426
FXUS66 KPQR 070020 CCA
AFDPQR
AREA FORECAST DISCUSSION...UPDATE
NATIONAL WEATHER SERVICE PORTLAND OR
520 PM PDT TUE OCT 6 2026
UPDATED AVIATION DISCUSSION
SYNOPSIS
UNSEASONABLY WARM AND DRY WEATHER WILL PERSIST THROUGH
THURSDAY. 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. COOL NIGHTS WILL BRING CHANCES FOR MORNING FROST IN
RURAL VALLEYS AWAY FROM URBAN CORES THIS WEEKEND INTO EARLY NEXT
WEEK.
SHORT TERM...NOW THROUGH THURSDAY NIGHT
THERE HAS BEEN MINIMAL
CHANGE TO THE SHORT TERM WEATHER FORECAST WITH THIS MORNING'S UPDATE.
THE REGION WILL REMAIN UNDER A PERSISTENT WEATHER PATTERN THROUGH
THURSDAY, WITH CONDITIONS STAYING DRY AND MUCH WARMER THAN AVERAGE. A
BROAD BUT LOW AMPLITUDE UPPER RIDGE WILL STEADILY BUILD OVER THE WEST
COAST, SUPPORTING THE DEVELOPMENT OF WEAK THERMAL TROUGHING AT THE
SURFACE ALONG THE COAST AND LIGHT OFFSHORE FLOW. WITH TEMPERATURES
ALOFT WARMING SLIGHTLY AND LESS MORNING CLOUD COVER OVER THE NEXT TWO
DAYS, EXPECT HIGH TEMPERATURES TO TREND SEVERAL DEGREES WARMER. THE
NBM 10TH-90TH PERCENTILE FOR HIGH TEMPERATURES DEPICTS VERY NARROW
SPREAD, SUGGESTING CONFIDENCE IN THE TEMPERATURE FORECAST IS HIGH.
HIGHS ARE STILL EXPECTED TO PEAK IN THE UPPER 70S TO LOWER 80S ON
WEDNESDAY AND LOWER 80S ON THURSDAY, WHICH IS 10-15 DEGREES ABOVE
NORMAL. DAILY RECORDS ON THURSDAY AT MOST CLIMATE SITES APPEAR TO BE
OUT OF REACH WITH A 5% CHANCE OR LESS OF TYING OR SURPASSING EXISTING
RECORD VALUES, EXCEPT FOR SLIGHTLY HIGHER CHANCES OF 15-20% AT SALEM
AND EUGENE. SEE THE CLIMATE SECTION BELOW FOR A FULL LIST OF RECORD
TEMPERATURES FOR OCTOBER 8.
THE LATEST SUITE OF HI-RES MODEL GUIDANCE NOW SUGGESTS FOG AND LOW
STRATUS WILL BE MUCH LESS PREVALENT TONIGHT INTO TOMORROW MORNING AND
WEDNESDAY NIGHT INTO THURSDAY MORNING, WITH MOST LOCATIONS
EXPERIENCING SUNNY SKIES FROM SUNRISE TO SUNSET. REFS PROBABILITIES
FOR LOW CLOUDS ARE LESS THAN 10-20% TOMORROW MORNING, EXCEPT 30-40%
IN THE COWLITZ VALLEY. PROBABILITIES FOR FOG ARE ALSO GENERALLY UNDER
20%, EXCEPT 30-40% ALONG THE CENTRAL OREGON COAST FROM LINCOLN CITY
TO FLORENCE. BASED ON THE LACK OF WIDESPREAD FOG OBSERVED TUESDAY
MORNING AND HOW QUICKLY LOW CLOUDS WERE ABLE TO DISSIPATE COMPARED TO
PREVIOUS MORNINGS, THE TREND OF EVEN LESS STRATUS AND FOG THE NEXT
TWO MORNINGS SEEMS REASONABLE, ESPECIALLY GIVEN THE RETURN OF LIGHT
OFFSHORE FLOW AND THE EXTENDED DURATION OF THE ONGOING DRY STRETCH.
