628
FXUS66 KPQR 221511
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
238 AM PDT WED OCT 22 2025
SYNOPSIS
A WEAK RIDGE WILL CONTINUE TO FLATTEN THROUGH TODAY
AS A BROAD LOW MOVES OVER THE NORTHEAST PACIFIC. THIS LOW WILL
SEND A SET OF WEAK FRONTS OVER THE REGION THROUGH THURSDAY THAT
WILL BRING LIGHT PRECIPITATION TO OUR CWA. AS FRIDAY APPROACHES
A MORE ROBUST LOW ALONG WITH AN ATMOSPHERIC RIVER (AR) WILL
BRING WIDESPREAD PRECIPITATION TO THE REGION THROUGH AT LEAST
THE START OF NEXT WEEK.
SHORT TERM...NOW THROUGH SATURDAY NIGHT
WEAK HIGH PRESSURE
WILL GIVE WAY TO A BROAD LOW OVER THE NORTHEAST PACIFIC AND THE
GULF OF ALASKA. THIS LOW WILL SEND MULTIPLE SYSTEMS INTO THE
REGION, WITH THE FIRST SYSTEM TODAY AND THURSDAY, FOLLOWED BY A
MUCH STRONGER COMBINATION OF SYSTEMS FOR THE LATTER PART OF
THIS WEEK AND INTO THE START OF NEXT WEEK. FOR THE FIRST SYSTEM,
WE WILL SEE A SURGE OF COOLER AIR AND WIDESPREAD, LIGHT
PRECIPITATION THERE IS AROUND A 20-30% CHANCE OF ACCUMULATING
PRECIPITATION (AROUND 0.01") THROUGH MOST INLAND AREAS. HIGHER
PROBABILITY CLOSER TO 50% ALONG THE COAST AND SOUTHWEST
WASHINGTON. THE HIGHEST PRECIPITATION ACCUMULATION WOULD BE
ALONG THE COAST, COAST RANGE, AND SOUTH WASHINGTON CASCADES. THERE
IS AROUND A 10% CHANCE OF SEEING ACCUMULATION AS HIGH AS 0.25"
WITHIN 24 HRS.
THE NEXT SYSTEM WILL IMPACT THE REGION STARTING ON FRIDAY AND
CARRY US INTO SUNDAY. LOOKING AT ENSEMBLE MODELED LOW CENTERS
THERE IS A LOT OF VARIABILITY WITH A SPLATTERING OF POSSIBILITIES
WITH A VARIETY OF PRESSURE DEPTH. NEEDLESS TO SAY, UNCERTAINTY
REMAINS ON THE HIGH SIDE. STILL, IT SHOULD BE NOTED THAT THE
DEEPER THIS LOW BECOMES THE STRONGER THE WINDS AND RAIN WILL BE.
IN ADDITION TO THIS ALASKAN LOW, THERE IS A STRONG SIGNAL FOR
AN ATMOSPHERIC RIVER (AR) AS WELL. THE COMBINATION OF BOTH THE
ALASKAN LOW AND AR SUPPORT WIDESPREAD, POTENTIALLY HEAVY
PRECIPITATION ACROSS THE CWA. 48 HOUR (EARLY FRIDAY MORNING-
EARLY SUNDAY MORNING) TOTAL PRECIPITATION RANGES FROM 1.75" ON
THE LOW END TOWARDS UPWARDS OF 3.75". NOW THE SPREAD IS VERY
DEPENDENT ON ELEVATION AS WELL AS POTENTIAL RAIN SHADOWING. SO,
EXPECT VALUES ON THE LOWER END OF THE RANGE FOR THE WILLAMETTE
VALLEY, WHILE THE COAST, COAST RANGE AND CASCADES SEE VALUES
TOWARDS THE MIDDLE AND UPPER END OF THAT RANGE.
