269
FXUS66 KPQR 021122
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
422 AM PDT SUN AUG 2 2026
SYNOPSIS
ENJOY ONE FINAL DAY OF BELOW NORMAL TEMPERATURES
BEFORE CONDITIONS RAPIDLY WARM/DRY MONDAY INTO THE MIDDLE OF THE
WEEK. COMPARED TO PRIOR FORECASTS, HEAT RELATED IMPACTS HAVE
EMBARKED ON A RATHER STARK UPWARD TRAJECTORY AS HIGHS ARE NOW
FORECAST TO REACH INTO THE MID TO UPPER 90S ACROSS THE INLAND
VALLEYS AND 70S/80S AT THE COAST TUESDAY/WEDNESDAY. THIS WILL
RESULT IN MODERATE TO LOCALLY MAJOR HEATRISK ACROSS THE REGION.
OFFSHORE EASTERLY WINDS HELP TO INCREASE WILDFIRE SMOKE WEST OF
THE CASCADES ON MONDAY AND TUESDAY AS WELL. CONDITIONS SLOWLY
MODERATE LATE WEEK INTO THE WEEKEND.
SHORT TERM...TODAY THROUGH WEDNESDAY
THE PACIFIC NORTHWEST
REMAINS UNDER THE INFLUENCE OF A LARGE SCALE UPPER-LEVEL TROUGH
SITTING TO OUR NORTH TODAY KEEPING TEMPERATURES SLIGHTLY BELOW
AVERAGE WITH HIGHS IN THE 70S, EXCEPT 60S AT THE COAST. OVERALL
CONDITIONS SHOULD STAY MOSTLY DRY, ALTHOUGH THERE IS A 5-10%
CHANCE FOR LIGHT RAIN OR DRIZZLE ALONG THE SOUTH WA/NORTH OR
COAST AND COAST RANGE THIS MORNING GIVEN CONDITIONS WILL BE NEAR
SATURATION IN THE LOWEST 1 KM OF THE ATMOSPHERE AND THERE WILL
BE AT LEAST SOME WEAK FORCING FOR ASCENT AHEAD OF AN INCOMING
EMBEDDED SHORTWAVE TROUGH THAT IS ON TRACK TO PUSH THROUGH
WESTERN WA LATER TODAY.
AT THIS POINT CONFIDENCE IS HIGH CONDITIONS BEGIN A RATHER SHARP
WARMING AND DRYING TREND ON MONDAY AS AN UPPER LEVEL RIDGE
BEGINS TO AMPLIFY OVER THE EASTERN PACIFIC. MODEL GUIDANCE IS
IN GOOD AGREEMENT FOR DAYTIME TEMPERATURES INLAND TO JUMP 9-12
DEGREES DAY TO DAY, PUSHING HIGHS INTO THE MID TO UPPER 80S
MONDAY AFTERNOON. THE DEVELOPMENT OF BREEZY NORTH WINDS ARE
ALSO EXPECTED MONDAY AFTERNOON AND EVENING AS A THERMALLY
INDUCED SURFACE TROUGH BUILDS NORTHWARD INTO THE AREA. THIS WILL
BRING ELEVATED FIRE WEATHER CONCERNS GIVEN THE DRY CONDITIONS
THAT WILL BE IN PLACE, MAINLY IN THE CENTRAL AND SOUTHERN
WILLAMETTE VALLEY. SEE THE FIRE WEATHER SECTION BELOW FOR MORE
DETAILS. IT CERTAINLY WORTH HIGHLIGHTING WINDS FROM THIS POINT
ONWARD GAIN AN EASTERLY COMPONENT AND TURN MORE OFFSHORE IN THE
CASCADES, WHICH WILL ALLOW AT LEAST SOME WILDFIRE SMOKE TO BEGIN
PUSHING WESTWARD ONTO THE WEST SLOPES OF THE CASCADES AND INTO
THE FOOTHILLS/WILLAMETTE VALLEY AND COLUMBIA RIVER GORGE.
