453
FXUS66 KPQR 171123
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
423 AM PDT SAT OCT 17 2026
SYNOPSIS
A WEAK COLD FRONT MOVING THROUGH THE AREA WILL BRING
LIGHT RAIN CHANCES THROUGH THE MORNING WITH CONDITIONS DRYING
OUT IN THE AFTERNOON. HIGH PRESSURE RETURNS LATER TODAY,
KEEPING CONDITIONS DRY THROUGH SUNDAY. LOW CHANCES FOR RAIN ON
MONDAY AS A LOW PRESSURE SYSTEM LIKELY REMAINS WELL OFFSHORE.
SEASONABLE TEMPERATURES AND DRY WEATHER EXPECTED TUESDAY AND
WEDNESDAY BEFORE ANOTHER CHANCE FOR LIGHT RAIN RETURNS THURSDAY.
SHORT TERM...NOW THROUGH SUNDAY NIGHT
AN EMBEDDED SHORTWAVE
TROUGH PASSING TO THE NORTH CONTINUES TO MOVE EAST ACROSS
SOUTHERN BRITISH COLUMBIA, SENDING A COLD FRONT THROUGH THE
AREA. SATELLITE AND RADAR IMAGERY AS OF 3 AM DEPICTS A SHALLOW
FRONTAL PRECIPITATION BAND MOVING EAST ACROSS THE COAST RANGE
WHICH IS PRODUCING LIGHT RAIN. MEAN QPF VALUES ARE STILL
EXPECTED TO RANGE FROM A TRACE TO 0.10 INCH, GENERALLY NORTH OF
LINCOLN CITY AT THE COAST AND FROM THE PORTLAND METRO AREA
NORTHWARD. CONDITIONS EXPECTED TO DRY OUT BY THE AFTERNOON WITH
NORTHERLY WINDS BEHIND THE FRONT. COULD SEE SOME BREEZY WINDS IN
THE WILLAMETTE VALLEY, SOUTH OF SALEM WITH GUSTS AROUND 20-25
MPH AFTER 10 PM. HIGHS THIS AFTERNOON WILL BE CLOSER TO NORMAL,
TOPPING OUT IN THE MID TO UPPER 60S ACROSS THE INTERIOR VALLEYS.
CLEARING SKIES BEHIND THE FRONT WILL ALLOW FOR OVERNIGHT LOWS
TO DROP INTO THE UPPER 30S TO LOW 50S. SOME SHELTERED LOCATIONS
COULD SEE TEMPERATURES BRIEFLY DROP BELOW 37 BUT THESE
CONDITIONS ARE NOT EXPECTED TO BE WIDESPREAD. THE ONLY
EXCEPTION WILL BE THE UPPER HOOD RIVER VALLEY WHERE TEMPERATURES
ARE EXPECTED TO DROP BETWEEN 33 AND 36 DEGREES FOR SEVERAL HOURS
BETWEEN 11 PM TONIGHT AND 9 AM SUNDAY MORNING. A FROST ADVISORY
HAS BEEN ISSUED FOR THIS ZONE FOR THE AFOREMENTIONED TIMEFRAME.
DRY WEATHER EXPECTED ON SUNDAY AS FLOW ALOFT BECOMES MORE ZONAL
WITH THE PASSAGE OF THE SHORTWAVE TROUGH. HIGHS A DEGREE OR TWO
COOLER COMPARED TO THE DAY PRIOR, 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. -19
LONG TERM...MONDAY THROUGH FRIDAY NIGHT
LOOKING AT THE START
OF NEXT WEEK, ENSEMBLES CONTINUE TO SHOW GOOD AGREEMENT IN A
ROBUST LOW PRESSURE SYSTEM DEVELOPING OVER THE NORTHEAST
PACIFIC. MODEL TRENDS CONTINUE TO KEEP THIS LOW WELL OFFSHORE,
MOVING ALMOST PARALLEL TO THE PACNW COAST AND JUST OFFSHORE
ALONG CALIFORNIA INTO THE MIDDLE OF THE WEEK. CHANCES FOR RAIN
HAVE PLUMMETED TO LESS THAN 25% AND EVEN THEN, ONLY A SMALL
PORTION OF THE FORECAST AREA HAS THAT HIGH OF A CHANCE FOR RAIN.
