188
FXUS66 KPQR 210526 AAA
AFDPQR
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PORTLAND OR
1026 PM PDT WED MAY 20 2026
UPDATED AVIATION DISCUSSION.
SYNOPSIS
DRY AND WARM WEATHER IS EXPECTED ACROSS THE REGION
THROUGH THE WEEKEND WITH HIGH PRESSURE OVER THE NORTHEAST
PACIFIC SPREADING EAST OVER THE PACIFIC NW. RAIN AND COOLER
TEMPERATURES RETURN TO THE AREA LATE SUNDAY INTO EARLY NEXT
WEEK, WHICH COULD IMPACT ANY OUTDOOR MEMORIAL DAY PLANS.
DISCUSSION...WEDNESDAY AFTERNOON THROUGH TUESDAY
VISIBLE
SATELLITE IMAGERY EARLY WEDNESDAY AFTERNOON SHOWS MOSTLY CLEAR
SKIES ACROSS NW OR WITH DISSIPATING STRATUS ACROSS SW WA AS HIGH
PRESSURE OVER THE EASTERN PACIFIC EXPANDS EAST OVER THE WEST
COAST. TEMPERATURES TODAY WILL BE SIMILAR TO YESTERDAY WITH
INLAND HIGHS IN THE LOW 70S AND MID 50S TO LOW 60S ALONG THE
COAST. DRY WEATHER CONTINUES THROUGH THE WEEKEND AS THE AREA
GENERALLY REMAINS UNDER HIGH PRESSURE.
WINDS TURN WEAKLY OFFSHORE BY THURSDAY MORNING AS THE HIGH
PRESSURE PEAKS OVER THE AREA AND A WEAK SURFACE THERMAL TROUGH
BUILDS ALONG THE N CA AND S OR COAST. SOME LOCATIONS IN THE
WILLAMETTE VALLEY MAY SEE STRATUS AGAIN THURSDAY MORNING, BUT
DRIER AIR FROM THE OFFSHORE WINDS WILL LIMIT WIDESPREAD
EXPANSION. THIS PATTERN CONTINUES INTO FRIDAY, ALLOWING
TEMPERATURES TO WARM TO AROUND 10-15 DEGREES ABOVE DAILY NORMALS
FOR THURSDAY AND FRIDAY. EXPECT DAYTIME TEMPERATURES TO PEAK IN
THE LOW TO MID 80S FOR INLAND VALLEYS AND 60S ALONG THE COAST.
THERE IS A 35-45% CHANCE FOR MODERATE HEAT RISK IN THE
PORTLAND METRO AREA AND TUALATIN VALLEY AND A 10-25% CHANCE IN
THE REST OF THE INTERIOR VALLEYS ON THURSDAY. THESE CHANCES FALL
TO 5-15% ON FRIDAY.
A WEATHER SYSTEM PUSHING THROUGH CANADA OVER THE WEEKEND WILL
BREAK DOWN THE HIGH PRESSURE OVER THE PACNW AND LEAD TO MORE
ZONAL FLOW. TEMPERATURES WILL FALL A FEW DEGREES BUT STILL
REMAIN ABOVE NORMAL, PEAKING IN THE MID TO UPPER 70S BOTH
SATURDAY AND SUNDAY FOR INLAND VALLEYS. THERE IS MUCH HIGHER
AGREEMENT THAT SUNDAY WILL REMAIN MAINLY DRY AND WARM, THOUGH
COULD BEGIN TO SEE INCREASING CLOUD COVER AHEAD OF AN
APPROACHING WEATHER SYSTEM.
