443
FXUS66 KPQR 032144
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
244 PM PDT MON AUG 3 2026
SYNOPSIS
OFFSHORE FLOW WILL BRING HOT, DRY, AND SMOKEY CONDITIONS
TO NORTHWEST OR AND SOUTHWEST WA TUESDAY THROUGH THURSDAY. HIGH
TEMPERATURES FOR MOST INLAND VALLEY LOCATIONS PEAK IN THE MID TO
UPPER 90S TUESDAY TO THURSDAY, RESULTING IN A WIDESPREAD MODERATE TO
LOCALLY MAJOR HEATRISK IMPACTS. TEMPERATURES BEGIN TO TREND COOLER
FRIDAY INTO THE WEEKEND WITH THE RETURN OF ONSHORE FLOW, WHICH WILL
ALSO PUSH ANY LINGERING WILDFIRE SMOKE AND HAZE EAST OF THE CASCADES.
FIRE WEATHER CONCERNS REMAIN IN THE FORECAST THROUGH WEDNESDAY IN THE
WESTERN COLUMBIA RIVER GORGE AND PORTIONS OF THE WILLAMETTE VALLEY.
DISCUSSION...NOW THROUGH SUNDAY NIGHT
SATELLITE IMAGERY FROM
MONDAY AFTERNOON SHOWED WIDESPREAD WILDFIRE SMOKE AND HAZE SPREADING
OVER SOUTHWEST WASHINGTON AND MUCH OF NORTHWEST OREGON TO THE NORTH
OF A LINE EXTENDING FROM NEWPORT TO SALEM TO TIMOTHY LAKE IN RESPONSE
TO INCREASING OFFSHORE WINDS. SMOKE HAS MIXED DOWN TO THE SURFACE
OVER SOME INLAND AREAS, LOWERING SURFACE VISIBILITIES DOWN TO 5-9
MILES OVER THE GREATER PORTLAND/VANCOUVER METRO AND CENTRAL/NORTHERN
WILLAMETTE VALLEY. VISIBILITIES APPEAR EVEN LOWER OVER PORTIONS OF
THE MT. HOOD NATIONAL FOREST, NORTH OR CASCADE FOOTHILLS, AND THE
WESTERN COLUMBIA RIVER GORGE DUE TO A MORE CONCENTRATED SMOKE PLUME
BLOWING WESTWARD FROM THE GRASSHOPPER FIRE. AS A RESULT OF THIS
SMOKE, AIR QUALITY HAS BEGUN TO DEGRADE IN THE AFOREMENTIONED AREAS.
THE OREGON DEPARTMENT OF ENVIRONMENTAL QUALITY (DEQ) AND THE
SOUTHWEST CLEAN AIR AGENCY HAVE ISSUED AIR QUALITY ALERTS FOR
PORTIONS OF SOUTHWEST WA AND NORTHWEST OR, INCLUDING THE
PORTLAND/VANCOUVER METRO. 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.
SMOKE AND HAZE WILL LIKELY CONTINUE IMPACTING THE AREA THROUGH AT
LEAST WEDNESDAY OR THURSDAY BEFORE ONSHORE FLOW RETURNS AND HELPS
CLEAR SMOKE OUT OF THE AREA FROM WEST TO EAST LATE THURSDAY INTO
FRIDAY. UNTIL THEN, OFFSHORE FLOW AND UPPER LEVEL RIDGING WILL NOT
ONLY MAINTAIN SMOKE AND HAZE BUT WILL ALSO BRING HEAT AND FIRE
WEATHER CONCERNS. FOR FIRE WEATHER CONCERNS, PLEASE REFER TO THE FIRE
WEATHER DISCUSSION BELOW. FOR HEAT, MODEL GUIDANCE REMAINS IN GOOD
AGREEMENT FOR HIGHS IN THE MID TO UPPER 90S ON TUESDAY AND WEDNESDAY,
AND SOMEWHERE IN THE 90S ON THURSDAY. HOWEVER, THE IMPACTS OF
WILDFIRE SMOKE ON TEMPERATURES NEEDS TO BE TAKEN INTO ACCOUNT, AS
AREAS WITH DENSE WILDFIRE SMOKE WILL SEE HIGH TEMPERATURES LIMITED BY
SEVERAL DEGREES. THE RRFS MODEL, WHICH DOES ACCOUNT FOR WILDFIRE
SMOKE, SUGGESTS HIGHS WILL BE MOST LIMITED OVER THE NORTHERN
WILLAMETTE VALLEY, COLUMBIA RIVER GORGE, PORTLAND/VANCOUVER METRO AND
MT. HOOD NATIONAL FOREST ON TUESDAY WITH HIGHS ONLY IN THE LOW TO MID
90S RATHER THAN UPPER 90S. MEANWHILE, SMOKE IMPACTS ON TEMPERATURES
OVER THE REST OF SOUTHWEST WA AND NORTHWEST OR ARE
MINIMAL. ON WEDNESDAY, THE RRFS MODEL SUGGESTS LITTLE TO NO IMPACTS
ON TEMPERATURES DUE TO A MORE DISPERSED AND THINNER SMOKE LAYER.