COME TUESDAY MODELS ARE IN GOOD AGREEMENT THIS EASTERLY
COMPONENT TO THE LOW TO MID LEVEL FLOW BEGINS TO PEAK THANKS TO
THE AXIS OF THE NEAR SURFACE THERMAL TROUGH SHIFTING TOWARDS THE
COASTLINE TO START THE DAY WHILE THE RIDGE OF HIGH PRESSURE
OFFSHORE NUDGES EVER-CLOSER TO THE PACIFIC NORTHWEST. ANTICIPATE
EASTERLY WINDS TO DEVELOP TUESDAY MORNING THROUGH THE COLUMBIA
GORGE AND CASCADE GAPS, ALTHOUGH LOCALIZED GUSTS GENERALLY STAY
IN THE 20-35 MPH RANGE FOR OUR MOST WIND-PRONE LOCATIONS (GUSTS
CLOSER TO 15-25 MPH FAR EAST PORTLAND METRO). WE'LL NEED TO
WATCH CLOSELY HOW FUTURE HIGH-RESOLUTION MODEL RUNS RESOLVE
THESE WINDS AS THIS CAN BE A CRITICAL FIRE WEATHER PATTERN THIS
TIME OF YEAR. AT LEAST WE CAN TAKE SOME SOLACE IN THE PRECEDING
COOLER CONDITIONS COUPLED WITH HIGHER RHS TODAY (SUNDAY) HELPING
TO TEMPER SOME OF THE POTENTIAL FIRE RELATED CONCERNS WITH THIS
PATTERN AT LEAST INITIALLY. ALL THIS BEING SAID, THE LOW-LEVEL
FLOW PATTERN IS DEFINITELY CONDUCIVE TO HOT CONDITIONS AS AIR
DESCENDING OFF THE CASCADES COMPRESSES AND WARMS BY THE TIME IT
GETS TO THE BASE OF THE FOOTHILLS. JUST HOW FAR THIS WARMER AIR
IS ABLE TO NAVIGATE WESTWARD WILL DEPEND ON THE PROGRESSION OF
THE THERMAL TROUGH THROUGH THE DAY. FOR NOW THOUGH IT APPEARS TO
STAY NEAR THE COAST/COAST RANGE LONG ENOUGH TO LAUNCH THE
INLAND VALLEYS INTO AT LEAST THE MID TO THE UPPER 90S COUPLED
WITH 70S TO 80S ALONG THE COAST. THE ONE FEATURE WHICH
INTRODUCES SOME UNCERTAINTY REGARDING TEMPERATURES TUESDAY (AND
WEDNESDAY AS WELL) IS WILDFIRE SMOKE GETTING TRANSPORTED INTO
THE AREA FROM EAST OF THE CASCADE CRESTS AS IT WOULD WORK
AGAINST WHAT WOULD OTHERWISE BE EFFICIENT DAYTIME INSOLATION.
THE RIDGE AXIS FINALLY TRACKS OVERHEAD ON WEDNESDAY
WITH MODELS NOW SHOWING THIS FEATURE ACTUALLY STRENGTHENING AS
IT MOVES EASTWARD. AS A RESULT, THIS CHANGE HAS LEAD TO AN
APPRECIABLE INCREASE IN FORECASTED DAYTIME HIGH TEMPERATURES
WEDNESDAY COMPARED TO WHERE THINGS STOOD 24HRS AGO. AND IT
WASN'T JUST A SMALL SUBSET OF MODELS PLAYING CATCH-UP EITHER,
THERE WAS A WHOLESALE RISE ACROSS ALMOST THE ENTIRE MODELING
SPACE. CONFIDENCE IS NOW MODERATE MAXIMUM TEMPERATURES PUSH
INTO THE MID TO UPPER 90S YET AGAIN ACROSS THE INLAND VALLEYS
WEDNESDAY WITH SLIGHTLY MORE ONSHORE FLOW WEST OF THE COAST
RANGE HELPING THOSE LOCATIONS MODERATE BACK INTO THE UPPER 60S
TO 70S. GIVEN THE FORECAST, HEATRISK IS NOW MODERATE TO LOCALLY
MAJOR ACROSS THE WILLAMETTE VALLEY, PORTLAND METRO, AND
SOUTHWEST WASHINGTON TUESDAY AND WEDNESDAY. PROBABILITIES FOR
MAJOR HEATRISK HAVE JUMPED TOO, RANGING BETWEEN 20-50%% FOR MOST
INLAND VALLEY LOCATIONS, HIGHEST IN THE PORTLAND METRO.
