581
FXUS66 KPQR 092125
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
225 PM PDT FRI OCT 9 2026
SYNOPSIS
A WEAK COLD FRONT WILL PROGRESS EASTWARD OVER THE
CASCADES THIS EVENING, BRINGING AN END TO ANY LINGERING RAIN SHOWERS
FOR MOST LOCATIONS. CHANCES FOR LIGHT SHOWERS INCREASE SLIGHTLY ON
SATURDAY, HOWEVER MOST LOCATIONS WILL STAY DRY THROUGH THE DAY WITH
NOTICEABLY COOLER TEMPERATURES. COOL NIGHTS WILL BRING CHANCES FOR
MORNING FROST IN RURAL VALLEYS AWAY FROM URBAN CORES THIS WEEKEND
INTO EARLY NEXT WEEK. DRY CONDITIONS ARE EXPECTED SUNDAY THROUGH AT
LEAST MONDAY, WITH CHANCES FOR LIGHT RAIN INCREASING SLIGHTLY LATE
TUESDAY. TEMPERATURES TREND A BIT WARMER LATE IN THE WEEK WITH DRY
WEATHER AS UPPER-LEVEL RIDGING AMPLIFIES OVER THE REGION.
SHORT TERM...NOW THROUGH SUNDAY NIGHT
RADAR, SATELLITE, AND
SURFACE WEATHER OBSERVATIONS FROM EARLY FRIDAY AFTERNOON DEPICTED A
NARROW BAND OF RAIN OCCURRING ALONG A SOUTHWEST-NORTHEAST ORIENTED
COLD FRONT DRAPED OVER THE NORTHERN WILLAMETTE VALLEY,
PORTLAND-VANCOUVER METRO, COLUMBIA RIVER GORGE, AND SOUTH WA/NORTH OR
CASCADES. BEHIND THIS WEAK FRONT, ISOLATED LIGHT SHOWERS AND
SPRINKLES WERE BEING OBSERVED. AS THIS FRONT CONTINUES PROGRESSING
EASTWARDS OVER THE CASCADES THIS EVENING, RAIN WILL QUICKLY COME TO
AN END ASIDE FROM A FEW STRAY SHOWERS. OBSERVED RAIN TOTALS ARE
GENERALLY TOPPING OUT BETWEEN A TRACE AND 0.10 INCHES, EXCEPT FOR
SLIGHTLY HIGHER AMOUNTS AT THE COAST AND OVER HIGHER TERRAIN. WHILE
THIS ISN'T VERY MUCH RAIN, IT AT LEAST BREAKS OUR IMPRESSIVE 13-DAY
DRY STREAK.
OBSERVED WIND GUSTS WITH THIS FRONTAL PASSAGE HAVE GENERALLY PEAKED
BETWEEN 15-30 MPH, RESULTING IN LITTLE TO NO IMPACTS. HOWEVER,
WESTERLY WINDS IN THE CENTRAL COLUMBIA RIVER GORGE AND ON EXPOSED
RIDGETOPS ADJACENT TO THE GORGE ARE NOT EXPECTED TO PEAK UNTIL LATER
THIS EVENING IMMEDIATELY BEHIND THE FRONTAL PASSAGE. THESE AREAS CAN
EXPECT MAX GUSTS BETWEEN 25-45 MPH, STRONGEST ON EXPOSED RIDGETOPS.
EVEN THEN, WIND IMPACTS SHOULD BE MINOR.
ALTHOUGH RAIN WILL QUICKLY END THIS EVENING IN THE WAKE OF THE COLD
FRONT, CHANCES FOR RAIN WILL INCREASE AGAIN LATE TONIGHT INTO
SATURDAY. THIS IS IN RESPONSE TO A CLOSED UPPER-LEVEL LOW THAT IS SET
TO MOVE SOUTHWARD OVER THE REGION ON SATURDAY, BRINGING WRAP-AROUND
MOISTURE ON THE RELATIVELY COOLER BACKSIDE OF THE LOW OVER WESTERN
WA/OR. GIVEN THE LIGHT AND SHOWERY NATURE OF PRECIPITATION ON
SATURDAY, RAIN TOTALS WILL BE EVEN LIGHTER THAN FRIDAY FOR MOST
LOCATIONS (70-90% CHANCE RAIN AMOUNTS WILL BE LESS THAN 0.10"). IN
FACT, MANY LOCATIONS WILL SEE LITTLE TO NO RAIN AT ALL ON SATURDAY,
ESPECIALLY DOWNWIND OF HIGHER TERRAIN WHERE RAIN-SHADOWING WILL BE
MOST PRONOUNCED.
