742
FXUS66 KPQR 012234
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
330 PM PDT SAT AUG 1 2026
SYNOPSIS
COOLER TEMPERATURES WILL CONTINUE THROUGH SUNDAY IN THE
WAKE OF A COLD FRONT. WARM AND DRY MONDAY THROUGH FRIDAY WITH BREEZY
WINDS DURING THE AFTERNOON AND EVENING ON MONDAY AND TUESDAY. THE
WARMEST TEMPERATURES WILL OCCUR ON TUESDAY AND WEDNESDAY WITH HIGHS
IN THE 90S FOR INLAND VALLEYS AND 70S AT THE COAST, RESULTING IN A
MODERATE HEATRISK FOR THE INTERIOR LOWLANDS. WILDFIRE SMOKE IS
EXPECTED TO INCREASE WEST OF THE CASCADES ON MONDAY AND TUESDAY AS
WINDS BEGIN TO TURN MORE OFFSHORE.
SHORT TERM...SATURDAY EVENING THROUGH MONDAY NIGHT
A COLD FRONT
WILL PUSH EAST OF THE CASCADES SATURDAY EVENING, BRINGING CLEARING
SKIES AND DECREASING WINDS. TEMPERATURES WILL BE SLIGHTLY COOLER
BEHIND THIS FRONT, WITH LOW TEMPERATURES IN THE UPPER 40S TO MID 50S
EXPECTED OVER INLAND VALLEYS TONIGHT. TEMPERATURES WILL BE COOLEST
OVER OUTLYING RURAL AREAS.
TEMPERATURES REMAIN SLIGHTLY BELOW AVERAGE ON SUNDAY WITH HIGHS IN
THE 70S, EXCEPT 60S AT THE COAST. CONDITIONS SHOULD BE DRY ON SUNDAY,
ALTHOUGH THERE IS A 5-10% CHANCE FOR LIGHT RAIN OR DRIZZLE ALONG THE
SOUTH WA/NORTH OR COAST IN THE 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 UPPER LEVEL
TROUGH THAT IS ON TRACK TO PUSH THROUGH WESTERN WA.
CONDITIONS THEN TREND WARM AND DRY ON MONDAY AS AN UPPER LEVEL RIDGE
BEGINS TO AMPLIFY AROUND 300-400 MILES OFFSHORE. MODEL GUIDANCE IS IN
GOOD AGREEMENT FOR HIGH TEMPERATURES IN THE MID TO UPPER 80S MONDAY
AFTERNOON FOR INLAND VALLEYS AND 70S AT THE COAST. 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.
DETAILS FOR THIS ARE DISCUSSED BELOW IN THE FIRE WEATHER SECTION. IT
IS ALSO WORTH MENTIONING THAT WINDS WILL BECOME 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. THE RRFS SMOKE
MODEL BACKS THIS EXPECTATION UP, BUT ALSO SUGGESTS SMOKE WILL NOT BE
PARTICULARLY DENSE WEST OF THE CASCADES. -23
LONG TERM...TUESDAY THROUGH FRIDAY NIGHT
MODELS AND THEIR
ENSEMBLES ARE IN GOOD AGREEMENT TUESDAY AND WEDNESDAY WILL BE THE
HOTTEST DAYS OF THE WEEK AS AN UPPER LEVEL RIDGE OVER THE COASTAL
WATERS MOVES INLAND. ALTHOUGH THE RIDGE AXIS IS EXPECTED TO MOVE
INLAND, THE RIDGE WILL BE DEAMPLIFYING AT THE SAME TIME. THIS WILL
PREVENT EXTREME HEAT WITH TRIPLE DIGIT TEMPERATURES FROM DEVELOPING.
HOWEVER, IT WILL STILL BE HOT WITH HIGH TEMPERATURES SOMEWHERE IN THE
LOW TO MID 90S FOR INLAND VALLEYS AND 70S AT THE COAST. THIS WILL
RESULT IN A MINOR HEATRISK AT THE COAST AND A MODERATE HEATRISK FOR
INLAND VALLEYS, BRINGING AN INCREASED RISK FOR HEAT-RELATED ILLNESSES
FOR VULNERABLE POPULATIONS THAT ARE SENSITIVE TO HEAT. PROBABILITIES
FOR A MAJOR HEATRISK ARE LOW, RANGING BETWEEN 5-20% FOR MOST INLAND
VALLEY LOCATIONS. THE GOOD NEWS IS OVERNIGHT LOWS IN THE MID 50S TO
LOWER 60S ALONG WITH LOW HUMIDITY WILL OFFER RELIEF FOR THOSE WITHOUT
ACCESS TO AIR CONDITIONING. TUESDAY WILL LIKELY SEE HAZY SKIES DUE TO
LINGERING WILDFIRE SMOKE IN THE AREA THAT IS EXPECTED TO BEGIN
PUSHING WEST OF THE CASCADES BEGINNING ON MONDAY AS LOW-LEVEL
OFFSHORE WINDS DEVELOP.
