815
FXUS66 KPQR 241735
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
1035 AM PDT MON AUG 24 2026
UPDATED AVIATION DISCUSSION.
SYNOPSIS
UPPER LEVEL RIDGING AND LOW-LEVEL OFFSHORE FLOW
DEVELOPS TODAY, CONTINUING INTO TUESDAY, BRINGING WARMER AND
SUNNIER CONDITIONS. WILDFIRE SMOKE WILL ALSO BEGIN TO INCREASE
OVER THE COLUMBIA RIVER GORGE, UPPER HOOD RIVER VALLEY, AND THE
GREATER PORTLAND/VANCOUVER METRO AREA THIS MORNING AND THEN
LINGER THROUGH TUESDAY; HOWEVER SMOKE IS NOT EXPECTED TO BE
DENSE FOR MOST LOCATIONS. ONSHORE FLOW ARRIVES BY WEDNESDAY,
WHICH WILL CLEAR LINGERING SMOKE OUT OF THE AREA AND BRING
COOLER, MORE SEASONABLE TEMPERATURES INTO THE WEEKEND.
SHORT TERM...NOW THROUGH TUESDAY NIGHT
A BUILDING UPPER
LEVEL RIDGE WILL BRING A WARM START TO THE WORK WEEK AS A
THERMAL TROUGH DEVELOPS OVER THE AREA TODAY. OFFSHORE FLOW IS
WILL DEVELOP ON THE WESTERN SLOPES OF THE CASCADES AND COAST
RANGE THIS AFTERNOON, HELPING SUPPORT THE WARMER TEMPERATURES.
WINDS ARE NOT EXPECTED TO BE PARTICULARLY STRONG BUT COULD BE
GUSTY IN THE WESTERN COLUMBIA RIVER GORGE WITH GUSTS OF 25-35
MPH POSSIBLE LATE THIS MORNING THROUGH THE AFTERNOON. 850 MB
TEMPERATURES ARE EXPECTED TO RISE TO BETWEEN 18-22 C SUPPORTING
A NOTICEABLE JUMP IN HIGH TEMPERATURES FROM YESTERDAY. 10TH-90TH
PERCENTILES FOR HIGHS SHOW A SMALL RANGE IN THE LOW TO MID 90S
FOR INTERIOR LOWLANDS AND UPPER 60S TO LOW 70S ALONG THE COAST.
OFFSHORE WINDS WILL ALSO BRING SOME NOTICEABLE WILDFIRE SMOKE TO
PORTIONS OF THE CENTRAL AND NORTHERN WILLAMETTE VALLEY, THE
PORTLAND METRO AND THE WESTERN COLUMBIA RIVER GORGE. DEPENDING
ON HOW THICK THIS SMOKE IS, IT COULD IMPACT AFTERNOON HIGHS BY
KNOCKING THEM DOWN A DEGREE OR TWO. AFTERNOON SEA BREEZES RETURN
LIGHT ONSHORE FLOW ALONG THE COAST AND WESTERN PORTIONS OF THE
COAST RANGE. A WEAK PASSING DISTURBANCE MAY BRIEFLY DECREASE
OFFSHORE WINDS ALONG THE WESTERN SLOPES OF THE CASCADES DURING
THE LATE AFTERNOON AND EVENING HOURS BUT OFFSHORE FLOW RETURNS
LATE IN THE EVENING INTO THE OVERNIGHT HOURS. OVERNIGHT
TEMPERATURES IN THE PORTLAND METRO AND CASCADE VALLEYS AND
FOOTHILLS WILL BE RATHER MILD IN THE LOW TO MID 60S WHILE TEMPS
DROP INTO THE MID 50S ELSEWHERE.