ENSEMBLE CLUSTERS REMAIN IN DECENT AGREEMENT FOR THE UPPER
LEVEL LOW TO PERSIST NEAR THE CALIFORNIA COAST ON WEDNESDAY,
WHILE SHORTWAVE RIDGING NUDGES INTO THE PACNW. THERE IS HIGH
CONFIDENCE FOR DRY CONDITIONS TO PERSIST ACROSS THE AREA TUESDAY
THROUGH MID THURSDAY, WITH TEMPERATURES WARMING BACK INTO THE
MID TO UPPER 60S. MORE UNCERTAINLY RETURNS LATER NEXT WEEK AS
ANOTHER UPPER LEVEL TROUGH BEGINS TO DROP OUT OF THE GULF OF
ALASKA. CHANCES FOR RAIN INCREASE ON THURSDAY, THOUGH CURRENTLY
REMAIN LESS THAN 40%. -19/DH
AVIATION...THROUGH 06Z SUNDAY
CURRENTLY VFR INLAND AND LIFR
FOG/STRATUS ALONG THE COAST. A FRONTAL SYSTEM APPROACHES FROM THE
NORTHWEST, EXPECTED TO ARRIVE AT KAST BY 07Z SAT, KPDX BY 12Z
SAT, AND KEUG BY 13Z SAT. THIS SYSTEM WILL MOVE THROUGH THE
AIRSPACE RATHER QUICKLY, RESULTING IN THE POSSIBILITY OF ONLY
BRIEF MVFR CONDITIONS AND RAIN. THERE IS LIMITED CONFIDENCE FOR
RAIN AT VARIOUS TERMINALS, WITH THE HIGHEST CONFIDENCE ALONG THE
NORTH OR/SOUTH WA COAST (KAST, KTMK). WHILE MOST COASTAL TERMINALS
WILL STAY UNDER LIFR/IFR CONDITIONS UNTIL AT LEAST 18Z SAT, KAST
MAY BE THE ONE EXCEPTION AS THE FRONTAL SYSTEM COULD PROVIDE
ENOUGH MIXING TO CLEAR THE STRATUS OUT BY 11-13Z SAT. AS FOR
INLAND TERMINALS, THERE IS A 30% CHANCE OF RAIN AND 30-60% CHANCE
OF MVFR CIGS BETWEEN 11-16Z SAT. OTHERWISE, EXPECT VFR CONDITIONS
WITH HIGH CLOUD COVERAGE AT INLAND TERMINALS THROUGH THE REST OF
THE TAF PERIOD. WHILE KAST WILL LIKELY STAY VFR THROUGH THE
REMAINDER OF THE PERIOD AFTER 11-13Z SAT, THERE LITTLE CONFIDENCE
REGARDING CONDITIONS AT KONP, WITH PROBABILISTIC GUIDANCE
SUGGESTING LOW CHANCES (15-25%) OF LIFR/IFR CONDITIONS BUT
DETERMINISTIC GUIDANCE SUGGESTING FOG.
EXPECT MOSTLY SOUTHERLY WINDS UNDER 8 KT OVERNIGHT, THEN BECOMING
NORTH TO NORTHWESTERLY AROUND 5 TO 10 KT BY THE AFTERNOON. KONP
WILL BE THE ONE EXCEPTION, WITH SUSTAINED WINDS AROUND 8 TO 12 KT
AND GUSTS UP TO 18 KT BETWEEN 21Z SAT AND 03Z SUN.
KPDX AND APPROACHES...MOSTLY VFR CONDITIONS WITH INCREASING HIGH
CLOUD COVER THROUGH THE TAF PERIOD. A PASSING FRONT WILL BRING
CHANCES FOR MVFR CIGS AND LIGHT RAIN BETWEEN 12-15Z SAT.
SOUTHERLY WINDS UNDER 8 KT AHEAD OF THE FRONTAL SYSTEM WILL BECOME
NORTHWESTERLY BY THE AFTERNOON. ~12
MARINE
WINDS BACK TODAY INTO TONIGHT AHEAD OF AN APPROACHING
COLD FRONT WHICH WILL TRAVERSE THE WATERS LATE TONIGHT, BEFORE
VEERING OUT OF THE NORTHWEST SATURDAY MORNING BEHIND THE FRONTAL
PASSAGE. SEAS OF 5-7 FT AT AROUND 12 SECONDS OTHERWISE CONTINUE
THROUGH SATURDAY. THE MID-PERIOD NORTHWEST SWELL WILL THEN
BUILD OVER THE WEEKEND, WITH SEAS RISING TO 8-10 FT. CHANCES FOR
SEAS TO EXCEED 10 FT REACH 10-20% BEYOND 30 NM NORTH OF CAPE
FALCON. THIS SWELL WILL ALSO POSE A MODERATE RISK FOR SNEAKER
WAVES ALONG THE COAST WHILE OVERALL SEAS REMAIN RELATIVELY
BENIGN; CAUTION SHOULD BE USED BY THOSE IN OR NEAR THE WATER
ALONG COASTAL BEACHES THROUGH THIS WEEKEND.
AS ANOTHER WEATHER SYSTEM LOOKS TO TRACK SOUTHWARD WELL OFFSHORE
OF THE OREGON AND WASHINGTON COASTS EARLY NEXT WEEK, AND MAY BRING
A PERIOD OF STEEPER SEAS MONDAY INTO TUESDAY ALTHOUGH THERE
REMAINS UNCERTAINTY IN THE TIMING AND POTENTIAL PEAK WAVE HEIGHT.
THE LATEST FORECAST DEPICTS THE WESTERLY SWELL REACHING 11-12 FT
AT 12-14 SECONDS MONDAY AFTERNOON AND EVENING BEFORE EASING BELOW
10 FT BY TUESDAY MORNING, WITH A 10-20% CHANCE SIGNIFICANT WAVE
HEIGHTS REACH 15 FT OR HIGHER BEYOND 20 NM. -36
PQR WATCHES/WARNINGS/ADVISORIES
OR...FROST ADVISORY FROM 11 PM THIS EVENING TO 9 AM PDT SUNDAY FOR
ORZ121.
WA...NONE.
PZ...NONE.
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