705
FXUS66 KPQR 040418
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
918 PM PDT WED SEP 3 2025
UPDATED SHORT TERM AND AVIATION DISCUSSIONS.
SYNOPSIS
HIGH PRESSURE INLAND CONTINUES TO DRIVE HOT WEATHER
ACROSS MUCH OF THE REGION, WITH WIDESPREAD MODERATE HEATRISK
AND LOCALIZED MAJOR HEATRISK FOCUSED IN THE COLUMBIA GORGE AND
HOOD RIVER VALLEY. A SLIGHT CHANCE OF ISOLATED THUNDERSTORMS
ALONG THE CASCADES AND FOOTHILLS THURSDAY AFTERNOON AND
EVENING. A SHIFT IN THE PATTERN LATER THIS WEEK WILL ALLOW
COOLER AND WETTER WEATHER TO ARRIVE BY THE WEEKEND.
SHORT TERM...NOW THROUGH FRIDAY NIGHT
ISOLATED SHOWERS COULD
CONTINUE ACROSS NW OREGON AND SW WASHINGTON THROUGH AROUND
MIDNIGHT OR SO, THOUGH VERY LITTLE RAINFALL IS EXPECTED WITH
SHOWERS. OVERNIGHT LOWS WILL AGAIN STAY WARM - MID 60S TO LOW
70S IN THE GORGE AND PORTLAND/VANCOUVER METRO, 50S TO 60S
ELSEWHERE.
THE CURRENT WEAKENING COMPACT LOW WILL LIFT NORTH INTO WESTERN
WASHINGTON BY THURSDAY, KEEPING SOME CHANCES FOR ADDITIONAL
CONVECTION MAINLY NEAR THE CASCADES, THOUGH COVERAGE LOOKS LESS
WIDESPREAD. WITH CLOUD COVER THINNING TOMORROW, HIGHS MAY END UP
A FEW DEGREES WARMER THAN TODAY ACROSS THE WILLAMETTE VALLEY
AND OTHER INLAND AREAS. HOWEVER, THE GORGE AND HOOD RIVER
VALLEY ARE STILL EXPECTED TO CLIMB INTO THE LOW TO MID 90S.
THIS CONTINUES TO SUPPORT MAJOR HEATRISK IN THE GORGE AND HOOD
RIVER VALLEY WHERE A HEAT ADVISORY REMAINS IN EFFECT THROUGH 8
PM THURSDAY.
BY FRIDAY, COOLER TEMPERATURES BECOME MORE NOTICEABLE AS THE
RIDGE WEAKENS FURTHER, WITH HIGHS TRENDING DOWN A FEW TO SEVERAL
DEGREES AND HEATRISK LOWERING TO MOSTLY MINOR INLAND, EXCEPT
FOR LOCALLY HIGHER VALUES IN THE NORTHERN WILLAMETTE VALLEY AND
GORGE WHERE OVERNIGHT LOWS REMAIN ELEVATED. ~HALL/HEC
LONG TERM...SATURDAY THROUGH TUESDAY
A MORE SIGNIFICANT
CHANGE SETS IN THIS WEEKEND AS TROUGHING STRENGTHENS OVER THE
NORTHEAST PACIFIC AND BEGINS TO SHIFT INLAND. THIS WILL BRING A
COOLING TREND WITH MODERATE TO HIGH PROBABILITIES (50-75%) THAT
INLAND VALLEYS DIP BELOW 80 DEGREES ON SATURDAY, WITH EVEN
HIGHER PROBABILITIES (70-90%) BY MONDAY. PRECIPITATION CHANCES
ALSO INCREASE WITH THIS SHIFT, THOUGH ENSEMBLE GUIDANCE VARIES
ON AMOUNTS. ROUGHLY HALF OF SOLUTIONS SUGGEST MEASURABLE RAIN
SOMETIME EARLY NEXT WEEK, ESPECIALLY NEAR THE CASCADES AND ALONG
THE COAST. OVERALL, EXPECT A TURN TOWARD COOLER, UNSETTLED
WEATHER BEGINNING THIS WEEKEND AND CONTINUING INTO EARLY NEXT
WEEK. ~HALL
AVIATION
EXPECT VFR CONDITIONS TO PERSIST THROUGH THE TAF
PERIOD AT INLAND SITES. ALONG THE COAST, MAINLY IFR/LIFR
CONDITIONS ARE EXPECTED, POSSIBLY LIFTING TO MVFR/VFR FOR A BRIEF
PERIOD SOMETIME BETWEEN 20Z THU THROUGH 00Z FRI. WINDS GENERALLY
VARIABLE AND LESS THAN 10 KTS, BECOMING NORTH TO NORTHWEST AFTER
18Z THU. CASCADE THUNDERSTORMS ARE POSSIBLE AGAIN AFTER 20Z THU.
IF TRAVELING OVER THE CASCADES, BE AWARE OF SMOKE/HAZE FROM
WILDFIRES OVER THE REGION.
PDX AND APPROACHES...VFR CONDITIONS PERSIST WITH HIGH CLOUD COVER
STREAMING OVERHEAD. WINDS GENERALLY REMAIN BELOW 10 KNOTS. -HEC
MARINE
MINIMAL CHANGE IN THE OVERALL FORECAST TODAY. A RIDGE
OF HIGH PRESSURE CONTINUES TO BUILD OVER THE FAR EASTERN
PACIFIC. THIS RIDGE WILL BRING STRONGER NORTHERLY WINDS ACROSS
ALL WATERS WITH GUSTS UP TO 20 KT DURING THE AFTERNOONS AND
EVENINGS THROUGH THE END OF THE WEEK. AS THE WEEKEND APPROACHES,
A PATTERN CHANGE IS EXPECTED AS A BROAD AREA OF LOW PRESSURE
FROM THE GULF OF ALASKA WILL SLOWLY START TO MOVE SOUTHWARD.
THIS WILL RESULT IN WINDS WEAKENING AND THEN BECOMING MORE
SOUTHERLY BY SATURDAY WITH WINDS REMAINING BELOW SMALL CRAFT
CONDITIONS.
SEAS HOLD AROUND 4-6 FT THROUGH FRIDAY DUE TO AN INCREASE IN WIND
WAVES AND A FRESH NORTHWESTERLY SWELL. AFTERWARDS, SEAS SUBSIDE
TOWARDS 2-4 FT BY THE WEEKEND AND INTO EARLY NEXT WEEK.
BROAD HIGH PRESSURE OVER THE WATERS WILL ALSO BRING ABOUT THE
PROBABILITY OF DENSE FOG, PRIMARILY FOR THE INNER WATERS AND THE
COLUMBIA RIVER BAR. THEREFORE, HAVE ISSUED A DENSE FOG ADVISORY
STARTING AT 8PM TONIGHT THROUGH 11AM THURSDAY MORNING AS
VISIBILITIES ARE EXPECTED TO FALL BELOW 1 NM. IT SHOULD BE NOTED,
THAT THERE REMAINS SOME UNCERTAINTY IN THE EXACT TIMING OF THE
DENSE FOG. /42
PQR WATCHES/WARNINGS/ADVISORIES
OR...HEAT ADVISORY UNTIL 8 PM PDT THURSDAY FOR ORZ120>122.
WA...HEAT ADVISORY UNTIL 8 PM PDT THURSDAY FOR WAZ209-210.
PZ...DENSE FOG ADVISORY UNTIL 11 AM PDT THURSDAY FOR PZZ210-251>253.
WWW.WEATHER.GOV/PORTLAND
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSPORTLAND
X.COM/NWSPORTLAND
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