684
FXUS66 KPQR 041205
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
405 AM PST WED FEB 4 2026
SYNOPSIS
HIGH PRESSURE IS FIRMLY ESTABLISHED OVER THE PACIFIC NORTHWEST
EARLY THIS MORNING AND WILL REMAIN THE DOMINANT WEATHER FEATURE
THROUGH THE END OF THE WORK WEEK. THIS PATTERN WILL SUPPORT DRY
CONDITIONS, LIMITED CLOUD COVER OUTSIDE OF VALLEY FOG AND
LOW STRATUS, AND UNSEASONABLY MILD TEMPERATURES. LIGHT WINDS
AND STRONG LOW-LEVEL INVERSIONS WILL PROMOTE AREAS OF FOG, FROST
AND AIR STAGNATION IN SHELTERED LOWLAND VALLEYS. IN CONTRAST,
STRENGTHENING EASTERLY FLOW THROUGH THE COLUMBIA RIVER GORGE
WILL LEAD TO WINDY CONDITIONS IN THE EASTERN PORTLAND/VANCOUVER
METRO AND ADJACENT TERRAIN THROUGH THURSDAY.
SHORT TERM
THIS MORNING OBSERVATIONS INDICATE INCREASING
LOW-LEVEL MOISTURE TRAPPED BENEATH THE INVERSION, LEADING TO FOG
AND LOW STRATUS BEGINNING TO DEVELOP AT CORVALLIS AND EUGENE.
EXPECT CONTINUED FOG DEVELOPMENT THIS MORNING, BECOMING
PREVALENT ACROSS PORTIONS OF THE WILLAMETTE VALLEY WHERE HIGH
LEVEL CLOUDS HAVE CLEARED. THESE CONDITIONS ARE FAVORED IN
AREAS REMOVED FROM TERRAIN-DRIVEN FLOW, WHERE WINDS REMAIN
LIGHT AND RADIATIONAL COOLING IS EFFICIENT. FOG AND STRATUS ARE
EXPECTED TO GRADUALLY ERODE LATER THIS MORNING, THOUGH SOME
LOCATIONS MAY SEE SLOW IMPROVEMENT DUE TO THE STRENGTH OF THE
INVERSION.
A STRONG UPPER-LEVEL RIDGE CENTERED OVER THE REGION WILL
MAINTAIN DRY WEATHER THROUGH FRIDAY. SUBSIDENCE ASSOCIATED WITH
THIS RIDGE WILL REINFORCE THE INVERSION, LIMITING VERTICAL
MIXING AND ALLOWING LOW CLOUDS TO REDEVELOP EACH NIGHT. ABOVE
THE INVERSION, CONDITIONS WILL REMAIN MOSTLY CLEAR, PARTICULARLY
TODAY AND THURSDAY, AS ANY MID-TO-HIGH LEVEL CLOUDINESS REMAINS
CONFINED WELL NORTH OF THE FORECAST AREA.