IT IS ALSO WORTH NOTING THAT CLEARING SKIES OVER THE UPPER HOOD RIVER
VALLEY TONIGHT MAY SUPPORT LOWS DIPPING INTO THE 30S DEPENDING ON HOW
QUICKLY WESTERLY WINDS COME TO AN END. IF WINDS BECOME CALM EARLY IN
THE NIGHT, LOWS COULD EASILY DROP TO 33-36 DEGREES. IF WINDS HANG ON
UNTIL SUNRISE, LOWS WOULD STRUGGLE TO FALL BELOW 40 DEGREES. THE
CURRENT FORECAST SUGGESTS WINDS WILL BECOME LIGHTER BY 4-5 AM, WHICH
WOULD ALLOW TEMPERATURES TO QUICKLY PLUMMET THEREAFTER UNTIL SUNRISE,
WITH AREAS OF FROST LIKELY FORMING SHORTLY BEFORE SUNRISE IN
WIND-SHELTERED AREAS WHERE LOWS BELOW 37 DEGREES ARE POSSIBLE. DEE
AND PARKDALE HAVE THE BEST CHANCE FOR FROST DEVELOPMENT BY SUNRISE ON
SATURDAY (80-90% CHANCE), AND THESE AREAS HAVE A FROST ADVISORY IN
EFFECT TO COVER THIS THREAT. ODELL MAY SEE PATCHY FROST AS WELL,
HOWEVER CHANCES ARE RELATIVELY LOWER AT AROUND 35-45%.
CHANCES FOR MORE WIDESPREAD AND IMPACTFUL MORNING FROST INCREASE
CONSIDERABLY SATURDAY NIGHT INTO SUNDAY MORNING GIVEN CLEAR SKIES AND
CALM WINDS WILL BE IN PLACE THROUGH THE NIGHT. THERE IS HIGH
CONFIDENCE FOR FROST AND MORNING LOWS BETWEEN 33-36 DEGREES OVER THE
UPPER HOOD RIVER VALLEY, CASCADE FOOTHILLS, NORTH OREGON COAST RANGE
VALLEYS, BATTLE GROUND/BRUSH PRAIRIE AREA, AND PORTIONS OF THE
CENTRAL/SOUTHERN WILLAMETTE VALLEY TO THE EAST OF THE I-5 CORRIDOR
NEAR THE FOOTHILLS (E.G. LEBANON, SCIO, ALBANY, HALSEY, BROWNSVILLE,
SWEET HOME, MARCOLA, MOHAWK, JASPER). SUB-FREEZING TEMPERATURES LESS
THAN 32 DEGREES ARE LIKELY IN DEE AND PARKDALE (70-90% CHANCE).
THEREFORE, VARIOUS FROST ADVISORIES ARE CURRENTLY IN EFFECT WHERE
CONFIDENCE IN FROST FORMATION IS HIGHEST. ANYONE GROWING OUTDOOR
PLANTS THAT ARE SUSCEPTIBLE TO FROST DAMAGE SHOULD COVER PLANTS OR
MOVE PLANTS INDOORS IF POSSIBLE. -23
LONG TERM...MONDAY THROUGH THURSDAY NIGHT
THE LONG TERM FORECAST
IS HIGHLIGHTED BY SEASONABLE TEMPERATURES MONDAY THROUGH WEDNESDAY
WITH TEMPERATURES BECOMING WARMER AND ABOVE AVERAGE LATE IN THE WEEK
AS AN UPPER-LEVEL RIDGE OVER THE FAR NORTHEAST PACIFIC EARLY IN THE
WEEK BECOMES MORE AMPLIFIED AND MOVES OVER THE U.S. WEST COAST. THIS
SET-UP WILL BRING MAINLY DRY CONDITIONS MONDAY THROUGH THURSDAY
NIGHT, WITH ONE POTENTIAL EXCEPTION LATE TUESDAY INTO WEDNESDAY
MORNING WHEN CHANCES FOR LIGHT RAIN INCREASE TO 10-30% AS A WEAK COLD
FRONT OVER THE COASTAL WATERS ATTEMPTS PUSHING INLAND. EVEN IF THIS
FRONT IS ABLE TO MOVE INLAND, IT WOULD BE DECAYING, WHICH SUGGESTS
RAIN AMOUNTS WOULD LIKELY BE VERY LIGHT (A TRACE TO 0.10 INCHES, IF
ANY AT ALL). CURRENTLY AROUND 50-70% OF THE TOTAL ENSEMBLE SPACE FROM
THE 00Z/OCT. 9 ITERATION OF THE ENS/GEFS/GEPS SHOWS NO RAIN AT ALL
TUESDAY INTO WEDNESDAY, WITH RAIN MOST FAVORED OVER SOUTHWEST WA,
COASTAL AREAS, AND HIGHER TERRAIN. NO IMPACTS ARE EXPECTED WITH THIS
FRONT.
FOR TEMPERATURES, EXPECT CHILLY MORNING LOWS TO CONTINUE MONDAY
MORNING AND TUESDAY MORNING, ESPECIALLY IN RURAL AREAS AND SHELTERED
VALLEYS WHERE LOWS IN THE MID 30S WILL SUPPORT FROST. LOCATIONS THAT
CURRENTLY HAVE FROST ADVISORIES IN EFFECT FOR SATURDAY NIGHT/SUNDAY
MORNING ARE THE AREAS WITH THE HIGHEST CHANCES FOR CONTINUED FROSTY
MORNINGS WITH LOWS BELOW 37 DEGREES ON MONDAY AND TUESDAY (40-65%
CHANCE, EXCEPT 80-90% IN THE UPPER HOOD RIVER VALLEY). AFTERNOON
TEMPERATURES WILL BE MUCH MORE MILD, WITH HIGHS IN THE MID TO UPPER
60S OVER THE LOWLANDS MONDAY THROUGH WEDNESDAY, WARMING INTO THE
UPPER 60S TO MID 70S ON THURSDAY. -23
AVIATION...THROUGH 00Z SUNDAY
A MIX ON CONDITIONS CONTINUE TO
AFFECT THE AIRSPACE AS A FRONTAL SYSTEM MOVES THROUGH THE AREA.
