837
FXUS66 KPQR 041751
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
1051 AM PDT TUE AUG 4 2026
UPDATED AVIATION DISCUSSION AND ADDED UPDATE SECTION BELOW.
UPDATE
VISIBLE SATELLITE IMAGERY AND AQI OBSERVATIONS
SNOW SMOKE IS PREVALENT NEAR THE SURFACE ACROSS NW OR AND SW WA
LATE THIS MORNING. 11AM TEMPERATURE OBSERVATIONS INDICATE THAT
ALTHOUGH TEMPERATURES ARE AROUND 6-10 DEGREES WARMER THAN 24
HOURS AGO, THEY HAVE NOT RISEN QUITE AS MUCH AS THEY SHOULD HAVE
AT THIS POINT TO REACH THE ORIGINAL FORECAST FOR TODAY, LIKELY
DUE TO THE IMPACT OF WILDFIRE SMOKE. ADDITIONALLY, THE 13Z NBM
HAS BROUGHT DOWN THE HIGH TEMPERATURE FORECAST FOR TODAY BY A
FEW DEGREES, ESPECIALLY FOR THE INTERIOR LOWLANDS WHICH ARE NOW
FORECAST TO PEAK IN THE LOW TO MID 90S INSTEAD OF MID TO UPPER
90S. AS SUCH, HAVE LOWERED TODAY'S TEMPERATURE FORECAST TO
MATCH.
SYNOPSIS
GOING THROUGH THE MIDDLE OF THE WEEK, HOT, DRY, AND
SMOKY CONDITIONS ARE ON TAP FOR SOUTHWESTERN WASHINGTON AND
NORTHWEST OREGON. HIGH TEMPERATURES FOR MOST INLAND VALLEY
LOCATIONS PEAK IN THE MID TO UPPER 90S TODAY THROUGH THURSDAY,
RESULTING IN A WIDESPREAD MODERATE TO LOCALLY MAJOR HEATRISK
IMPACTS. TEMPERATURES BEGIN TO TREND TOUCH COOLER FRIDAY INTO
THE WEEKEND WITH THE RETURN OF ONSHORE FLOW, WHICH WILL ALSO
PUSH ANY LINGERING WILDFIRE SMOKE AND HAZE BACK EAST OF THE
CASCADE CRESTS. FIRE WEATHER CONCERNS REMAIN IN THE FORECAST
THROUGH TODAY WEDNESDAY/THURSDAY PRIMARILY FOCUSED IN THE
COLUMBIA RIVER GORGE AND CASCADES.
DISCUSSION...NOW THROUGH MONDAY
A RIDGE OF HIGH PRESSURE
CONTINUES TO AMPLIFY JUST OFF THE COASTLINE OVER THE FAR EASTERN
PACIFIC HELPING TO DRIVE OUR HOT, DRY, AND RATHER SMOKY
CONDITIONS TODAY. DETERMINISTIC AND ENSEMBLE MODELS ARE IN GOOD
AGREEMENT SHOWING HIGH TEMPERATURES JUMPING ANOTHER 6-8 DEGREES
THIS AFTERNOON COMPARED TO YESTERDAY (MONDAY) LEADING TO MID TO
UPPER 90S ACROSS THE INLAND VALLEYS. DUE TO THE OFFSHORE FLOW
PATTERN FROM THE SURFACE TO ROUGHLY 800MB (~6000FT) FACILITATING
DOWNSLOPE COMPRESSIONAL WARMING OFF THE CASCADES, THE HOTTEST
RELATIVE TEMPERATURES REGIONALLY WILL MOST LIKELY BE FOUND AT
THE BASE OF THE FOOTHILLS INTO THE EASTERN WILLAMETTE VALLEY.
