360
FXUS66 KPQR 250601 AAA
AFDPQR
AREA FORECAST DISCUSSION...UPDATE
NATIONAL WEATHER SERVICE PORTLAND OR
1100 PM PDT THU SEP 24 2026
UPDATED AVIATION DISCUSSION AND W/W/A SECTION
SYNOPSIS
AN EARLY-SEASON FRONTAL SYSTEM WILL BRING WIDESPREAD
RAIN AND GUSTY WINDS TO THE REGION THIS EVENING THROUGH MUCH OF
FRIDAY. THE PROGRESSIVE PATTERN WILL SEE DRY WEATHER QUICKLY
RETURN LATE FRIDAY THROUGH THE WEEKEND, BEFORE CHANCES FOR
RAIN INCREASE AGAIN EARLY NEXT WEEK.
SHORT TERM...NOW THROUGH FRIDAY NIGHT
AN AREA OF SURFACE LOW
PRESSURE CURRENTLY LOCATED NEAR 44N/130W, OR ROUGHLY 300 MILES
WEST OF FLORENCE, IS EXPECTED TO TRACK TO THE NORTHEAST BEFORE
MOVING ONSHORE SOMEWHERE NEAR THE MOUTH OF THE COLUMBIA RIVER
FRIDAY MORNING. A WEAK WARM FRONTAL BOUNDARY LIFTED NORTHWARD
EARLIER TODAY, BRINGING LIGHT RAIN SHOWERS TO THE SOUTH
WASHINGTON AND FAR NORTH OREGON COASTS, WHILE THE ASSOCIATED
COLD FRONTAL BOUNDARY CURRENTLY SITS SOME 20-60 MILES OFFSHORE.
THIS FRONT WILL BRING STEADY RAIN TO THE COAST LATER THIS
AFTERNOON, BEGINNING BETWEEN 4-6 PM PDT, BEFORE PUSHING INLAND
TO THE I-5 CORRIDOR BY 7-10 PM PDT THIS EVENING. THERE IS A
15-20% CHANCE FOR AN ISOLATED EMBEDDED THUNDERSTORM WITHIN THE
COLD FRONT ALONG THE OREGON COAST AND WESTERN SLOPES OF THE
COAST RANGE THIS AFTERNOON BEFORE CHANCES DECREASE AFTER SUNSET.
WINDS BLOWING OUT OF THE SOUTH WILL INCREASE AT PRECIPITATION
ONSET, REACHING 20-30 MPH ALONG THE COAST AND 15-25 MPH INLAND.
WINDS GUSTS WILL BE HIGHER, AT LEAST UP TO 40-45 AT THE COAST
AND 35-40 MPH INLAND.
STEADY RAIN WILL TRANSITION TO ON-AND-OFF RAIN SHOWERS BEHIND
THE COLD FRONT BY 10 PM-12 AM PDT THIS EVENING AT THE COAST AND
1-3 AM PDT FRIDAY ALONG I-5. COOLER AIR IN PLACE ALOFT NEAR THE
LOW CENTER WILL SUPPORT SUFFICIENT INSTABILITY TO MAINTAIN RAIN
SHOWERS INTO THE DAY FRIDAY, WHEN DAYTIME SURFACE HEATING WILL
ACT TO FURTHER INCREASE INSTABILITY AND GENERATE 15-20% CHANCES
FOR THUNDER ANYWHERE BETWEEN THE COAST AND THE CASCADE CREST. AN
ISOLATED COLD CORE FUNNEL ALSO CANNOT BE RULED OUT, MOST LIKELY
ALONG THE COAST, BUT IMPACTS AT THE GROUND FROM THESE FEATURES
ARE UNLIKELY. AS THE SURFACE LOW NEARS THE COAST FRIDAY
MORNING, WINDS WILL SHIFT OUT OF THE SOUTHWEST TO WEST AND
STEADILY WEAKEN THROUGH MUCH OF THE DAY WEST OF THE CASCADES,
HOWEVER TO THE EAST OF THE CREST WITHIN THE HOOD RIVER VALLEY,
DOWNSLOPE ACCELERATION ON EAST- FACING SLOPES WILL SEE STRONG
WINDS PROLONGED THROUGH FRIDAY AFTERNOON. A WIND ADVISORY HAS
BEEN ISSUED FROM 8 AM THROUGH 8 PM PDT FRIDAY IN THE UPPER HOOD
RIVER VALLEY, PARTICULARLY FOR AREAS WEST OF OREGON ROUTE 281,
WHERE WIND GUSTS HAVE THE HIGHEST CHANCE OF EXCEEDING 50 MPH.
WHILE THESE FORECAST WINDS MAY BE LOWER THAN TYPICAL WINTERTIME
WIND STORMS, THE EARLY SEASON NATURE OF THIS SYSTEM MAY FAVOR
TREE DAMAGE AT LOWER WIND SPEEDS AS FULL LEAF COVER ACTS TO
INCREASE DRAG ON TREE LIMBS.
