717
FXUS66 KPQR 051123
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
423 AM PDT WED AUG 5 2026
SYNOPSIS
THE REGION REMAINS UNDERNEATH A PATTERN FAVORING
HOT, DRY, AND RATHER SMOKY CONDITIONS AGAIN TODAY BUT RELIEF IS
ON THE HORIZON, EVENTUALLY. HIGH TEMPERATURES FOR MOST INLAND
VALLEY LOCATIONS PEAK IN THE LOW TO UPPER 90S THROUGH THURSDAY
AND FRIDAY ALTHOUGH WILDFIRE SMOKE MAY DAMPEN HIGH TEMPERATURES
SEVERAL DEGREES - MOST NOTABLY TODAY. HOWEVER, TEMPERATURES WILL
STILL BE WARM ENOUGH FOR WIDESPREAD MODERATE TO LOCALLY MAJOR
HEATRISK IMPACTS. TEMPERATURES BEGIN TO TREND TOUCH COOLER OVER
THE WEEKEND WITH THE RETURN OF STRONG ONSHORE FLOW EVICTING ANY
LINGERING WILDFIRE SMOKE AND HAZE BACK EAST OF THE CASCADE
CRESTS BY THIS POINT. MORE SEASONABLE CONDITIONS ARE ANTICIPATED
EARLY NEXT WEEK.
DISCUSSION...TODAY THROUGH TUESDAY
A SMOKY SKY MUTING THE
SUN TO A BURNT ORANGE AND RED HUE IS CERTAINLY A GLOOMY WAY TO
START THE DAY FOR MOST, BUT THE COMBINATION OF OFFSHORE FLOW AND
AMPLE WILDFIRE ACTIVITY JUST TO OUR EAST HAS UNFORTUNATELY LED
TO SUCH CONDITIONS PERSISTING. THE RIDGE OF HIGH PRESSURE
HELPING TO DRIVE OUR OFFSHORE WINDS, HOT TEMPERATURES, AND LOW
DAYTIME HUMIDITY PEAKS OVER THE REGION TODAY INTO THURSDAY
ALLOWING TEMPERATURES TO WARM EVEN MORE COMPARED TO THE UPPER
80S AND LOW 90S WE SAW YESTERDAY (TUE). CURRENT MODEL OUTPUTS
INDICATE HIGH TEMPERATURES COULD RISE INTO THE UPPER 90S THROUGH
TOMORROW AFTERNOON, HOWEVER, THE SILVER LINING TO THE ALL THE
SMOKE GIVING US "MORDOR" VIBES IS DECREASING INSOLATION AND THUS
SLIGHTLY COOLER TEMPERATURES THAN THERE OTHERWISE WOULD BE.
CONFIDENCE IS HIGH MAXIMUM TEMPERATURES WILL ONCE AGAIN BE
IMPACTED BY THE SMOKE AND WHILE THE FORECAST WAS ADJUSTED
SOMEWHAT TO COMPENSATE, A 1-3 DEGREE DECREASE STILL MIGHT NOT
BE ENOUGH. WE'LL CONTINUE TO ASSESS THE FORECAST THIS MORNING
ONCE WE GET A BETTER HANDLE ON THE THICKNESS OF THE SMOKE POST-
SUNRISE.
THERE IS A GROWING DEGREE OF HOPE FOR THE RETURN TO CLEARER
SMOKE-FREE SKIES LATE THIS WEEK. MODELS ARE IN EXCELLENT
AGREEMENT SHOWING THE AXIS OF THE UPPER LEVEL RIDGE SLOWLY
MOVING INTO EASTERN OR/WA LATE WEDNESDAY INTO THURSDAY ALLOWING
THE FLOW WILL BEGIN SHIFTING ONSHORE FROM THE WEST. BEYOND THE
BROADER ~24HR PERIOD OF THIS TRANSITION THERE IS SOME
UNCERTAINTY ON EXACTLY WHEN THIS SHIFT OCCURS AT THE SURFACE
ALONG THE I-5 CORRIDOR PORTLAND SOUTHWARD, BUT IT WILL BEGIN
PUSHING SMOKE BACK EAST OF THE CASCADES IN EARNEST LATE
THURSDAY INTO FRIDAY, ALBEIT SLOWLY FOR OUR INLAND VALLEYS
INITIALLY. IF SMOKE CLEARS OUT BY THE FIRST HALF OF THURSDAY,
THEN TEMPERATURES COULD PEAK CLOSER TO THE MID TO UPPER 90S. IF
IT DOESN'T CLEAR OUT UNTIL LATER THURSDAY OR THURSDAY NIGHT,
SMOKE WOULD CONTINUE IMPACTING TEMPERATURES AND KEEP THEM
PINNED IN THE LOW TO MID 90S.