TROUGHING OVER THE GULF OF ALASKA IS EXPECTED TO SLOWLY DRIFT
SOUTHEAST WHILE A SHORTWAVE OVER THE NORTHEAST PACIFIC GETS SWUNG
TOWARD THE PACNW EARLY TUESDAY. THIS WILL BRING SLIGHTLY LOWER
HEIGHTS ALOFT AND A DECREASE IN 850 MB TEMPERATURES TO AROUND 16-18
C BUT WILL STILL SUPPORT HIGH TEMPERATURES IN THE MID TO UPPER
80S ACROSS THE INTERIOR LOWLANDS AND 60S ALONG THE COAST. WINDS
WILL ALSO SHIFT ONSHORE ACROSS THE ENTIRE AREA. BY TUESDAY
EVENING, SURFACE HIGH PRESSURE BUILDING ALONG THE COAST WILL
BRING A STRONG MARINE PUSH OF WESTERLY WINDS. ANY LINGERING
WILDFIRE SMOKE SHOULD SHIFT BACK EAST OF THE CASCADES BY
WEDNESDAY. -19
LONG TERM...WEDNESDAY THROUGH SUNDAY
CONFIDENCE REMAINS HIGH
HEADING INTO THE LATTER HALF OF THE WEEK AND INTO THE WEEKEND.
CLUSTER ANALYSIS IS HEAVILY FAVORING TROUGHING OVER THE PACNW
AND WESTERN CANADA WITH SEVERAL EMBEDDED IMPULSES REINFORCING
THIS PATTERN FOR SEVERAL DAYS. THIS WILL BRING A SIGNIFICANT
DOWNWARD TREND IN TEMPERATURES STARTING WEDNESDAY WITH HIGHS
CLOSE TO AVERAGE THEN GRADUALLY DROPPING INTO THE UPPERS 70S
THURSDAY AND FRIDAY AND POSSIBLY THE MID 70S BY SATURDAY.
PRECIPITATION SIGNALS REMAIN WEAK BUT THE BEST CHANCE FOR LIGHT
RAIN LOOKS TO BE SATURDAY, THOUGH THERE IS SIGNIFICANT MODEL
SPREAD THIS FAR OUT. COULD SEE SOME LIGHT DRIZZLE ASSOCIATED
WITH WEAK FRONTAL PASSAGES THURSDAY MORNING AND A BETTER CHANCE
SATURDAY. -19
AVIATION...THROUGH 18Z TUESDAY
OFFSHORE FLOW HAS BEGUN TO
DEVELOP ACROSS THE AIRSPACE RESULTING IN NORTHERLY FLOW OF 5-10
KT AT INLAND TERMINALS WHICH IS EXPECTED TO TURN NORTHEASTERLY
TO EASTERLY IN THE PORTLAND-AREA, WITH GUSTS TO 20 KT AT KTTD
NEAR THE WESTERN ENTRANCE OF THE COLUMBIA GORGE. THESE WINDS
WILL TRANSPORT SMOKE FROM THE COLUMBIA BASIN WEST OF THE
CASCADES, WHICH WILL LIKELY RESULT IN RESTRICTED SLANTWISE VIS,
IF NOT ALSO SURFACE VIS TO 5-7 SM. SEVERE RESTRICTIONS WITHIN
DENSE SMOKE ARE NOT ANTICIPATED EXCEPT IN VERY NEAR PROXIMITY TO
ONGOING FIRES. TEMPERATURES WARMING INTO THE 90S WITHIN THE
WILLAMETTE VALLEY WILL RESULT IN HIGH DENSITY ALTITUDE WHICH MAY
REDUCE AIRCRAFT PERFORMANCE. AFTER 00Z TUE, THE OFFSHORE
GRADIENT WILL BEGIN TO RELAX, ALLOWING WINDS TO BECOME LIGHT AND
VARIABLE BEFORE BUILDING OUT OF THE SOUTH TO SOUTHWEST LATE IN
THE PERIOD. CHANCES FOR MVFR CIGS INCREASE AS ONSHORE FLOW AIDS
IN THE INLAND PENETRATION OF MARINE STRATUS, WITH THE HIGHEST
CHANCES IN THE SOUTHERN WILLAMETTE VALLEY AFTER 12-15Z TUE.