THE MAJORITY OF OF DETERMINISTIC AND ENSEMBLE GUIDANCE CONTINUE TO
SUGGEST DEPICT A RETURN TO ONSHORE WINDS BY LATE THURSDAY AND FRIDAY,
BRINGING SLIGHTLY COOLER TEMPERATURES BUT STILL A BIT ABOVE AVERAGE
WITH HIGHS IN THE MID TO UPPER 80S FOR INLAND VALLEYS. THE INCREASING
ONSHORE FLOW LATE IN THE WEEK WILL ALSO HELP CLEAR OUT ANY SMOKE AND
HAZE LINGERING IN THE AREA FROM MID-WEEK. -23
FIRE WEATHER...MONDAY THROUGH TUESDAY
THERE ARE ELEVATED FIRE
WEATHER CONCERNS IN THE WILLAMETTE VALLEY ON MONDAY AND TUESDAY
DURING THE AFTERNOON AND EVENING HOURS DUE TO BREEZY NORTH WINDS AND
LOW HUMIDITY. HOWEVER, CONFIDENCE LEVELS IN RED FLAG WARNING CRITERIA
BEING MET ARE LOWER THAN 50% ON BOTH DAYS, CURRENTLY RANGING BETWEEN
20-40%. THEREFORE, FIRE WEATHER WATCHES HAVE NOT BEEN ISSUED AT THIS
TIME, BUT BOTH DAYS BEAR A CLOSE WATCH. DETAILS ARE DISCUSSED BELOW.
THE OUTCOME WILL BE 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. CURRENTLY IT APPEARS IT WILL FORM 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 ISDUE 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.
AVIATION...THROUGH 00Z MON
VFR CONDITIONS HAVE RETURNED TO THE
AIRSPACE, WITH LINGERING LOW VFR CLOUDS HOLDING ON A BIT AS THE
FRONTAL SYSTEM DISSIPATES. WHILE VFR CONDITIONS WILL CONTINUE
THROUGH THE TAF PERIOD FOR INLAND TERMINALS, THERE IS A 30-50%
CHANCE OF MVFR CIGS RETURNING ALONG THE COAST FROM 05-19Z SUN.
CURRENT WEST TO NORTHWESTERLY WINDS AROUND 5-10 KT WILL SHIFT
ENTIRELY NORTHWESTERLY THIS EVENING AND CONTINUE SO THROUGH THE
PERIOD. THE ONE EXCEPTION IS WINDS ALONG THE COAST WILL INCREASE
TO AROUND 10-15 KT WITH GUSTS UP TO 20-25 KT BY 18-20Z SUN.
KPDX AND APPROACHES...VFR CONDITIONS THROUGH THE TAF PERIOD, WITH
A 10-20% CHANCE OF MVFR CIGS REDEVELOPING BETWEEN 11-15Z SUN.
NORTHWESTERLY WINDS 5-10 KT WILL CONTINUE THROUGH THE PERIOD. ~12
MARINE
WESTERLY FLOW TODAY WILL SHIFT NORTHERLY INTO SUNDAY AS
SURFACE HIGH PRESSURE BUILDS OFFSHORE. CHANCES FOR MAXIMUM WIND
GUSTS OF AT LEAST 21 KT ARE AROUND 85-95% FROM SUNDAY
AFTERNOON/EVENING THROUGH AT LEAST TUESDAY NIGHT WITH THE HIGHEST
RELATIVE PROBABILITIES ACROSS THE OUTER WATERS. GIVEN THIS HIGH
CONFIDENCE IN SMALL CRAFT CONDITIONS, A SMALL CRAFT ADVISORY WAS
ISSUED FOR THE INNER AND OUTER WATERS, INCLUDING THE COLUMBIA
RIVER BAR, STARTING MONDAY MID/LATE AFTERNOON. ONCE WE GET IN TO
THE MIDDLE OF THE WEEK THESE SMALL CRAFT CONCERNS PRIMARILY SHIFT
TO THE OUTER WATERS BUT LIKELY PERSIST THROUGH THE END OF THE
WEEK. WAVE HEIGHTS THROUGH THE FORECAST PERIOD REMAIN AROUND 5-8
FT AT 7-9 SECONDS. ~12/99
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FROM 5 PM SUNDAY TO 2 AM PDT MONDAY FOR
PZZ210.
SMALL CRAFT ADVISORY FROM 5 PM SUNDAY TO 5 AM PDT TUESDAY FOR
PZZ251-252-271-272.
SMALL CRAFT ADVISORY FROM 2 PM SUNDAY TO 5 AM PDT TUESDAY FOR
PZZ253-273.
WWW.WEATHER.GOV/PORTLAND
INTERACT WITH US VIA SOCIAL MEDIA:
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X.COM/NWSPORTLAND
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