WHILE WIDESPREAD IMPACTS FROM WINDS ARE NOT ANTICIPATED, SOME
AREAS OF LOCALLY STRONGER WINDS MAY RESULT IN POCKETS OF TREE OR
LIMB DAMAGE WHICH COULD IN TURN YIELD DOWNED POWER LINES AND
OUTAGES. WHILE LIMITED INSTABILITY WILL CAP THUNDERSTORM
INTENSITY, THE AVAILABILITY OF HIGHER MOMENTUM AIR AT LOW
ALTITUDES WILL MAKE ANY THUNDERSTORM OR HEAVY RAIN SHOWER
CAPABLE OF PRODUCING GUSTY OUTFLOW THROUGH FRIDAY AFTERNOON,
WHICH MAY ALSO SUPPORT LOCAL AREAS OF WIND DAMAGE. RAINFALL
AMOUNTS REMAIN UNLIKELY TO CAUSE IMPACTS, WITH ANNUAL MINIMUM
STREAMFLOWS ABLE TO HANDLE RUNOFF WITHOUT FLOODING CONCERNS.
RAIN SHOWERS WILL END ACROSS MOST AREAS WEST OF THE CASCADES BY
FRIDAY AFTERNOON, AND IN THE CASCADES BY MIDNIGHT FRIDAY NIGHT.
PROGRESSIVE SHORTWAVE RIDGING WILL THEN FAVOR RAPID DRYING
THROUGH FRIDAY NIGHT. TEMPERATURES WILL REMAIN BELOW AVERAGE
DURING THIS PERIOD, WITH AFTERNOON HIGHS ONLY IN THE UPPER 50S
TO LOW 60S ACROSS THE REGION ON FRIDAY. COOLER AIR BEHIND THE
FRONTAL BOUNDARY WILL SEE OVERNIGHT LOWS FALL INTO THE 40S
THROUGH FRIDAY NIGHT, AND PERHAPS TO THE UPPER 30S IN THE HOOD
RIVER VALLEY. THERE IS A 10-15% CHANCE OF LOW TEMPERATURES BELOW
37 DEGREES IN THE ODELL AREA, AND 40-60% CHANCES FARTHER UP THE
VALLEY NEAR DEE AND PARKDALE. FROST ADVISORIES MAY BE NEEDED IN
THESE AREAS IF CONFIDENCE IN FROST IMPACTS INCREASE. -36
LONG TERM...SATURDAY THROUGH THURSDAY
THE PROGRESSIVE PATTERN
ALOFT WILL SEE UPPER-LEVEL RIDGING AND SURFACE HIGH PRESSURE
SUPPORT DRY WEATHER THROUGH THE WEEKEND, ALTHOUGH MODERATING
TEMPERATURES ARE STILL LIKELY TO REMAIN BELOW SEASONAL NORMS.
COOL OVERNIGHT LOWS MAY FAVOR FURTHER CHANCES FOR FROST IN THE
UPPER HOOD RIVER VALLEY, WITH DECREASING CONFIDENCE AFTER
SATURDAY MORNING. THE MAJORITY OF LONG-RANGE ENSEMBLE MEMBERS
FAVOR TROUGHING TO RETURN TO THE PACIFIC NORTHWEST EARLY NEXT
WEEK, ALTHOUGH THERE REMAINS MUCH SPREAD IN ITS INTENSITY AND
LOCATION. CHANCES FOR RAINFALL THEREFORE INCREASE AGAIN TO
20-40% MONDAY THROUGH WEDNESDAY, GENERALLY HIGHER TO THE NORTH
AND WITHIN AREAS OF TERRAIN. -36
AVIATION...THROUGH 06Z FRIDAY
RAIN IS QUICKLY MOVING ACROSS THE
FORECAST AREA AS THE INITIAL FRONT IS PUSHING TOWARD THE CASCADES
THIS EVENING. SOUTHERLY FLOW ALOFT TURNS WESTERLY FRIDAY MORNING
AS AN UPPER LEVEL TROUGH MOVES ACROSS THE REGION, WHILE A COMPACT
LOW NEAR THE COAST IS EXPECTED TO BRING BREEZY SOUTH TO SOUTHWEST
WINDS IN THE LOWER LEVELS TONIGHT INTO FRIDAY MORNING. VSBYS HAVE
BEEN REDUCED TO 3-5 SM WITH THE RAIN BAND THIS EVENING, BUT IS
EXPECTED TO PUSH EAST BY 08-09Z FRIDAY. CIGS ARE BEGINNING TO
LOWER AT THE COAST TO AROUND FL015-025 AND SHOULD CONTINUE TO
LOWER INLAND AS WELL RESULTING IN PREDOMINATELY MVFR CONDITIONS,
WITH HIGHEST PROBS FOR MVFR OCCURRING BETWEEN 14-20Z FRIDAY. AT
THE COAST, PROBS FOR IFR PEAK BETWEEN 12-18Z AT AROUND 20-40%.
