659
FXUS66 KPQR 291141 AAA
AFDPQR
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PORTLAND OR
441 AM PDT FRI MAY 29 2026
UPDATED AVIATION AND MARINE DISCUSSION.
SYNOPSIS
HIGH PRESSURE CONTINUES WELL OFFSHORE WITH GENERAL
WESTERLY FLOW OVER THE REGION. SHOWERS FROM THE THURSDAY SYSTEM
WILL CONTINUE TO DISSIPATE THROUGH THE MORNING WITH ANY
LINGERING RAIN ISOLATED TO THE CASCADES. MARINE STRATUS EXPECTED
TODAY. HIGH PRESSURE INTENSIFIES THROUGH TUESDAY LEADING TO
INCREASING CONFIDENCE IN NEAR RECORD HIGH TEMPERATURES ON MONDAY
AND TUESDAY. PATTERN SHIFT EXPECTED ON WEDNESDAY.
SHORT TERM...NOW THROUGH SUNDAY NIGHT
SYNOPTICALLY, THE
PATTERN IS FAIRLY SPRING LIKE WITH HIGH PRESSURE BUILDING OVER
THE NORTHEAST PACIFIC, AND LOW PRESSURE OVER THE NORTHERN
ROCKIES. THE SYSTEM THAT BROUGHT WIDESPREAD LIGHTNING AND GUSTY
WINDS TO THE PACIFIC NORTHWEST HAS SHIFTED OUT OF THE AREA WITH
JUST A FEW SHOWERS LINGERING OVER THE HIGH CASCADES. ONSHORE
FLOW WITH A ZONAL PATTERN WILL LINGER TODAY THOUGH IN THE POST
FRONTAL ENVIRONMENT LEADING TO MARINE STRATUS MOVING IN THROUGH
THE MORNING. THIS MARINE STRATUS WILL SLOWLY DISSIPATE THROUGH
THE DAY, BUT OVERALL IT WILL AID IN KEEPING DAYTIME HIGHS NEARLY
15 DEGREES COOLER THAN THURSDAY. WITHIN THE WILLAMETTE VALLEY,
COLUMBIA RIVER GORGE, UPPER HOOD RIVER VALLEY AND THE LOWER I-5
CORRIDOR WILL SEE HIGH TEMPERATURES IN THE MID 60S WHILE THE
COAST WILL SEE HIGHS IN THE 50S.
THERE WILL BE MINIMAL CHANGE ON SATURDAY AS THE UPPER-AIR
PATTERN REMAINS SIMILAR. THERE ARE A FEW SHORTWAVE TROUGHS THAT
MOVE THROUGH THE ZONAL FLOW, SOME WITH ELEVATED VORTICITY
ADVECTION, BUT OVERALL THEY WILL HAVE LITTLE IMPACT ON SENSIBLE
WEATHER. SUNDAY HOWEVER WILL BE A DAY OF TRANSITION AS THE HIGH
PRESSURE OVER THE NORTHEAST PACIFIC BEGINS TO SHIFT EASTWARD. AS
IT DOES, WE WILL SEE A GRADUAL INCREASE IN TEMPERATURES AND THE
OVERALL WEATHER WILL DRY THROUGH ALL LAYERS OF THE ATMOSPHERE.
NORTHEASTERLY FLOW ALOFT WILL USHER IN WARMER AND DRIER AIR WITH
850 MB TEMPERATURES RISING FROM 3 DEG C ON SATURDAY TO 6 DEG C
ON SUNDAY AFTERNOON. EVEN WITH THE WARMER AIR FILTERING IN, WE
ARE STILL EXPECTING SEASONABLE TEMPERATURES WITH ONLY AROUND A
5-7 DEGREE RISE. DUE TO CLEAR SKIES, OVERNIGHT TEMPERATURES WILL
BE FAVORABLE FOR COOLING WITH LOWS ON SUNDAY NIGHT INTO MONDAY
MORNING BEING IN THE UPPER 40S.-27
LONG TERM...MONDAY THROUGH THURSDAY
MONDAY STARTS THE FIRST
OF TWO DAYS OF DRASTICALLY INCREASING TEMPERATURES. 500 MB
HEIGHTS ARE IN GOOD AGREEMENT OF THE RIDGE OF HIGH PRESSURE
INTENSIFYING, AND THE RIDGE AXIS SHIFTING CLOSER TO THE SHORE.
