089
FXUS66 KPQR 210455
AFDPQR
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PORTLAND OR
955 PM PDT TUE OCT 20 2026
UPDATED AVIATION DISCUSSION.
SYNOPSIS
MAINLY DRY CONDITIONS WILL CONTINUE THROUGH FRIDAY.
LOW-LEVEL OFFSHORE FLOW AND ABUNDANT SUNSHINE WILL RESULT IN
AFTERNOON HIGH TEMPERATURES THAT ARE AROUND TEN DEGREES ABOVE NORMAL
FOR INLAND VALLEYS THROUGH WEDNESDAY. TRENDING COOLER THURSDAY
THROUGH MONDAY WITH WIDESPREAD MORNING FROST FRIDAY AND SATURDAY.
CHANCES FOR RAIN ARE MAINLY FOCUSED ON THE SATURDAY EVENING THROUGH
SUNDAY MORNING TIME FRAME WHEN CHANCES INCREASE TO 30-50%.
DISCUSSION...NOW THROUGH MONDAY NIGHT
CURRENT SATELLITE AND
SURFACE WEATHER OBSERVATIONS FROM EARLY TUESDAY AFTERNOON DEPICTED
MOSTLY CLEAR SKIES ASIDE FROM SOME SCATTERED THIN HIGH CLOUDS ALONG
WITH INCREASING LOW-LEVEL OFFSHORE FLOW. AS OF 2 PM TUESDAY, WINDS
WERE GUSTING AS HIGH AS 30-40 MPH IN WIND-PRONE AREAS OF THE WESTERN
COLUMBIA RIVER GORGE AND TROUTDALE/NORTHERN GRESHAM AREA, EXCEPT UP
TO 45 MPH AT CROWN POINT. THE OBSERVED PRESSURE GRADIENT BETWEEN
TROUTDALE AND THE DALLES WAS AROUND -4.5 MB EARLIER THIS AFTERNOON,
AND MODEL ENSEMBLE GUIDANCE SUGGESTS THE GRADIENT WILL HOVER CLOSE TO
THIS RANGE THROUGH TONIGHT WITH ONLY SLIGHT WEAKENING, WHICH SUGGESTS
THE ONGOING GUSTY EAST WINDS WILL CONTINUE IN THESE AREAS BEFORE
DISSIPATING LATE WEDNESDAY MORNING INTO THE AFTERNOON. ELSEWHERE,
WINDS WILL REMAIN RELATIVELY LIGHT. ASIDE FROM WEAKENING OFFSHORE
WINDS TOMORROW, CONDITIONS WILL BE VERY SIMILAR TO WHAT HAS BEEN
OBSERVED TODAY. EXPECT MOSTLY SUNNY SKIES AND HIGH TEMPERATURES IN
THE MID 70S FOR INLAND VALLEYS AND 60S AT THE COAST.
CONFIDENCE IS HIGH TEMPERATURES WILL TREND COOLER THURSDAY AND FRIDAY
WITH HIGHS BACK INTO THE 60S OVER THE LOWLANDS, EXCEPT UPPER 50S AT
THE COAST. THE COOLER TEMPERATURES WILL BE IN RESPONSE TO AN INCOMING
UPPER LEVEL TROUGH AND A SWITCH TO LOW-LEVEL ONSHORE FLOW.
TEMPERATURES WILL THEN REMAIN SEASONABLY COOL OVER THE UPCOMING
WEEKEND. THE MAIN CONCERN DURING THIS TIME PERIOD WILL BE WIDESPREAD
MORNING FROST FRIDAY AND SATURDAY, BRINGING IMPACTS TO THOSE WITH
AGRICULTURAL INTERESTS. SATURDAY MORNING IS SHAPING UP TO BE THE
COLDEST MORNING, AS THIS IS WHEN SOME LOCATIONS COULD FALL
BELOW-FREEZING; THE NBM IS SHOWING A 25-50% CHANCE FOR LOWS OF 32
DEGREES OR COLDER IN THE SOUTHERN WILLAMETTE VALLEY, EXCEPT A 70-80%
CHANCE FROM CRESWELL TO COTTAGE GROW AND NEAR 15% IN EUGENE.
MOISTURE WILL BE LIMITED WITH THE AFOREMENTIONED TROUGH THURSDAY INTO
FRIDAY, AND THE LATEST MODEL GUIDANCE NOW SUGGESTS BOTH DAYS WILL
EITHER BE COMPLETELY DRY OR MOSTLY DRY WITH ONLY TRACE AMOUNTS OF
RAIN. NBM POPS BACK THIS UP AND HAVE FALLEN BELOW 10-15%, EXCEPT IN
THE MT. HOOD NATIONAL FOREST WHERE POPS ARE NEAR 20%. EVEN IF RAIN
DOES OCCUR, NO IMPACTS ARE EXPECTED.