THEN HOT CONDITIONS PEAK ON WEDNESDAY AND THURSDAY, HOWEVER,
NOT WITHOUT A BIT OF FORECAST UNCERTAINTY FROM THE SMOKE AND
HAZE BEING PUSHED WEST OF THE CASCADES BY OFFSHORE/EASTERLY
FLOW. AREAS WITH DENSE WILDFIRE SMOKE WILL SEE HIGH TEMPERATURES
LIMITED BY SEVERAL DEGREES. FOR TODAY AT LEAST, MODELS GUIDANCE
SUGGESTS HIGHS WILL BE MOST LIMITED OVER THE NORTHERN
WILLAMETTE VALLEY, COLUMBIA RIVER GORGE, PORTLAND/VANCOUVER
METRO AND MT. HOOD NATIONAL FOREST. MEANWHILE, SMOKE IMPACTS TO
TEMPERATURES OVER THE REST OF SOUTHWEST WA AND NORTHWEST OR
SHOULD BE MINIMAL (MAYBE A DEGREE OR TWO) ASSUMING SIMILAR FIRE
ACTIVITY TO PAST DAYS. ON WEDNESDAY, THE LATEST RRFS MODEL
POINTS TO LITTLE IMPACT ON TEMPERATURES DUE TO A MORE DISPERSED
AND THINNER SMOKE LAYER. OVERNIGHT TEMPERATURES BEGINNING
TONIGHT THROUGH AT LEAST WEDNESDAY NIGHT ONLY BOTTOM OUT IN THE
UPPER 50S TO MID 60S AS WELL LIMITING THE TIME PERIOD OF
OVERNIGHT RELIEF, ESPECIALLY IN URBAN CENTERS. IT SHOULD QUICKLY
BE NOTED SMOKE HAS A MINIMAL IMPACT ON OVERNIGHT TEMPERATURES,
EVEN WHEN THICK. BUT REGARDLESS OF THE EXACT OUTCOME OF OUR
TEMPERATURES, CONDITIONS WILL BE HOT ENOUGH TO BRING AN
INCREASED RISK OF HEAT-RELATED ILLNESSES. AS SUCH, VARIOUS HEAT
ADVISORIES REMAIN IN EFFECT FOR MOST INLAND VALLEYS STARTING
TODAY. 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 THE AXIS OF THE BROAD UPPER-LEVEL RIDGE
FEATURE MEANDERS FURTHER EAST OF WESTERN OREGON/SOUTHWESTERN
WASHINGTON HELPING TO INCREASE ONSHORE FLOW. THAT SAID,
THERE'LLWINDYLIKELY BE ENOUGH INFLUENCE FROM THE HIGH PRESSURE
RIDGE ALOFT TO KEEP HIGH TEMPERATURES IN THE LOW 90S ACROSS THE
INLAND VALLEYS. AT LEAST AT THIS POINT ANY LINGERING WILDFIRE
SMOKE SHOULD BE FLUSHED FROM WEST OF THE CASCADE CRESTS. ONSHORE
FLOW IS EXPECTED TO STRENGTHEN FURTHER OVER THE WEEKEND INTO
EARLY NEXT WEEK BRINGING MORE APPRECIABLE MODERATION - MODERATE
TO HIGH CONFIDENCE FOR MAXIMUM TEMPERATURES RETURNING TO THE LOW
TO MID 80S BY SUNDAY/MONDAY. -99/23
AVIATION...THROUGH 18Z WED
SATELLITE IMAGERY AND TERMINAL
OBSERVATIONS AS OF LATE TUESDAY MORNING DEPICTS WIDESPREAD SMOKE
ACROSS NORTHWEST OREGON AND SOUTHWEST WASHINGTON AS WINDS FROM THE
EAST PUSH WILDFIRE SMOKE INTO THE AREA FROM CENTRAL/EASTERN
OREGON. LATEST PIREPS AND METARS SUGGEST THAT THIS SMOKE LAYER IS
GENERALLY AROUND 5-6 KFT, WITH SMOKE ALSO MIXING DOWN TO THE
SURFACE. GIVEN THAT OFFSHORE WINDS WILL CONTINUE INTO WEDNESDAY
AND KEEP SMOKE IN THE AREA, FU AND HZ HAS BEEN INCLUDED IN THE
TAFS THROUGHOUT THE FORECAST PERIOD. STILL EXPECTING
PREDOMINATELY VFR CONDITIONS, BUT SMOKE WILL LIKELY REDUCE
VISIBILITY TO 5-6 SM FOR MOST TERMINALS. THE NEAREST MAJOR
WILDFIRE IS THE GRASSHOPPER FIRE EAST OF MT. HOOD, AND AREAS IN
THE VICINITY AND TO THE WEST OF THIS FIRE WILL EXPERIENCE THE
DENSEST SMOKE WITH THE GREATEST VIS IMPACTS. WHILE WINDS REMAIN
PREDOMINATELY EASTERLY THROUGH THE COLUMBIA RIVER GORGE AND
CASCADES, EXPECT WINDS OUT OF THE NORTH/NORTHEAST FOR THE MAJORITY
OF TERMINALS TODAY WITH GUSTS UP TO 25 KT ALONG THE COAST AND UP
TO 20 KT ACROSS THE WILLAMETTE VALLEY. WINDS EASE OVERNIGHT.
