092
FXUS66 KPQR 271112
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
412 AM PDT THU AUG 27 2026
SYNOPSIS
A COOL AND INCREASINGLY UNSETTLED PATTERN WILL
CONTINUE THROUGH THE WEEKEND AS UPPER-LEVEL TROUGHING SETTLES
OVER THE PACIFIC NORTHWEST. PERIODIC MARINE PUSHES AND WEAK
FRONTAL PASSAGES WILL BRING INCREASING CLOUD COVER AND LOW
CHANCES FOR PRECIPITATION, WITH THE BEST OPPORTUNITIES ALONG THE
COAST AND HIGHER TERRAIN. TEMPERATURES MAY BRIEFLY REBOUND
SUNDAY, ALTHOUGH UNCERTAINTY INCREASES INTO EARLY NEXT WEEK.
DISCUSSION...NOW THROUGH WEDNESDAY
CONDITIONS CONTINUE TO BE
DOMINATED BY UPPER LEVEL TROUGHING OVER THE NORTHEAST PACIFIC.
MARINE STRATUS ALONG THE COAST IS AGAIN EXPECTED TO PUSH INTO
THE INTERIOR AS ONSHORE FLOW CONTINUES. A SHORTWAVE EMBEDDED
WITHIN THE LARGER UPPER LEVEL TROUGH WILL PASS OVERHEAD THIS
MORNING, SENDING A WEAK COLD FRONT THROUGH THE AREA. CHANCES
FOR MEASURABLE PRECIPITATION CONTINUE TO VARY ACROSS THE AREA
WITH THE BEST CHANCES OVER THE COAST, COAST RANGE, AND CASCADE
FOOTHILLS. CHANCES OVER THESE AREA ARE 10-30% WITH LOCALLY
HIGHER CHANCES OVER PACIFIC AND WAHKIAKUM COUNTIES IN WA AT
40-60%. ELSEWHERE, CHANCES ARE 5% OR LESS. THE DOWNWARD TREND IN
HIGHS CONTINUES WITH TEMPERATURES LIKELY TOPPING OUT IN THE
UPPER 70S ACROSS THE INTERIOR LOWLANDS WHILE THE COAST REMAINS
IN THE 60S.
THE PATTERN REMAINS VERY SIMILAR HEADING INTO FRIDAY. UPPER LEVEL
TROUGHING PERSISTS WITH NORTHERLY ONSHORE AT THE SURFACE SUPPORTING
MARINE STRATUS DURING THE MORNING AND AFTERNOON HIGH TEMPERATURES IN
THE UPPER 70S. HEADING INTO SATURDAY, TROUGHING PERSISTS BUT A
REINFORCING DISTURBANCE COULD BRING A BETTER CHANCE FOR
PRECIPITATION. PROBABILITIES FOR MEASURABLE RAINFALL (0.01
INCHES) ARE 10-30% FOR AREAS NORTH SALEM.
THE PATTERN BEGINS TO FLATTEN OUT DURING THE SECOND HALF OF THE
WEEKEND WHICH WOULD ALLOW TEMPERATURES TO REBOUND TOWARD THE UPPER
70S. ENSEMBLE CLUSTERS FAVOR A COOLER, POSSIBLY WET PATTERN HEADING
INTO EARLY TO MIDDLE OF NEXT WEEK. AN INCREASING NUMBER OF ENSEMBLE
MEMBERS DO SHOW MEASURABLE PRECIPITATION ACROSS MUCH OF THE
AREA BUT DO STILL SHOW CONSIDERABLE DIFFERENCES IN TIMING AND
STRENGTH OF UPPER LEVEL TROUGHING THAT DEVELOPS. -19
AVIATION...THROUGH 12Z FRIDAY
AN UPPER LEVEL LOW OFF THE
WASHINGTON COAST WILL CONTINUE TO SUPPORT ONSHORE FLOW. AT THE
COAST, MVFR/IFR CIGS ARE FAVORED THROUGH THE MORNING, ALTHOUGH
THERE IS ONLY MODERATE CONFIDENCE, 40-70%, IN IFR OCCURRENCE,
HIGHEST ALONG THE CENTRAL OREGON COAST AND DECREASING TO THE
NORTH. AT INLAND TERMINALS, THE HIGHEST CHANCES FOR MVFR CIGS
ARE ALONG THE LOWER COLUMBIA, IN THE PORTLAND AREA, AND IN THE
SOUTHERN WILLAMETTE VALLEY. MVFR CHANCES REACH 50-70% IN THE
HOURS THROUGH 17Z. WIDELY SCATTERED RAIN SHOWERS ARE POSSIBLE
NEAR THE UPPER LOW, WITH 30% CHANCES FOR RESTRICTED VIS WITHIN
LIGHT RAIN AT KAST FROM 15-20Z.
CONDITIONS TREND TOWARD VFR INLAND AND MVFR AT COASTAL
TERMINALS THIS AFTERNOON. SOUTH TO SOUTHWESTERLY WINDS AROUND 5
KT EARLY BECOME MORE WESTERLY 5-10 KT BY THE AFTERNOON. GUSTS TO
20 KT ARE EXPECTED CLOSER TO THE LOW AT KAST.
KPDX AND APPROACHES...INCREASING CHANCES FOR MVFR CIGS AFTER
12Z THU, REACHING 50-70% FROM 14-17Z BEFORE LOW CLOUDS BEGIN TO
MIX OUT. SOUTHERLY WINDS AROUND 3-5 KT EARLY BECOMING WESTERLY
THEN NORTHWESTERLY IN THE AFTERNOON AND EVENING 6-8 KT. -19/36
MARINE
LOW PRESSURE CONTINUES TO TRACK TOWARD VANCOUVER
ISLAND TODAY, SUPPORTING SOUTHERLY WINDS ACROSS THE COASTAL
WATERS, GENERALLY AROUND 10-15 KT. A WEAK FRONT WILL MOVE ACROSS
THE WATERS THURSDAY MORNING BRIEFLY INCREASING SOUTHERLIES UP
TO 20 KT. COULD SEE A BRIEF PERIOD OF ISOLATED GUSTS UP TO 25 KT
ACROSS THE INNER WATERS NORTH OF CAPE FALCON AND AROUND THE
COLUMBIA RIVER BAR THROUGH EARLY THIS AFTERNOON.
HIGH PRESSURE BEGINS TO REBUILD OVER THE WATERS LATER TODAY
INTO FRIDAY, RETURNING NORTH TO NORTHWEST WINDS ACROSS THE
COASTAL WATERS INTO THE WEEKEND. PREDOMINATELY WIND DRIVEN SEAS
ARE EXPECTED TO REMAIN AROUND 3 TO 6 FT THROUGH THE WEEKEND.
SOMEWHAT MORE ACTIVE PATTERN MAY RETURN EARLY NEXT WEEK. -19/DH
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...NONE.
WWW.WEATHER.GOV/PORTLAND
INTERACT WITH US VIA SOCIAL MEDIA:
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