754
FXUS66 KPQR 091116
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
316 AM PST SUN NOV 9 2025
SYNOPSIS
DRY WEATHER CONTINUES TODAY AS HIGH PRESSURE
CONTINUES TO BUILD OVER THE PACIFIC NORTHWEST. OFFSHORE FLOW
WILL PEAK THIS MORNING AND GRADUALLY WEAKEN THROUGHOUT THE DAY.
A WEAK SHORTWAVE TROUGH WILL BRING CHANCES FOR LIGHT RAIN ACROSS
THE AREA TONIGHT INTO MONDAY. HIGH PRESSURE RE-BUILDS ON
TUESDAY, BRIEFLY RETURNING DRY WEATHER. A STRONGER LOW PRESSURE
SYSTEM ARRIVES WEDNESDAY, RETURNING WIDESPREAD RAIN. SNOW LEVELS
DROP LATE IN THE WEEK, RETURNING CHANCES FOR SNOW OVER THE
CASCADE PASSES.
DISCUSSION...TODAY THROUGH SATURDAY NIGHT
AN UPPER LEVEL
RIDGE WILL CONTINUE TO AMPLIFY TODAY, MAINTAINING DRY WEATHER
AND SLIGHTLY ABOVE NORMAL HIGH TEMPERATURES ACROSS NORTHWEST
OREGON AND SOUTHWEST WASHINGTON. HIGHS ARE FORECAST TO PEAK IN
THE LOW TO MID 60S FOR MOST AREAS, EXCEPT SLIGHTLY COOLER IN THE
COLUMBIA RIVER GORGE, SOUTH WA CASCADES, AND UPPER HOOD RIVER
VALLEY AS EASTERLY WINDS CONTINUE TO BRING COOLER AIR FROM
CENTRAL/EASTERN OREGON.
THE LATEST SURFACE OBSERVATIONS AS OF 3 AM SATURDAY SHOW
EASTERLY WIND GUSTS UP TO 30-35 MPH IN THE FAR EASTERN
PORTLAND/VANCOUVER METRO AND UP TO 45-50 MPH AT EXPOSED
RIDGETOPS (THREE CORNER ROCK). LIGHT EASTERLY WINDS ARE ALSO
PRESENT ALONG THE COAST. PRESSURE GRADIENTS FROM TROUTDALE TO
THE DALLES (KTTD-KDLS) ARE PEAKING EARLY SUNDAY MORNING AROUND
-6 TO -7 MB AND ARE EXPECTED TO GRADUALLY EASE TODAY. AS THESE
PRESSURE GRADIENTS EASE, EASTERLY WINDS WILL ALSO WEAKEN THROUGH
THE GORGE AND ALONG THE COAST. EXPECT A TRANSITION TO MORE
SOUTHERLY WINDS ALONG THE COAST AFTER 1-3 PM TODAY.
LATE TONIGHT INTO MONDAY, THE UPPER RIDGE BEGINS TO FLATTEN AS
A SHORTWAVE TROUGH PUSHES INTO SOUTHERN BRITISH COLUMBIA AND FAR
NORTHWEST WASHINGTON. HIGH-RES ENSEMBLE GUIDANCE SUGGESTS THAT
THE FRONT ASSOCIATED WITH THIS UPPER LEVEL SHORTWAVE WILL BE
VERY WEAK AS IT QUICKLY BRUSHES OUR AREA TONIGHT. THIS SCENARIO
WOULD RESULT IN VERY LIGHT RAIN WITH LOW PRECIPITATION AMOUNTS.
THERE IS HIGH CONFIDENCE (70-80% CHANCE) THAT 24 HOUR RAIN
AMOUNTS BETWEEN 10 PM SUNDAY TO 10 PM MONDAY REMAIN LESS THAN
0.10" FOR MOST PLACES. CURRENTLY, THE HIGHEST CHANCES FOR RAIN
ARE ALONG THE COAST AND SOUTHWEST WASHINGTON (50-80%) AS THIS
WEAK FRONT IS TRACKING FURTHER NORTH, WHILE CHANCES FOR RAIN ARE
LOWER (20-40%) ACROSS INTERIOR NORTHWEST OREGON. IN TERMS OF
TIMING, LIGHT RAIN MAY ARRIVE AS EARLY AS THIS EVENING ALONG
THE COAST, SPREADING INLAND THROUGH MONDAY MORNING. CONDITIONS
GRADUALLY DRY UP MONDAY EVENING AS THE WEAK FRONT PROGRESSES
INLAND.