OVERNIGHT TEMPERATURES FOR THE LATTER AREA INTO THE COLUMBIA
GORGE AND ALONG THE BASE OF THE CASCADE FOOTHILLS MAY ONLY DROP
INTO THE LOW TO MID 60S TUESDAY NIGHT AND WEDNESDAY NIGHT
LIMITING POTENTIAL RELIEF. SHOULD THE CURRENT FORECAST HOLD,
HEAT RELATED HIGHLIGHTS MAY BE NECESSARY DURING THE TUESDAY AND
WEDNESDAY TIME PERIOD. IF YOU PLAN ON SPENDING TIME OUTDOORS
KEEP IN MIND THE INCREASED RISK FOR HEAT-RELATED ILLNESSES EARLY
TO MID-WEEK. -99
LONG TERM...THURSDAY THROUGH SATURDAY
MODEL UNCERTAINTY HAS
INCREASED LATE WEEK, PARTICULARLY ON THURSDAY, THANKS IN-PART
TO DETERMINISTIC AND ENSEMBLE GUIDANCE DEVIATING ON JUST HOW
QUICKLY THE RIDGE OF HIGH PRESSURE MOVES EASTWARD. A FASTER
PROGRESSION WOULD LEAD TO MORE NOTICEABLE MODERATION ON
THURSDAY, HOWEVER, GUIDANCE HAS BEEN TRENDING TOWARDS A SLOWER
AND THUS WARMER SCENARIO WHICH LEAVES THE INFLUENCE OF THE
RIDGE OVERHEAD A TOUCH LONGER. OF PARTICULAR NOTE IS THE
DIFFERENCE IN PROJECTED HIGH TEMPERATURES ON THURSDAY BETWEEN
LONGSTANDING NUMERICAL ENSEMBLE MODELING SYSTEMS AND THEIR
NEWER AI BASED COUNTERPARTS. THE LATTER AI ENSEMBLES (ECMWF
AIFS, AIGEFS) LEAN TOWARDS A SLOWLY (WARMER) SOLUTION COMPARED
TO THE FORMER WHICH HAS INCREASING ONSHORE INFLUENCE RESULTING
IN A ROUGHLY 3-6 DEGREE DISCREPANCY (LOW 90S VS MID TO UPPER 90S
INLAND). IT'LL BE INTERESTING TO SEE WHICH OF THESE SYSTEMS END
UP WINNING OUT IN THE END BUT THE FORECAST REFLECTS THE MORE
"OPTIMISTIC" NUMERICAL MODELING AT THE MOMENT. SHOULD THE
CURRENT TREND OF MODEL RUN TO RUN TEMPERATURES INCREASES
CONTINUE, HIGH TEMPERATURES ON THURSDAY MAY NEED TO BE BOOSTED
FURTHER, THUS EXTENDING HEAT IMPACTS. FORTUNATELY, THERE APPEARS
TO BE MORE CONSENSUS FOR TEMPERATURES TO MODERATE BACK TOWARDS
NORMAL FRIDAY INTO THE WEEKEND AS WEAK ONSHORE INFLUENCE
RETURNS. THE INCREASING ONSHORE FLOW WILL ALSO HELP CLEAR OUT
ANY SMOKE AND HAZE LINGERING IN THE AREA AS WELL, A NICE ADDED
BONUS. -99
AVIATION...THROUGH 12Z MON
GENERALLY VFR CONDITIONS REMAIN OVER
THE AIRSPACE THIS MORNING WITH CIGS SCT TO BKN AT 4-6KFT. THE
LATEST GUIDANCE SUGGESTS CHANCES FOR MVFR CIGS ALONG THE COAST THROUGH
18Z WITH HOURLY PROBABILITIES OF 20-40%. VFR CONDITIONS ARE
LIKELY TO PERSIST INLAND BUT THERE IS A LOW (10-20%) CHANCE OF
MVFR CIGS BETWEEN 12-19Z BUT LIKELY NOT PERSISTENT OVER ONE
PARTICULAR AREA. HIGH CONFIDENCE IN VFR CONDITIONS THIS AFTERNOON
INLAND TERMINALS. OVERALL LIGHT NORTHWEST WINDS BECOMING MORE
NORTHERLY AFTER 15-18Z WITH WIND GUSTS OF 15-25 KT POSSIBLE INTO
THE EVENING HOURS.