REGARDLESS OF THE EXACT OUTCOME OF THE TEMPERATURES THE NEXT
SEVERAL DAYS, CONDITIONS WILL BE WARM ENOUGH TO BRING AN
INCREASED RISK OF HEAT-RELATED ILLNESSES. AS SUCH, VARIOUS HEAT
ADVISORIES REMAIN IN EFFECT FOR MOST INLAND VALLEYS THROUGH
TODAY AND THURSDAY. 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. THIS COULD ALSO CAUSE AN IMPACT EVEN WITH
SLIGHTLY LOWER DAYTIME TEMPERATURES AS HOUSES MAY RETAIN MORE
HEAT IF WINDOWS CAN'T BE OPENED TO ADEQUATELY COOL OFF.
HEADING INTO FRIDAY THE AXIS OF THE BROAD UPPER-LEVEL RIDGE
FEATURE MOVES EVEN EAST OF OR/WA, HELPING TO INCREASE ONSHORE
FLOW. THAT SAID, THERE WILL LIKELY BE ENOUGH INFLUENCE FROM THE
HIGH PRESSURE RIDGE ALOFT AND SLIGHT INCREASE IN UPPER-LEVEL
HEIGHTS TO KEEP HIGH TEMPERATURES IN THE LOW 90S ACROSS THE
INLAND VALLEYS. AT LEAST AT THIS POINT ANY LINGERING WILDFIRE
SMOKE SHOULD BE COMPLETELY FLUSHED FROM WEST OF THE CASCADE
CRESTS ASSUMING NO ADDITIONAL NEW STARTS LOCALLY. ONSHORE FLOW
IS EXPECTED TO STRENGTHEN FURTHER OVER THE WEEKEND INTO EARLY
NEXT WEEK HELPING TEMPERATURES TO MODERATE BACK CLOSE TO NORMAL
WITH MODERATE TO HIGH CONFIDENCE FOR MAXIMUM TEMPERATURES
RETURNING TO THE LOW TO MID 80S SUNDAY THROUGH TUESDAY. IF
YOU'RE LOOKING FOR ANY SORT OF RAINFALL HEADED THROUGH THE
MIDDLE OF NEXT WEEK YOU'RE LIKELY OUT OF LUCK. THERE ARE NO
SIGNS OF ANY APPRECIABLE PRECIPITATION FOR THE REGION HEADED
INTO THE MIDDLE OF AUGUST. -99/03
AVIATION...THROUGH 12Z THU
SMOKE AND HAZE ARE THE PRIMARY
IMPACTS WE'RE MONITORING TODAY AS OFFSHORE FLOW NEAR THE SURFACE
KEEPS PUMPING WILDFIRE SMOKE FROM EASTERN OREGON AND WASHINGTON
OVERHEAD. EARLY THIS MORNING CONDITIONS ARE A MIX OF VFR TO
MVFR WITH SEVERAL TERMINALS IN THE WILLAMETTE VALLEY AND
PORTLAND METRO REPORTING 4-5SM VIS. IMPROVEMENT WILL BE HARD TO
COME BY FOR MOST SITES ALONG THE I-5 CORRIDOR TODAY BEYOND AN
OCCASIONAL RISE TO 6SM WITH THE BEST CHANCE FOR P6SM VIS AT
KHIO AND ALONG THE COAST. OTHERWISE MVFR VIS LIKELY PREVAILS
MOST HOURS. ONE OF THE MAIN DRIVERS OF OUR DEGRADED CONDITIONS
IS THE GRASSHOPPER FIRE BY MT. HOOD, AND AREAS IN THE VICINITY
AND TO THE WEST OF THIS FIRE WILL EXPERIENCE THE DENSEST SMOKE
WITH THE GREATEST VIS IMPACTS. HOWEVER, WINDS ARE EXPECTED TO
BECOME MORE WESTERLY IN THE LOWER LEVELS LATER WED AFTERNOON AND
EVENING, WHICH COULD HELP CONDITIONS IMPROVE SLIGHTLY BACK TO
6SM VFR AFTER 00-06Z THU - LOW CONFIDENCE REGARDING THE EXACT
TIMING. FOR COASTAL SITES, EXPECT THIS WESTERLY PUSH OF AIR THIS
EVENING TO BE ACCOMPANIED BY MARINE STRATUS AND THUS A GROWING
LIKELIHOOD (50-80%) FOR MVFR/IFR CONDITIONS AFTER 05-08Z
THURSDAY.
