354
FXUS66 KPQR 022255
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
348 PM PDT SUN AUG 2 2026
SYNOPSIS
THE UPCOMING WEEK IS HIGHLIGHTED BY HOT AND DRY
CONDITIONS WITH INCREASING WILDFIRE SMOKE LATE MONDAY INTO TUESDAY AS
OFFSHORE FLOW DEVELOPS. HIGH TEMPERATURES FOR MOST INLAND VALLEY
LOCATIONS ARE NOW EXPECTED TO PEAK BETWEEN 95-100 DEGREES ON TUESDAY
AND WEDNESDAY, AND POTENTIALLY INTO THURSDAY AS WELL. THIS WILL
RESULT IN WIDESPREAD MODERATE TO LOCALLY MAJOR HEATRISK. TRENDING
RELATIVELY COOLER BY FRIDAY WITH THE RETURN OF ONSHORE FLOW, WHICH
WILL ALSO HELP PUSH WILDFIRE SMOKE EAST OF THE CASCADES. FIRE WEATHER
CONCERNS REMAIN IN THE FORECAST MONDAY AND TUESDAY AS WIND SPEEDS
INCREASE AND RELATIVE HUMIDITY VALUES DROP.
SHORT TERM...SUNDAY NIGHT THROUGH WEDNESDAY NIGHT
CONFIDENCE
REMAINS HIGH FOR A WARMING AND DRYING TREND MONDAY THROUGH AT LEAST
WEDNESDAY AS AN UPPER LEVEL RIDGE BEGINS TO AMPLIFY OVER THE EASTERN
PACIFIC AND PACIFIC NORTHWEST. MODEL GUIDANCE IS IN GOOD AGREEMENT
FOR HIGHS IN THE MID TO UPPER 80S OVER INLAND VALLEYS ON MONDAY,
95-100 DEGREES ON TUESDAY AND WEDNESDAY, AND LOW TO MID 90S ON
THURSDAY. THIS WILL RESULT IN WIDESPREAD MODERATE TO LOCALLY MAJOR
HEATRISK AND BRING AN INCREASED RISK FOR HEAT-RELATED ILLNESSES FOR
THOSE WHO DO NOT HAVE ACCESS TO AIR CONDITIONING. THE PROBABILITY FOR
HIGH TEMPERATURES OF 100 DEGREES OR WARMER PEAK ON WEDNESDAY, RANGING
BETWEEN 30-50% FOR INLAND VALLEYS. FOR THE COAST, HIGHS WILL
GENERALLY BE IN THE 70S GIVEN LIGHT ONSHORE WINDS DURING THE
AFTERNOON FOLLOWING OFFSHORE WINDS IN THE MORNING, EXCEPT 80S FOR
INLAND COASTAL COMMUNITIES SUCH AS TILLAMOOK AND POSSIBLY ASTORIA
WHERE OFFSHORE WINDS WILL LAST A BIT LONGER. IF OFFSHORE WINDS MANAGE
TO LINGER INTO THE MID AFTERNOON HOURS AT TILLAMOOK AND ASTORIA,
HIGHS IN THE LOW 90S WOULD BE POSSIBLE. THE BEST SHOT OF THIS
HAPPENING IS ON TUESDAY, HOWEVER CHANCES ARE LOW AT 5-10%. FOR MORE
INLAND AREAS, IT IS WORTH MENTIONING THAT THE IMPACTS OF INCREASING
WILDFIRE SMOKE ARE NOT TAKEN INTO ACCOUNT BY MOST MODELS. AS ONSHORE
WINDS TRANSITION TO OFFSHORE WINDS MONDAY INTO TUESDAY, WILDFIRE
SMOKE WILL BEGIN TO INCREASE WEST OF THE CASCADES. EVEN WITH PLENTY
OF SUNSHINE, THE INCREASING SMOKE AND HAZE MAY LIMIT HIGH
TEMPERATURES BY APPROXIMATELY 1-3 DEGREES. HOWEVER, TEMPERATURES WILL
STILL BE HOT ENOUGH TO BRING AN INCREASED RISK OF HEAT-RELATED
ILLNESSES EVEN IF TEMPERATURES ARE DAMPENED A FEW DEGREES FROM SMOKE.