THE PRESSURE GRADIENT BETWEEN THE INTERIOR COLUMBIA BASIN AND
WESTERN OREGON WILL CONTINUE TO TIGHTEN TODAY, RESULTING IN
INCREASING EASTERLY WINDS THROUGH THE COLUMBIA RIVER GORGE AND
INTO THE EASTERN PORTLAND/VANCOUVER METRO AREA. MODEL GUIDANCE
INDICATES THE STRONGEST GRADIENTS DEVELOPING LATE TONIGHT INTO
EARLY THURSDAY, WITH TROUTDALE TO THE DALLES VALUES REACHING -7
TO -8 MB AND LOCALLY STRONGER IN SOME ENSEMBLE SOLUTIONS. THESE
GRADIENTS SUPPORT A 40-60% PERCENT PROBABILITY OF WIND GUSTS
APPROACHING 45 MPH IN THE EASTERN METRO AREA, WITH HIGH
PROBABILITIES OF GUSTS NEAR OR ABOVE 50 TO 55 MPH ALONG EXPOSED
RIDGELINE SUCH AS CROWN POINT AND THREE CORNER ROCK. WHILE
THESE PROBABILITIES STILL SUGGEST UNCERTAINTY, INCREASING
PRESSURE GRADIENT AND WINDS ALOFT, TUESDAY EVENINGS WIND GUSTS
AROUND 40 MPH AT TROUTDALE, AND THE POTENTIAL FOR NORTHEASTERLY
DOWNSLOPING WINDS IMPROVES CONFIDENCE FOR IMPACTFUL WINDS. AS A
RESULT, A WIND ADVISORY HAS BEEN ISSUED FOR WINDS 25 TO 35 MPH
WITH GUSTS UP TO 40 TO 45 MPH FROM 10 PM THIS EVENING TO 1 PM
THURSDAY FOR THE EAST PORTLAND METRO. STRONGEST WIND GUSTS WILL
BE LOCATED FROM TROUTDALE EAST, WITH THE HIGHEST WINDS OCCURRING
AFTER 3 AM THURSDAY. WINDS ARE EXPECTED TO EASE THURSDAY
EVENING INTO FRIDAY AS GRADIENTS RELAX.
AWAY FROM THE INFLUENCE OF EASTERLY WINDS, STAGNANT CONDITIONS
WILL PERSIST. LIGHT SURFACE FLOW COMBINED WITH SHALLOW MIXING
HEIGHTS WILL CONTINUE TO LIMIT DISPERSION, INCREASING THE
POTENTIAL FOR DETERIORATED AIR QUALITY. AN AIR STAGNATION
ADVISORY REMAINS IN EFFECT THROUGH FRIDAY AFTERNOON FOR THE
SOUTHERN AND EAST CENTRAL WILLAMETTE VALLEY, CASCADE FOOTHILLS,
NORTH CLARK COUNTY LOWLANDS, AND THE LOWER COLUMBIA AND COWLITZ
RIVER VALLEYS. THE PORTLAND/VANCOUVER METRO AREA AND WEST-
CENTRAL WILLAMETTE VALLEY REMAIN EXCLUDED DUE TO BETTER MIXING
FROM EASTERLY AND NORTHERLY FLOW.
CLEAR NIGHTS AND CALM WINDS WILL ALSO MAINTAIN A FAVORABLE
ENVIRONMENT FOR FROST DEVELOPMENT IN COLDER VALLEYS,
PARTICULARLY THURSDAY AND FRIDAY MORNING. THE FROST GREATEST
POTENTIAL CONTINUES TO BE IN THE UPPER HOOD RIVER VALLEY, WITH
MORE LOCALIZED AND PATCHY FROST POSSIBLE ACROSS PORTIONS OF THE
CENTRAL AND SOUTHERN WILLAMETTE VALLEY.
INTO THE WEEKEND, ENSEMBLE GUIDANCE CONTINUES TO FAVOR A
TRANSITION TOWARD COOLER AND WETTER CONDITIONS AS AN UPPER-LEVEL
TROUGH APPROACHES AND THE RIDGE SHIFTS EAST. WHILE CONFIDENCE IS
HIGH IN A PATTERN CHANGE, UNCERTAINTY REMAINS REGARDING THE
TIMING AND COVERAGE OF PRECIPITATION. CURRENT ENSEMBLE SOLUTIONS
RANGE FROM LIMITED PRECIPITATION NEAR THE COAST SATURDAY TO MORE
WIDESPREAD RAINFALL BY SUNDAY. SNOW LEVELS ARE EXPECTED TO LOWER
INTO THE 3000 TO 4000 FOOT RANGE AS COOLER AIR ARRIVES ON MONDAY,
SUPPORTING RENEWED SNOWFALL IN THE CASCADES.
