138
FXUS66 KPQR 251525
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
825 AM PDT FRI SEP 25 2026
UPDATE
A HIGH WIND WARNING HAS BEEN ISSUED FOR CLATSOP AND
PACIFIC COUNTY COASTS THROUGH 11 AM TODAY, AS A RESULT OF A
STING JET FROM THE LOW PRESSURE SYSTEM MOVING INLAND AND
BRINGING GUSTS AROUND 50-70 MPH.
SYNOPSIS
A ROBUST EARLY-SEASON LOW PRESSURE SYSTEM WILL
BRING CONTINUED SHOWERS ACROSS THE REGION TODAY IN ADDITION TO
A BURST OF GUSTY WINDS (MAINLY THIS MORNING). WIND ADVISORIES
ARE IN EFFECT FOR THE CENTRAL AND NORTHERN WILLAMETTE VALLEY
INTO SOUTHWEST WASHINGTON THROUGH 11AM. AT LEAST THE RATHER
PROGRESSIVE PATTERN ENSURES DRIER WEATHER QUICKLY RETURNS BY
SATURDAY MORNING THROUGH THE REMAINDER OF THE WEEKEND. CHANCES
(20-45%) FOR RAIN INCREASE AGAIN TUESDAY AND WEDNESDAY ALONG
WITH FORECAST UNCERTAINTY.
DISCUSSION..NOW THROUGH THURSDAY
THIS MORNING THE CORE OF AN
UPPER LEVEL LOW PRESSURE SYSTEM IS RAPIDLY APPROACHING FAR
NORTHWEST OREGON AND SOUTHWEST WASHINGTON WITH THE REGION
TRANSITIONING TO A POST-FRONTAL AIRMASS AS THE INITIAL COLD
FRONT WHICH BROUGHT WIDESPREAD STRATIFORM RAINFALL SHIFTED
EAST OF THE CASCADE CREST-LINE. THE IMMEDIATE FOCUS THIS MORNING
REGARDS GUSTY SOUTHWEST TO SOUTH WINDS ASSOCIATED WITH THIS
SYSTEM WHICH ARE ALREADY BEING OBSERVED ALONG THE COAST AND IN
PORTIONS OF THE WILLAMETTE VALLEY. CONFIDENCE HAS INCREASED
SURFACE LOW WILL COME ONSHORE AROUND PACIFIC COUNTY, WA BEFORE
SWINGING NORTHEASTWARD INTO THE PUGET SOUND. THIS SETS THE STAGE
FOR A PERIOD OF TIME THIS MORNING WHEN A DECENT SURFACE
PRESSURE GRADIENT ORIENTS ITSELF PERPENDICULAR TO I-5. WHILE
THIS ALONE CAN DRIVE BREEZY WINDS, THE GRADIENT LIKELY COMES
INTO ALIGNMENT DURING A PERIOD OF TIME WHEN INCREASING
INSTABILITY NEAR THE SURFACE HAS THE POTENTIAL TO TAP INTO THE
PASSING LOW LEVEL STING-JET WRAPPING AROUND THE BACKSIDE OF THE
LOW PRESSURE CENTER. THE MAJORITY OF THE LATEST DETERMINISTIC
GUIDANCE DEPICTS 925-850MB WINDS PEAKING NEAR 40-50 KNOTS AS
THAT N TO S SURFACE PRESSURE GRADIENT IS OVERHEAD. SO THE
INGREDIENTS YOUR LOOKING FOR WHEN IT COMES TO DRIVING NEAR
ADVISORY LEVEL WIND GUST, AND EXCEEDING THOSE PROJECTED BY THE
BASELINE NBM, WILL BE PRESENT. EXPLORING THE LATEST CAMS ADD A
NOTABLE AMOUNT OF CONFIDENCE IN WIND GUSTS REACHING IN THE 35-50
MPH RANGE FROM THE CENTRAL WILLAMETTE VALLEY NORTHWARD INTO
SOUTHWEST WASHINGTON. EXPECT YOUR HIGHEST GUSTS IN VALLEY
LOCATIONS WITH A GOOD SOUTH TO NORTH FETCH AND EXPOSED
RIDGETOPS. ANOTHER AREA WHICH WILL LIKELY SEE SOME LOCALLY
STRONGER WINDS IS EAST OF THE CREST WITHIN THE HOOD RIVER
VALLEY, DOWNSLOPE ACCELERATION ON EAST- FACING SLOPES WILL SEE
STRONG WINDS PROLONGED THROUGH FRIDAY AFTERNOON. WIND ADVISORIES
ARE IN EFFECT FOR THE AFOREMENTIONED AREAS. WHILE THESE
FORECAST WINDS MAY NOT BE THAT IMPRESSIVE COMPARED TO SOME OF
OUR STRONGER WINTER-TIME STORMS, THE EARLY SEASON NATURE OF THIS
SYSTEM MAY FAVOR EXACERBATED TREE DAMAGE AT LOWER WIND SPEEDS
AS FULL LEAF COVER ACTS TO INCREASE DRAG ON TREE LIMBS.