IN FACT, THE DIFFERENCES BETWEEN CLUSTERS IS MINIMAL. THIS
RIDGING IS COMBINED WITH WIDESPREAD EAST FLOW ALOFT OF
SIGNIFICANTLY WARMER TEMPERATURES IN THE MIDLEVELS. 850 MB
TEMPERATURES WILL RISE TO AROUND 12-13 DEG C. THIS PATTERN WILL
CAUSE TEMPERATURES TO SPIKE ONCE AGAIN BY ABOUT 10 DEG F WITH
HIGHS FORECAST TO BE IN THE MID TO UPPER 80S INLAND, IN THE
UPPER 60S TO LOW 70S ALONG THE COAST, AND THE CASCADES IN THE
60S. THERE IS CURRENTLY AROUND A 30-40% CHANCE OF THE GREATER
PORTLAND-VANCOUVER METRO AREA SEEING HIGHS OF 90 DEG F OR MORE
ON MONDAY, WITH THE CENTRAL WILLAMETTE VALLEY SITTING CLOSER TO
20%. ELSEWHERE, CHANCES ARE LESS THAN 5%. THE BIG COMPONENT TO
CONSIDER ON MONDAY IS THE URBAN HEAT ISLAND EFFECT AND THUS WHY
PORTLAND WILL BE WARMER. OVERNIGHT TEMPERATURES WILL STILL COOL,
BUT ARE NOT EXPECTED TO BE AS COOL AS PREVIOUS NIGHTS. THIS IS
DUE TO THE EASTERLY FLOW ALOFT CAUSING A WEAK DOWNSLOPE FEATURE.
THIS WILL CAUSE WARMING FROM COMPRESSION WITHIN THE LOWER
ELEVATIONS.
TUESDAY IS MARKED TO BE THE HOTTEST DAY OF THE WEEK WITH NEAR
RECORD BREAKING TEMPERATURES FORECAST. THERE IS HIGH CONFIDENCE
(GREATER THAN 75%) THAT THE PORTLAND-VANCOUVER AREA WILL SEE
HIGHS OF 90 DEG F OR MORE, AROUND 50% IN SALEM, 45% IN LONGVIEW, AND
25% IN EUGENE. IF WE WERE TO BUMP UP THAT TEMPERATURE TO 95 DEG
F OR GREATER, THE PORTLAND AREA REMAINS THE HIGHEST AROUND 31%
WHILE OTHER URBAN AREAS AND ALONG THE I-5 CORRIDOR HAS LESS
THAN A 10% CHANCE. OVERNIGHT TEMPERATURES WILL PROVIDE LITTLE
RELIEF IN MAJOR URBAN AREAS BUT ELSEWHERE, LOWS OF 50-55 DEG F
ARE EXPECTED. THERE IS CURRENTLY WIDESPREAD MODERATE HEATRISK,
AND AROUND A 10% CHANCE OF MAJOR HEATRISK IN THE GREATER
PORTLAND-VANCOUVER METRO. THIS MEANS THAT THOSE WITHOUT COOLING
AND HYDRATION, AS WELL AS THOSE EXPOSED MAY BE AFFECTED.
THEREFORE, TAKE PRECAUTIONS ON TUESDAY IF PARTICIPATING IN
OUTDOOR ACTIVITIES - ESPECIALLY IN THE AFTERNOONS DURING PEAK
HEATING.
LUCKILY THIS HEAT WILL BE SHORT LIVED AS THE HIGH PRESSURE MOVES
INLAND AND A LOW PRESSURE SYSTEM BEGINS TO DROP DOWN FROM THE
GULF OF ALASKA. 500 MB HEIGHT CLUSTER ANALYSIS HAS A MODERATE
LEVEL OF CONSENSUS IN THIS LOW WITH AROUND 32% OF THE MEMBERS
SHOWING HIGHER HEIGHTS, AND AROUND 10% SHOWING SIGNIFICANTLY
LOWER HEIGHTS. WITH THAT BEING SAID, THE FLOW SHOULD BECOME MORE
ZONAL USHERING IN MUCH NEEDED RELIEF FROM THE PACIFIC. NBM
TEMPERATURES SHOW A STEADY TEMPERATURE DECLINE THROUGH THE
REMAINDER OF THE WEEK. IN ADDITION TO THE ZONAL FLOW, A FRONTAL
SYSTEM WILL MOVE OVER THE AREA WITH AROUND THREE QUARTERS OF THE
CLUSTERS SHOWING PRECIPITATION OF SOME KIND OVER THE REGION. AT
THIS TIME, CONFIDENCE IS LOW IN THE EXACT ACCUMULATIONS. ONE
CAVEAT TO THIS IS THE FACT THAT WE WILL HAVE HAD A FEW DAYS OF
VERY DRY AIR IN PLACE WHICH MAY CAUSE THIS FRONT TO WEAKEN AS IT
NEARS. THEREFORE, THERE REMAINS AROUND A 10% CHANCE OF HIGHS IN
THE UPPER 80S ON WEDNESDAY.
