERSIST THROUGH TONIGHT.
KPDX AND APPROACHES...VFR FLYING CONDITIONS ARE EXPECTED TO
CONTINUE THROUGH WEDNESDAY MORNING BENEATH BKN HIGH CLOUDS AT 20
KFT. EAST WINDS AROUND 5 KT AT KPDX AND NEAR 20 KT WITH GUSTS NEAR
30 KT AT KTTD WILL LIMIT CHANCES FOR FOG TO ONLY 10-15% AND NEAR
0%, RESPECTIVELY. IF EASTERLY WINDS BECOME LIGHT AND VARIABLE OR
SHIFT NORTHERLY AT KPDX, VIS RESTRICTIONS IN FOG WILL BECOME MORE
LIKELY. OTHERWISE, SKIES CLEAR AFTER 18-19Z WED. -36
MARINE
VARIABLE WINDS WITH GUSTS UP TO 15 KT WILL BE THE
TREND THROUGH FRIDAY. WAVE HEIGHTS THIS MORNING ARE AROUND 7-9
FT AT 10-12 SECONDS, AND WILL REMAIN HERE THROUGH THIS EVENING.
AN INCREASING WESTERLY SWELL WILL PUSH INTO THE WATERS LATE
TONIGHT, INCREASING SEAS AGAIN TO AROUND 10-12 FEET AROUND 12-16
SECONDS. SEAS WILL REMAIN ELEVATED ABOVE 10 FEET THROUGH THE
END OF THE WEEK. A SMALL CRAFT ADVISORY HAS BEEN ISSUED
BEGINNING AT 9 PM PST TONIGHT FOR ZONES PZZ251, 252, 271, AND
272 AND AT 4 AM PST FOR ZONES PZZ253, 273, AND 210. THE SMALL
CRAFT ADVISORY EXTENDS THROUGH 4 PM PST FRIDAY. -03
BEACH HAZARDS
A MODERATE THREAT FOR SNEAKER WAVES CONTINUES
TODAY BEFORE ANOTHER LONG-PERIOD WESTERLY SWELL PUSHES INTO THE
WATERS TONIGHT THROUGH WEDNESDAY NIGHT, CAUSING ANOTHER HIGH
THREAT FOR SNEAKER WAVES. A BEACH HAZARDS STATEMENT HAS BEEN
ISSUED FOR 4 AM PST WEDNESDAY THROUGH 1 AM PST THURSDAY FOR THE
COASTS OF NORTHERN/CENTRAL OREGON AND SOUTHERN WASHINGTON. WAVES
WILL BE ABLE TO RUN SIGNIFICANTLY FARTHER UP ON A BEACH THAN
NORMAL, INCLUDING OVER ROCKS AND JETTIES. SNEAKER WAVES CAN
SUDDENLY KNOCK PEOPLE OFF OF THEIR FEET AND QUICKLY PULL THEM
INTO THE FRIGID OCEAN WHICH MAY LEAD TO SERIOUS INJURY OR
DROWNING. CAUTION SHOULD BE USED WHEN IN OR NEAR THE WATER,
ESPECIALLY THOSE WHO WILL BE RAZOR CLAMMING THIS WEEK. -03
PQR WATCHES/WARNINGS/ADVISORIES
OR...AIR STAGNATION ADVISORY UNTIL 4 PM PST FRIDAY FOR ORZ108-
115>118-123>125.
WA...AIR STAGNATION ADVISORY UNTIL 4 PM PST FRIDAY FOR WAZ204-205.
PZ...SMALL CRAFT ADVISORY FROM 4 AM WEDNESDAY TO 4 PM PST FRIDAY
FOR PZZ210-253-273.
SMALL CRAFT ADVISORY UNTIL 4 PM PST FRIDAY FOR PZZ251-252-271-
272.
WWW.WEATHER.GOV/PORTLAND
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