434
FXUS66 KPQR 031320 AAA
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
517 AM PST TUE FEB 3 2026
SYNOPSIS
HIGH PRESSURE CONTINUES TO BUILD OVER THE PACIFIC NORTHWEST TODAY,
ESTABLISHING A DRY AND MILD PATTERN THAT IS EXPECTED TO PERSIST
THROUGH AT LEAST FRIDAY. CLEAR SKIES, LIGHT WINDS, AND PERSISTENT
LOW-LEVEL INVERSIONS WILL SUPPORT AREAS OF FOG AND FROST ACROSS
INTERIOR LOWLAND VALLEYS THROUGH MUCH OF THE WEEK. IN ADDITION,
STAGNANT AIR CONDITIONS MAY DEVELOP IN SOME INTERIOR VALLEYS. BREEZY
EASTERLY WINDS THROUGH THE COLUMBIA RIVER GORGE WILL HELP LIMIT AIR
STAGNATION IMPACTS ACROSS THE PORTLAND AND VANCOUVER METRO AREA AND
PORTIONS OF THE WEST-CENTRAL WILLAMETTE VALLEY.
DISCUSSION...NOW THROUGH SUNDAY
UPPER-LEVEL RIDGING BECOMES
FIRMLY ESTABLISHED OVER THE REGION TODAY, MARKING THE START OF AN
EXTENDED PERIOD OF DRY WEATHER AND ABOVE-NORMAL TEMPERATURES.
MID TO HIGH-LEVEL CLOUD COVER MAY LINGER THROUGH PORTIONS OF THE DAY
AS A PACIFIC SYSTEM TRACKS WELL NORTH INTO BRITISH COLUMBIA ALONG
THE NORTHERN PERIPHERY OF THE RIDGE. HOWEVER, CLOUDS ARE EXPECTED TO
GRADUALLY THIN AND CLEAR, WITH SUNNIER CONDITIONS BECOMING MORE
WIDESPREAD WEDNESDAY AND THURSDAY. AFTERNOON HIGH TEMPERATURES
THROUGH THE END OF THE WORK WEEK ARE FORECAST TO REACH THE UPPER 50S
TO LOWER 60S, ROUGHLY 10 DEGREES ABOVE CLIMATOLOGICAL AVERAGE FOR
EARLY FEBRUARY. WEDNESDAY LOOKING TO BE THE WARMEST DAY OF THE WORK
WEEK BY A DEGREE OR TWO.
DESPITE THE MILD DAYTIME TEMPERATURES, CLEAR NIGHTS AND LIGHT WINDS
WILL PROMOTE STRONG NOCTURNAL INVERSIONS ACROSS INTERIOR VALLEYS.
THESE INVERSIONS WILL FAVOR THE DEVELOPMENT OF FOG AND LOW STRATUS
DURING THE OVERNIGHT AND MORNING HOURS, PARTICULARLY WITHIN THE
WILLAMETTE VALLEY AND OTHER SHELTERED LOWLAND LOCATIONS. THERE
REMAINS SOME UNCERTAINTY REGARDING THE LOW-LEVEL MOISTURE, AS MODEL
SOUNDINGS INDICATE EASTERLY TO EAST-SOUTHEASTERLY FLOW AROUND 1000
TO 2000 FEET ABOVE GROUND LEVEL MAY INHIBIT STRATUS FORMATION IN
SOME AREAS WHILE SURFACE WINDS REMAIN CALM. THIS SCENARIO WOULD
RESULT IN A FAVORED FOG PATTERN RATHER THAN STRATUS, ESPECIALLY IN
LOCATIONS REMOVED FROM THE INFLUENCE OF THE COLUMBIA RIVER GORGE
OUTFLOW. PATCHY FROST WILL ALSO BE POSSIBLE DURING THE OVERNIGHT AND
EARLY MORNING HOURS WHERE SKIES REMAIN CLEAR AND WINDS DECOUPLE.