REGARDLESS OF THE EXACT OUTCOME, IT WILL STILL BE HOT ENOUGH TO BRING
AN INCREASED RISK OF HEAT-RELATED ILLNESSES. AS SUCH, VARIOUS HEAT
ADVISORIES REMAIN IN EFFECT FOR MOST INLAND VALLEYS BEGINNING TUESDAY
AFTERNOON. IN AREAS WITH AIR QUALITY ADVISORIES IN EFFECT, IT IS
RECOMMENDED TO KEEP WINDOWS AND DOOR SHUT TO PREVENT SMOKE FROM GOING
INDOORS. HOWEVER, THOSE WITHOUT AIR CONDITIONING WHO ARE COUNTING ON
OPENING THEIR WINDOWS AT NIGHT TO HELP COOL DOWN WILL HAVE LESS
OPTIONS. IN THIS SCENARIO, SOMETHING AS SIMPLE AS A LARGE BOX FAN
WITH A DAMP TOWEL DRAPED OVER THE FRONT OF IT CAN BE SURPRISINGLY
EFFECTIVE GIVEN THE DRY AIRMASS IN PLACE.
HEADING INTO FRIDAY AND NEXT WEEKEND, MODEL ENSEMBLE GUIDANCE
CONTINUES TO SUGGEST ONSHORE FLOW WILL STRENGTHEN WITH TEMPERATURES
TRENDING COOLER EACH DAY. THIS WILL SCOUR OUT ANY LINGERING SMOKE AND
HAZE IN THE AREA, BRING AN END TO HEAT CONCERNS ALONG WITH DECREASING
FIRE WEATHER CONCERNS. -23
AVIATION...THROUGH 18Z TUE
SMOKE ALOFT BETWEEN 5000-9000 FT
WITH EASTERLY FLOW. THERMAL TROUGH FORMS TONIGHT CAUSING WINDS TO
SHIFT TO THE NORTH, ESPECIALLY ALONG THE COAST AND THE WILLAMETTE
VALLEY. GUSTS UPWARDS OF 25-30 KT ALONG THE COAST AND SOUTH OF
KSLE. CANNOT RULE OUT GUSTS UP TO 25 KT AROUND KSLE AND KUAO THIS
AFTERNOON, BUT NOT EXPECTED TO BE AS WIDESPREAD. FOR THE EASTERLY
FLOW, SOME OBSERVATIONS THROUGH THE COLUMBIA RIVER GORGE ARE
AROUND 25 KT BUT THOSE SHOULD EASE THROUGH THE DAY.
OVERNIGHT, THE SMOKE ALOFT WILL SETTLE TOWARDS THE SURFACE AS
WINDS EASE. THIS SMOKE WILL CAUSE SLIGHT REDUCTIONS TO VISIBILITY
DOWN TO 6SM NORTH OF SALEM. HOWEVER, WE CANNOT RULE OUT DENSER
SMOKE AROUND K4S2 AND SMALLER RUNWAYS WEST OF THE GRASSHOPPER
FIRE, OR ANY NEW FIRES THAT MAY IGNITE TODAY.
