731
FXUS66 KPQR 171213 AAA
AFDPQR
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PORTLAND OR
513 AM PDT SAT OCT 17 2026
UPDATED AVIATION AND MARINE DISCUSSIONS.
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 12Z SUNDAY
A WEAK COLD FRONT CONTINUES TO
MOVE ACROSS THE AREA, BRING LOW CHANCES FOR LIGHT RAIN. CONDITIONS
ACROSS THE AIRSPACE VARY AS KAST IS ALREADY ON THE BACKSIDE OF THE
FRONT AND HAS STARTED TO MIX OUT THE LOW CLOUDS IN THE AREA. KONP
REMAINS IFR AND COULD HANG ONTO THOSE CONDITIONS THROUGH 16-18Z OR
SO. AS FOR INLAND TERMINALS, THERE IS A 30% CHANCE OF RAIN AND
30-60% CHANCE OF MVFR CIGS THROUGH 16Z. VFR CONDITIONS RETURN BY
THE AFTERNOON WITH HIGH CLOUDS THROUGH THE REST OF THE TAF
PERIOD. LIGHT SOUTHERLY WINDS AHEAD OF THE FRONT WILL TURN
NORTHWEST ALONG THE COAST AND NORTHERLY INLAND BEHIND THE COLD
FRONT. SPEEDS ALONG THE COAST 8-12 KT WITH GUST TO AROUND 15 KT AT
KONP. INLAND SPEEDS 5-8 KT. KEUG COULD SEE SOME GUSTS UP TO 20 KT
LATE THIS EVENING INTO EARLY TONIGHT.
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 THROUGH 16Z. LIGHT SOUTHERLY
WINDS TURN NORTHWEST BEHIND THE COLD FRONT AROUND 5 KT. -19
MARINE
WEST WINDS WILL VEER TO THE NORTHWEST TODAY BEHIND A
WEAK COLD FRONT. SEAS 5 TO 7 FEET AT 11 TO 12 SECONDS BUILD
TOWARD 8 TO 9 FEET TONIGHT. CHANCES FOR SIGNIFICANT WAVE HEIGHTS
TO BUILD TO 10 FEET REMAIN LOW AT 10-15% BEYOND 30 NM. 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 THE NEWEST
GUIDANCE HAS DECREASED SIGNIFICANTLY, BRINGING SEAS OF 7 TO 9 FEET AT
11-12 SECONDS MONDAY AFTERNOON AND EVENING. CHANCES FOR WAVE
HEIGHTS ABOVE 10 FEET ARE 20-40% FOR WATERS BEYOND 20 NM. -19/36
PQR WATCHES/WARNINGS/ADVISORIES
OR...FROST ADVISORY FROM 11 PM THIS EVENING TO 9 AM PDT SUNDAY FOR
ORZ121.
WA...NONE.
PZ...NONE.
WWW.WEATHER.GOV/PORTLAND
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSPORTLAND
X.COM/NWSPORTLAND
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