KPDX AND APPROACHES...VFR CONDITIONS THROUGH THE TAF PERIOD WITH
SMOKE REDUCING VIS TO 5-6 SM AT TIMES, MAINLY THE LATTER. NORTH TO
NORTHWESTERLY WINDS AROUND 5-10 KT INCREASING THIS AFTERNOON AND
WEAKENING TONIGHT. -10
MARINE
HEADED INTO THE MIDDLE OF THE WEEK A RIDGE OF HIGH
PRESSURE WILL CONTINUE TO FACILITATE SMALL CRAFT ADVISORY
NORTHERLY WINDS ACROSS THE INNER AND OUTER WATERS AT TIMES,
INCLUDING THE COLUMBIA RIVER BAR. EXPECT THE STRONGEST RELATIVE
WINDS DURING THE AFTERNOON AND EVENING HOURS. THE ON THURSDAY
THE WINDS AT THE SURFACE BEGIN TO GAIN A SLIGHT WESTERLY
COMPONENT, GENERALLY SHIFTING TO THE NORTHWEST. OVERALL WIND
SPEEDS WILL DECREASE WITH GUSTS HOLDING IN THE 15-20 KNOT RANGE,
HIGHEST OUTER WATERS, BUT SEAS REMAIN RELATIVELY SIMILAR AROUND
5 TO 8 FT AT 8-9 SECONDS AND BEING MOSTLY WIND WAVE/FRESH SWELL
DRIVEN. -99
FIRE WEATHER...TODAY THROUGH THURSDAY
EASTERLY FLOW
CONTINUES TO INCREASE THROUGH THE COLUMBIA RIVER GORGE AND ALONG
THE CASCADE CREST-LINE DOWN INTO THE FOOTHILLS EARLY THIS
MORNING WITH GUSTS AROUND 15-30 MPH ALREADY BEING OBSERVED
COUPLED WITH FAIRLY POOR TO MODERATE RELATIVE HUMIDITY VALUES
(BELOW ~30-40%) AS WELL. THESE WINDS ARE EXPECTED TO PEAK MIDDAY
INTO THE EARLY AFTERNOON, LIKELY STRONGEST IN THE WESTERN GORGE
WITH GUSTS UP TO 30-40 MPH IN THE MOST WIND-PRONE LOCATIONS
(THREE CORNER ROCK). GIVEN FURTHER DEGRADED RELATIVE HUMIDITY
VALUES IN PLACE AFTER HEATING GETS UNDERWAY TODAY, CRITICAL FIRE
WEATHER CONDITIONS CAPABLE OF RAPID FIRE SPREAD WILL BE
POSSIBLE. CONDITIONS THEN REMAIN DRY AND BREEZY IN THE WESTERN
GORGE AS EASTERLY WINDS CONTINUE TONIGHT THROUGH A GOOD CHUNK OF
WEDNESDAY. A RED FLAG WARNING REMAINS IN EFFECT FOR THE WESTERN
GORGE, FIRE WEATHER ZONE 636, FROM 11 AM PDT TODAY THROUGH 8 PM
PDT WEDNESDAY. THROUGH THIS SAME TIME PERIOD 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 WILL 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. FIRE WEATHER CONCERNS DECREASE ON THURSDAY ALBEIT 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 TO NEAR CRITICAL WEATHER CONCERNS REMAIN
IN PLACE. -99/23
PQR WATCHES/WARNINGS/ADVISORIES
OR...HEAT ADVISORY UNTIL 11 PM PDT WEDNESDAY FOR ORZ104-105-108>118.
WA...HEAT ADVISORY UNTIL 11 PM PDT WEDNESDAY FOR WAZ204>208.
RED FLAG WARNING UNTIL 8 PM PDT WEDNESDAY FOR WAZ636.
PZ...SMALL CRAFT ADVISORY UNTIL 11 PM PDT THIS EVENING FOR PZZ210.
SMALL CRAFT ADVISORY UNTIL 5 AM PDT WEDNESDAY FOR PZZ251>253-
271>273.
WWW.WEATHER.GOV/PORTLAND
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