855
FXUS66 KPQR 161124
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
424 AM PDT FRI OCT 16 2026
SYNOPSIS
CONDITIONS REMAIN DRY WITH WELL ABOVE AVERAGE
TEMPERATURES. EASTERLY WINDS WILL GRADUALLY WEAKEN AS A TROUGH
APPROACHES. A WEAK COLD FRONT WILL BRING CHANCES FOR LIGHT RAIN
LATE TONIGHT INTO SATURDAY MORNING, BEFORE HIGH PRESSURE
RETURNS DRY WEATHER SATURDAY NIGHT INTO SUNDAY. THE NEXT CHANCES
FOR RAIN ARE MONDAY INTO EARLY TUESDAY WITH AN APPROACHING LOW
PRESSURE SYSTEM, ALTHOUGH GUIDANCE CONTINUES TO TREND DRIER.
SHORT TERM...NOW THROUGH SATURDAY NIGHT
UPPER LEVEL RIDGING WILL
CONTINUE SHIFTING EAST AS TROUGHING OVER THE NORTHEAST PACIFIC
AND ALASKA PROGRESSES EASTWARD. CONDITIONS REMAIN DRY ACROSS THE
REGION WITH ANOTHER DAY OF ABOVE NORMAL TEMPERATURES. HIGHS IN
THE MID TO UPPER 70S ACROSS THE INTERIOR LOWLANDS, 10-15 DEGREES
ABOVE THE NORMAL LOW TO MID 60S. HIGHS ALONG THE COAST WILL BE
MUCH CLOSER TO NORMAL AS THE OFFSHORE PRESSURE GRADIENT
CONTINUES TO WEAKEN, ALLOWING WESTERLY ONSHORE FLOW TO RETURN
AND MARINE STRATUS TO PUSH INTO THE COAST. HIGHS EXPECTED TO TOP
OUT IN THE LOW TO MID 60S. HIGH LEVEL CLOUDS WILL ALSO INCREASE
THROUGH THE DAY AS THE UPPER LEVEL TROUGH PROGRESSES. THE
OFFSHORE PRESSURE GRADIENT BETWEEN TROUTDALE AND THE DALLES WILL
CONTINUE TO WEAKEN THROUGH THE DAY WHICH WILL GRADUALLY
DECREASE EASTERLY WINDS TO LESS THAN 10 MPH BY THE AFTERNOON.
AN EMBEDDED SHORTWAVE TROUGH PASSING TO THE NORTH WILL GLANCE
THE REGION, SENDING A COLD FRONT THROUGH THE AREA TONIGHT AND
INTO SATURDAY MORNING. THIS WILL BRING MODERATE TO LOW CHANCES
OF LIGHT RAIN TO NORTHERN PORTIONS OF THE FORECAST AREA FOR
SATURDAY MORNING. MEAN QPF VALUES RANGE FROM A TRACE TO 0.10
INCH, GENERALLY NORTH OF LINCOLN CITY AT THE COAST AND FROM THE
PORTLAND METRO AREA NORTHWARD, WITH HIGHEST CHANCES FOR RAIN IN
THE SOUTHWEST WA CASCADES. CONDITIONS EXPECTED TO DRY OUT BY THE
AFTERNOON WITH NORTHERLY WINDS BEHIND THE FRONT. HIGHS WILL BE
CLOSER TO NORMAL, TOPPING OUT IN THE MID TO UPPER 60S ACROSS THE
INTERIOR VALLEYS. WILL NEED TO KEEP AN EYE ON SATURDAY NIGHT AS
CLOUDS CLEAR AND TEMPERATURES DROP INTO THE 30S. OUTSIDE OF THE
CASCADES, THE COOLEST TEMPERATURES ARE EXPECTED IN THE UPPER
HOOD RIVER VALLEY. -19/DH
LONG TERM...SUNDAY THROUGH THURSDAY
DRY WEATHER EXPECTED ON
SUNDAY AS FLOW ALOFT BECOMES MORE ZONAL WITH THE PASSAGE OF THE
SHORTWAVE TROUGH. HIGHS VERY SIMILAR TO SATURDAY PEAKING IN THE
MID 60S FOR MOST INTERIOR LOWLANDS AND MID 50S TO LOW 60S ALONG
THE COAST. SUNDAY NIGHT INTO MONDAY MORNING WILL BRING ANOTHER
CHANCE FOR FROST IN THE UPPER HOOD RIVER VALLEY AND THE SOUTHERN
WILLAMETTE VALLEY AS LOWS COULD DROP INTO THE MID TO UPPER 30S.
CLUSTER ANALYSIS CONTINUES TO DEPICT A TROUGH IMPACTING THE
REGION MONDAY AND TUESDAY BUT TRENDS HAVE THE TROUGH TAKING A
MORE SOUTHEAST TRAJECTORY AND JUST GLANCING NW OR AND SW WA.