~12
AVIATION
VFR FLYING CONDITIONS CONTINUE ACROSS THE REGION AS
HIGH PRESSURE BUILDS OVER MUCH OF THE WEST. FOR ALL TERMINALS
EXCEPT KEUG, KSLE, AND KHIO, EXPECT VFR CONDITIONS THROUGH AT
LEAST 06Z THURSDAY. AS FOR THE AFOREMENTIONED TERMINALS,
DETERIORATED CONDITIONS WILL PERSIST UNTIL 18-20Z WEDNESDAY,
THEN IMPROVE BACK TO VFR. SPECIFICALLY, KEUG WILL EXPERIENCE
LIFR FOG, KSLE MAY EXPERIENCE MVFR VIS, AND KHIO MAY EXPERIENCE
LIFR CIGS. THERE IS LESS CERTAINTY FOR KSLE AND KHIO DUE TO
LOW AGREEMENT BETWEEN PROBABILISTIC AND DETERMINISTIC GUIDANCE.
LATER IN THE TAF PERIOD AROUND 06-09Z THURSDAY, MOST TERMINALS
MAY SEE LIFR FOG DEVELOPMENT, WITH THE EXCEPTION OF TERMINALS
AFFECTED BY THE COLUMBIA RIVER GORGE OUTFLOW (KPDX, KTTD).
OTHERWISE, EXPECT EASTERLY FLOW AT TERMINALS ALONG THE COLUMBIA
RIVER AND A VARIABLE TO NORTHERLY IN THE CENTRAL AND SOUTHERN
WILLAMETTE VALLEY. WINDS WILL GENERALLY BE 5-10 KT, WITH KTTD
BEING THE EXCEPTION WITH 20-25 KT WINDS AND GUSTS UP TO 30-35
KT.
KPDX AND APPROACHES...VFR CONDITIONS THROUGH THE TAF PERIOD.
EASTERLY TO SOUTHEASTERLY WINDS AROUND 5-10 KT. WINDS FROM THE
GORGE WILL KEEP THE TERMINAL CLEAR OF FOG. WITH INCREASING WINDS
IN THE GORGE NEAR THE END OF THE TAF PERIOD, COULD SEE GUSTS UP
TO 20 KT AROUND 12Z THURSDAY.
~12
MARINE
VARIABLE WINDS WITH GUSTS UP TO 15 KT WILL BE THE TREND THROUGH
FRIDAY. A LONG-PERIOD WESTERLY SWELL HAS PUSHED INTO THE WATERS
TODAY, INCREASING SEAS TO AROUND 9 TO 11 FEET AT AROUND 12 TO
15 SECONDS. SEAS WILL REMAIN ELEVATED ABOVE 10 FEET THROUGH THE
END OF THE WEEK. A SMALL CRAFT ADVISORY WILL REMAIN IN EFFECT
FROM NOW UNTIL 4 PM PST FRIDAY FOR ALL THE WATERS. INTO THE
WEEKEND, SMALL CRAFT WINDS LIKELY WITH A 40-60% CHANCE OF GALE
FORCE WINDS. ~12/03
BEACH HAZARDS
A LONG-PERIOD WESTERLY SWELL HAS PUSHED INTO THE WATERS TODAY,
CAUSING A HIGH THREAT FOR SNEAKER WAVES. A BEACH HAZARDS
STATEMENT IS IN EFFECT UNTIL 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. ~12
PQR WATCHES/WARNINGS/ADVISORIES
OR...AIR STAGNATION ADVISORY UNTIL 4 PM PST FRIDAY FOR ORZ108-
115>118-123>125.
WIND ADVISORY FROM 10 PM THIS EVENING TO 1 PM PST THURSDAY FOR
ORZ112.
WA...AIR STAGNATION ADVISORY UNTIL 4 PM PST FRIDAY FOR WAZ204-205.
PZ...SMALL CRAFT ADVISORY UNTIL 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
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSPORTLAND
X.COM/NWSPORTLAND
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page