OTHERWISE, COOLER AIR IN PLACE ALOFT NEAR THE LOW CENTER WILL
SUPPORT SUFFICIENT INSTABILITY TO MAINTAIN RAIN SHOWERS AT TIMES
TODAY, AND 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. IT'S
WORTH NOTING 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 THE AFTERNOON HOURS,
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
THIS EVENING, AND IN THE CASCADES TONIGHT. PROGRESSIVE
SHORTWAVE RIDGING FROM THIS POINT INTO SATURDAY WILL THEN FAVOR
RAPID DRYING. TEMPERATURES HOLD BELOW AVERAGE DURING THIS
PERIOD, WITH AFTERNOON HIGHS ONLY IN THE UPPER 50S TO LOW 60S
ACROSS THE REGION TODAY. COOLER AIR BEHIND THE FRONTAL BOUNDARY
WILL SEE OVERNIGHT LOWS FALL INTO THE 40S BY SUNRISE SATURDAY
MORNING, PERHAPS TO THE UPPER 30S IN THE HOOD RIVER VALLEY.
THERE IS A 15-30% CHANCE OF LOW TEMPERATURES BELOW 37 DEGREES IN
THE ODELL AREA, AND 40-60% CHANCES FARTHER UP THE VALLEY NEAR
DEE AND PARKDALE - HEAVILY DEPENDENT ON CLEARING SKIES. FROST
ADVISORIES MAY BE NEEDED IN THESE AREAS IF CONFIDENCE IN FROST
IMPACTS INCREASE.
THE PROGRESSIVE PATTERN ALOFT WILL SEE UPPER-LEVEL RIDGING AND
SURFACE HIGH PRESSURE SUPPORT DRY WEATHER INTO EARLY NEXT WEEK,
ALTHOUGH MODERATING TEMPERATURES ARE STILL LIKELY TO REMAIN
BELOW SEASONAL NORMS WITH HIGHS IN THE MID TO UPPER 60S ACROSS
THE LOWLANDS. 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 TUESDAY INTO WEDNESDAY OF NEXT WEEK, ALTHOUGH THERE
REMAINS MUCH SPREAD IN ITS INTENSITY AND LOCATION. CHANCES FOR
RAINFALL THEREFORE INCREASE TO 20-40% DURING THIS PERIOD,
GENERALLY HIGHER TO THE NORTH, ALONG THE COAST, AND WITHIN
AREAS OF TERRAIN. -99/36
AVIATION...THROUGH 12Z FRIDAY
THE REGION SITS IN A LULL AS
FAR AS PRECIPITATION IS CONCERNED AS THE MAIN RAINFALL BAND
SHIFTS FURTHER EAST OF THE CASCADES AND RAIN SHOWERS BEGIN TO
MAKE THEIR WAY ONSHORE. SOUTHERLY FLOW ALOFT TURNS WESTERLY
LATER FRIDAY MORNING AS AN UPPER LEVEL TROUGH MOVES ACROSS THE
REGION, WHILE A COMPACT SURFACE LOW NEAR THE COAST DRIVES GUSTY
SURFACE WINDS THIS MORNING. CURRENT CONDITIONS ARE A MIX OF VFR
TO MVFR ALTHOUGH WE'LL TREND TOWARDS THE LATTER THROUGH THE
MORNING HOURS. AT THE COAST, PROBS FOR IFR PEAK BETWEEN 12-18Z
AT AROUND 30-50%. SHOWERS ARE EXPECTED TO CONTINUE THROUGH
THIS AFTERNOON INTO THE EARLY EVENING. BEST CHANCE FOR
THUNDERSTORMS (20%) APPEARS TO BE NEAR THE NORTH OREGON COAST,
WITH CHANCES FOR AFTERNOON THUNDERSTORMS GENERALLY 15%. SOUTH
WINDS PEAK THROUGH 17-19Z THIS MORNING WITH GUSTS UP TO 30-40
KT.