THE HIGHEST CHANCE FOR RAIN OVER THE NEXT SEVEN DAYS IS SATURDAY
EVENING THROUGH SUNDAY MORNING AS A LOW PRESSURE SYSTEM OVER THE
NORTHEAST PACIFIC ATTEMPTS MOVING CLOSER TO THE COAST. THAT BEING
SAID, A SIGNIFICANT AMOUNT OF ENSEMBLE GUIDANCE HAS TRENDED DRIER
WITH TODAY'S FORECAST UPDATE AS MANY ENSEMBLE MEMBERS NOW KEEP THE
LOW PRESSURE SYSTEM WELL OFFSHORE AND/OR TOO FAR TO THE NORTH INTO
CANADA. AS SUCH, POPS HAVE DECREASED TO 30-50% AND FORECAST RAIN
AMOUNTS HAVE DECREASED AS WELL. CHANCES FOR AT LEAST 0.25 INCHES OF
RAIN THIS WEEKEND HAVE DECREASED TO 25-40%. LASTLY, CHANCES FOR
IMPACTFUL WINDS HAVE ALSO DECREASED WITH THE POTENTIAL SYSTEM THIS
WEEKEND, WITH ONLY A 1-5% CHANCE FOR WIND GUSTS OF 40-45 MPH OR
STRONGER. THEREFORE, IMPACTS ARE UNLIKELY TO OCCUR THIS WEEKEND AND
THERE'S A NOTABLE CHANCE CONDITIONS WILL REMAIN DRY. CHANCES FOR RAIN
DECREASE EVEN MORE ON MONDAY TO 10-15%. -23
AVIATION...THROUGH 06Z THURSDAY
VFR FLIGHT CONDITIONS WILL
CONTINUE ACROSS THE AREA THROUGH THE TAF PERIOD WITH THIN HIGH
CLOUDS FROM TIME TO TIME. CEILINGS WITH THESE HIGH CLOUDS ARE ABOVE
15-20 KFT. WINDS WILL GENERALLY BE LESS THAN 8 KTS AT MOST TERMINALS
THROUGH THE TAF PERIOD. THE ONE EXCEPTION IS KTTD AND THROUGH
CASCADE GAPS WHERE EAST WINDS WILL REMAIN ELEVATED AROUND 8-12 KTS
THROUGH AROUND 09-12Z WED WHEN WINDS BEGIN DECREASING. WINDS SHIFT
WEST TO NORTHWESTERLY AFTER 15-18Z WED ALONG THE COAST AS A WEAK
WEATHER SYSTEM APPROACHES THE REGION FROM THE WEST.
KPDX AND APPROACHES...VFR WITH A FEW THIN HIGH CLOUDS WITH CEILINGS
ABOVE 20 KFT. NORTHWEST WINDS LESS THAN 6 KTS. -03
MARINE
NORTHERLY WINDS CONTINUE ACROSS THE WATERS IN THE
WAKE OF A SYSTEM THAT IS DROPPING SOUTHWARD. WIDESPREAD WIND
GUSTS UP TO 25 KT CONTINUE OVER THE NORTHERN OUTER WATERS
BEYOND 10 NM OFFSHORE THIS AFTERNOON. A SMALL CRAFT ADVISORY REMAINS
IN EFFECT FOR THE NORTHERN OUTER WATERS THROUGH 5 PM TODAY. WINDS
HAVE ALREADY DECREASED SIGNIFICANTLY OVER THE CENTRAL AND SOUTHERN
OUTER WATERS, AND THE SMALL CRAFT ADVISORY THAT WAS INITIALLY IN
EFFECT UNTIL 5 PM TODAY HAS BEEN CANCELLED FOR THESE MARINE ZONES.
WINDS AND SEAS ARE SET TO INCREASE AGAIN THURSDAY INTO FRIDAY
MORNING WITH THE PASSAGE OF A DECAYING COOL FRONT, ESPECIALLY OVER
THE NORTHERN WATERS TO THE NORTH OF CAPE FALCON WHERE CONDITIONS WILL
LIKELY BE HAZARDOUS TO SMALL CRAFT. THERE IS THE POTENTIAL FOR A
STRONGER LOW PRESSURE SYSTEM OVER THE UPCOMING WEEKEND, BRINGING A
10-30% CHANCE FOR GALE FORCE WIND GUSTS AND SEAS OVER 10 FEET.
OVERALL CONFIDENCE IN THE EXACT TRACK AND STRENGTH OF THIS POTENTIAL
LOW PRESSURE SYSTEM REMAINS LOW AT THIS TIME. IT IS WORTH NOTING THAT
CHANCES HAVE DECREASED FOR SIGNIFICANT WINDS AND SEAS WITH TODAY'S
FORECAST UPDATE DUE TO A LESS FAVORABLE LOW TRACK. -23
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...NONE.
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