TUESDAY, ANOTHER SHORTWAVE UPPER LEVEL RIDGE BUILDS OVER THE
PACIFIC NORTHWEST AND THIS WILL BRING A BRIEF RETURN OF DRY
WEATHER. HOWEVER, BY WEDNESDAY, THIS RIDGE QUICKLY GETS PUSHED
EASTWARD AS A MORE ROBUST LOW PRESSURE SYSTEM IN THE NE PACIFIC
TAKES AIM AT THE PACIFIC NORTHWEST. THIS STRONGER SYSTEM WILL
BRING RAIN AND COOLER AIR BACK INTO THE FORECAST. CURRENT
ENSEMBLE GUIDANCE HAS PRECIPITATION LIKELY (70% CHANCE) STARTING
WEDNESDAY MORNING AS THE ASSOCIATED COLD FRONT MOVES IN. BEHIND
THE FRONT, COOLER AIR WILL SETTLE IN AND BRING SNOW LEVELS DOWN
TO PASS-LEVEL IN THE CASCADES THURSDAY-FRIDAY. CURRENT GUIDANCE
SUGGESTS A 40-60% CHANCE THAT 48-HOUR SNOW TOTALS BETWEEN 4 AM
THURSDAY TO 4 AM SATURDAY EXCEED 6 INCHES THROUGH THE PASSES,
WITH THE HIGHEST CHANCES AT THE SANTIAM AND WILLAMETTE PASSES.
AN ACTIVE WEATHER PATTERN CONTINUES INTO THE WEEKEND. -10
AVIATION
HIGH PRESSURE INLAND CONTINUES TO SUPPORT OFFSHORE
FLOW AND LARGELY VFR CONDITIONS ACROSS THE REGION. GUSTS OF
20-30 KT REACH WEST OF THE COLUMBIA GORGE TO KPDX/KTTD AND
THROUGH OTHER EAST-WEST ORIENTED TERRAIN GAPS, BUT WILL TREND
DOWNWARD THIS MORNING AS THE PRESSURE GRADIENT BEGINS TO WEAKEN.
THESE EAST WINDS WILL INHIBIT ANY FOG FORMATION AT BOTH
PORTLAND-AREA TERMINALS AS WELL AS ALONG THE COAST. ACROSS THE
CENTRAL AND SOUTHERN WILLAMETTE VALLEY, THERE IS A 20-30% CHANCE
FOR IFR/LIFR VIS AND CIGS DUE TO POTENTIAL FOG/MIST AND LOW
STRATUS DEVELOPMENT BETWEEN 12-18Z SUN. IF NORTHERLY WINDS IN
THESE AREAS REMAIN HIGHER, A LOW STRATUS DECK MAY BE FAVORED
INSTEAD OF SURFACE-BASED FOG. HIGH CLOUD COVER MAY ALSO PREVENT
FOG. ANY FOG AND LOW STRATUS THAT DEVELOPS THIS MORNING SHOULD
CLEAR OUT BY 18-20Z SUN AS DAYTIME HEATING PROGRESSES.
CIGS BEGIN TO TREND DOWNWARD LATE IN THE TAF PERIOD AS A WEAK
FRONTAL SYSTEM APPROACHES THE COAST, BRINGING A 60-80% CHANCE
FOR IFR/MVFR CIGS ALONG THE COAST AFTER 06-09Z MON AND CHANCES
FOR LIGHT RAIN.
KPDX AND APPROACHES...VFR CONDITIONS EXPECTED THROUGH THE TAF
PERIOD WITH SCT/BKN HIGH CLOUDS. EASTERLY WINDS AROUND 5-10 KT,
STRONGEST THIS MORNING AND GRADUALLY WEAKENING. -10/36
MARINE
HIGH PRESSURE INLAND WILL CONTINUE TO DRIVE OFFSHORE
EASTERLY WINDS, TURNING SOUTHERLY TO SOUTHEASTERLY ON SUNDAY AS
A WEAK FRONT APPROACHES THE WATERS, DECREASING TO 8-12 KT AS
GAP- FLOW EASTERLY WINDS END. SEAS WILL GENERALLY REMAIN 6-9 FT
AT 10-12 SECONDS THROUGH SUNDAY.
WIND DIRECTION VARIES THROUGH THE FIRST HALF OF NEXT WEEK, BUT
WIND SPEEDS LOOK TO REMAIN AT 5-10 KT THROUGH WEDNESDAY MORNING.
THERE IS ALSO HIGH CONFIDENCE (GREATER THAN 95% CHANCE) THAT
SEAS REMAIN BELOW 10 FT THROUGH MIDWEEK AS WELL. AN AREA OF
LOW PRESSURE STRENGTHENING WELL OFFSHORE WILL RETURN BREEZY
SOUTHERLY WINDS AND BUILDING SEAS, INCREASING THE CHANCES
(60-80% CHANCE) FOR ANOTHER PERIOD OF CONDITIONS HAZARDOUS TO
SMALL CRAFT LATE WEDNESDAY INTO THURSDAY. THERE IS ALSO A 30-60%
CHANCE FOR GALE-FORCE WIND GUSTS GREATER THAN 34 KT DURING THIS
PERIOD, WITH THE HIGHEST CHANCES ACROSS THE OUTER WATERS BEYOND
20-30 NM. -10/36
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 10 PM PST THIS
EVENING FOR PZZ210.
WWW.WEATHER.GOV/PORTLAND
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