255
FXUS66 KPQR 161020
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
320 AM PDT SUN AUG 16 2026
SYNOPSIS
SEASONABLY WARM AND DRY CONDITIONS EXPECTED THROUGH
MUCH OF THE WEEK WITH MORNING CLOUDS AND AFTERNOON CLEARING.
WINDS GENERALLY OUT OF THE WEST/NORTHWEST, STRONGEST IN THE
AFTERNOON AND ALONG THE CENTRAL COLUMBIA RIVER GORGE AND UPPER
HOOD RIVER VALLEY. CHANCES FOR PRECIPITATION RETURN AT THE END
OF THE WEEK, BUT UNCERTAINTY REMAINS WITH EXACTLY HOW MUCH
PRECIPITATION WE WOULD RECEIVE.
DISCUSSION...TODAY THROUGH SATURDAY
SEASONABLY DRY AND WARM
CONDITIONS CONTINUE THROUGH THE WEEK WITH MINIMAL WEATHER
IMPACTS. THE LARGE-SCALE PATTERN REMAINS FAIRLY STAGNANT THROUGH
THE PERIOD, WITH BROAD AND RELATIVELY FLAT UPPER-LEVEL RIDGING
OVER THE MAJORITY OF CONUS AND A WEAK, POSITIVELY-TILTED UPPER-
LEVEL TROUGHING OVER THE NORTHEAST PACIFIC. THIS PATTERN WILL
SUPPORT CONTINUED ONSHORE FLOW, MAINTAINING NEAR-NORMAL DAILY
HIGH TEMPERATURES IN THE 80S WITHIN INLAND VALLEYS AND 60S ALONG
THE COAST, AND OVERNIGHT LOWS IN THE 50S ACROSS THE REGION. EACH
MORNING WILL BE CHARACTERIZED BY MORNING CLOUDS (AT LEAST ALONG
THE COAST) WHICH CLEAR UP IN THE AFTERNOON. EXPECT MOSTLY LIGHT
WINDS FROM THE WEST/NORTHWEST ACROSS THE REGION THIS WEEK,
STRONGEST EACH AFTERNOON AND ALONG THE CENTRAL COLUMBIA RIVER
GORGE AND UPPER HOOD RIVER VALLEY.
THE MAJORITY OF ENSEMBLE MEMBERS ARE IN AGREEMENT THAT UPPER-
LEVEL RIDGING OVER THE ROCKIES AND GREAT BASIN WILL BUILD LATE
IN THE WORKWEEK, WHICH WOULD FAVOR A BRIEF WARM-UP ON THURSDAY.
HOWEVER, ENSEMBLE GUIDANCE SHOWS THE BROAD UPPER-LEVEL TROUGH
OVER THE NORTHEAST PACIFIC PROGRESSING TOWARD THE PACIFIC
NORTHWEST BY FRIDAY INTO THE WEEKEND, RESULTING IN SLIGHTLY
COOLER TEMPERATURES AND WINDS COMING FROM THE WEST/SOUTHWEST.
CHANCES FOR PRECIPITATION ALSO INCREASE TO 10-30% ACROSS THE
REGION DURING THIS TIME, HOWEVER, THERE IS STILL HIGH
UNCERTAINTY WITH HOW MUCH PRECIPITATION WE WOULD RECEIVE AND THE
EXACT TIMING. IF THE A POTENTIAL FRONT AT THE END OF THE WEEK IS
TOO WEAK, IT WILL HAVE A HARD TIME COUNTERACTING THE OVERALL DRY
AIRMASS AND MAKE IT UNLIKELY FOR US TO RECEIVE SUBSTANTIAL
RAINFALL. -10/36
AVIATION...THROUGH 12Z MONDAY
SATELLITE IMAGERY AND TERMINAL
OBSERVATIONS AS OF EARLY SUNDAY MORNING DEPICTS A MIX OF LOW
STRATUS AND HIGH CLOUDS ACROSS THE REGION, RESULTING IN HIGH-END
MVFR (2-3 KFT) AND LOW-END VFR CONDITIONS ACROSS TERMINALS. HIGH
CONFIDENCE FOR MVFR CIGS CONTINUING ALONG THE COAST AND NORTHERN
WILLAMETTE VALLEY THROUGH 18-20Z SUN, WITH A 30-50% CHANCE FOR
MVFR CIGS DEVELOPING AT ANY GIVEN HOUR BETWEEN 13-16Z SUN FOR THE
CENTRAL AND SOUTHERN WILLAMETTE VALLEY. AFTER 18-20Z SUN, STRATUS
ACROSS THE REGION WILL BEGIN TO DISSIPATE AS DAYTIME HEATING
PROGRESSES, RETURNING VFR CONDITIONS. CHANCES INCREASE FOR
IFR/MVFR STRATUS RETURNING TO THE COAST AFTER 06Z MON.
NORTHWESTERLY WINDS AROUND 5-10 KT TODAY ACROSS THE WILLAMETTE
VALLEY AND 10-15 KT WITH GUSTS UP TO 20 KT ALONG THE COAST.
KPDX AND APPROACHES...MVFR CIGS THROUGH 17-18Z SUN, THEN IMPROVING
TO VFR THROUGH THE REST OF THE TAF PERIOD. NORTHWESTERLY WINDS 3-7
KT, STRONGEST IN THE AFTERNOON AND EVENING. -10
MARINE
A LARGELY STAGNANT PATTERN CONTINUES THROUGH MUCH OF
THE WEEK WITH HIGH PRESSURE OFFSHORE SUPPORTING NORTHERLY TO
NORTHWESTERLY WINDS OF 8-15 KT AND GUSTS UP TO 20 KT. FRIDAY INTO
THE WEEKEND, WEAK LOW PRESSURE OVER THE NORTHEAST PACIFIC WILL
SHIFT WINDS MORE WESTERLY/SOUTHWESTERLY ACROSS THE WATERS, BUT
CHANCES FOR SMALL CRAFT WIND GUSTS EXCEEDING 21 KT REMAIN 5-10%.
BENIGN SEAS OF 3-6 FT PERSIST THROUGH THE PERIOD. -10/36
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...NONE.
WWW.WEATHER.GOV/PORTLAND
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