WINDS DURING THE RIDGING PERIOD WILL GENERALLY BE LIGHT ACROSS MOST
OF THE FORECAST AREA, THOUGH NOTABLE EXCEPTIONS ARE EXPECTED IN AND
NEAR THE COLUMBIA RIVER GORGE. STRENGTHENING EAST-WEST PRESSURE
GRADIENTS WILL LEAD TO BREEZY EASTERLY GAP WINDS, PARTICULARLY ON
WEDNESDAY AND THURSDAY. DETERMINISTIC AND ENSEMBLE GUIDANCE SUGGESTS
PRESSURE GRADIENTS BETWEEN TROUTDALE AND THE DALLES WILL RANGE FROM
APPROXIMATELY -5 TO -6 MB ON WEDNESDAY AND INCREASING OVERNIGHT TO
AROUND -7 TO -8 MB BY THURSDAY MORNING. FEW MEMBERS INDICATE
GRADIENTS AS STRONG AS -9 MB DURING THURSDAY MORNING. PROBABILITIES
FOR WIND GUSTS EXCEEDING 35 MPH ARE AROUND 15 TO 25 PERCENT IN THE
FAR EASTERN PORTLAND AND VANCOUVER METRO AREA ON WEDNESDAY AND 25 TO
35 PERCENT ON THURSDAY. ADDITIONALLY, THERE IS A 70 TO 90 PERCENT
CHANCE FOR GUSTS TO EXCEED 35 MPH WITHIN THE WESTERN GORGE AND
ADJACENT TERRAIN. EXPOSED RIDGETOPS SUCH AS CROWN POINT AND THREE
CORNER ROCK HAVE A 30 TO 50% CHANCE OF EXPERIENCING GUSTS EXCEEDING
50 MPH.
AWAY FROM THE GORGE, PERSISTENT RIDGING, LIGHT WINDS, AND LOW MIXING
HEIGHTS WILL CONTRIBUTE TO STAGNANT AIR CONDITIONS. AN AIR
STAGNATION ADVISORY REMAINS IN EFFECT FROM EARLY TUESDAY MORNING
THROUGH FRIDAY AFTERNOON FOR THE SOUTHERN WILLAMETTE VALLEY, EAST-
CENTRAL WILLAMETTE VALLEY, NORTH AND CENTRAL OREGON CASCADE
FOOTHILLS, NORTH CLARK COUNTY LOWLANDS, AND THE LOWER COLUMBIA AND
COWLITZ RIVER VALLEYS. THE PORTLAND AND VANCOUVER METRO AREA AND THE
WEST-CENTRAL WILLAMETTE VALLEY WERE EXCLUDED FROM THE ADVISORY DUE
TO BETTER LOW-LEVEL MIXING ASSOCIATED WITH EASTERLY GORGE WINDS,
WHICH GRADUALLY VEER MORE NORTHERLY FARTHER SOUTH INTO THE WEST-
CENTRAL VALLEY. IN ADDITION TO AIR QUALITY CONCERN, THE STAGNANT
PATTERN WILL CONTINUE TO SUPPORT FOG AND FROST POTENTIAL ACROSS
INTERIOR VALLEYS THROUGHOUT THE WEEK, WITH FRONT POTENTIAL MOST
NOTABLE ON THURSDAY AND FRIDAY.
ATTENTION THEN TURNS TO THE WEEKEND, WHEN CONFIDENCE DECREASES
REGARDING THE TIMING OF THE NEXT PRECIPITATION EVENT. ENSEMBLE
GUIDANCE INDICATES A RETURN TO WETTER CONDITIONS IS LIKELY, THOUGH
TIMING VARIES. APPROXIMATELY 75 PERCENT OF ENSEMBLE MEMBERS BRING
PRECIPITATION BACK INTO THE REGION BY SATURDAY AFTERNOON, WHILE
OTHERS DELAY THE ONSET UNTIL SUNDAY MORNING. MOST ENSEMBLE GUIDANCE
ALSO SUGGEST A TRANSITION TOWARD COOLER TEMPERATURES THROUGH THE
WEEKEND AND INTO NEXT WEEK. WHILE DETAILS REMAIN UNCERTAIN, THE
OVERALL PATTERN SUGGESTS A COOLER AND WETTER REGIME DEVELOPING LATE
THIS WEEKEND INTO EARLY NEXT WEEK. ~12
AVIATION
SATELLITE SHOWS A FEW HIGH CLOUDS OVER THE REGION BUT
CONDITIONS REMAIN VFR. HIGH PRESSURE IS BEGINNING TO DEVELOP OVER
THE REGION WHICH IS LEADING TO STABLE CONDITIONS. THE CLEAR SKIES
AND HIGH THIN CLOUDS FROM EARLIER IN THE EVENING HAVE ALLOWED FOR
RADIATIONAL COOLING AND THUS FOG HAS BEGUN TO FORM. FOG IS DENSEST
AROUND KHIO, KKLS, AND WITHIN PORTIONS OF THE WILLAMETTE VALLEY.
