057
FXUS66 KPQR 181224 AAA
AFDPQR
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PORTLAND OR
524 AM PDT SUN OCT 18 2026
UPDATED AVIATION AND MARINE DISCUSSIONS.
SYNOPSIS
LARGELY DRY WEATHER EXPECTED THROUGH MIDWEEK WHILE
TEMPERATURES REMAIN NEAR TO ABOVE AVERAGE FOR MID-OCTOBER.
CHANCES FOR RAIN AND COOLER TEMPERATURES RAMP UP LATE IN THE
WORK WEEK.
DISCUSSION...NOW THROUGH SATURDAY
CLEAR SKIES AND LIGHT WINDS
HAVE ALLOWED TEMPERATURES TO COOL OFF INTO THE 40S THROUGHOUT
THE WILLAMETTE VALLEY AND INTO THE MID TO UPPER 30S IN SOME OF
THE TYPICAL COOL SPOTS. THE FROST ADVISORY FOR THE UPPER HOOD
RIVER VALLEY, COAST RANGE VALLEYS AND THE SW WA LOWLANDS REMAINS
IN PLACE AS OBSERVED TEMPERATURES CONTINUE TO COOL INTO THE MID
TO UPPER 30S. DESPITE A COOL START TO THE MORNING, TODAY SHOULD
TURN OUT TO BE A PLEASANT FALL DAY. CONDITIONS REMAIN DRY AS
WITH HIGHS TOPPING OUT IN THE MID TO UPPER 60S ACROSS THE
INTERIOR LOWLANDS AND UPPER 50S TO LOW 60S ALONG THE COAST.
AN APPROACHING TROUGH WILL BRING INCREASING MID AND UPPER LEVEL
CLOUD COVER DURING THE EVENING WHICH WILL HELP KEEP
TEMPERATURES A BIT WARMER TONIGHT. GOOD AGREEMENT AMONG THE
ENSEMBLES HEADING INTO MONDAY WITH THE APPROACHING TROUGH
ELONGATING AND PINCHING OFF INTO A CLOSED UPPER LOW THAT DRIFTS
SOUTHWARD TOWARD NORTHERN CALIFORNIA. PRECIPITATION CHANCES
REMAIN LOW OVER LAND WITH THE BEST CHANCE OVER THE LANE COUNTY
CASCADES AT 20%. COOLER AIR ASSOCIATED WITH THE TROUGH WILL
DROP HIGHS TO RIGHT AROUND NORMAL ON MONDAY WITH THE INTERIOR
LOWLANDS REACHING THE LOW 60S AND THE COASTAL AREAS THE UPPER
50S. MONDAY NIGHT WILL BRING MORE WIDESPREAD CHANCES FOR
OVERNIGHT LOWS IN THE 30S FOR MANY VALLEYS AWAY FROM THE CORE
URBAN CENTERS.
HEADING INTO THE MIDDLE OF THE WEEK, THE UPPER LOW WILL CONTINUE TO
DRIFT TOWARD CALIFORNIA WHILE HEIGHTS REBOUND LOCALLY. THIS WILL
KEEP CONDITIONS DRY AND WILL HELP TEMPERATURES JUMP BACK ABOVE
NORMAL INTO THE LOW 70S ACROSS THE INTERIOR LOWLANDS ON TUESDAY AND
WEDNESDAY. OVERNIGHT LOWS DROP INTO THE LOW 40S FOR MOST LOCATIONS
BUT THE TYPICAL COOL SPOTS MAY DROP INTO THE UPPER 30S. WILL NEED TO
WATCH TRENDS AND POTENTIAL FOR MORE FROST DEVELOPMENT. THE LATTER
HALF OF THE WEEK AGAIN TRENDS TOWARD COOLER TEMPERATURES AND MODEST
CHANCES FOR RAIN. CLUSTER ANALYSIS SHOWS GOOD AGREEMENT IN TROUGHING
DEVELOPING OVER THE GULF OF ALASKA AND DROPPING SOUTHEAST TOWARD THE
PACNW THURSDAY INTO FRIDAY. THIS PATTERN WOULD FAVOR A RETURN TO
NEAR NORMAL TEMPERATURES AND CHANCES FOR LIGHT PRECIPITATION.