KPDX AND APPROACHES...VFR CONDITIONS ARE EXPECTED TO CONTINUE
LOCALLY. NORTHERLY WINDS AROUND 5-10 KNOTS THIS MORNING INCREASE
LATE MORNING/MIDDAY WITH OCCASIONAL GUSTS AROUND 20 KNOTS POSSIBLE
THROUGH THE AFTERNOON INTO THE EARLY EVENING. SMOKE MAY SETTLE
OVERNIGHT REDUCING VIS TO AROUND 6SM. CONFIDENCE IS AROUND 35-50%
FOR THIS OCCURRING. -27/99
MARINE
AN UPPER-LEVEL RIDGE OF HIGH PRESSURE BUILDING OFF THE
COAST CONTINUES TO DRIVE NORTHERLY WINDS ACROSS THE WATERS TODAY
WITH GUSTS GREATER THAN 21 KT BEING REPORTED ON AREA BUOYS. THE
NORTHERN BUOYS HAVE STRUGGLED TO SEE THE RISES WHICH ISN'T
UNCOMMON FOR A NORTHERLY WIND, BUT THEY ARE STILL HOVERING RIGHT
AROUND 21 KT FOR GUSTS. A SMALL CRAFT ADVISORY REMAINS IN EFFECT
FOR ALL OF THE WATER INTO THE MIDDLE OF THE WEEK WHICH, IF WIND
WAVES REMAIN ELEVATED, COULD EXTEND FURTHER. THE COLUMBIA RIVER
BAR IS INCLUDED IN THESE SMALL CRAFTS DUE TO WIND. THERE IS A
SLIGHT CHANCE (15-30%) THAT THE BAR COULD SEE A RETURN OF THE WIND
ON TUESDAY EVENING, BUT RIGHT NOW THE LENGTH OF TIME WOULD BE FOR
JUST A FEW HOURS BETWEEN 1500-2000. THEY WOULD ALSO BE MARGINAL
AND IMPACT THE MAIN ENTRANCE TO THE BAR AND NOT THE INTERIOR
PORTIONS OF PZZ210.
STARTING THURSDAY, FLOW BECOMES ZONAL AND WINDS WILL SHIFT
SLIGHTLY TO THE NORTHWEST. THEREFORE WILL SEE WIND WAVES SHIFT
SLIGHTLY. OVERALL WIND SPEEDS WILL DECREASE BUT SEAS WILL STAY
RELATIVELY SIMILAR AROUND 6 TO 8 FT AT 10 SECONDS AND BEING MOSTLY
WIND WAVE DRIVEN. -27
FIRE WEATHER...TODAY THROUGH THURSDAY
CRITICAL FIRE WEATHER
CONDITIONS ARE EXPECTED THIS AFTERNOON AND EVENING OVER THE
CENTRAL/SOUTHERN WILLAMETTE VALLEY MAINLY TO THE SOUTH OF SALEM
THIS AFTERNOON AND EVENING DUE TO BREEZY NORTH WINDS WITH GUSTS
UP TO APPROXIMATELY 25 MPH COMBINED WITH LOW RELATIVE HUMIDITY
VALUES DOWN TO 20-25%. A FEW MAX GUSTS UPWARDS OF 28 MPH ARE
POSSIBLE. THIS MEANS ANY NEW OR EXISTING FIRES IN THIS AREA
COULD EXHIBIT RAPID FIRE SPREAD. AS SUCH, A RED FLAG WARNING
REMAINS IN EFFECT FOR FIRE WEATHER ZONE 685. 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 WITH CONDITIONS APPROACHING RED FLAG
WARNING CRITERIA. WE HAVE A DEVELOPING THERMALLY INDUCED SURFACE
TROUGH CAUSING THESE WINDS AS IT LIFTS NORTHWARD INTO THE REGION.