KPDX AND APPROACHES...VFR CONDITIONS ARE HEAVILY FAVORED THROUGH
THE TAF PERIOD, WITH A ~15% CHANCE OF MVFR CIGS DEVELOPING
BETWEEN 12-18Z SUN. BASED ON CURRENT OBSERVATIONS, THIS LOW
PROBABILITY SEEMS REASONABLE. EXPECT NORTH TO NORTHWEST WINDS TO
PEAK IN THE LATE AFTERNOON WITH GUSTS AROUND 20 KNOTS POSSIBLE
BETWEEN 23Z-04Z. -99
MARINE
BEHIND THE FRONTAL BOUNDARY WHICH PASSED OVERHEAD
YESTERDAY (SATURDAY) NORTHERLY FLOW BEGINS TO INCREASE IN
EARNEST ACROSS THE COAST WATERS TODAY, ESPECIALLY THIS
AFTERNOON. CHANCES FOR MAXIMUM WIND GUSTS OF AT LEAST 21 KNOTS
REMAIN AROUND 85-95%+ FROM THIS LATE AFTERNOON AND EVENING
THROUGH THE MIDDLE OF THE WEEK WITH THE HIGHEST RELATIVE
PROBABILITIES ACROSS THE OUTER WATERS. THUS, A SMALL CRAFT
ADVISORY REMAINS IN EFFECT STARTING THIS AFTERNOON ACROSS THE
INNER AND OUTER WATERS INCLUDING THE COLUMBIA RIVER BAR. IT
STILL APPEARS THE SMALL CRAFT WIND CONCERNS SHIFT MORESO 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. -99/12
FIRE WEATHER...MONDAY THROUGH WEDNESDAY
THERE REMAIN
ELEVATED FIRE WEATHER CONCERNS IN PORTIONS OF THE WILLAMETTE
VALLEY ON MONDAY AND TUESDAY DURING THE AFTERNOON AND EVENING
HOURS DUE TO BREEZY NORTH-NORTHEAST WINDS AND LOW HUMIDITY.
HOWEVER, CONFIDENCE LEVELS IN RED FLAG WARNING CRITERIA BEING
MET ARE STILL LOWER THAN 50% ON BOTH DAYS, RANGING BETWEEN
20-40%. DUE TO DEVELOPING EASTERLY FLOW THE WESTERN COLUMBIA
RIVER GORGE IS ALSO AN AREA TO WATCH TUESDAY INTO WEDNESDAY AS
WELL. FIRE WEATHER WATCHES HAVE NOT BEEN ISSUED AT THIS TIME,
BUT THIS TIME PERIOD BEARS A CLOSE WATCH.
