003
FXUS66 KPQR 261813
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
1113 AM PDT TUE MAY 26 2026
..UPDATED AVIATION DISCUSSION
SYNOPSIS...A SHOWERY, COOL PATTERN CONTINUES TODAY AS
YESTERDAY’S FRONT GIVES WAY TO AN UPPER-LEVEL LOW OVER THE
OREGON COASTAL WATERS. SCATTERED THUNDERSTORMS REMAIN POSSIBLE
THIS AFTERNOON (10-20%), WITH THE BEST WINDOW LATE MORNING
THROUGH THE AFTERNOON. DRIER AND WARMER WEATHER RETURNS
WEDNESDAY INTO THURSDAY AS HIGH PRESSURE REBUILDS, BUT WRAP-
AROUND MOISTURE MAY KEEP SHOWER CHANCES GOING OVER THE CASCADES
LATE WEEK. ANOTHER COOL-DOWN IS POSSIBLE HEADING INTO FRIDAY AND
THROUGH THE WEEKEND. RIDGING AND MUCH WARMER TEMPERATURES MAY
RETURN AT THE START OF NEXT WEEK.
DISCUSSION...TODAY THROUGH MONDAY
EARLY THIS TUESDAY
MORNING, THE REGION SITS IN THE WAKE OF MONDAY’S COLD FRONTAL
PASSAGE WITH AN UPPER-LEVEL TROUGH BECOMING A CLOSED LOW OVER
THE OREGON COASTAL WATERS. AS A RESULT, EXPECT A CLASSIC POST-
FRONTAL DAY: VARIABLE CLOUDS, SCATTERED SHOWERS, AND COOL
TEMPERATURES FOR LATE MAY. ANY SHOWER ACTIVITY WILL BE
INTERMITTENT RATHER THAN ORGANIZED, BUT BRIEF HEAVIER BURSTS ARE
POSSIBLE UNDER STRONGER CELLS.
THE POTENTIAL FOR THUNDERSTORMS PERSISTS TODAY, ALTHOUGH
INSTABILITY REMAINS MODEST. LATEST GUIDANCE SUGGESTS CAPE
GENERALLY AROUND 80-100 J/KG BY MIDDAY/AFTERNOON, SUPPORTING A
10-15% CHANCE OF THUNDERSTORMS, MOST FAVORED FROM LATE MORNING
INTO THE AFTERNOON (ROUGHLY 11 AM TO 5 PM). COMPARED WITH
MONDAY, THE BETTER THUNDER POTENTIAL TODAY SHIFTS MORE INTO THE
INTERIOR (INCLUDING PORTIONS OF THE I-5 CORRIDOR), GENERALLY
FROM EUGENE TO THE PORTLAND/VANCOUVER METRO. ANY THUNDERSTORMS
THAT DEVELOP COULD PRODUCE LIGHTNING, BRIEF DOWNPOURS, SMALL
HAIL, AND LOCALLY GUSTY/ERRATIC WINDS.
BY WEDNESDAY AND THURSDAY, CONFIDENCE INCREASES IN A TRANSITION
BACK TOWARD A WARMER AND DRIER REGIME AS THE UPPER LOW DROPS
INTO THE GREAT BASIN AND 500 MB HEIGHTS RISE OVER THE PACIFIC
NORTHWEST. HIGH TEMPERATURES SHOULD REBOUND TO NEAR OR SLIGHTLY
ABOVE NORMAL, WITH THE WARMEST OUTCOMES FAVORED ACROSS THE
PORTLAND/VANCOUVER METRO, SALEM, AND SOUTHWEST WASHINGTON
LOWLANDS. CURRENT PROBABILITIES FOR 80 DEGREES HAVE INCREASED:
ABOUT 50-70% IN THE PORTLAND/VANCOUVER METRO WEDNESDAY,
INCREASING TO 60-80% THURSDAY. ELSEWHERE ACROSS INTERIOR
VALLEYS, CHANCES FOR 80 DEGREES ARE AROUND 30-50% ON WEDNESDAY
AND THURSDAY (HIGHEST CHANCES ON THURSDAY).
ONE POSSIBLE SCENARIO LATE WEEK IS WRAP-AROUND MOISTURE
ROTATING BACK NORTH ON THE EAST SIDE OF THE DEPARTING LOW. THIS
KEEPS A 50-80% CHANCE FOR SHOWERS OVER THE CASCADES ON THURSDAY,
ALONG WITH A 15-30% CHANCE OF THUNDERSTORMS (HIGHEST CHANCES IN
THE MARION, LINN, AND LANE COUNTY CASCADES). WEST OF THE
CASCADES, MOST LOCATIONS STAY DRY, THOUGH A STRAY SHOWER CAN’T
BE RULED OUT IF MOISTURE WRAPS FARTHER WEST THAN CURRENTLY
EXPECTED. ADDITIONALLY, MORE EXTENSIVE CLOUD COVER WOULD ALSO
LIMIT HIGHS (MORE LOWER 70S VERSUS UPPER 70S/LOW 80S).