WHILE WINDS AT THE SURFACE HAVE A LARGE NORTHERLY COMPONENT TODAY,
EASTERLY WINDS WILL BE DEVELOPING ALOFT AROUND 3000-6000 FT THIS
MORNING. 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
AS LOW AS 18-25%.
TONIGHT INTO TUESDAY, THE SURFACE THERMAL TROUGH IS EXPECTED TO
AMPLIFY WHILE THE AXIS OF THIS FEATURE SHIFTS TOWARDS THE
OREGON COAST. THIS WILL FURTHER INCREASE EASTERLY WINDS IN THE
COLUMBIA RIVER GORGE AND CASCADES, IN ADDITION TO A LOWERING
SUBSIDENCE INVERSION WITH SHARP OVERNIGHT THERMAL BELTS/POOR
OVERNIGHT HUMIDITY RECOVERIES, PARTICULARLY IN THE CASCADES.
EASTERLY WINDS ON TUESDAY 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. CONDITIONS THEN REMAIN DRY AND WINDY IN
THE WESTERN GORGE AS EASTERLY WINDS CONTINUE TUESDAY NIGHT THROUGH
WEDNESDAY EVENING. WINDS IN THE GORGE WILL BE STRONGEST TUESDAY
MORNING THROUGH EARLY TUESDAY AFTERNOON, AND AGAIN TUESDAY NIGHT
THROUGH EARLY WEDNESDAY AFTERNOON. RELATIVE HUMIDITY VALUES WILL BE
LOWEST TUESDAY AFTERNOON AND WEDNESDAY AFTERNOON, DOWN TO 15-20%.
POOR OVERNIGHT HUMIDITY RECOVERIES ARE EXPECTED TUESDAY NIGHT WITH
MAXIMUM RELATIVE HUMIDITY VALUES RANGING BETWEEN 35-45%. THEREFORE, A
RED FLAG WARNING HAS BEEN ISSUED FOR THE WESTERN GORGE, FIRE WEATHER
ZONE 636, FROM 11 AM PDT TUESDAY THROUGH 8 PM PDT WEDNESDAY. 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. NEVERTHELESS, ELEVATED FIRE WEATHER CONCERNS STILL
EXIST IN THESE AREAS, AS WELL AS IN THE PORTLAND METRO AND WILLAMETTE
VALLEY WHERE NNE TO NE WINDS ARE EXPECTED TO GUST UP TO APPROXIMATELY
15-20 MPH IN THE AFTERNOON. AGAIN EXPECT POOR RIDGETOP RELATIVE
HUMIDITY RECOVERIES IN THE CASCADES AND ROAST RANGE TUESDAY NIGHT.
FIRE WEATHER CONCERNS DECREASE MORE CONSIDERABLY BY THURSDAY, WITH
ONE POTENTIAL EXCEPTION. THURSDAY IS WHEN WE TRANSITION TO ONSHORE
FLOW, WHICH WILL BRING BREEZY WESTERLY WINDS IN THE CENTRAL GORGE AND
HOOD RIVER AREA. GIVEN CONDITIONS WILL STILL BE DRY, ELEVATED FIRE
WEATHER CONCERNS WILL REMAIN IN PLACE. -23/99
PQR WATCHES/WARNINGS/ADVISORIES
OR...HEAT ADVISORY FROM NOON TUESDAY TO 11 PM PDT WEDNESDAY FOR
ORZ104-105-108>118.
RED FLAG WARNING UNTIL 8 PM PDT THIS EVENING FOR ORZ685.
WA...HEAT ADVISORY FROM NOON TUESDAY TO 11 PM PDT WEDNESDAY FOR
WAZ204>208.
RED FLAG WARNING FROM 11 AM TUESDAY TO 8 PM PDT WEDNESDAY FOR
WAZ636.
PZ...SMALL CRAFT ADVISORY UNTIL 1 AM PDT TUESDAY FOR PZZ210.
SMALL CRAFT ADVISORY UNTIL 5 AM PDT WEDNESDAY FOR PZZ251>253-
271>273.
WWW.WEATHER.GOV/PORTLAND
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSPORTLAND
X.COM/NWSPORTLAND
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