ONE POTENTIAL EXCEPTION IS IN THE COLUMBIA RIVER GORGE, UPPER HOOD
RIVER VALLEY, AND NORTH OR CASCADES AND ADJACENT FOOTHILLS; THE RRFS
SMOKE MODEL SUGGESTS THESE AREAS WILL HAVE RELATIVELY DENSER WILDFIRE
SMOKE ASSOCIATED WITH A SMOKE PLUME BLOWING WESTWARD FROM THE ONGOING
GRASSHOPPER FIRE BURNING IN THE MT. HOOD NATIONAL FOREST. AS SUCH,
THESE AREAS HAVE A BETTER SHOT OF OBSERVING RELATIVELY COOLER HIGH
TEMPERATURES AS SMOKE WILL HELP ABSORB AND SCATTER INCOMING SOLAR
RADIATION MORE EFFICIENTLY. THEREFORE, HAVE DECIDED TO LEAVE THESE
AREAS OUT OF THE HEAT ADVISORY THAT HAS BEEN ISSUED FOR THE
WILLAMETTE VALLEY, PORTLAND/VANCOUVER METRO, COWLITZ VALLEY, LOWER
COLUMBIA, SOUTH WA CASCADES, AND OREGON COAST RANGE LOWLANDS. THIS
HEAT ADVISORY IS CURRENTLY IN EFFECT FROM NOON PDT TUESDAY THROUGH 11
PM PDT WEDNESDAY, HOWEVER THERE IS A CHANCE THE ADVISORY MAY NEED TO
BE EXTENDED THROUGH THURSDAY DEPENDING ON HOW MODEL GUIDANCE TRENDS
AND HOW DENSE WILDFIRE SMOKE BECOMES. DEGRADED AIR QUALITY WILL ALSO
BE A CONCERN IN AREAS WITH DENSER SMOKE NEAR THE SURFACE. FOR UPDATES
REGARDING THE AIR QUALITY FORECAST AND ANY AIR QUALITY ADVISORIES
THAT ARE IN EFFECT, PLEASE VISIT THE OREGON SMOKE BLOG AT
OREGONSMOKE.ORG AND THE WASHINGTON SMOKE BLOG AT
WASMOKE.BLOGSPOT.COM.
WITH THE UPCOMING HEAT, A THERMALLY INDUCED SURFACE TROUGH IS
EXPECTED TO DEVELOP INLAND, WHICH WILL BRING INCREASING WIND SPEEDS
AND FIRE WEATHER CONCERNS. MODEL GUIDANCE IS IN BETTER AGREEMENT NOW
REGARDING THE TIMING AND EVOLUTION OF THIS SURFACE TROUGH AND WIND
SPEEDS. FOR DETAILS REGARDING THIS SURFACE TROUGH AND THE FIRE
WEATHER IMPLICATIONS THAT WILL COME WITH IT, PLEASE REFER TO THE FIRE
WEATHER DISCUSSION BELOW. -23
LONG TERM...THURSDAY THROUGH SATURDAY NIGHT
THE LONG TERM FORECAST
IS HIGHLIGHTED BY GRADUALLY COOLING TEMPERATURES, DECREASING WILDFIRE
SMOKE WEST OF THE CASCADES, AND DECREASING FIRE WEATHER CONCERNS. IT
APPEARS THURSDAY WILL BE A TRANSITION DAY AS A THERMALLY INDUCED
SURFACE THERMAL TROUGH THAT WILL RESIDE OVER WESTERN OREGON EARLY TO
MID WEEK FINALLY SHIFTS EAST OF THE CASCADE CREST, BRINGING A RETURN
TO ONSHORE FLOW. MODEL ENSEMBLE GUIDANCE IS ALSO IN AGREEMENT THE
UPPER LEVEL RIDGE AXIS WILL BEGIN SHIFTING EAST OF THE CASCADES ON
THURSDAY AS WELL. THIS SHOULD BRING SLIGHTLY LOWER TEMPERATURES ON
THURSDAY WITH WILDFIRE SMOKE BEGINNING TO SLOWLY DECREASE FROM WEST
TO EAST. THAT BEING SAID, THE ONSHORE FLOW WILL BE WEAK, WHICH MEANS
AT LEAST SOME HAZE FROM WILDFIRE SMOKE IS LIKELY TO REMAIN AND
TEMPERATURES WILL STILL BE TRENDING RATHER HOT WITH HIGHS SOMEWHERE
IN THE 90S FOR MOST INLAND VALLEYS.