SHOWERS ARE EXPECTED TO CONTINUE THROUGH FRIDAY AFTERNOON. BEST
CHANCE FOR THUNDERSTORMS (20%) APPEARS TO BE NEAR THE NORTH OREGON
COAST LATE TONIGHT INTO FRIDAY MORNING, WHICH CHANCES FOR
AFTERNOON THUNDERSTORMS GENERALLY 15% OR LESS. SOUTH WINDS ARE
EXPECTED TO INCREASE ALONG THE COAST AND THROUGH THE CENTRAL AND
NORTHERN WILLAMETTE VALLEY, PEAKING BETWEEN 10-18Z FRIDAY WITH
GUSTS UP TO 30-40 KT.
KPDX AND APPROACHES...EXPECT A MIX OF VFR AND MVFR CONDITIONS THIS
EVENING BECOMING PREDOMINATELY MVFR BETWEEN 14-20Z FRIDAY AS CIGS
LOWER BEHIND THE INITIAL FRONTAL PASSAGE. STRONGER SHOWERS WILL
BRING POTENTIAL FOR REDUCED VIS TO 3-5SM THROUGH EARLY FRIDAY
AFTERNOON. SOUTH WINDS ARE EXPECTED TO INCREASE OVERNIGHT WITH
GUSTS UP TO 25-35 KT THROUGH 18Z. WINDS TURN MORE WESTERLY AFTER
21Z FRIDAY ALONG WITH HIGH CHANCES OF RETURNING TO VFR. /DH
MARINE
A STRONG LOW PRESSURE SYSTEM WILL MOVE OVER THE COASTAL
WATERS TONIGHT INTO FRIDAY, BRINGING RAPIDLY INCREASING WINDS AND
SEAS ALONG WITH WIDESPREAD RAIN. GALE WARNINGS ARE IN EFFECT
BEGINNING 5 PM THURSDAY FOR THE WATERS SOUTH OF CAPE FOULWEATHER,
AND 11 PM THURSDAY FOR THE WATERS NORTH OF CAPE FOULWEATHER
INCLUDING THE COLUMBIA RIVER BAR. THESE GALE WARNINGS ARE FOLLOWED
BY HAZARDOUS SEAS WARNINGS THAT LAST THROUGH FRIDAY AFTERNOON/EVENING.
GIVEN THAT THE LOW PRESSURE SYSTEM WILL BE COMING FROM THE
SOUTHWEST, WILL SEE WINDS RAMP UP ACROSS THE SOUTHERN WATERS AT
FIRST, THEN GRADUALLY INCREASE TOWARDS THE NORTHERN WATERS HEADING
INTO TONIGHT. EXPECT WIDESPREAD WIND GUSTS AS HIGH AS 40-45 KT
WITH A 30-50% CHANCE FOR BRIEF AND ISOLATED STORM-FORCE WIND GUSTS
TO 50-55 KT. EXPECT STEEP AND CHOPPY SEAS THAT ARE WIND-DRIVEN.
SEAS BUILD TO AROUND 9-11 FT AT 10 SEC TONIGHT INTO EARLY FRIDAY
MORNING, PEAKING LATE MORNING AROUND 15-17 FT FOR THE WATERS
BEYOND 10 NM, AND PEAKING EARLY AFTERNOON AROUND 14-16 FT FOR THE
INNER WATERS UP TO 10 NM OFFSHORE. SEAS WILL GRADUALLY SUBSIDE
FRIDAY AFTERNOON AS WINDS QUICKLY WEAKEN. BY LATE FRIDAY EVENING,
SEAS FALL TO AROUND 7-9 FT AT 9 SECONDS. NORTHERLY WINDS INCREASE
OVER THE WEEKEND, STRONGEST SATURDAY AFTERNOON AND EVENING WHEN
WIND GUSTS INCREASE TO 20-25 KT. -10
PQR WATCHES/WARNINGS/ADVISORIES
OR...WIND ADVISORY FROM 3 AM TO 11 AM PDT FRIDAY FOR ORZ109>115.
WIND ADVISORY FROM 8 AM TO 8 PM PDT FRIDAY FOR ORZ121.
WA...WIND ADVISORY FROM 3 AM TO 11 AM PDT FRIDAY FOR WAZ205>207.
PZ...GALE WARNING UNTIL 2 PM PDT FRIDAY FOR PZZ210-251-252-271-272.
HAZARDOUS SEAS WARNING FROM 2 PM TO 8 PM PDT FRIDAY FOR PZZ210-
251-252-271-272.
GALE WARNING UNTIL 11 AM PDT FRIDAY FOR PZZ253-273.
HAZARDOUS SEAS WARNING FROM 11 AM TO 5 PM PDT FRIDAY FOR PZZ253-
273.
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