660
FXUS66 KPQR 161054
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
354 AM PDT TUE SEP 16 2025
SYNOPSIS
DRY WEATHER WILL PREVAIL TODAY UNDER CLEAR SKIES AND
STRENGTHENING OFFSHORE FLOW. THIS WILL LEAD TO WARM TEMPERATURES
AND BREEZY TO LOCALLY STRONG EASTERLY WINDS THROUGH THE COLUMBIA
RIVER GORGE AND CASCADE GAPS THIS MORNING. ONSHORE FLOW RETURNS
MIDWEEK AS A WEAK FRONT BRUSHES THE COAST, WITH LIMITED
PRECIPITATION POTENTIAL. A BROADER TROUGH DIGGING INTO THE
REGION FROM THE NORTHEAST PACIFIC WILL BRING BETTER RAIN CHANCES
INTO THE WEEKEND, ESPECIALLY NEAR THE COAST AND ACROSS
SOUTHWEST WASHINGTON.
SHORT TERM...NOW THROUGH WEDNESDAY MORNING
CLEAR SKIES AND
DRY CONDITIONS ARE IN PLACE EARLY THIS MORNING, WITH MINIMUM
HUMIDITY LATE TODAY EXPECTED TO BOTTOM OUT IN THE 20-30% RANGE
ACROSS MUCH OF THE FORECAST AREA. OFFSHORE GRADIENTS HAVE
TIGHTENED OVERNIGHT, NOW PROJECTED AT -5 TO 6 MB TTD-DLS THROUGH
LATE MORNING. WINDS ARE ALREADY GUSTING 25-35 MPH IN THE
WESTERN GORGE AND CASCADE GAPS, WITH ISOLATED 40 MP GUSTS
OBSERVED. GUSTS WILL LIKELY PEAK FROM NOW UNTIL 10 AM, WITH A
40-60% PROBABILITY OF EXCEEDING 40 MPH MOSTLY IN THE CASCADE
LOCKS EASTWARD TOWARD THE HOOD RIVER VALLEY. WINDS WILL
GRADUALLY EASE THROUGH THE AFTERNOON, AND MOST LOCATIONS SHOULD
FALL BELOW 20 MPH BY LATE EVENING. TEMPERATURES RISE WELL ABOVE
SEASONABLE AVERAGES TODAY, WITH HIGHS REACHING THE UPPER 80S TO
NEAR 90 INLAND AND MID 70S AT THE COAST. NBM PROBABILITIES SHOW
A 70-90% CHANCE OF REACHING 85 DEGREES ACROSS INTERIOR VALLEYS,
AND A 10-30% CHANCE OF TOUCHING 90 DEGREES AT SELECT LOCATIONS.
WHILE OVERLAP OF STRONGER WINDS AND LOWEST DAYTIME HUMIDITIES
WILL BE LIMITED, FIRE WEATHER CONCERNS REMAIN ELEVATED TODAY.
FORTUNATELY, RECENT WIDESPREAD RAINFALL HAS REDUCED FUEL
RECEPTIVENESS, PREVENTING CONDITIONS FROM REACHING CRITICAL
THRESHOLDS.
LONG TERM...WEDNESDAY THROUGH SUNDAY
A WEAK FRONT BRUSHING
THE COAST WEDNESDAY WILL REINTRODUCE ONSHORE FLOW, THOUGH
PRECIPITATION POTENTIAL LOOKS MINIMAL. PROBABILITIES FOR
MEASURABLE RAINFALL ARE 10-20% ALONG THE COAST WEDNESDAY
MORNING, WITH DRY WEATHER FAVORED INLAND. TEMPERATURES REMAIN
OLD WITH HIGHS IN THE MID TO UPPER 70S INLAND AND MID 60S ALONG
THE COAST.
BY FRIDAY, ENSEMBLE GUIDANCE CONVERGES ON A GENERALLY DRY
PATTERN UNDER A NARROW RIDGE, KEEPING HIGHS IN THE UPPER 70S TO
NEAR 80 INLAND. A LARGER-SCALE TROUGH BEGINS TO DIG
SOUTHEASTWARD FROM THE GULF OF ALASKA INTO THE WEEKEND,
INCREASING RAIN POTENTIAL. PRECIPITATION CHANCES CLIMB TO
20-40% ACROSS THE FORECAST AREA SATURDAY THROUGH SUNDAY, WITH
HIGHER PROBABILITIES (50-70%) ALONG THE SOUTHWEST WASHINGTON
COAST AND NEAR ASTORIA SATURDAY NIGHT INTO SUNDAY. TEMPERATURES
COOL BACK INTO THE 70S INLAND AND LOW TO MID 60S ALONG THE COAST
UNDER THIS MORE UNSETTLED REGIME.