ONSHORE FLOW IS EXPECTED TO STRENGTHEN MORE CONSIDERABLY FRIDAY INTO
NEXT WEEKEND, BRINGING MORE SEASONABLE TEMPERATURES BACK INTO THE 80S
BY SATURDAY. ONSHORE FLOW SHOULD BE STRONG ENOUGH AT THAT POINT TO
PUSH ANY LINGERING SMOKE AND HAZE EAST OF THE CASCADES. DESPITE THE
INCREASING ONSHORE FLOW, DRY WEATHER IS EXPECTED TO CONTINUE THROUGH
AT LEAST AUGUST 9TH WITH NO SIGNS OF ANY PRECIPITATION. -23
AVIATION...THROUGH 00Z TUE
WIDESPREAD VFR CONDITIONS WILL
CONTINUE THROUGH THE PERIOD FOR MOST TERMINALS. THE ONLY EXCEPTION
IS FOR SOME COASTAL TERMINALS, WHERE MARINE STRATUS WILL PUSH
INTO THE COAST AROUND 11-12Z MON AND MAINTAIN MVFR CONDITIONS
THROUGH 18Z MON (20-50% CHANCE OF MVFR, 10-20% CHANCE OF IFR).
OTHERWISE, EXPECT INCREASED NORTH TO NORTHWESTERLY WINDS THIS
AFTERNOON AND EVENING AT MANY TERMINALS, AROUND 12-17 KT WITH
GUSTS UP TO 20-25 KT.
KPDX AND APPROACHES...VFR THROUGH THE TAF PERIOD. NORTHWESTERLY
WINDS AROUND 10-15 KT WITH GUSTS UP TO 20 KT IN THE LATE
AFTERNOON, WEAKENING AND SHIFTING NORTHERLY AROUND 06-12Z MON. ~12
MARINE
NORTHERLY FLOW BEGINS TO INCREASE ACROSS THE COASTAL
WATERS THIS AFTERNOON. CHANCES FOR MAXIMUM WIND GUSTS OF AT LEAST
21 KNOTS REMAIN GREATER THAN 85% TODAY THROUGH THE MIDDLE OF THE
WEEK WITH THE HIGHEST RELATIVE PROBABILITIES ACROSS THE OUTER
WATERS. A SMALL CRAFT ADVISORY REMAINS IN EFFECT ACROSS THE INNER
AND OUTER WATERS INCLUDING THE COLUMBIA RIVER BAR. WHILE AT THIS
MOMENT THE SMALL CRAFT ADVISORY FOR THE COLUMBIA RIVER BAR WILL
COME TO AN END AT 2 AM MONDAY, THE SMALL CRAFT ADVISORIES FOR THE
REST OF THE WATERS WILL REMAIN THROUGH AT LEAST LATE TUESDAY
AFTERNOON. SMALL CRAFT WIND CONCERNS WILL SHIFT TO THE OUTER
WATERS ON WEDNESDAY THROUGH THE END OF THE WEEK. EXPECT WAVE
HEIGHTS THROUGH THE WEEK TO HOLD AROUND 4-8 FT AT 7-9 SECONDS. ~12/99
FIRE WEATHER...MONDAY THROUGH WEDNESDAY
CRITICAL FIRE WEATHER
CONDITIONS ARE EXPECTED OVER THE SOUTHERN WILLAMETTE VALLEY TO THE
SOUTH OF SALEM MONDAY AFTERNOON AND EVENING DUE TO BREEZY NORTH WINDS
WITH GUSTS UP TO 25 MPH COMBINED WITH LOW RELATIVE HUMIDITY VALUES
DOWN TO 20-25%. THIS MEANS ANY NEW OR EXISTING FIRES IN THIS AREA
COULD EXHIBIT RAPID FIRE SPREAD TOWARDS THE SOUTH. THEREFORE, A RED
FLAG WARNING HAS BEEN ISSUED FOR FIRE WEATHER ZONE 685 DURING THAT
TIME. ALTHOUGH WIND SPEEDS ARE NOT FORECAST TO BE QUITE AS STRONG TO
THE NORTH OF SALEM, CONDITIONS WILL STILL BE DRY AND BREEZY ENOUGH
FOR ELEVATED FIRE WEATHER CONCERNS. THE REASON FOR THE INCREASE IN
WIND SPEEDS IS DUE TO THE DEVELOPMENT OF A THERMALLY INDUCED SURFACE
TROUGH OVER FAR SOUTHWEST OREGON TODAY INTO MONDAY, WHICH IS SET TO
MOVE FARTHER INLAND AND LIFT NORTHWARD INTO THE WILLAMETTE VALLEY
MONDAY AFTERNOON. THIS PROGRESSION WILL CAUSE NORTHERLY WINDS TO
INCREASE IN THE WILLAMETTE VALLEY WHILE INCREASING EASTERLY WINDS
ALOFT AROUND 5000 FT, INCLUDING IN THE HIGH CASCADES. THESE EASTERLY
WINDS WILL BRING IN DRIER AIR FROM EAST OF THE CASCADES AND THE
DOWNSLOPING ACTION WILL INCREASE COMPRESSIONAL WARMING AND DRYING IN
THE LOWER ELEVATIONS AND IN THE WILLAMETTE VALLEY. COMBINE THIS WITH
DAYTIME HEATING AND A DEEP LAYER OF DRY AIR, WE WILL SEE RELATIVE
HUMIDITY DROP WITHIN THE INTERIOR LOWLANDS ON MONDAY TO AS LOW AS 20-
25%. THE SLIGHTLY STRONGER WINDS IN THE SOUTH VALLEY IS DUE TO A
CHANNELING/FETCH COMPONENT AND A TIGHTER NORTH-SOUTH PRESSURE
GRADIENT. THESE DRY AND BREEZY CONDITIONS WILL LEAD TO CRITICAL FIRE
WEATHER CONCERNS AS THEY BEGIN TO OVERLAP BY MID MONDAY AFTERNOON
INTO THE EARLY EVENING HOURS.