HOWEVER, AREAS OF ELEVATED WINDS HAVE REMAINED FOG FREE. SCATTERED
LIFR STRATUS IS PRESENT THOUGH IN AREAS WITHOUT FOG IN THE
WILLAMETTE VALLEY. EASTERLY OFFSHORE WINDS ALONG THE COAST WILL KEEP
THOSE AREAS FOG- FREE. FOG WILL LIKELY BE SPOTTY DEVELOPING THEN
DISSIPATING THROUGH THE NIGHT.
AS THE SUN RISES, SUN WILL BURN OFF MOST AREAS OF FOG LEADING TO
CLEAR AND DRY CONDITIONS WITH VFR VIS/CIGS. WINDS WILL REMAIN
EASTERLY THROUGH THE COLUMBIA RIVER GORGE WITH GUSTS AROUND KTTD
REACHING AROUND 20 KT. WITHIN THE WILLAMETTE VALLEY, WINDS ABOVE
1000 FT AGL WILL BE SOUTHERLY WHILE AT THE SURFACE WINDS WILL BE
VARIABLE. 30-40% CHANCE OF IFR CONDITIONS REFORMING FROM KUAO SOUTH
AFTER 09Z WED.
KPDX AND APPROACHES...QUITE VARIABLE CONDITIONS WITH A FEW/SCT LAYER
AT 100 FT AGL. FOG IS BEGINNING TO FORM, BUT WILL BE PATCHY AND WILL
SURGE IN AND OUT. DUE TO VERY HIGH CLOUDS, THERE MAY BE ENOUGH
INSULATION FOR DENSE FOG TO FORM. THERE IS LESS THAN A 10% CHANCE OF
DENSE FOG FORMATION (1/2 SM OR LESS) SO HAVE TRENDED TOWARDS MVFR
VIS TO ACCOUNT FOR THE PATCHY FOG. WINDS WILL BECOME EASTERLY AROUND
18Z TUE CAUSING THE LOWER ATMOSPHERE TO DRY AND CONDITIONS TO
IMPROVE. AFTER 06Z WED, IF CONDITIONS REMAIN EASTERLY THEN THERE IS
A LOW PROBABILITY OF FOG REFORMATION. -27
MARINE
VARIABLE WINDS WITH GUSTS UP TO 15 KT WILL BE THE TREND
OVER THE NEXT 24-HOURS. WIND WAVES WILL BE MINIMAL THROUGH AT LEAST
THURSDAY. THE SMALL CRAFT ADVISORY IS BEING PRIMARILY DRIVEN BY THE
OVERALL COMBINED SEAS. CURRENTLY, BUOYS SHOW OBSERVATIONS HOVERING
RIGHT AROUND THE 10 FT AT 11 SECONDS MARK WITH A FEW OBSERVATIONS
SHOWING SLIGHTLY BELOW THRESHOLD CONDITIONS. THIS WILL BE THE TREND
FOR AT LEAST THE NEXT SEVERAL HOURS SO HAVE EXTENDED THE SCA THROUGH
7 AM TODAY. HOWEVER, IF CONDITIONS PERSIST THAT ADVISORY MAY HAVE TO
BE EXTENDED. MINIMAL THREAT FOR ANY MARINE RELATED HAZARDS, BUT
SMALL CRAFT ADVISORY LEVEL SEAS RETURN AS EARLY AS 2200 TONIGHT.
SEAS AGAIN HOVER RIGHT ALONG THE THRESHOLD SO HAVE NOT ISSUED
ANOTHER HAZARD AT THIS TIME. HOWEVER, AS NEWER MODEL DATA COMES IN
THAT WILL BE REEVALUATED. WILL SEE MORE PERSISTENT CONDITIONS OF
SEAS AROUND 9-11 FT AT 12 SECONDS THROUGH AT LEAST THURSDAY.
-27
BEACH HAZARDS
WHILE A BEACH HAZARD STATEMENT IS NO LONGER IN
EFFECT FOR SNEAKER WAVES, THERE REMAINS A MARGINAL THREAT FOR
SNEAKER WAVES TODAY. PERIODS WILL HOVER AROUND 11-12 SECONDS WHICH
IS PROMPTING THE END OF THE STATEMENT. HOWEVER THE RISK REMAINS.
CONTINUE TO BE VIGILANT FOR THE INCREASED POTENTIAL, ESPECIALLY FOR
THOSE WHO MAY BE CLAMMING ON BEACHES TODAY. MARGINAL RISK PROMPTING
CONDITIONS PERSIST THROUGH MUCH OF THE WEEK.-27
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 UNTIL 7 AM PST THIS MORNING FOR PZZ210-
251>253-271>273.
WWW.WEATHER.GOV/PORTLAND
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