KPDX AND APPROACHES....CONDITIONS LIKELY REMAIN A MIX OF VFR TO
MVFR THIS MORNING WITH LOWER CIGS/VIS PRESENT IN SHOWERS
THROUGHOUT THE DAY. EXPECT A RETURN TO DRY WEATHER TONIGHT.
SOUTH WINDS HAVE ALREADY BEGIN TO INCREASE, PEAKING AROUND 30-35
KNOTS 14-18Z BEFORE DECREASING THEN TURNING MORE WESTERLY AFTER
21Z. LIGHTER WESTERLY WINDS RETURN TONIGHT. -99/DH
MARINE
THE CENTER OF A ROBUST LOW PRESSURE SYSTEM IS
CURRENTLY TRACKING INTO FAR NORTHWEST OREGON AND SOUTHWEST
WASHINGTON THIS MORNING BRINGING A NOTICEABLE INCREASE TO WINDS
AND SEAS. GALE WARNINGS ARE CURRENT IN EFFECT FOR THE INNER AND
OUTER WATERS, INCLUDING THE COLUMBIA RIVER BAR, THROUGH THE
MIDDAY INTO THE AFTERNOON HOURS BEFORE THEY SEQUENTIALLY
TRANSITION TO HAZARDOUS SEAS WARNINGS INTO THE LATE AFTERNOON
AND EVENING. WINDS AND SEAS HAVE ALREADY INCREASED ACROSS THE
WATERS OFF THE CENTRAL OREGON COAST WITH BUOY 50 RECORDING GUSTS
OF 35-40 KNOTS ACCOMPANIED BY STEEP 12 FT AT 8 SECOND SEAS.
EXPECT SIMILAR CONDITIONS TO SHIFT FURTHER NORTH OVER THE NEXT
FEW HOURS. WHILE WINDS BEGIN TO DECREASE LATE MORNING, EXPECT
WIND-DRIVEN STEEP AND CHOPPY SEAS TO PEAK AROUND 13-16 FT,
GRADUALLY SUBSIDING LATE FRIDAY AFTERNOON INTO THE EVENING. BY
SATURDAY MORNING, SEAS SETTLE BACK TO AROUND 5-7FT AT 8-9
SECONDS.
FROM THIS POINT OUR FOCUS SHIFT TO NORTHERLY WINDS INCREASING
OVER THE WEEKEND, STRONGEST SATURDAY AFTERNOON AND EVENING WHEN
WIND GUSTS INCREASE TO 20-25 KT, MAINLY OVER THE OUTER WATERS.
BACK TO RATHER BENIGN WEATHER CONDITIONS ON MONDAY AS WINDS STAY
BELOW 20 KNOTS AND SEAS HOLD IN THE 5-8FT RANGE BEFORE A SLIGHT
INCREASE IN WAVE HEIGHTS ON TUESDAY INTO WEDNESDAY (7-10FT) DUE TO
THE ARRIVAL OF A WNW SWELL. -99
PQR WATCHES/WARNINGS/ADVISORIES
OR...HIGH WIND WARNING UNTIL 11 AM PDT THIS MORNING FOR ORZ101.
WIND ADVISORY UNTIL 11 AM PDT THIS MORNING FOR ORZ108>115-123.
WIND ADVISORY UNTIL 8 PM PDT THIS EVENING FOR ORZ121.
WA...HIGH WIND WARNING UNTIL 11 AM PDT THIS MORNING FOR WAZ201.
WIND ADVISORY UNTIL 11 AM PDT THIS MORNING FOR WAZ203>208.
PZ...GALE WARNING UNTIL 2 PM PDT THIS AFTERNOON FOR PZZ210-251-252-
271-272.
HAZARDOUS SEAS WARNING FROM 2 PM THIS AFTERNOON TO 8 PM PDT
THIS EVENING FOR PZZ210-251-252-271-272.
GALE WARNING UNTIL 11 AM PDT THIS MORNING FOR PZZ253-273.
HAZARDOUS SEAS WARNING UNTIL 5 PM PDT THIS AFTERNOON FOR
PZZ253-273.
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