KPDX AND APPROACHES...CONDITIONS HAVE DROPPED TO MVFR EARLY THIS
MORNING WITH LITTLE IMPROVEMENT ANTICIPATED THROUGH THE DAY DUE TO
THE PROXIMITY TO THE GRASSHOPPER FIRE AND EASTERLY WINDS ALOFT
THIS MORNING. DEPENDING ON FIRE ACTIVITY, WOULD ESTIMATE THERE IS
A 15-20% CHANCE FOR SUB 3SM VIS BEFORE 00-03Z THUR, AFTER WHICH
POINT CONDITIONS BEGIN TO GRADUALLY IMPROVE. NORTHWEST WINDS
AROUND ARE 5-10 KT EXPECTED, STRONGEST IN THE AFTERNOON AND
EVENING. -99
MARINE
AS WE GO THROUGH THE REST OF THE WEEK INTO THE
WEEKEND HIGH PRESSURE WILL MAINTAIN NORTHERLY WINDS ACROSS THE
INNER AND OUTER WATERS. SMALL CRAFT ADVISORIES ARE IN EFFECT FOR
THE OUTER WATERS UNTIL 5 PM TODAY DUE TO BOTH WINDS AND A
CHOPPY SEAS STATE WITH CONDITIONS JUST UNDER CRITERIA ACROSS THE
INNER WATERS AND AT THE COLUMBIA RIVER BAR. WINDS AND SEAS
GRADUALLY SUBSIDE TONIGHT INTO THURSDAY, WITH A TYPICAL
SUMMERTIME PATTERN CONTINUING INTO NEXT WEEK. SEAS THROUGH THIS
PERIOD GENERALLY HOLD IN THE 4-7 FT RANGE AT 7-9 SECONDS WITH
WIND GUSTS BETWEEN 14-20 KNOTS, HIGHEST DURING THE AFTERNOON
HOURS AND ACROSS THE OUTER WATERS. -99/10
FIRE WEATHER...TODAY THROUGH THURSDAY
OFFSHORE EASTERLY FLOW
CONTINUES ACROSS THE CASCADES EARLY THIS MORNING WITH
OBSERVATIONS SHOWING GUSTS GENERALLY AROUND 10-20 MPH COUPLED
WITH POOR TO MODERATE RELATIVE HUMIDITY VALUES (28-40%
RIDGETOPS). THE LATEST MODEL GUIDANCE HAS DECREASED WIND SPEEDS
TODAY WITH GUSTS ONLY PEAKING BETWEEN 10-25 MPH LATE MORNING,
MAKING WHAT WAS ALREADY A MARGINAL RED FLAG WARNING TOUGHER TO
JUSTIFY. THUS, THE RED FLAG WARNING FOR THE WESTERN GORGE WAS
CANCELLED EARLY FOR FIRE WEATHER ZONE 636, ALTHOUGH IT SHOULD BE
EMPHASIZED ELEVATED FIRE WEATHER CONDITIONS ARE STILL
ANTICIPATED FOR MUCH OF THE REGION, ESPECIALLY THE WESTERN
COLUMBIA GORGE AND IN THE CASCADE/CASCADE FOOTHILLS. THE ON
THURSDAY WE TRANSITION TO ONSHORE FLOW WHICH WILL BRING BREEZY
WESTERLY WINDS IN THE CENTRAL GORGE AND HOOD RIVER AREA, FURTHER
INCREASING ON FRIDAY. GIVEN CONDITIONS WILL STILL BE DRY,
ELEVATED FIRE TO NEAR CRITICAL WEATHER CONCERNS REMAIN IN PLACE
HERE. -99
PQR WATCHES/WARNINGS/ADVISORIES
OR...HEAT ADVISORY UNTIL 11 PM PDT THIS EVENING FOR ORZ104-105.
HEAT ADVISORY UNTIL 11 PM PDT THURSDAY FOR ORZ108>118.
WA...HEAT ADVISORY UNTIL 11 PM PDT THURSDAY FOR WAZ204>208.
PZ...SMALL CRAFT ADVISORY UNTIL 5 PM PDT THIS AFTERNOON FOR
PZZ271>273.
WWW.WEATHER.GOV/PORTLAND
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