THE OUTCOME REMAINS HIGHLY DEPENDENT ON THE EVOLUTION OF A
SURFACE THERMAL TROUGH THAT WILL BEGIN LIFTING NORTHWARD INTO
WESTERN OREGON MONDAY INTO TUESDAY. TYPICALLY IT BUILDS OVERHEAD
FROM SOUTHWESTERN OREGON (DRY NORTHERLY WINDS WHEN THIS OCCURS)
THEN IT MODULATES DIURNALLY BACK-AND-FORTH FROM THE COAST/COAST
RANGE (AM) TOWARDS I-5 AND/OR THE CASCADES (PM) HELPING TO
INFLUENCE THE MAGNITUDE AND PLACEMENT OF OFFSHORE FLOW. MODELS
INDICATE IT'LL DEVELOP ALONG THE SOUTH OREGON COAST MONDAY
MORNING BEFORE MOVING INLAND AND FURTHER TO THE NORTH IN THE
AFTERNOON. THIS PROGRESSION WOULD CAUSE NORTHERLY WINDS TO
AMPLIFY IN THE WILLAMETTE VALLEY, AND INCREASE 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 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
NEAR 25%. AS THE THERMAL TROUGH BUILDS INTO THE AREA, COULD SEE
GUSTS UP TO 20-25 MPH WITHIN THE WILLAMETTE VALLEY, CLARK
COUNTY LOWLANDS, AND ALONG THE COAST. IN THE SOUTHERN WILLAMETTE
VALLEY AROUND EUGENE THERE IS A HIGHER PROBABILITY OF SEEING
THESE WIND SPEEDS THAN IN THE NORTH. THIS IS DUE TO MORE OF A
CHANNELING/FETCH COMPONENT AND A TIGHTER NORTH-SOUTH PRESSURE
GRADIENT. THESE DRY AND BREEZY CONDITIONS WILL LEAD TO ELEVATED
FIRE WEATHER CONCERNS AS THEY OVERLAP MID/LATE AFTERNOON INTO
THE EARLY EVENING ON MONDAY, HOWEVER WINDS MAY BE JUST SHY OF
MEETING CRITERIA FOR A RED FLAG WARNING IN MOST LOCATIONS.
TUESDAY WILL BE EVEN DRIER WITH HUMIDITY VALUES WELL BELOW
CRITICAL THRESHOLDS, HOWEVER NORTHERLY WINDS WILL BE TRENDING
WEAKER AND ARE NOT EXPECTED TO MEET CRITERIA FOR A RED FLAG
WARNING AT THIS TIME.
OUR ATTENTION ALSO TURNS TO THE WESTERN COLUMBIA RIVER GORGE
TUESDAY WHERE OFFSHORE EASTERLY WINDS APPEAR INCREASINGLY LIKELY
TO START THE MORNING, CONTINUING THROUGH THE DAY WHILE RELATIVE
HUMIDITY VALUES DEGRADE. LOCALIZED GUSTS FOR PLACES LIKE
CORBETT AND THREE CORNER ROCK GENERALLY STAY IN THE 25-35 MPH
RANGE, CLOSER TO 15-25 MPH FAR EAST PORTLAND METRO. AT LEAST
CONCERNS ARE PARTIALLY TEMPERED BY THE PRECEDING COOLER/MOISTER
CONDITIONS TODAY. WHILE THE NEAR SURFACE THERMAL TROUGH DRIVING
THESE WINDS WEAKENS BY WEDNESDAY MORNING, PERSISTENT OFFSHORE
WINDS REMAIN PRESENT. FOR TUESDAY, IF FORECAST WINDS INCREASE
ANY FURTHER, AND/OR FORECAST RHS DROP, THIS IS ANOTHER REGION
WHICH MAY NEED A RED FLAG WATCH/WARNING ASSUMING FUELS ARE READY
TO BURN. LASTLY, THE PATTERN FAVORS POOR RELATIVE HUMIDITY
RECOVERIES FOR MID TO UPPER SLOPE LOCATIONS IN THE CASCADES,
CASCADE FOOTHILLS, AND PORTIONS OF THE COAST RANGE STARTING
MONDAY NIGHT THROUGH THE MIDDLE OF THE WEEK. -99/23
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
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 AM PDT
TUESDAY FOR PZZ251-252-271-272.
SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 5 AM 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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