MONDAY NIGHT INTO TUESDAY, THE AXIS OF THE SURFACE THERMAL TROUGH IS
EXPECTED TO LIFT FARTHER TO THE NORTH TOWARDS THE COLUMBIA RIVER
GORGE, WHILE ALSO PUSHING WESTWARD TOWARDS THE OREGON COAST. THIS
WILL BRING INCREASING EASTERLY WINDS IN THE COLUMBIA RIVER GORGE AND
CASCADES AND A LOWERING SUBSIDENCE INVERSION WITH SHARP OVERNIGHT
THERMAL BELTS/POOR OVERNIGHT HUMIDITY RECOVERIES IN THE CASCADES.
EASTERLY WINDS ARE EXPECTED TO BE STRONGEST IN THE WESTERN GORGE
WITH GUSTS UP TO 30-40 MPH IN THE MOST WIND-PRONE LOCATIONS. GIVEN
THE LOW RELATIVE HUMIDITY VALUES IN PLACE AT THAT TIME, CRITICAL
FIRE WEATHER CONDITIONS CAPABLE OF RAPID FIRE SPREAD WILL BE
POSSIBLE. THEREFORE, A FIRE WEATHER WATCH HAS BEEN ISSUED FOR FIRE
WEATHER ZONE 636 TUESDAY AFTERNOON THROUGH TUESDAY EVENING. THE REST
OF THE CASCADES WILL HAVE RELATIVELY WEAKER EASTERLY WINDS WITH
GUSTS GENERALLY IN THE 15-25 MPH RANGE. ONE EXCEPTION WOULD BE ON
EXPOSED RIDGETOPS AND WEST-EAST ORIENTED VALLEYS WHERE SLIGHTLY
HIGHER WIND GUSTS ARE LIKELY. GIVEN THE MAJORITY OF OUR CASCADE
ZONES AWAY FROM THE GORGE SHOULD SEE WIND SPEEDS BELOW RED FLAG
WARNING CRITERIA, HAVE DECIDED NOT TO INCLUDE THESE ZONES WITHIN THE
FIRE WEATHER WATCH AT THIS TIME. NEVERTHELESS, ELEVATED FIRE WEATHER
CONCERNS WILL STILL EXIST IN THESE ZONES, AS WELL AS IN THE PORTLAND
METRO AND WILLAMETTE VALLEY WHERE NORTHEAST TO NORTH-NORTHEAST WINDS
ARE EXPECTED TO GUST UP TO APPROXIMATELY 20 MPH IN THE AFTERNOON.
FIRE WEATHER CONCERNS GRADUALLY DECREASE ON WEDNESDAY AS OFFSHORE
WINDS BEGIN TO WEAKEN. -23
PQR WATCHES/WARNINGS/ADVISORIES
OR...HEAT ADVISORY FROM NOON TUESDAY TO 11 PM PDT WEDNESDAY FOR
ORZ104-105-108>118.
RED FLAG WARNING FROM 1 PM TO 8 PM PDT MONDAY FOR ORZ685.
WA...HEAT ADVISORY FROM NOON TUESDAY TO 11 PM PDT WEDNESDAY FOR
WAZ204>208.
FIRE WEATHER WATCH FROM TUESDAY AFTERNOON THROUGH TUESDAY
EVENING FOR WAZ636.
PZ...SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO 2 AM PDT
MONDAY FOR PZZ210.
SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO 5 PM PDT
TUESDAY FOR PZZ251-252-271-272.
SMALL CRAFT ADVISORY UNTIL 5 PM PDT TUESDAY FOR PZZ253-273.
WWW.WEATHER.GOV/PORTLAND
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSPORTLAND
X.COM/NWSPORTLAND
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