037
FXUS66 KPQR 091032
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
332 AM PDT FRI OCT 9 2026
SYNOPSIS
A WEAK FRONTAL SYSTEM WILL MOVE IN TODAY, RETURNING
COOLER TEMPERATURES AND LIGHT RAIN THROUGH SATURDAY. COOL
NIGHTS WILL BRING CHANCES FOR MORNING FROST IN RURAL VALLEYS
AWAY FROM URBAN CORES THIS WEEKEND INTO EARLY NEXT WEEK. DRY
CONDITIONS WITH SEASONABLE TEMPERATURES ARE EXPECTED SUNDAY AND
MONDAY BEFORE CHANCES FOR PRECIPITATION RETURN MID-WEEK.
SHORT TERM...TODAY THROUGH SUNDAY NIGHT
UPPER-LEVEL TROUGHING
IS ENTERING BRITISH COLUMBIA AS OF EARLY FRIDAY MORNING, AND
RADAR AND SATELLITE IMAGERY DEPICTS THE ASSOCIATED SURFACE FRONT
MOVING INTO THE OLYMPIC PENINSULA WITH A BAND OF LIGHT RAIN.
THIS DECAYING FRONT WILL CONTINUE TO PROGRESS SOUTHEASTWARD,
BRINGING RAIN TO THE NORTH OREGON AND SOUTH WASHINGTON COASTS BY
5-8 AM, AND THE I-5 CORRIDOR BY 8-11 AM. THE BEST CHANCES
(60-90%) FOR RAIN TOTALS EXCEEDING 0.10 INCH TODAY ARE ACROSS
THE NORTH OREGON COAST RANGE, WILLAPA HILLS, AND SOUTH
WASHINGTON/NORTH OREGON CASCADES DUE TO OROGRAPHIC ENHANCEMENT.
MEANWHILE, AREAS ALONG THE CENTRAL OREGON COAST AND WITHIN THE
WILLAMETTE VALLEY ARE MORE LIKELY TO STAY DRIER GIVEN THAT THIS
SYSTEM IS RELATIVELY WEAK AND TRACKING FURTHER NORTH. CHANCES
FOR EXCEEDING 0.10 INCH ACROSS THE WILLAMETTE VALLEY TODAY
REMAIN AROUND 20-40%.
WHEN IT COMES TO WINDS, WILL SEE BREEZY WEST/NORTHWESTERLY WINDS
PEAKING AROUND 25-35 MPH WITH THE INITIAL FRONTAL PASSAGE ACROSS
THE SOUTH WASHINGTON COAST, WILLAPA HILLS, NORTH OREGON COAST
RANGE, COLUMBIA RIVER GORGE, AND UPPER HOOD RIVER VALLEY. COULD
SEE SOME LOCALLY HIGHER GUSTS OF 35-45 MPH FOR HIGHER PEAKS AND
EXPOSED RIDGETOPS. CAN'T RULE OUT SOME ISOLATED GUSTS UP TO 50
MPH ALONG THE CENTRAL COLUMBIA RIVER GORGE (5-10% CHANCE).
EVERYWHERE ELSE, WINDS GENERALLY REMAIN LIGHT AND NON-IMPACTFUL.
AS THE UPPER TROUGH PROGRESSING EASTWARD INTO THE CANADIAN
ROCKIES, A SECOND SHORTWAVE IMPULSE WILL MOVE SOUTH ON ITS
WESTERN FLANK ON SATURDAY. WILL SEE THE TROUGH ELONGATE AND
EVENTUALLY PINCH OFF INTO A CLOSED UPPER LOW, WHICH WILL SETTLE
SOUTH OVER CALIFORNIA BY EARLY NEXT WEEK. THIS FEATURE WILL
PRODUCE A SECOND CHANCE OF LIGHT RAIN LATER FRIDAY NIGHT INTO
SATURDAY AS SCATTERED SHOWERS DEVELOP WITHIN THE COOLER AIR
ALOFT. THE RAIN FROM THIS SECOND SHORTWAVE WILL BE EVEN LIGHTER,
AS CHANCES FOR EXCEEDING 0.10 INCH OF RAIN ACROSS NORTHWEST
OREGON AND SOUTHWEST WASHINGTON FALL TO 10-30%, WITH EVEN LOWER
CHANCES AS YOU HEAD SOUTH OF SALEM AND LINCOLN CITY.
