596
FXUS66 KPQR 242128
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
228 PM PDT MON AUG 24 2026
SYNOPSIS
HIGH PRESSURE ALOFT REMAINS DOMINANT TODAY WITH
PRONOUNCED OFFSHORE FLOW ESTABLISHED ACROSS THE REGION. THIS
SETUP WILL SUSTAIN WARMTH INTO THIS EVENING, WITH HIGHS IN THE
LOW 90S ACROSS THE INTERIOR LOWLANDS AND NEAR 95 DEGREES IN THE
PORTLAND/VANCOUVER METRO. SMOKE FROM WILDFIRES MAY REACH THE
SURFACE AT TIMES ACROSS CLACKAMAS, MARION, AND MULTNOMAH
COUNTIES, AS WELL AS THE COLUMBIA GORGE AND UPPER HOOD RIVER
VALLEY. BY LATE TUESDAY, A SHORTWAVE TROUGH APPROACHES FROM THE
NORTHEAST PACIFIC, GRADUALLY WEAKENING THE OFFSHORE REGIME AND
INTRODUCING ONSHORE FLOW. THIS TRANSITION USHERS IN NOTABLY
COOLER CONDITIONS BY MIDWEEK AND INTO THE WEEKEND.
SHORT TERM...NOW THROUGH TUESDAY NIGHT
OFFSHORE FLOW PERSISTS
ON THE WESTERN CASCADES AND COAST RANGE SLOPES, REINFORCING
TEMPERATURES IN THE LOW TO MID 90S FOR INTERIOR LOWLANDS WHILE
COASTAL AREAS REMAIN THE THE UPPER 60S TO NEAR 70 DEGREES. GUSTY
OFFSHORE WINDS CONTINUE IN THE WESTERN GORGE THIS AFTERNOON
WITH GUSTS 25 TO 35 MPH, CREATING HAZARDOUS TRAVEL CONDITIONS;
THESE SHOULD DIMINISH AFTER SUNSET AS THE WEAK SURFACE BOUNDARY
MOVES THROUGH THE REGION AND OFFSHORE FLOW RETURNS.
SMOKE PLUMES FROM REGIONAL FIRES ARE NOW PRESENT ACROSS PORTIONS
OF THE CENTRAL AND NORTHERN WILLAMETTE VALLEY, THE PORTLAND
METRO AREA, AND STRETCHING INTO THE WESTERN GORGE. ANY THICK
SMOKE MAY SUPPRESS TEMPERATURE A DEGREE OR TWO IN AREAS WITH
SMOKE ALOFT, MAINLY NORTH OF SALEM. COASTAL REGIONS WILL SEE A
RETURN OF A LIGHT SEA BREEZE THIS AFTERNOON, MODERATING WINDS
THERE. OVERNIGHT, OFFSHORE FLOW RETURNS INLAND, WITH
TEMPERATURES DROPPING TO THE LOW TO MID 60S IN THE PORTLAND
METRO AND VALLEY/FOOTHILL CORRIDORS, AND TO THE MID-50S
ELSEWHERE.
TUESDAY BRINGS SLIGHTLY LOWER HEIGHTS ALOFT AS A SHORTWAVE
TROUGH NEARS THE REGION. THIS WILL NUDGE AFTERNOON HIGH
TEMPERATURES TO THE MID TO UPPER 80S ACROSS INTERIOR LOWLANDS
AND NEAR 60 DEGREES ON THE COAST. THE OFFSHORE WIND REGIME
WEAKENS AS ONSHORE BEGINS PREVAILING ACROSS ALL AREAS. BY
TUESDAY EVENING, HIGH PRESSURE OVER THE WATERS WILL DRIVE A
PRONOUNCED WESTERLY PUSH, CLEARING ANY REMAINING SMOKE EAST OF
THE CASCADES BY WEDNESDAY MORNING.