~HALL
AVIATION
CLEAR SKIES AND WIDESPREAD VFR FLIGHT CONDITIONS
PREVAIL THROUGH TUESDAY AS HIGH PRESSURE PROGRESSES ACROSS THE
REGION. LOW-LEVEL OFFSHORE FLOW CONTINUES THROUGH THE DAY,
BRINGING GUSTY EASTERLY WINDS UP TO 25 KT AT KTTD AND POTENTIALLY
KPDX FOR TUESDAY MORNING AS WELL AS GUSTS UP TO 35 KTS THROUGH THE
COLUMBIA RIVER GORGE. THESE WINDS BEGIN DECREASING AFTER 20Z
TUESDAY. OFFSHORE WINDS ALONG THE COAST TURN SOUTHERLY AFTER
18-21Z TUESDAY. WINDS FROM KUAO TO KEUG WILL MAINLY BE VARIABLE
LESS THAN 6 KTS, TURNING WESTERLY AND INCREASING UP TO 8-10 KTS
FROM 21Z TUESDAY THROUGH 03Z WEDNESDAY.
THERE IS HIGH CONFIDENCE VFR CONDITIONS WILL CONTINUE THROUGH THE
DAY AT ALL TERMINALS. PROBABILITIES FOR MVFR/IFR CONDITIONS BEGIN
TO INCREASE AGAIN ALONG THE COAST LATE TONIGHT DUE TO RETURNING
ONSHORE FLOW. CHANCES INCREASE TO 40-60% AFTER 01-04Z WEDNESDAY
FOR KONP. STRATUS CHANCES SLOWLY BUILD NORTH, INCREASING TO 40-60%
AT KAST AFTER 08-10Z WEDNESDAY.
KPDX AND APPROACHES...VFR CONDITIONS ARE EXPECTED TO CONTINUE
THROUGH THROUGH THE PERIOD. VARIABLE WINDS ARE EXPECTED TO TURN
EASTERLY AND INCREASE AROUND OR JUST AFTER SUNRISE. STRONGEST
WINDS ARE EXPECTED BETWEEN 15-21Z TUESDAY WHEN OCCASIONAL GUSTS
UP TO 20-25 KT ARE POSSIBLE. WINDS DECREASE AFTER 21Z, BECOMING
LESS THAN 10 KTS AFTER 00Z WEDNESDAY. -SCHULDT/HEC
MARINE
WINDS WILL SHIFT FROM NORTHEAST TO EAST THIS MORNING,
WITH LOCALIZED WIND GUSTS UP TO 25 KT OVER THE INNER WATERS
DOWNWIND OF GAPS IN THE COASTAL TERRAIN AS WELL AS IN THE NORTHERN
HALF OF ZONES PZZ272 AND 252 OUT TO 60 NM. WINDS WILL QUICKLY
BECOME SOUTHERLY AND DECREASE THIS AFTERNOON AT AROUND 10 KT OR
LESS IN RESPONSE TO A SURFACE FRONT THAT WILL BE APPROACHING THE
COASTAL WATERS TUESDAY NIGHT INTO WEDNESDAY MORNING. NO IMPACTS
ARE EXPECTED WITH THIS FRONT AS IT WILL DECAY OVER THE WATERS.
HOWEVER, WINDS WILL QUICKLY SWITCH NORTHERLY AND INCREASE BEHIND
THIS FRONT WEDNESDAY EVENING INTO THURSDAY. WIDESPREAD SMALL
CRAFT ADVISORY LEVEL WIND GUSTS UP TO 25 KT LIKELY (90% CHANCE).
OCCASIONAL GUSTS UP TO 30 KT CANNOT BE RULED OUT OVER THE
SOUTHERN WATERS (50-70% CHANCE). -TK/HEC
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...NONE.
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