AS THE CORE OF COOLER AIR ALOFT MOVES OVERHEAD BEHIND THIS
GENERAL SYSTEM, TEMPERATURES WILL QUICKLY FALL BACK TOWARD
SEASONAL NORMS IN THE UPPER 50S AND 60S TODAY AND SATURDAY.
OVERNIGHT LOWS WILL SIMILARLY TREND COOLER, ESPECIALLY TONIGHT.
TONIGHT INTO EARLY SATURDAY MORNING, THERE IS HIGH CONFIDENCE
THAT HIGHER ELEVATION PORTIONS OF THE UPPER HOOD RIVER VALLEY
NEAR DEE AND PARKDALE WILL SEE TEMPERATURES IN THE MID 30S,
RESULTING IN AN ELEVATED POTENTIAL FOR FROST. A FROST ADVISORY
IS IN EFFECT FOR PORTIONS OF THE UPPER HOOD RIVER VALLEY COUNTY
LATE TONIGHT INTO SATURDAY MORNING.
CONDITIONS DRY OUT BY SUNDAY AS LOW PRESSURE EXITS THE REGION
AND UPPER-LEVEL RIDGING BUILDS ALOFT. TEMPERATURES WARM UP A FEW
DEGREES ON SUNDAY BUT REMAIN NEAR SEASONAL NORMS. SUNDAY MORNING
WILL FEATURE A NEAR-REPEAT OF SATURDAY MORNING, IF NOT COLDER
UNDER MORE CLEAR SKIES AND CALM WINDS. THIS WOULD FAVOR
INCREASING CHANCES (20-40%) FOR FROST IN SHELTERED VALLEYS AWAY
FROM URBAN AREAS AND A FREEZE WITHIN THE UPPER HOOD RIVER
VALLEY. -10/DH
LONG TERM...MONDAY THROUGH THURSDAY
ENSEMBLE GUIDANCE REMAINS
IN GOOD AGREEMENT THAT THE ELONGATED UPPER TROUGH WILL DROP
SOUTHWARD INTO CALIFORNIA BY EARLY NEXT WEEK. MEANWHILE, UPPER
LEVEL RIDGING OVER THE NE PACIFIC WILL NUDGE BACK OVER THE
REGION, LEADING TO DRY AND MORE SEASONABLY WARM TEMPERATURES
INTO THE MID TO UPPER 60S. BY TUESDAY-WEDNESDAY, 45% OF ENSEMBLE
MEMBERS ARE SHOWING TROUGHING DROPPING DOWN FROM CANADA,
RETURNING CHANCES FOR PRECIPITATION. MEANWHILE, THE OTHER 55%
CONTINUE TO SHOW WEAK RIDGING OVER THE REGION, MAINTAINING DRIER
CONDITIONS. HOWEVER, BY THURSDAY, THE MAJORITY OF ENSEMBLE
MEMBERS ARE HINTING AT MORE AMPLIFIED RIDGING OVER THE PACIFIC
NORTHWEST, SUGGESTING A CONTINUATION OF DRY CONDITIONS WITH
SLIGHTLY WARMER TEMPERATURES. -10/DH
AVIATION...THROUGH 06Z SATURDAY
VFR CONDITIONS PERSIST INLAND
WHILE MARINE STRATUS HAS MOVED IN ALONG THE ENTIRE COAST,
SUPPORTING MVFR OR LOWER CIGS. UPPER LEVEL CLOUDS ARE STREAMING IN
ALONG WESTERLY FLOW AHEAD OF AN APPROACHING TROUGH AND FRONTAL
SYSTEM. THE TROUGH IS EXPECTED TO BRING RAIN TO KAST AROUND 12Z
AND THEN INTERIOR LOWLAND TERMINALS AROUND 15-20Z AS THE FRONT
MOVES SOUTHWARD (KPDX: AROUND 15Z, KEUG: AROUND 19Z). ADDITIONALLY,
THIS TROUGH WILL BRING A 40-70% CHANCE OF MVFR CIGS.
