782
FXUS66 KPQR 030518 AAA
AFDPQR
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PORTLAND OR
1018 PM PDT SUN AUG 2 2026
UPDATED AVIATION DISCUSSION.
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 06Z TUE
VFR CONDITIONS EXPECTED TO PERSIST
THROUGH THE TAF PERIOD AS SKIES REMAIN MOSTLY CLEAR AND MARINE
STRATUS IS EXPECTED TO STAY OFFSHORE. THERE IS A CHANCE COASTAL
TERMINALS SEE BRIEF MVFR CIGS BUT GUIDANCE ONLY SUGGESTS A 30-40%
CHANCE THROUGH 12Z. THERE IS ALSO A SMALL CHANCE INLAND ALONG THE
CASCADE FOOTHILLS BUT PROBABILITIES ARE LOWER AT 10-20%. NORTH TO
NORTHWEST WINDS AROUND 5-10 KT WILL TURN MORE NORTHEAST TO
EASTERLY AFTER 12Z, ESPECIALLY ALONG THE WESTERN SLOPES OF THE
CASCADES AND COAST RANGE. THIS WIND SHIFT WILL ALSO SEND SMOKE
FROM WILDFIRES ON THE EAST SIDE OF THE CASCADES TO THE WEST SIDE.
GIVEN THE LATEST MODEL RUNS, HAVE OPTED TO ADD SMOKE INTO THE LATE
MORNING/AFTERNOON PORTION OF INLAND TAF SITES WHERE CONCENTRATIONS
WILL BE MORE NOTICEABLE.
KPDX AND APPROACHES...VFR CONDITIONS EXPECTED. LOW (10-20%) CHANCE
FOR MVFR CIGS TO DEVELOP IN THE WESTERN COLUMBIA RIVER GORGE.
NORTHERLY WINDS AROUND 5 KT OVERNIGHT, INCREASING TO AROUND 10 KT
LATE IN THE MORNING. -19
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 UNTIL 2 AM PDT MONDAY FOR PZZ210.
SMALL CRAFT ADVISORY UNTIL 5 PM PDT TUESDAY 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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