ALONG WITH RAIN WILL BE WIND. NBM MAXIMUM WINDS GUSTS WITHIN A
24 HOUR PERIOD WILL BE DESCRIBED BELOW. NOTE THAT THESE VALUES
REPRESENT THE HIGHEST WIND GUST SPEEDS WITHIN THAT 24 HOUR
PERIOD AND NOT NECESSARILY THE MOST PROLONGED AND DOMINATE
WINDS. A WEAK COASTAL JET WILL BEGIN TO FORM ON FRIDAY WHICH
WILL SPREAD INLAND. THEREFORE THE HIGH END SOLUTION (90TH
PERCENTILE) SHOWS WINDS ALONG THE BEACHES AND HEADLANDS AROUND
50-60 MPH THOUGH THE MOST LIKELY SCENARIO SHOWS GUSTS UP TO 45
MPH. THERE IS AROUND A 5-15% CHANCE OF HIGH WIND WARNING LEVELS
WINDS OF FREQUENT GUSTS OF 58 MPH OR GREATER. INLAND VALLEY WINDS
WILL BE LOWER WITH GUSTS AROUND 35 MPH. RAIN AND WIND THROUGH
SATURDAY COULD RESULT IN TREES BECOMING MORE SUSCEPTIBLE TO FALLING
GIVEN THAT MOST STILL HAVE A MAJORITY OF THEIR LEAVES. /42-27
LONG TERM...SUNDAY THROUGH TUESDAY
AS THE FRIDAY/SATURDAY
SYSTEM EXITS THE AREA THE NEXT IS QUICK ON IT'S HEELS. THIS NEXT
LOW CONTINUES TO LOOK MORE ROBUST AND ORGANIZED BASED ON
DETERMINISTIC MODELS. HOWEVER WHEN LOOKING AT THE ENSEMBLES
THERE IS MUCH MORE SPREAD IN REGARDS TO LOCATION. IF THE LOW
TAKES THE CURRENT PATH OF THE "MEAN" THEN IT WILL SET UP IN A
FAVORABLE SPOT FOR STRONG WINDS. IN ADDITION, THERE ARE A FEW
ENSEMBLES SHOWING A FAIRLY ROBUST LOW SITTING IN ONE OF THE MORE
IDEAL LOCATIONS FOR VERY STRONG WINDS. IF THE MORE ROBUST
SOLUTION OCCURS, IT WOULD BE HIGHLY FAVORED FOR WIND ADVISORY
LEVEL WINDS WITHIN THE WILLAMETTE VALLEY (FREQUENT GUSTS OF
45-57 MPH). THE NBM CURRENTLY SHOWS AROUND A 5-10% CHANCE OF
ADVISORY LEVEL WINDS AT THIS TIME. HOWEVER, TO SHOW JUST HOW
UNCERTAIN THE FORECAST IS, THE 10TH PERCENTILE (LOW END
FORECAST) SHOWS WIND GUSTS OF 20 MPH IN EUGENE WHILE THE 90TH
PERCENTILE (HIGH END FORECAST) HAS WINDS FORECAST AT 50 MPH.
NEARLY A 30 MPH SHIFT. THEREFORE, CONFIDENCE IN THE WIND
FORECAST OVERALL IS UNCERTAIN AT THIS TIME.
WHILE RAIN IS EXPECTED WEST OF THE CASCADES, COLDER AIR IS ALSO
EXPECTED TO MOVE INTO THE REGION LATE SATURDAY INTO SUNDAY. THIS
LOW WILL RESULT IN SNOW LEVELS TO DROP TOWARDS PASS LEVEL
(4000-5000 FT), WITH SNOW LEVELS BEING THE LOWEST ON SUNDAY
AROUND 3500 FT. THE CURRENT DETERMINISTIC 48 HR FORECAST FOR
SATURDAY NIGHT INTO SUNDAY SHOWS ANYWHERE FROM 4 TO 18 INCHES
OF SNOW WITH THE HIGHEST ACCUMULATION ALONG THE VOLCANOES. WE
WILL CONTINUE TO EVALUATE IF A WINTER WEATHER ADVISORY IS NEEDED
AS THE NEXT FEW DAYS PASS.