LIGHT NORTH TO NORTHWEST WINDS AROUND 5 KT WILL EASE OVERNIGHT.
WINDS INLAND ARE EXPECTED TO INCREASE AHEAD OF THE FRONT,
INITIALLY OUT OF THE SOUTH AROUND 5 KT BUT WILL QUICKLY TURN
WESTERLY WITH THE PASSAGE OF THE FRONT ALONG WITH INCREASING TO
AROUND 10 KT AND GUSTS. WINDS ALONG THE COAST WILL REMAIN
NORTHWESTERLY THROUGH THE PERIOD BUT WILL INCREASE BEHIND THE
FRONT TO 10-15 KT WITH GUSTS AROUND 20 KT.
KPDX AND APPROACHES...VFR WITH HIGH CLOUD COVER THROUGH MOST OF
THE PERIOD. A TROUGH APPROACHING WILL BRING A CHANCE OF RAIN TO
AROUND 16Z FRI AND A 40-60% CHANCE OF MVFR CIGS. ADDITIONALLY,
WINDS WILL LIKELY INCREASE TOMORROW AFTERNOON, TO AROUND 8 TO 10
KT. -19
MARINE
A FRONTAL SYSTEM WILL MOVE THROUGH THE WATERS TODAY,
BRINGING BREEZY NORTHWESTERLY WINDS WITH GUSTS UP TO 25 KT. GIVEN
THAT THE FRONT WILL BE COMING OUT OF THE NORTH, WILL SEE WINDS
STRENGTHEN FIRST OVER THE WATERS NORTH OF CAPE FALCON THIS MORNING,
THEN GRADUALLY INCREASE TOWARD THE SOUTH THROUGHOUT THE DAY. A
NORTHWESTERLY SWELL WILL ALSO FOLLOW BEHIND THE FRONT, RESULTING
IN SEAS BUILDING TO 10-13 FEET AT 9-10 SECONDS BY THIS EVENING.
SMALL CRAFT ADVISORIES GO IN EFFECT THIS MORNING FOR THE WATERS
NORTH OF CAPE FALCON, BUT DUE TO STEEP AND CHOPPY SEAS NEAR 12-13
FT, A HAZARDOUS SEAS WARNING WAS ALSO ISSUED FOR THE WATERS
BEYOND 10 NM AND NORTH OF CAPE FALCON BEGINNING THIS AFTERNOON.
SMALL CRAFT ADVISORIES FOR THE WATERS SOUTH OF CAPE FALCON BEGIN
THIS AFTERNOON AND LAST THROUGH EARLY SATURDAY MORNING, MAINLY FOR
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. -10
PQR WATCHES/WARNINGS/ADVISORIES
OR...FROST ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM PDT SATURDAY FOR
ORZ121.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 5 AM PDT
SATURDAY FOR PZZ210.
SMALL CRAFT ADVISORY FROM 8 AM THIS MORNING TO 5 AM PDT SATURDAY
FOR PZZ251.
SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 2 AM PDT
SATURDAY FOR PZZ252-272-273.
SMALL CRAFT ADVISORY UNTIL 2 PM PDT THIS AFTERNOON FOR PZZ271.
HAZARDOUS SEAS WARNING FROM 2 PM THIS AFTERNOON TO 5 AM PDT
SATURDAY FOR PZZ271.
WWW.WEATHER.GOV/PORTLAND
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