ABOUT 85-90% OF ENSEMBLE MEMBERS FROM THE GFS, EURO, AND
CANADIAN ENSEMBLES INDICATE THE WEATHER SYSTEM WILL PUSH INTO
THE PACNW SOMETIME LATE SUNDAY NIGHT INTO MONDAY BRINGING SHOWER
CHANCES THROUGH TUESDAY. SOME UNCERTAINTY STILL REMAINS IN
GENERAL TIMING OF RAIN AS WELL AS RAIN TOTALS, BUT LATEST
CONSENSUS IS THAT RAIN WILL HOLD OFF UNTIL AT LEAST LATE SUNDAY
NIGHT ALONG THE FAR N OR AND SW WA COAST, THEN SPREAD SOUTHEAST
MONDAY MORNING. CONFIDENCE IS HIGH THAT THIS WILL BE NON-
IMPACTFUL RAIN. THE NBM 90TH PERCENTILE (ONLY 10% CHANCE OF
OCCURRING) FOR 48 HOUR RAIN TOTALS THROUGH 5 AM WEDNESDAY
INDICATES 0.5-0.95 INCH FOR THE WILLAMETTE VALLEY, 0.8-1.6
INCHES ALONG THE COAST AND COAST RANGE, AND 1-1.5 INCHES ALONG
THE CASCADES. WHEN LOOKING AT THE PROBABILITY OF REACHING OR
EXCEEDING 0.5 INCH FOR THE SAME TIME PERIOD, THERE'S A 10-20%
CHANCE FOR THE WILLAMETTE VALLEY, 20-40% FOR THE PORTLAND AND
VANCOUVER METRO AREA AND SW WA LOWLANDS, 30-60% FOR THE COAST
AND COAST RANGE, AND 45-60% FOR THE CASCADES. TEMPERATURES WILL
ALSO DROP SUBSTANTIALLY FOR MONDAY AND TUESDAY WITH HIGH
TEMPERATURES IN THE MID 60S FOR THE INTERIOR LOWLANDS. -03
AVIATION
HIGH PRESSURE MAINTAINS CONTROL OVER THE AREA,
SUPPORTING A SUMMER-LIKE PATTERN. OVERNIGHT, NORTH/NORTHWEST FLOW
5-10 KT EXPECTED ALONG THE COAST WITH LIGHT AND VARIABLE WINDS
INLAND. VFR CONDITIONS EXPECTED INLAND WITH MVFR CIGS RETURNING TO
THE COAST OVERNIGHT. SATELLITE IMAGERY AS OF 10 PM SHOWS PATCHY
STRATUS OFF THE OREGON COAST, SLOWLY BUILDING TOWARD THE KAST AND
KONP TERMINALS. THE VERY SLIGHT OFFSHORE COMPONENT OF THE WIND
MAY HINDER STRATUS FROM IMPACTING THE TERMINALS INITIALLY BUT
SHOULD MANAGE TO COME ONSHORE LATE TONIGHT. GUIDANCE SUGGESTS
STRATUS DEVELOPING ALONG THE CASCADE FOOTHILLS WITH A 40-60%
CHANCE OF MVFR CIGS. STRATUS IS NOT EXPECTED TO BE AS WIDESPREAD
THURSDAY MORNING AND SHOULD REMAIN CONFINED TO THE FOOTHILLS AND
AWAY FROM TERMINALS WITHIN THE WILLAMETTE VALLEY AND PORTLAND
METRO. WINDS INCREASE AFTER 16-18Z THURSDAY TO 5-10 KT FROM THE
NORTH/NORTHEAST. COULD SEE SOME GUSTS AROUND 20 KT THURSDAY
AFTERNOON, MAINLY ALONG THE COAST.
KPDX AND APPROACHES...VFR CONDITIONS THROUGH THE TAF PERIOD. LIGHT
WINDS OVERNIGHT BECOMING NORTHERLY THURSDAY MORNING TO AROUND 10
KT. COULD SEE SOME EASTERLY WINDS EARLY THURSDAY MORNING AROUND
KTTD. -19
MARINE
HIGH PRESSURE OFFSHORE WILL MAINTAIN BREEZY NORTHERLY
WINDS THROUGH THE END OF THE WEEK. THE STRONGEST WINDS ARE
EXPECTED DURING THE AFTERNOON AND EVENING PERIODS AS THE SURFACE
THERMAL TROUGH STRENGTHENS OVER THE NORTHERN CA/SOUTHERN OR
COAST. SMALL CRAFT ADVISORIES REMAIN IN EFFECT FOR THE WATERS
SOUTH OF CAPE FALCON THROUGH EARLY FRIDAY MORNING FOR NORTHERLY
WIND GUSTS UP TO 25 KT. WILL NOTE THAT THERE MAY BE A BRIEF LULL
IN THE WINDS BETWEEN 5-11 AM THURSDAY FOR THE INNER WATERS
ZONES (FROM THE COAST TO 10 NM OFFSHORE) BEFORE INCREASING AGAIN
TOMORROW AFTERNOON. FOR THE OUTER WATERS NORTH OF CAPE FALCON,
SMALL CRAFT ADVISORIES REMAIN ARE IN EFFECT THROUGH TONIGHT, AND
AGAIN THURSDAY EVENING. A SMALL CRAFT ADVISORY HAS ALSO BEEN
ISSUED FOR THE COLUMBIA RIVER BAR BETWEEN 7 AM-12 PM THURSDAY
FOR A STRONG EBB CURRENT BRINGING SEAS UP TO 7 FT ALONG THE MAIN
CHANNEL. SEAS 6 TO 9 FEET EXPECTED ACROSS ALL WATERS THROUGH
THIS WEEKEND. THE SUMMER-LIKE PATTERN IS LIKELY TO BREAK DOWN
SUNDAY NIGHT AS A FRONT APPROACHES THE WATERS AND RETURNS
SOUTHWESTERLY WINDS. -10/DH
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FROM 7 AM TO NOON PDT THURSDAY FOR PZZ210.
SMALL CRAFT ADVISORY UNTIL 5 AM PDT FRIDAY FOR PZZ252-253-272-
273.
SMALL CRAFT ADVISORY UNTIL 5 AM PDT THURSDAY FOR PZZ271.
SMALL CRAFT ADVISORY FROM 5 PM THURSDAY TO 5 AM PDT FRIDAY FOR
PZZ271.
WWW.WEATHER.GOV/PORTLAND
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