NIGHTLY CHANCES FOR FROST CONTINUE WITHIN INLAND VALLEYS. TOWARD
THE END OF THE 7 DAY PERIOD, A MORE ROBUST TROUGH AND
ASSOCIATED SURFACE LOW COULD BRING MORE SIGNIFICANT RAINFALL TO
THE REGION NEXT WEEKEND. -19/36
AVIATION...THROUGH 12Z MONDAY
MAINLY VFR CONDITIONS WITH LIGHT
TO CALM WINDS ACROSS THE AIRSPACE. PATCHY FOG AND LOW CLOUDS HAVE
DEVELOPED ALONG THE COAST AND WITHIN THE CASCADE FOOTHILLS. COULD
SEE SOME PATCHY FOG DEVELOP IN THE WILLAMETTE VALLEY THROUGH 18Z
OR SO. THERE IS A 20-30% CHANCE FOR MVFR/IFR CONDITIONS AT KEUG,
KSLE AND KUAO THROUGH THAT TIME. IF ANY FOG DOES DEVELOP, IT
SHOULD CLEAR BY MID TO LATE MORNING. WINDS INCREASE FROM THE NORTH
TO AROUND 5 KT INLAND AND FROM THE NORTHWEST ALONG THE COAST UP O
10 KT. AN APPROACHING TROUGH WILL BRING INCREASING MID AND HIGH
LEVEL CLOUDS TO THE AIRSPACE LATE IN THE TAF PERIOD.
KPDX AND APPROACHES...EXPECT MAINLY VFR CONDITIONS THROUGH 12Z
MONDAY. CLEAR SKIES AND LIGHT WINDS COULD ALLOW FOR PATCHY FOG TO
DEVELOP IN THE AREA. CHANCES REMAIN LOW AT 10-15% THAT THEY IMPACT
THE TERMINAL DIRECTLY THROUGH 17Z. LIGHT WINDS WILL INCREASE TO 5
KT FROM THE NORTH AFTER 18Z. INCREASING MID AND UPPER LEVEL CLOUDS
AHEAD OF AN APPROACHING TROUGH LATE IN THE TAF PERIOD. -19
MARINE
A WESTERLY SWELL WILL CONTINUE TO MOVE INTO THE
WATERS, KEEPING SEAS IN THE 7-9 FOOT RANGE AT 11-12 SECONDS
THROUGH EARLY TONIGHT. NORTHERLY WINDS WILL GRADUALLY DECREASE
THROUGH THE DAY, DROPPING BELOW 10 KT TONIGHT. THIS SWELL WILL
ALSO CONTINUE TO POSE A MODERATE RISK FOR SNEAKER WAVES ALONG
THE COAST; CAUTION SHOULD BE USED BY THOSE IN OR NEAR THE WATER
ALONG BEACHES THROUGH THIS WEEKEND.
ANOTHER WEATHER SYSTEM DROPPING SOUTHWARD OFF THE COAST MONDAY INTO
TUESDAY WILL GENERATE ANOTHER WESTERLY SWELL THAT MOVES INTO THE
WATERS. THERE IS A 10-30% CHANCE FOR SEAS TO PUSH TO 10 FT ACROSS
THE WATERS, PARTICULARLY BEYOND 20 NM TUESDAY. HIGHER CHANCES FOR
THE OUTER WATERS SOUTH OF CAPE FOULWEATHER UP TO 50%. IN
ADDITION, THERE IS A 40-70% CHANCE FOR WIND GUSTS TO CLIMB INTO
THE 21-25 KT RANGE TUESDAY. WINDS AND SEAS APPEAR TO TREND
DOWNWARD MIDWEEK WITH MORE ACTIVE WEATHER LATE IN THE WORK WEEK.
PQR WATCHES/WARNINGS/ADVISORIES
OR...FROST ADVISORY UNTIL 9 AM PDT THIS MORNING FOR ORZ104-105-121.
WA...FROST ADVISORY UNTIL 9 AM PDT THIS MORNING FOR WAZ205-208.
PZ...NONE.
WWW.WEATHER.GOV/PORTLAND
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