293
FXUS66 KPQR 032118
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
118 PM PST TUE FEB 3 2026
SYNOPSIS
HIGH PRESSURE BUILDS OVER THE PACIFIC NORTHWEST
TODAY 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
PREDOMINATELY VFR CONDITIONS THROUGH THE REST OF THE
DAY. HIGH CLOUDS WILL SPREAD OVER THE REGION OVER THE NEXT FEW
HOURS, REMAINING THROUGH MOST OF THE TAF PERIOD BEFORE CLEARING
AFTER 18-21Z WED. FOG/LOW STRATUS FORMATION IS POSSIBLE (30-50%
CHANCE) AGAIN TONIGHT INTO WEDNESDAY MORNING ACROSS THE INLAND
VALLEYS, THOUGH THE INCOMING HIGH CLOUDS COULD INHIBIT
WIDESPREAD FORMATION. CONDITIONS COULD BEGIN TO DETERIORATE
LOCALLY TO MVFR/IFR BETWEEN 06-09Z WED WITH MORE WIDESPREAD
IFR/LIFR VIS BY 10-12Z WED. BEST CHANCES ARE IN THE CENTRAL AND
SOUTHERN WILLAMETTE VALLEY, SW WASHINGTON INLAND VALLEYS, AND
AROUND KHIO. CHANCES FOR FOG FORMATION ARE MUCH LOWER (10-15%)
AROUND KPDX DUE TO CONTINUED EAST WINDS FROM THE COLUMBIA RIVER
GORGE. ANY LOWERED CONDITIONS SHOULD IMPROVE TO VFR BY 18-21Z
WED.
WINDS WILL REMAIN EASTERLY THROUGH THE COLUMBIA RIVER GORGE,
STRONGER THAN YESTERDAY WITH GUSTS AROUND KTTD REACHING 25-30 KT,
UP TO 45 KTS JUST EAST OF KTTD. WITHIN THE WILLAMETTE VALLEY,
WINDS ABOVE 1000 FT AGL WILL BE SOUTHERLY WHILE AT THE SURFACE
WINDS WILL BE VARIABLE.
KPDX AND APPROACHES...VFR CONDITIONS THROUGH THE MAJORITY OF THE
TAF PERIOD WITH INCREASING HIGH CLOUD COVER AFTER 21Z TUE.
EASTERLY WINDS LESS THAN 10 KTS. AFTER 06-09Z WED, THERE'S A
10-15% CHANCE OF FOG REFORMATION. THE HIGH CLOUDS AND WINDS WILL
DETERMINE THE POTENTIAL FOR FOG. IF WINDS REMAIN EASTERLY THEN
THERE FOG LIKELY WON'T REFORM. HOWEVER, IF WINDS SHIFT NORTHERLY
OR BECOME VARIABLE, CHANCES INCREASE FOR FOG FORMATION. -03
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 FROM 9 PM THIS EVENING TO 4 PM PST FRIDAY
FOR PZZ251-252-271-272.
WWW.WEATHER.GOV/PORTLAND
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X.COM/NWSPORTLAND
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