LONG TERM...WEDNESDAY THROUGH SUNDAY
MODEL GUIDANCE REMAINS
HIGHLY CONSISTENT REGARDING THE PATTERN EVOLUTION THROUGH THE
WEEKEND. MULTIPLE ENSEMBLE MEMBERS SUPPORT AN ACTIVE TROUGH
SETTLING INTO THE PACIFIC NORTHWEST, WITH SUCCESSIVE IMPULSES
REINFORCING TROUGHING THROUGH SATURDAY. THIS WILL DRIVE A SHARP
AND SUSTAINED TEMPERATURE DROP BEGINNING WEDNESDAY, WITH HIGHS
QUICKLY SLIDING FROM NEAR- AVERAGE VALUES TO THE UPPER 70S
THURSDAY AND FRIDAY, POTENTIALLY DROPPING TO THE MID 70S BY
SATURDAY.
WHILE PRECIPITATION REMAINS MODEST THIS WEEK, SATURDAY PRESENTS
THE MOST ROBUST SIGNAL FOR LIGHT RAIN AS A STRONGER IMPULSE
PASSES. WEAKEN DRIZZLE IS POSSIBLE THURSDAY MORNING WITH AN
INITIAL FRONTAL PASSAGE, BUT ORGANIZATION AND AREAL COVERAGE OF
ANY SHOWER ACTIVITY REMAIN UNCERTAIN GIVEN SIGNIFICANT MODEL
SPREAD AT THIS EXTENDED TIMEFRAME.
~12
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
HIGH PRESSURE OFFSHORE MAINTAINS NORTHERLY WINDS ACROSS
THE WATERS THIS AFTERNOON, STRONGEST NORTH OF CAPE LOOKOUT AND
CAPE MEARES. SMALL CRAFT ADVISORIES REMAIN IN EFFECT ACROSS MOST
OF THE WATERS THROUGH 5 PM PDT THIS EVENING TO THE SOUTH OF CAPE
FALCON AND THROUGH 8 PM PDT THIS EVENING TO THE NORTH, INCLUDING
THE COLUMBIA RIVER BAR FOR NORTHERLY WIND GUSTS OF 20-25 KT. WINDS
AND GUSTS WILL EASE THIS EVENING AS HIGH PRESSURE BEGINS TO
WEAKEN, WITH WINDS TURNING SOUTH-SOUTHWESTERLY BY MIDDAY TUESDAY.
LARGELY WIND-DRIVEN SEAS CONTINUE AT 2-6 FT THROUGH TUESDAY.
SOUTHERLY FLOW AT 5-15 KT WILL THEN PERSIST ACROSS THE WATERS
THROUGH MUCH OF THE WORKWEEK. PERIODS OF WINDS TO 20 KT ALONG THE
SOUTHERN WASHINGTON AND FAR NORTHERN OREGON COASTS INCLUDING THE
MOUTH OF THE COLUMBIA ARE POSSIBLE TUESDAY AFTERNOON, HOWEVER THE
CONFIDENCE IN THE PERSISTENCE OF THESE WINDS LONG ENOUGH TO
WARRANT ANOTHER SMALL CRAFT ADVISORY IN WITHIN 10 NM FROM CAPE
SHOALWATER TO CAPE FALCON AND ACROSS THE COLUMBIA RIVER BAR ARE
TOO LOW AT THIS POINT. INTERMITTENT GUSTS TO 25 KT ARE MOST
LIKELY BETWEEN 11 AM AND 8 PM PDT TUESDAY.
THE NEXT PATTERN SHIFT LOOKS TO OCCUR THURSDAY NIGHT INTO FRIDAY,
WHEN TROUGHING MOVES INTO THE PACIFIC NORTHWEST. THIS WILL BRING A
RETURN TO NORTHWESTERLY FLOW WITH LOW TO MODERATE CHANCES FOR
LIGHT RAIN SHOWERS. SEAS OTHERWISE CONTINUE AT 3-6 FT THROUGH THIS
WEEKEND. -36
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-
272-273.
WWW.WEATHER.GOV/PORTLAND
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSPORTLAND
X.COM/NWSPORTLAND
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