114
FXUS66 KPQR 180956
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
256 AM PDT TUE AUG 18 2026
SYNOPSIS
WARM AND DRY CONDITIONS EXPECTED THROUGH MUCH OF
THE WEEK WITH MORNING CLOUDS AND AFTERNOON CLEARING. DAYTIME
HIGHS ARE EXPECTED TO BE IN THE 80S THROUGH THE WEEK. WINDS
GENERALLY OUT OF THE WEST TO NORTHWEST, STRONGEST IN THE
AFTERNOON AND ALONG THE CENTRAL COLUMBIA RIVER GORGE AND UPPER
HOOD RIVER VALLEY. SPOTTY CHANCES FOR LIGHT SHOWERS ARRIVE
FRIDAY NIGHT INTO SATURDAY, BUT CONDITIONS MOST LIKELY REMAIN
DRY. SEASONABLE WEATHER CONTINUES LATE THIS WEEKEND INTO EARLY
NEXT WEEK.
DISCUSSION...TODAY THROUGH MONDAY
LITTLE CHANGE TO THE
FORECAST AS PREDOMINATELY DRY AND WARM CONDITIONS CONTINUE
THROUGH THE WEEK WITH MINIMAL IMPACTS. THE LARGE-SCALE PATTERN
REMAINS STAGNANT THROUGH THE PERIOD, WITH BROAD AND RELATIVELY
FLAT UPPER-LEVEL RIDGING OVER THE ROCKIES AND GREAT BASIN, AND
BROAD 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. WITH MOIST AIR FLOWING INTO THE REGION, EACH NIGHT
WILL BE CHARACTERIZED BY MARINE STRATUS ALONG THE COAST WITH
SOME STRATUS FILTERING INTO THE I-5 CORRIDOR. THESE CLOUDS
SHOULD CLEAR OUT EACH AFTERNOON AS DAYTIME HEATING PROGRESSES.
EXPECT LIGHT WINDS FROM THE WEST/NORTHWEST FOR MOST PLACES,
PEAKING EACH AFTERNOON. AN EXCEPTION WOULD BE THE CENTRAL
COLUMBIA RIVER GORGE AND HOOD RIVER VALLEY, WHERE WEST WINDS
WILL BE STRONGEST WITH GUSTS TO 25-35 MPH THIS AFTERNOON.
CHANCES FOR WIND GUSTS EXCEEDING 35 MPH TODAY ALONG THE CENTRAL
GORGE ARE AROUND 30-50%.
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, THAT WARM-UP WILL LIKELY BE SHORT-LIVED AS ENSEMBLE
GUIDANCE CONTINUES TO SHOW THE UPPER-LEVEL TROUGH OVER THE
NORTHEAST PACIFIC SHIFTING ONSHORE FRIDAY INTO THE WEEKEND,
RESULTING IN SLIGHTLY COOLER TEMPERATURES AND WINDS COMING FROM
THE SOUTH/SOUTHWEST. THERE REMAINS SPOTTY CHANCES (10-25%) FOR
SHOWERS ACROSS PORTIONS OF THE COAST RANGE AND CASCADES, BUT THE
OVERALL AIRMASS WILL REMAIN TOO DRY TO SUPPORT ACCUMULATING
RAINFALL FROM A WEAK FRONT. LATE THIS WEEKEND INTO EARLY NEXT
WEEK, THE TROUGH WEAKENS AND MOST ENSEMBLE MEMBERS SUGGEST A
RETURN OF ZONAL FLOW BEFORE ANOTHER UPPER-LEVEL TROUGH DROPS
DOWN FROM THE GULF OF ALASKA AND APPROACHES BRITISH COLUMBIA. AT
THIS POINT, THERE STILL REMAINS UNCERTAINTY WITH THE EXACT
MAGNITUDE AND PLACEMENT OF THE TROUGH. HOWEVER, THIS WOULD
SUGGEST THAT ONSHORE FLOW CONTINUES ACROSS THE REGION WITH
SEASONABLE TEMPERATURES FOR LATE AUGUST. -10
AVIATION...THROUGH 06Z WEDNESDAY
VFR CONDITIONS FOR ALL INLAND
TERMINALS WITH HIGH LEVEL CLOUDS MOVING ACROSS THE AREA. MARINE
STRATUS HAS DEVELOPED ALONG THE COAST, PRODUCING IFR CONDITIONS.
SUB-VFR CONDITIONS ARE EXPECTED TO PERSIST ALONG THE COAST THROUGH
MUCH OF TUESDAY MORNING, POSSIBLY CLEARING OUT BY NOON OR EARLY
AFTERNOON FOR KAST AND KONP. THERE'S A 30-50% CHANCE OF MVFR
STRATUS PUSHING EAST ALONG THE COLUMBIA RIVER AND FORMING IN THE
NORTHERN WILLAMETTE VALLEY AFTER 12Z TUE, INCLUDING KPDX, KTTD,
AND KUAO. THERE'S A 10-30% CHANCE OF MVFR CIGS FORMING AT KSLE AND
KEUG, AS WELL. ANY MVFR CONDITIONS AT INLAND TERMINALS SHOULD
IMPROVE TO VFR BY 18-20Z TUE. NORTHWEST WINDS AROUND 10 KT
CONTINUE ALONG THE COAST WITH LIGHT WINDS INLAND OVERNIGHT,
INCREASING AGAIN FROM THE NORTHWEST LATE TUESDAY MORNING TO 5-10
KT.
KPDX AND APPROACHES...VFR CONDITIONS WITH HIGH CLOUDS. MARINE
STRATUS IS EXPECTED TO MOVE EAST ALONG THE COLUMBIA RIVER,
EVENTUALLY REACHING THE PORTLAND METRO AFTER 10-12Z. THIS IS
EXPECTED TO BRING MVFR CIGS THROUGH 18-20Z. LIGHT OVERNIGHT
WINDS, BECOMING NORTHWEST AROUND 6-8 KT LATE TUESDAY MORNING.
-19/03
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 AFTERNOON GUSTS UP TO 20 KT.
WEAK LOW PRESSURE MOVING OVER THE NORTHEAST PACIFIC FRIDAY INTO
THE WEEKEND WILL SHIFT WINDS OUT OF THE SOUTH TO SOUTHWEST
ACROSS THE WATERS, BUT CHANCES FOR GUSTS EXCEEDING 21 KT REMAIN
LOW, ONLY 5% OR LESS. HIGH PRESSURE AND NORTHERLY WINDS RETURN BY
SUNDAY. SEAS OF 3-6 FT PERSIST THROUGH THE PERIOD. INCREASING
PERIODS OF 12-14 SEC TODAY AND WEDNESDAY MAY RESULT IN A MODERATE
RISK FOR SNEAKER WAVES ALONG THE COAST. CAUTION SHOULD BE USED
WHEN IN OR NEAR THE WATER. -10
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...NONE.
WWW.WEATHER.GOV/PORTLAND
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