APPROXIMATELY 40% OF ENSEMBLE MEMBERS HAVE LIGHT QPF FOR THE
PORTLAND AREA WHILE 60% OF MEMBERS HAVE LIGHT QPF AROUND
NEWPORT. MODELS CONTINUE TO TRACK THIS TROUGH MORE TOWARDS
NORTHERN CALIFORNIA, LIMITING ANY DECENT RAINFALL ACROSS THE
FORECAST AREA. CHANCES FOR 24-HOUR RAINFALL TOTALS EXCEEDING
0.25 INCHES BETWEEN 5 AM MONDAY TO 5 AM TUESDAY HAVE DROPPED TO
10-15% ALONG THE COAST AND COAST RANGE, SOUTHERN WILLAMETTE
VALLEY, AND THE OR CASCADE FOOTHILLS.
BY WEDNESDAY, ENSEMBLES SHOW THE UPPER TROUGH SWINGING INTO
CENTRAL CALIFORNIA, WHILE WEAK HIGH PRESSURE SHIFTS OVER THE
PACIFIC NORTHWEST, FAVORING PREDOMINATELY DRY CONDITIONS. AT THE
SAME TIME, IT DOES APPEAR THAT ANOTHER UPPER-LEVEL TROUGH WILL
BEGIN TO APPROACH BRITISH COLUMBIA AND POTENTIALLY MAKE ITS WAY
DOWN INTO THE PACIFIC NORTHWEST LATE NEXT WEEK, RETURNING
CHANCES FOR PRECIPITATION. -19/DH
AVIATION...THROUGH 06Z SATURDAY
UPPER-LEVEL HIGH PRESSURE
MOVES OVER THE PACIFIC NORTHWEST. EXPECT MOSTLY VFR CONDITIONS
THROUGH THE TAF PERIOD, WITH THE EXCEPTION OF DETERIORATED
CONDITIONS ALONG THE COAST OVERNIGHT THROUGH THE EARLY AFTERNOON
AND LOW CHANCES WITHIN THE INTERIOR LOWLANDS OVERNIGHT.
SPECIFICALLY, THERE IS A 50-60% CHANCE OF IFR AND 40-50% CHANCE OF
LIFR CONDITIONS ALONG THE COAST BETWEEN 13-23Z FRI, EARLIEST AT
KONP AND LATEST AT KAST. AS FOR INLAND TERMINALS, THERE IS A
10-20% CHANCE OF LIFR/IFR CONDITIONS BETWEEN 11-18Z FRI, WITH THE
HIGHEST CHANCES AT KEUG.
EXPECT MOSTLY EASTERLY WINDS UNTIL 18Z FRI, THEN BECOMING LIGHT
AND VARIABLE THROUGH THE REST OF THE TAF PERIOD. THE CENTRAL AND
SOUTHERN WILLAMETTE VALLEY WILL LIKELY REMAIN LIGHT AND VARIABLE
THROUGH THE TAF PERIOD. ELEVATED WINDS AT AND EAST OF KTTD WILL
DECREASE TOWARDS 18-21Z FRI.
KPDX AND APPROACHES...VFR WITH CLEAR SKIES THROUGH THE TAF PERIOD.
BREEZY EASTERLY WINDS CONTINUE TO DECREASE TONIGHT, WITH EAST
WINDS AROUND 4-6 KT EXPECTED THROUGH THE REST OF THE TAF PERIOD
BEYOND 11Z FRI. ADDITIONALLY, THERE IS A LOW 10-15% CHANCE OF
LIFR/IFR CIGS BETWEEN 12-18Z FRI.~12
MARINE
BENIGN MARINE CONDITIONS CONTINUE. LIGHT
EAST/NORTHEASTERLY WINDS ARE TRANSITIONING TO
NORTH/NORTHWESTERLY WINDS OVER THE WATERS THROUGH TONIGHT AS A
THERMAL TROUGH SLOWLY BREAKS DOWN. A SERIES OF FRONTS PASSING
THROUGH THE WATERS WILL TURN WINDS SOUTHERLY FRIDAY NIGHT INTO
SATURDAY MORNING, AND SUNDAY NIGHT INTO MONDAY. SEAS REMAIN
AROUND 4-7 FT AT 10-12 SECONDS THROUGH EARLY SATURDAY MORNING.
A STEEPER NORTHWESTERLY SWELL ARRIVES THIS WEEKEND, BUILDING SEAS
TO 7-9 FT BY SATURDAY EVENING AND 10-13 FT EARLY NEXT WEEK.
UNCERTAINTY REMAINS ON HOW HIGH SEAS WILL RISE EARLY NEXT WEEK DUE
TO UNCERTAINTY ON THE TRACK OF THE LOW PRESSURE SYSTEM ASSOCIATED
WITH THE SWELL. THERE IS A 15-30% CHANCE FOR SEAS EXCEEDING 15 FT
ON MONDAY, WITH THE HIGHEST CHANCES BEYOND 30-40 NM. WILL ALSO
NOTE THAT THE LONG PERIODS FROM THE SWELLS WILL RESULT IN A
MODERATE SNEAKER WAVE THREAT FRIDAY INTO EARLY NEXT WEEK. CAUTION
SHOULD BE USED WHEN IN OR NEAR THE WATER. -03
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...NONE.
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