OFFSHORE FLOW MAY NOT REACH ALL THE WAY TO THE COAST, WITH
COASTAL TERMINALS INSTEAD EXPECTING NORTH-NORTHWEST FLOW OF
10-15 KT WITH GUSTS AS HIGH AS 20-25 KT THROUGH THIS AFTERNOON.
VFR CONDITIONS CONTINUE UNTIL THE GRADIENT BEGINS TO TURN
ONSHORE, FAVORING A SWITCH TO SOUTH-SOUTHWESTERLY WINDS BY
06-12Z TUE AS WELL AS RESURGENT MARINE STRATUS WHICH WILL
SUPPORT INCREASING CHANCES FOR IFR/LIFR CIGS THIS EVENING INTO
TONIGHT.
KPDX AND APPROACHES...NORTHWEST FLOW WILL TURN NORTHEASTERLY IN
THE COMING FEW HOURS AS OFFSHORE FLOW THROUGH THE COLUMBIA GORGE
DEVELOPS. GUSTS TO 20 KT ARE EXPECTED IN THE EASTERN METRO
INCLUDING AT KTTD, BUT ARE UNLIKELY TO EXTEND WEST TO KPDX,
WHERE WINDS WILL BE CLOSER TO 10 KT. SMOKE WILL LIKELY INCREASE
THROUGH THE AFTERNOON, RESULTING IN INTERMITTENT VIS
RESTRICTIONS TO 5-7 SM. TEMPERATURES WARMING INTO THE 90S WILL
RESULT IN HIGH DENSITY ALTITUDE WHICH MAY REDUCE AIRCRAFT
PERFORMANCE. WINDS BECOME VARIABLE AFTER 00Z TUE AND ULTIMATELY
TURN OUT OF THE SOUTHWEST LATE IN THE PERIOD, FAVORING LOWER
SMOKE CONCENTRATIONS THROUGH TONIGHT. -36
MARINE
GUSTY NORTHERLY WINDS PERSIST THROUGH THE AFTERNOON
ACROSS ALL WATERS WITH GUSTS UP TO 25 KT EXPECTED. WINDS
DECREASE FROM FROM SOUTH TO NORTH THIS EVENING. THE SMALL CRAFT
ADVISORY (SCA) FROM FLORENCE TO CAPE FALCON WILL DROP OFF FIRST
AT 5 PM AND THE SCA FOR WATERS NORTH OF CAPE FALCON TO CAPE
SHOALWATER AND THE COLUMBIA RIVER BAR ARE EXPECTED TO END AT 8
PM AS WINDS DECREASE.
A SOUTHERLY WIND REVERSAL ARRIVES EARLY TUESDAY MORNING OVER THE
INNER WATERS WITH GUSTS UP TO 15-20 KT EXPECTED BY TUESDAY
AFTERNOON OVER THE NORTHERN INNER WATERS. THIS WILL ALSO BRING
INCREASING CHANCES FOR MARINE FOG BEGINNING EARLY TUESDAY
MORNING, ESPECIALLY OVER THE INNER WATERS. VISIBILITIES MAY FALL
BELOW 1 SM AT TIMES AS THE SOUTHERLY WINDS DEVELOP AND
UPWELLING OCCURS. ASIDE FROM THE INCREASING WINDS AND POTENTIAL
MARINE FOG, SIGNIFICANT WAVE HEIGHTS LOOK TO REMAIN RELATIVELY
LOW AT AROUND 3 TO 5 FT THROUGH FRIDAY. -19/23
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 8 PM PDT THIS EVENING FOR PZZ210-
251-271.
SMALL CRAFT ADVISORY UNTIL 5 PM PDT THIS AFTERNOON FOR PZZ252-
253-272-273.
WWW.WEATHER.GOV/PORTLAND
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSPORTLAND
X.COM/NWSPORTLAND
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