WHILE COASTAL TERMINALS HAVE IMPROVED TO VFR AS OF 21Z FRI, A MIX
OF CONDITIONS FROM VFR TO IFR CONTINUE AT INLAND TERMINALS AS RAIN
REDUCES CIGS AND VIS. EXPECT THESE DETERIORATED CONDITIONS TO MIX
OUT BY 22Z FRI, RESULTING IN VFR CONDITIONS THROUGHOUT THE
AIRSPACE, OF WHICH WILL CONTINUE THROUGH AT LEAST 08Z SAT. AROUND
08-12Z SAT, CHANCES FOR LOW STRATUS/FOG INCREASE AT A FEW
TERMINALS, NOTABLY AT KONP, KHIO, AND KEUG WITH CHANCES OF LIFR
CONDITIONS AROUND 10-20%. AS FOR OTHER TERMINALS, THERE IS A
15-25% CHANCE OF MVFR CIGS. ANY DETERIORATED CONDITIONS THAT OCCUR
WILL LIKELY IMPROVE BACK TO VFR BY 18-20Z SAT.
OTHERWISE, WEST/NORTHWESTERLY WINDS AROUND 6-12 KT CONTINUE ACROSS
THE INTERIOR LOWLANDS, THEN EASE AROUND 03Z SAT. ALONG THE COAST,
10-15 KT WINDS WITH GUSTS UP TO 21 KT WILL EASE AROUND 03-06Z SAT.
KPDX AND APPROACHES...VFR CONDITIONS THROUGH THE PERIOD.
WEST/NORTHWESTERLY WINDS AROUND 5-9 KT WILL EASE AFTER 03Z FRI.
THERE IS A 15-25% CHANCE OF MVFR CIGS BETWEEN 12-19Z SAT. ~12
MARINE
A FRONTAL SYSTEM HAS MOVED THROUGH MOST OF THE WATERS
TODAY, WITH THE REMAINDER OF THE FRONT MOVING THROUGH THE WATERS
SOUTH OF CAPE FOULWEATHER AS OF 2 PM. BREEZY NORTHWESTERLY WINDS
WITH GUSTS UP TO 25 KT CONTINUE TONIGHT INTO SATURDAY MORNING OVER
THE WATERS NORTH OF CAPE FALCON. WITH THIS FRONTAL SYSTEM BRINGING
A NORTHWESTERLY SWELL, SEAS WILL BUILD TO 9-12 FT AT 9-10 SECONDS
FROM NORTH TO SOUTH OVER MOST OF THE WATERS THIS EVENING THROUGH
SATURDAY AFTERNOON.
AS A RESULT OF SEAS BUILDING AND BECOMING STEEP AND CHOPPY, A
HAZARDOUS SEAS WARNING REMAINS IN EFFECT FOR THE OUTER WATERS
NORTH OF CAPE FALCON UNTIL 5 AM SATURDAY. ADDITIONALLY, SMALL
CRAFT ADVISORIES REMAIN IN EFFECT OVER ALL OF THE WATERS
(INCLUDING THE COLUMBIA BAR) EXCEPT FOR THE INNER WATERS SOUTH OF
CAPE FOULWEATHER AND OUTER WATERS NORTH OF CAPE FALCON UNTIL 2 PM
SATURDAY DUE TO STEEP AND CHOPPY SEAS OF 8-10 FT AT 9-10 SECONDS.
BY SUNDAY, WINDS WEAKEN AND VEER OUT OF THE NORTH/NORTHEAST WHILE
SEAS FALL BACK TO 6-8 FT THROUGH EARLY NEXT WEEK. ~12/10
PQR WATCHES/WARNINGS/ADVISORIES
OR...FROST ADVISORY FROM MIDNIGHT SATURDAY NIGHT TO 9 AM PDT SUNDAY
FOR ORZ104-106-113-117-121-123>125.
FROST ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM PDT SATURDAY FOR
ORZ121.
WA...FROST ADVISORY FROM MIDNIGHT SATURDAY NIGHT TO 9 AM PDT SUNDAY
FOR WAZ205-208.
PZ...SMALL CRAFT ADVISORY UNTIL 2 PM PDT SATURDAY FOR PZZ210-251.
SMALL CRAFT ADVISORY UNTIL 2 PM PDT SATURDAY FOR PZZ252-272-273.
HAZARDOUS SEAS WARNING UNTIL 5 AM PDT SATURDAY FOR PZZ271.
SMALL CRAFT ADVISORY FROM 5 AM TO 2 PM PDT SATURDAY FOR PZZ271.
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