-23
LONG TERM...FRIDAY THROUGH MONDAY
MODEL ENSEMBLE GUIDANCE IS IN
BETTER AGREEMENT ON FRIDAY AND SATURDAY IN REGARDS TO THE
SYNOPTIC-SCALE PATTERN AND THE POTENTIAL FOR LIGHT RAIN. WPC'S
CLUSTER ANALYSIS FOR 500 MB HEIGHTS AND ANOMALIES SUGGESTS A TROUGH
WILL MOVE OVER B.C. AND WESTERN WA FRIDAY AFTERNOON BEFORE BECOMING
MORE AMPLIFIED AND FORMING A POTENTIAL CLOSED CUT-OFF LOW ON SATURDAY
OVER THE PACIFIC NORTHWEST. THIS WILL BRING TWO SEPARATE CHANCES FOR
RAIN. THE FIRST CHANCE WILL BE WITH A WEAK PACIFIC COLD FRONT
ASSOCIATED WITH THE INCOMING TROUGH ON FRIDAY; RAIN CHANCES BEGIN
FRIDAY MORNING FOR MUCH OF SOUTHWEST WA AND THE NORTH OR COAST/COAST
RANGE BEFORE SPREADING INLAND FRIDAY AFTERNOON/EVENING. MODEL
ENSEMBLE GUIDANCE SUGGESTS EASTERN SLOPES OF THE COAST RANGE AND
LOCATIONS TO THE WEST OF THE I-5 CORRIDOR WITHIN THE WILLAMETTE
VALLEY WILL BE MOSTLY RAIN-SHADOWED, WITH ONLY A TRACE TO A FEW
HUNDREDTHS OF AN INCH OF RAIN FALLING, IF ANY AT ALL. THE NBM BACKS
THIS UP, AS POPS ONLY PEAK AROUND 10-15% IN THESE AREAS. MEANWHILE,
POPS AND FORECAST RAIN AMOUNTS ARE RELATIVELY HIGHER FOR THE COAST,
WILLAPA HILLS, COWLITZ VALLEY, WESTERN SLOPES OF THE COAST RANGE AND
CASCADES, CASCADE FOOTHILLS, AND LOCATIONS EAST OF THE I-5 CORRIDOR
WITHIN THE WILLAMETTE VALLEY AND PORTLAND-VANCOUVER METRO. THAT SAID,
EVEN THESE AREAS HAVE LOW FORECAST RAIN AMOUNTS, WITH ONLY A 15-35%
CHANCE FOR 0.10 INCHES OF RAIN OR MORE, EXCEPT A 30-50% CHANCE ALONG
AND NEAR THE SOUTH WA/NORTH OR COAST, AND IN THE SOUTH WA/NORTH OR
CASCADES AND ADJACENT FOOTHILLS. THEREFORE, NO IMPACTS ARE EXPECTED
WITH THIS FRONTAL PASSAGE. QPF GUIDANCE SUGGESTS MINIMAL POST-FRONTAL
SHOWERY ACTIVITY FRIDAY NIGHT, EXCEPT FOR THE CASCADES AND FOOTHILLS
WHERE OROGRAPHIC LIFT WILL ALLOW SHOWERS TO LINGER FOR A BIT LONGER.
CHANCES FOR RAIN THEN INCREASE AGAIN ON SATURDAY AS THE CUT-OFF LOW
MOVES OVER THE AREA, ESPECIALLY FOR LOCATIONS NORTH OF FLORENCE,
EUGENE-SPRINGFIELD, AND OAKRIDGE. NORTHERN ZONES HAVE A 20-40% CHANCE
OF RAIN SATURDAY AFTERNOON AND AROUND A 10-25% CHANCE FOR 0.10 INCHES
OF RAIN OR MORE. RAIN CHANCES FALL BELOW 5-10% ON SUNDAY AND MONDAY
AS DRY LOW-LEVEL OFFSHORE FLOW DEVELOPS, BRINGING BREEZY EASTERLY
WINDS TO THE CASCADES, FOOTHILLS, WESTERN COLUMBIA RIVER GORGE, AND
EASTERN PORTLAND-VANCOUVER METRO. MEANWHILE, BREEZY NORTH WINDS WILL
DEVELOP IN THE WILLAMETTE VALLEY.
THE SET-UP THIS WEEKEND WILL FINALLY BRING NOTICEABLY COOLER
TEMPERATURES, WITH HIGHS IN THE 60S TO AROUND 70 DEGREES ON FRIDAY,
LOWERING TO THE UPPER 50S TO LOWER 60S ON SATURDAY. SUNDAY AND MONDAY
TREND A TOUCH WARMER AS UPPER LEVEL HEIGHTS RISE AGAIN AND OFFSHORE
FLOW STRENGTHENS, HOWEVER GUIDANCE IS CONFIDENT TEMPERATURES WILL BE
MUCH CLOSER TO SEASONAL NORMALS COMPARED TO WHAT HAS BEEN OBSERVED
THUS FAR THIS MONTH. MORNING LOWS
WILL SIMILARLY COOL, YIELDING INCREASING CHANCES FOR FROSTY
TEMPERATURES IN THE LOW TO MID 30S FROM FRIDAY NIGHT THROUGH
MONDAY NIGHT. FROST MAY OCCUR AS EARLY AS FRIDAY NIGHT IN THE
UPPER HOOD RIVER VALLEY, WITH 30-40% CHANCES OF FALLING TO 36F
OR LOWER NEAR PARKDALE AND DEE. SATURDAY AND SUNDAY NIGHTS LOOK
TO BE THE COLDEST, WITH NEARLY 10% CHANCES FOR FROST IN HOOD
RIVER PROPER, 50% NEAR ODELL, AND 90% IN PARKDALE AND DEE.