AS THE START OF NEXT WEEK APPROACHES, FALL WEATHER (COOL AND
WET) REMAINS IN THE FORECAST. NEEDLESS TO SAY, FALL HAS COME TO
THE PACIFIC NW AND NOW IS THE TIME TO CHECK YOUR SUPPLIES AS
WINTER WILL BE HERE SOONER THAN YOU MIGHT THINK. /42-27
AVIATION
GENERALLY VFR CONDITIONS WITH CLEAR SKIES CURRENTLY
RESIDE ACROSS THE FORECAST AREA. LIGHT WINDS, MOIST SURFACE AND
MINIMAL SKY COVER WILL FAVOR PATCHY FOG FORMATION STARTING AROUND
10Z-12Z WEDNESDAY WITHIN THE WILLAMETTE VALLEY. AS A RESULT,
EXPECT IFR/LIFR CONDITIONS TO MANIFEST AND PERSIST THROUGH 16Z-18Z
WEDNESDAY BEFORE RETURNING TOWARDS MVFR/VFR.
AS WEDNESDAY PROGRESSES, CONDITIONS GRADUALLY FALL TOWARDS LOW-
END VFR/HIGH-END MVFR AROUND 18Z-20Z WEDNESDAY ALONG THE COAST,
WITH A 40-60% CHANCE OF MVFR CONDITIONS ALONG THE COAST AS A
FRONT MOVES ONSHORE WITH LIGHT RAIN. THIS FRONT WILL ALSO BRING
CLOUD COVER TO INLAND LOCATIONS, BUT NOT EXPECTING CONDITIONS
BELOW FL040, LIGHT RAIN ALSO IS EXPECTED AFTER 20Z WEDNESDAY AS
WELL. SOUTHERLY WINDS ON WEDNESDAY WILL GENERALLY BE AROUND 10-15
KT WITH GUSTS UP TO 20 KT ALONG THE COAST, AND 5-10 KT ACROSS THE
WILLAMETTE VALLEY.
KPDX AND APPROACHES...PREDOMINATELY VFR CONDITIONS THROUGH THE
TAF PERIOD. ALTHOUGH, THERE IS A 10-20% CHANCE PERIOD OF MVFR/IFR
CONDITIONS DUE TO FOG/LOW STRATUS THROUGH 16Z WEDNESDAY. ANY
LOWERED FLIGHT CONDITIONS ARE EXPECTED TO IMPROVE TO VFR AFTER 18Z
WEDNESDAY WITH LIGHT PRECIPITATION EXPECTED AFTER 21Z WEDNESDAY.