FRIDAY INTO THE WEEKEND, ENSEMBLES SUGGEST ANOTHER TROUGH
APPROACHING FROM THE NORTHEAST PACIFIC, BRINGING COOLER
TEMPERATURES AGAIN. LINGERING WRAP-AROUND MOISTURE COULD
MAINTAIN SOME SHOWER CHANCES INTO FRIDAY (WITH CURRENT
FORECASTED CHANCES AROUND 40-60% IN THE OREGON CASCADES), WHILE
THE WEEKEND CURRENTLY TRENDS TOWARD DRIER WEATHER OVERALL GIVEN
LIMITED MOISTURE WITH THE BROADER TROUGHING. SATURDAY INTO
SUNDAY, THE TROUGH DIGS SOUTH RATHER THAN SHIFTING EAST TOWARDS
THE REGION, ALLOWING FOR HIGH PRESSURE TO BUILD INTO THE
BEGINNING OF NEXT WEEK. UNCERTAINTY IN TEMPERATURES DRASTICALLY
INCREASE FOR EARLY NEXT WEEK, WITH ENSEMBLE GUIDANCE SUGGESTING
THE POSSIBILITY OF AN AFTERNOON HIGH TEMPERATURE ANYWHERE
BETWEEN 73 AND 93 DEGREES ON MONDAY. WE WILL CONTINUE TO MONITOR
THIS RANGE OF VALUES AS ENSEMBLE GUIDANCE HONES IN ON THE
POTENTIAL OUTCOMES OF THIS LATE WEEKEND INTO EARLY NEXT WEEK
RIDGE. ~12
AVIATION
CURRENTLY A MIX BAG OF MVFR AND VFR CIGS AS LOW
PRESSURE CONTINUES TO DROP SOUTHWARD. MOIST NORTHERLY FLOW
ACROSS THE AREA IS SUPPORTING LOWER CLOUD COVER BUT SHOULD
LIFT TO LOW- END VFR THIS AFTERNOON. LIGHT SHOWERS REMAIN
POSSIBLE THROUGH THE FIRST HALF OF THE TAF PERIOD, MAINLY OVER
THE HIGHER TERRAIN AND IN THE SOUTHERN WILLAMETTE VALLEY.
CHANCES AROUND TERMINALS ARE RELATIVELY LOW SO HAVE KEPT OUT OF
THE FORECAST AT THIS TIME. NORTH/NORTHWEST WINDS AT 8-14 KT WITH
GUSTS TO AROUND 20 KT POSSIBLE BETWEEN 22Z TUESDAY AND 04Z
WEDNESDAY.
THERE REMAINS A 10-15% CHANCE OF THUNDERSTORMS TODAY THROUGH 00Z
WEDNESDAY, MAINLY IN THE SOUTHERN AND CENTRAL WILLAMETTE VALLEY
AROUND KSLE AND KEUG.
KPDX AND APPROACHES...MAINLY VFR CONDITIONS EXPECTED THROUGH THE
TAF PERIOD. LOW PRESSURE TO THE SOUTHWEST IS SUPPORTING
NORTHERLY FLOW AND SCT TO BKN CLOUD COVER AROUND 1500-2500 FT.
THIS IS BRINGING BRIEF PERIODS OF MVFR CIGS TO THE TERMINALS
BUT SHOULD LIFT TO LOW-END VFR THIS AFTERNOON. NORTHERLY WINDS
8-12 KT WITH A FEW GUSTS TO AROUND 20 KT POSSIBLE THIS
AFTERNOON. COULD SEE MVFR CIGS REDEVELOP LATE TONIGHT AFTER
12-14Z WEDNESDAY. THERE IS A 20-50% CHANCE OVER THE EASTERN
METRO. -19
MARINE
A COLD FRONT CONTINUES TO MOVE EAST OF THE WATERS,
LEADING TO DECREASING SOUTHERLY WINDS THROUGH THE DAY. SMALL
CRAFT ADVISORIES CONTINUE ACROSS ALL WATERS FOR STEEP AND
HAZARDOUS SEAS HAZARDOUS TO SMALL CRAFT THROUGH 5 PM. A WESTERLY
SWELL MOVES INTO THE WATERS LATER THIS AFTERNOON AND EVENING,
PUSHING SEAS IN THE MID TEENS AROUND 14-16 SECONDS. HAVE UPGRADED
THE HAZARDOUS SEAS WATCH TO A WARNING FOR ALL WATERS EXCEPT THE
COLUMBIA RIVER BAR WHERE CONDITIONS ARE MORE MARGINAL. THE
WARNING CONTINUES THROUGH 11 AM TUESDAY AND AT THE SAME TIME,
THE SMALL CRAFT ADVISORY FOR THE COLUMBIA RIVER BAR HAS BEEN
EXTENDED FOR THE SAME TIME FRAME. THERE IS A 10-20% CHANCE FOR
THUNDERSTORMS ACROSS THE WATERS THIS EVENING. ANY PASSING
THUNDERSTORMS MAY PRODUCE LIGHTNING, BRIEF HEAVY DOWNPOURS THAT
REDUCE VISIBILITY, ERRATIC WINDS, AND/OR SMALL HAIL.SEAS SUBSIDE
TO 10-12 FT BY TUESDAY EVENING AND GRADUALLY SUBSIDE INTO
WEDNESDAY. -19
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...HAZARDOUS SEAS WARNING UNTIL 11 AM PDT THIS MORNING FOR PZZ210-
251>253-271>273.
SMALL CRAFT ADVISORY UNTIL 11 PM PDT THIS EVENING FOR PZZ210-
251>253-271>273.
WWW.WEATHER.GOV/PORTLAND
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