ELSEWHERE, FROST CHANCES REACH 15-35% IN NORTH OREGON COAST
RANGE VALLEYS, THE CENTRAL AND SOUTHERN WILLAMETTE VALLEY AWAY
FROM URBAN CORES, AND THE CASCADE FOOTHILLS FROM COWLITZ COUNTY
SOUTH TO LANE COUNTY ON SUNDAY NIGHT. CHANCES FOR A TRUE FREEZE
PEAK SUNDAY NIGHT AT 50-60% NEAR PARKDALE AND DEE AND 15-20%
NEAR ODELL IN THE UPPER HOOD RIVER VALLEY, AND AT 20-35% ALONG
THE OR-58 CORRIDOR BETWEEN EUGENE AND OAKRIDGE. THOSE WITH
AGRICULTURAL INTERESTS OR HOME GROWERS WITH SENSITIVE OUTDOOR
PLANTS SHOULD CONTINUE TO MONITOR THE FORECAST THIS WEEK. -23/36
AVIATION...THROUGH 00Z THURSDAY
A BROAD RIDGE OF HIGH PRESSURE
REMAINS OVER THE REGION WITH LIGHT SOUTHWEST FLOW ALOFT. SATELLITE
IMAGERY SHOWS MOSTLY CLEAR SKIES ACROSS THE AREA, EXCEPT FOR THE
MARINE STRATUS DECK PUSHING ONTO THE COAST SOUTH OF KTMK. MODEL
GUIDANCE SUGGESTS THAT THE MARINE STRATUS CONTINUES TO PUSH SOUTH
WITH CIGS IMPROVING BY 04Z WED. HOWEVER, THERE IS A 40-50% CHANCE
THAT VIS REMAINS REDUCED DUE TO MIST OR FOG OVERNIGHT. VFR
CONDITIONS ARE EXPECTED INLAND THROUGH AT LEAST 10Z WED. LIGHT
OFFSHORE FLOW DEVELOPING LATER TONIGHT MAY MIX IN ENOUGH DRY AIR
TO DISRUPT THE LOW STRATUS AND FOG THAT HAS DEVELOPED THESE PAST
FEW NIGHTS THROUGHOUT MUCH OF THE INTERIOR LOWLANDS. THERE REMAINS
A 20-30% CHANCE FOR MVFR/IFR CONDITIONS DEVELOPING AT INLAND
TERMINALS, EXCEPT FOR AROUND A 30-50% CHANCE WITHIN THE SOUTHERLY
WILLAMETTE VALLEY NEAR KEUG, BETWEEN 12-18Z WED. NORTH TO
NORTHWEST WINDS AGAIN INCREASE ALONG THE COAST WITH GUSTS TO
AROUND 20 KT NEAR KONP BY 20Z WED.
KPDX AND APPROACHES...VFR CONDITIONS ARE EXPECTED TO PERSIST
UNDER MOSTLY CLEAR SKIES THROUGH AT LEAST 12Z WED. THERE IS A LOW
CHANCE (20-30%) OF MVFR/IFR STRATUS RETURNING BETWEEN 13-17Z WED.
NORTHWEST WINDS AROUND 6-10 KT ARE EXPECTED TO BECOME LIGHT
OVERNIGHT. /DH
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 THURSDAY. SMALL
CRAFT ADVISORIES REMAIN IN EFFECT ACROSS THE WATERS FROM 2 PM PDT
THIS AFTERNOON INTO TONIGHT, AND ANOTHER ROUND OF SMALL CRAFT
ADVISORIES HAVE BEEN ISSUED FOR 2 PM PDT WEDNESDAY THROUGH
WEDNESDAY EVENING. 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 AT THE COAST.
CHANCES FOR RAIN RETURN TO THE REGION FRIDAY INTO THE WEEKEND,
THOUGH RAIN AMOUNTS ARE NOT EXPECTED TO BE IMPACTFUL. -36/03
CLIMATE
DAILY RECORD HIGH TEMPERATURES FOR OCTOBER 8
LOCATIONVALUE (YEAR)
ASTORIA 81 (1951, 1971)
PORTLAND INT'L87 (2022)
VANCOUVER, WA89 (1891)
HILLSBORO89 (2022)
MCMINNVILLE88 (2022)
SALEM84 (1971, 2022)
EUGENE83 (1934, 1943)
PQR WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 2 AM PDT WEDNESDAY FOR PZZ210-251>253.
SMALL CRAFT ADVISORY FROM 1 PM WEDNESDAY TO 2 AM PDT THURSDAY
FOR PZZ210-251>253.
SMALL CRAFT ADVISORY UNTIL 5 AM PDT WEDNESDAY FOR PZZ271>273.
SMALL CRAFT ADVISORY FROM 1 PM WEDNESDAY TO 5 AM PDT THURSDAY
FOR PZZ271>273.
WWW.WEATHER.GOV/PORTLAND
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSPORTLAND
X.COM/NWSPORTLAND
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