/42
MARINE
AN ACTIVE WEATHER PATTERN CONTINUES THE REST OF THE WEEK
THROUGH THE WEEKEND FACILITATING PERIODS OF GUSTY WINDS ALONG WITH
STEEP AND HAZARDOUS SEAS. SEAS ARE EXPECTED TO SLOWLY IMPROVE
HEADED THROUGH THE MORNING HOURS SETTLING AROUND 10-12 FEET AT
14-15 SECONDS. HOWEVER ANY BREAK IS SHORT LIVED AS A DEEP LOW WILL
DRAG A COLD FRONT ACROSS ALL WATERS RESULTING IN A A PERIOD OF
GALE FORCE, POSSIBLY STORM FORCE SOUTHERLY WIND GUSTS STARTING
THURSDAY EVENING THROUGH AT LEAST LATE FRIDAY MORNING. PROBABILITIES
FOR GALE FORCE GUSTS ARE 50-80%, WHILE THE PROBABILITIES FOR
STORM FORCE ARE ONLY AROUND 5-10%. NOTE THAT PROBABILITIES ARE
HIGHEST OVER THE INNER WATERS OF NORTHERN OREGON AND SOUTHWEST
WASHINGTON DUE TO THE DEVELOPMENT OF A COASTAL JET AROUND THE TIME
OF THE FRONTAL PASSAGE. A GALE WATCH REMAINS IN EFFECT FOR ALL
WATERS FROM 5 PM THURSDAY TO 11 AM FRIDAY. DEPENDING ON THE SPEED
AND TRACK OF THIS SYSTEM, COULD SEE GALES PERSIST THROUGH THE
WEEKEND. HOWEVER, THERE REMAINS A FAIR AMOUNT OF UNCERTAINTY IN
THE STRENGTH AND TIMING OF THIS SYSTEM. IN ADDITION TO THE
ELEVATED WINDS, THIS SYSTEM WILL LIKELY PUSH SEAS TOWARDS 18-20
FT, WITH A 10-15% CHANCE FOR SEAS GREATER THAN 20 FT FRIDAY NIGHT
THROUGH AT LEAST SUNDAY MORNING.
SEAS ARE EXPECTED TO REMAIN ELEVATED THROUGH THE WEEKEND INTO
EARLY NEXT WEEK AS A SERIES OF COMPACT WEATHER SYSTEMS APPROACH
THE REGION, PARTICULARLY SATURDAY NIGHT INTO SUNDAY. THERE REMAINS
SOME UNCERTAINTY AS TO JUST HOW STRONG WINDS MAY GET DURING THIS
PERIOD OWING TO A DECENT SPREAD IN THE EXACT TRACKS OF THE
AFOREMENTIONED WEATHER SYSTEMS. SHOULD ONE OF THESE TRACK CLOSE
TO OR THROUGH THE COASTAL WATERS, A COMBINATION OF A WESTERLY
SWELL AND WIND WAVES WOULD PUSH COMBINED SEAS INTO THE 20-25 FT
RANGE WITH 15-25% CHANCE OF THIS OCCURRING LATE SATURDAY INTO
SUNDAY MORNING. CERTAINLY A PERIOD OF TIME WORTH MONITORING AS WE
CONTINUE THROUGH THE WEEK. /42-99
BEACH HAZARDS
A BEACH HAZARDS STATEMENT REMAINS IN EFFECT
ACROSS THE NORTHERN/CENTRAL OREGON COAST AND SOUTH WASHINGTON COAST
THROUGH FRIDAY MORNING AS A LONG PERIOD, WEST-NORTHWESTERLY SWELL
WILL BRING A HIGH THREAT FOR SNEAKER WAVES. RAZOR CLAM DIGGERS AT
THE COAST WILL NEED TO EXERCISE EXTREME CAUTION THIS WEEK.
SNEAKER WAVES CAN RUN UP SIGNIFICANTLY FARTHER ON A BEACH THAN
NORMAL, INCLUDING OVER ROCKS, LOGS, AND JETTIES. SNEAKER WAVES CAN
SUDDENLY KNOCK PEOPLE OFF OF THEIR FEET AND QUICKLY PULL THEM
INTO THE OCEAN WHICH MAY LEAD TO SERIOUS INJURY OR DROWNING.
CAUTION SHOULD BE USED WHEN IN OR NEAR THE WATER. ALWAYS KEEP AN
EYE ON THE WAVES, AND BE ESPECIALLY WATCHFUL OF CHILDREN AND PETS.
REMEMBER, NEVER TURN YOUR BACK ON THE OCEAN!
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 5 PM PDT THURSDAY FOR PZZ210-251>253-
271>273.
GALE WATCH FROM THURSDAY AFTERNOON THROUGH FRIDAY MORNING FOR
PZZ210-251>253-271>273.
WWW.WEATHER.GOV/PORTLAND
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSPORTLAND
X.COM/NWSPORTLAND
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page