152
FXUS66 KPQR 052004
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
103 PM PDT MON OCT 5 2026
SYNOPSIS
UNSEASONABLY WARM AND DRY CONDITIONS CONTINUE
THROUGH THURSDAY WITH AREAS OF EARLY MORNING VALLEY AND COASTAL
FOG. WEAK OFFSHORE FLOW WILL BRING SLIGHTLY WARMER TEMPERATURES
WEDNESDAY AND THURSDAY, BEFORE A TROUGH BRINGS A RETURN TO COOLER
TEMPERATURES WITH CHANCES FOR LIGHT RAIN FRIDAY INTO SATURDAY.
CHANCES FOR MORNING FROST INCREASE NEXT WEEKEND, ESPECIALLY SUNDAY
MORNING IN RURAL VALLEYS AWAY FROM URBAN CORES.
SHORT TERM...NOW THROUGH THURSDAY NIGHT
SATELLITE IMAGERY FROM
EARLY MONDAY AFTERNOON DEPICTED CLEAR SKIES ACROSS NEARLY ALL OF
NORTHWEST OREGON AND SOUTHWEST WASHINGTON, ASIDE FROM SOME SCATTERED
LOW CLOUDS LINGERING ALONG THE COAST AND IN THE COWLITZ VALLEY FROM
KELSO TO CASTLE ROCK. WITH HIGH PRESSURE REMAINING FIRMLY IN PLACE
BETWEEN NOW AND THURSDAY, EXPECT A "WASH-RINSE-REPEAT" FORECAST WITH
AREAS OF MORNING FOG AND LOW STRATUS OVER THE LOWLANDS EACH MORNING
GIVING WAY TO SUNNY SKIES IN THE AFTERNOON. THE ONLY CHANGE IN THE
WEATHER PATTERN IS A SLIGHT WARM-UP IN TEMPERATURES WEDNESDAY AND
THURSDAY IN RESPONSE TO THE RE-AMPLIFICATION OF UPPER-LEVEL RIDGING
OVER THE WEST COAST AHEAD OF A CLOSED UPPER-LEVEL LOW CENTERED WELL
OFFSHORE FROM THE CENTRAL CALIFORNIA COAST. THE NBM CONTINUES TO
SUGGEST HIGHS IN THE UPPER 70S TO NEAR 80 DEGREES ON WEDNESDAY FOR
INLAND VALLEYS, WARMING INTO THE LOW TO MID 80S ON THURSDAY.
TEMPERATURES THIS WARM ARE AROUND 10-15 DEGREES ABOVE AVERAGE FOR
THIS TIME OF YEAR.
DESPITE THE ABNORMAL WARMTH, DAILY RECORD HIGHS ON THURSDAY WILL BE
OUT OF REACH FOR MOST SITES, ESPECIALLY FOR NORTHERN WILLAMETTE
VALLEY SITES (PORTLAND, VANCOUVER, HILLSBORO, MCMINNVILLE) AS HIGHS
WOULD NEED TO TOP OUT IN THE UPPER 80S OR WARMER. HOWEVER, DAILY
RECORDS AT SALEM (84F SET IN 1971 AND 2022) AND EUGENE (83F SET IN
1934 AND 1943) MAY BE IN JEOPARDY. -23
LONG TERM...FRIDAY THROUGH SUNDAY NIGHT
LATE IN THE WEEK AND INTO
THIS WEEKEND, LONG-RANGE ENSEMBLE GUIDANCE SUPPORTS AN UPPER-
LEVEL TROUGH DEVELOPING OVER THE PACIFIC NORTHWEST, BRINGING A
RETURN TO ONSHORE FLOW, COOLER AND MORE SEASONABLE TEMPERATURES,
AND LOW CHANCES FOR LIGHT RAIN. WHILE THERE CONTINUES TO BE
UNCERTAINTY IN ITS EVOLUTION, THE MAJORITY OF ENSEMBLE MEMBERS
FROM THE ENS/GEPS STILL MAINTAIN LIGHT RAIN ARRIVING ALONG THE NORTH
OREGON AND SOUTH WASHINGTON COAST AROUND MIDDAY FRIDAY, REACHING
INLAND AREAS BY FRIDAY AFTERNOON. THE GEFS IS STILL TRENDING DRIER
THAN THE ENS/GEPS, WITH 30-45% OF THE TOTAL ENSEMBLE SPACE REMAINING
DRY THROUGH SATURDAY. POTENTIAL RAINFALL AMOUNTS CONTINUE
TO LOOK VERY LIGHT, WITH ONLY A 1-10% CHANCE FOR RAIN AMOUNTS OF
0.10" OR HIGHER FRIDAY INTO SATURDAY, EXCEPT FOR A 15-30% CHANCE IN
THE SOUTH WA CASCADES AND NORTH OREGON CASCADES.