SOME MODELS ARE SUGGESTING A TRANSIENT RIDGE FORMING ON THURSDAY
WHICH WOULD CAUSE CONDITIONS TO DRY ONCE AGAIN. HOWEVER,
CONFIDENCE IS QUITE LOW AS IT WILL GREATLY DEPEND ON HOW THE
FRONTAL SYSTEM ON WEDNESDAY SHAKES OUT. -27
AVIATION
SATELLITE IMAGERY SHOWS MARINE STRATUS MOVING IN
CREATING WIDESPREAD MVFR CONDITIONS. WHILE HIGH END MVFR, THE
MARINE STRATUS WILL LINGER WELL INTO THE MORNING THROUGHOUT THE
AREA UNTIL WINDS START TO INCREASE AND HIGH PRESSURE BEGINS TO
SHIFT EASTWARD. THERE IS ANYWHERE FROM A 10-50% CHANCE OF SHOWERS
TODAY THOUGH THEY WILL BE LIGHT AND LIGHTNING IS NOT EXPECTED.
CANNOT RULE OUT A STRAY OUTFLOW WIND GUST THOUGH WITH ANY PASSING
SHOWERS. WILL SEE A GRADUAL LIFT TO VFR TODAY AND WINDS INCREASING
AFTER 22Z FRI FROM THE NORTH. HIGH RESOLUTION MODELS ARE
ATTEMPTING TO KEEP THE COAST FROM FILLING BACK IN OVERNIGHT BUT IF
THE FLOW BECOMES MORE WESTERLY, IT WILL BE DIFFICULT TO KEEP THE
CLOUDS AT BAY. ELSEWHERE, CLOUDY BUT VFR CONDITIONS EXPECTED.
KPDX AND APPROACHES...MVFR THROUGH AT LEAST 16Z FRI BUT MAY LAST
AS LATE AS 20Z FRI IF WINDS REMAIN LIGHTER. GUSTY CONDITIONS
EXPECTED AFTER 22Z FRI WITH GUSTS AS HIGH AS 20 KT. THERE IS
AROUND A 20% CHANCE OF GUSTS EXCEEDING 25 KT THIS EVENING. -27
MARINE
HIGH PRESSURE REMAINS OVER THE AREA WITH A PERSISTENT
NORTHWESTERLY SWELL. A LOW PRESSURE SYSTEM INLAND IS ENCOURAGING
A SLIGHTLY ELEVATED NORTHWESTERLY WIND WAVE WHICH, WHEN COMBINED
WITH THE NORTHWESTERLY SWELL, IS MAINTAINING ELEVATED SMALL
CRAFT ADVISORY SEAS. SEAS HAVE BEEN A BIT MORE DYNAMIC AS THEY
ARE FLUCTUATING GREATLY BETWEEN 8-10 FT AT 15 SECONDS
OVERNIGHT. BECAUSE WE ARE EXPECTING THESE CONDITIONS TO
CONTINUE, HAVE EXTENDED THE ADVISORY THROUGH THE EARLY AFTERNOON
AS A SIGN OF CAUTION. SOME MODELS ARE SUGGESTING A 10% CHANCE
THAT SEAS GREATER THAN 10 FT COULD LAST WELL INTO TONIGHT THOUGH
BASED ON THE OVERALL PATTERN THAT LOOKS LESS LIKELY. WILL NOTE
THAT SEAS WILL EASE FROM SOUTH TO NORTH WITH THE WATERS OF
PZZ252/253, AND PZZ272/273 EASING BELOW 10 FT BY AS EARLY AS
1100.
WINDS ARE BEGINNING TO RAMP UP AS A WEAK DISTURBANCE PASSES
OVER THE WATERS. THROUGH THE WEEK, WE WILL MAINTAIN THE
NORTHWESTERLY PRIMARY SWELL WITH A STEADY DECLINE BELOW 8 FT AT 10
SECONDS. ON SUNDAY, AN INCREASING PRESSURE GRADIENT DUE TO THE
PLACEMENT OF A HIGH PRESSURE SYSTEM WILL CAUSE WINDS TO INCREASE
IN A TYPICAL SUMMER LIKE PATTERN. CANNOT RULE OUT GUSTS AS HIGH AS
30 KT IN THE SOUTHERN OUTER WATERS ON SUNDAY AFTERNOON.
A SERIES OF STRONG EBBS WILL TAKE PLACE THROUGH THE COLUMBIA
RIVER BAR IN THE EVENING THROUGH AT LEAST SUNDAY. -27
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 2 PM PDT THIS AFTERNOON FOR PZZ210-
251>253-271>273.
SMALL CRAFT ADVISORY FROM 1 AM TO 7 AM PDT SATURDAY FOR PZZ210.
WWW.WEATHER.GOV/PORTLAND
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