AS THE CORE OF THE UPPER TROUGH MOVES OVERHEAD, MUCH COOLER AIR
ALOFT WILL ALLOW FOR SHARPLY COOLER LOW TEMPERATURES SATURDAY MORNING
AND ESPECIALLY SUNDAY MORNING. CHANCES FOR TEMPERATURES IN THE MID
30S SUPPORTING FROST WILL REACH 25-35% IN THE UPPER HOOD RIVER VALLEY
AROUND PARKDALE AND DEE ON SATURDAY MORNING, INCREASING TO 35-70% AND
INCLUDING LOWER ELEVATIONS NEAR ODELL ON SUNDAY MORNING, AND NEAR 10%
IN HOOD RIVER PROPER. CHANCES FOR FROST SUNDAY MORNING REACH
15-30% IN NORTH OREGON COAST RANGE VALLEYS, THE SOUTHERN WILLAMETTE
VALLEY AND CASCADE FOOTHILLS FROM COWLITZ COUNTY SOUTH TO LANE
COUNTY, AND 5-10% IN THE CENTRAL WILLAMETTE VALLEY. CHANCES FOR A
TRUE FREEZE SUNDAY MORNING ARE LIMITED TO 25-35% IN THE UPPER HOOD
RIVER VALLEY NEAR PARKDALE AND DEE, AND 5-15% ALONG OR-58 BETWEEN
EUGENE AND OAKRIDGE. THOSE WITH AGRICULTURAL INTERESTS OR HOME
GROWERS WITH SENSITIVE OUTDOOR PLANTS SHOULD CONTINUE TO MONITOR THE
FORECAST THIS WEEK. -36/23
AVIATION...THROUGH 00Z WEDNESDAY
MVFR/IFR/LIFR CONDITIONS ARE
SLOWLY DISSIPATING ALONG THE COAST MONDAY AFTERNOON. AS DIURNAL
NORTHWEST WINDS CONTINUE TO INCREASE TO 10-15 KT WITH GUSTS OF
20-25 KT, MIXING WILL HELP LIFT AND BREAK UP LOW CLOUDS, WITH A
PERIOD OF VFR CONDITIONS FAVORED AFTER 20-21Z MON. HOWEVER,
THERE'S A 20-35% CHANCE THAT LOWERED CONDITIONS DO NOT IMPROVE TO
VFR AT ALL AT TAF SITES. WINDS ARE EXPECTED TO EASE BELOW 10 KTS
AFTER 00-03Z TUE, ALLOWING THE RETURN OF MARINE STRATUS AND
IFR/LIFR RESTRICTIONS THROUGH TUESDAY MORNING.
AT INLAND TERMINALS, VFR CONDITIONS PREVAIL. FOG/LOW STRATUS ARE
LIKELY TO RETURN AT MOST TERMINALS AGAIN AROUND SUNRISE TUESDAY,
WITH IFR/LIFR CONDITIONS EXPECTED BY 12-14Z. EXPECT THESE
CONDITIONS TO REMAIN THROUGH AROUND 17-20Z TUE. NORTH TO NORTHWEST
WINDS TODAY RISE TO 7-10 KT AFTER 21Z, FALLING BELOW 5 KTS AFTER
00-04Z TUE.
KPDX AND APPROACHES...PREVAILING VFR CONDITIONS. THERE'S HIGH
CONFIDENCE THAT FOG/LOW STRATUS RETURNS TUESDAY MORNING AROUND
11-13Z WITH IFR/LIFR CONDITIONS. EXPECT THESE CONDITIONS TO REMAIN
THROUGH 18-20Z TUE. NORTH TO NORTHWEST WINDS INCREASE TO AROUND
6-8 KTS AFTER 21Z MON, DECREASING TO LESS THAN 5 KTS AFTER 02-04Z
TUE. -03
MARINE
HIGH PRESSURE OFFSHORE WILL CONTINUE TO MAINTAIN
DIURNAL NORTHERLY WINDS THROUGH THE WEEK WITH PEAK AFTERNOON
AND EVENING WIND GUSTS OF 20-25 KT TODAY THROUGH WEDNESDAY.
SMALL CRAFT ADVISORIES REMAIN IN EFFECT FROM 11 AM UNTIL 11 PM
PDT TODAY WITHIN 10 NM SOUTH OF CAPE FALCON AND OUT TO 60 NM
SOUTH OF CAPE FOULWEATHER. EXPECT LARGELY WIND-DRIVEN SEAS
AROUND 4-6 FT THROUGH MIDWEEK, WITH A WEST-NORTHWEST SWELL OF
3-4 FT AT 10-12 SECONDS. HIGH PRESSURE ALOFT WILL ALSO SUPPORT
AREAS OF DENSE FOG DEVELOPING NIGHTLY THROUGH THE MORNING HOURS
AS CLOUD BASES ARE COMPRESSED DOWN TO THE SURFACE.
MORE ACTIVE MARINE CONDITIONS ARE LIKELY IN THE LATTER HALF OF
THE WEEK AS TROUGHING OVER THE GULF OF ALASKA GENERATES A
BUILDING NORTHWEST SWELL. SEAS WILL INCREASE TO 7-10 FT WEDNESDAY
INTO THURSDAY, WITH THE LONGER-PERIOD SWELL ALSO SUPPORTING A
MODERATE RISK FOR SNEAKER WAVES TO THE COAST. CHANCES FOR RAIN
RETURN TO THE REGION FRIDAY INTO THE WEEKEND, THOUGH RAIN AMOUNTS
ARE NOT EXPECTED TO BE VERY IMPACTFUL. -03/36
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 11 PM PDT THIS EVENING FOR
PZZ252-253-273.
WWW.WEATHER.GOV/PORTLAND
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSPORTLAND
X.COM/NWSPORTLAND
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