151
FXUS66 KPQR 101705
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
1005 AM PDT SAT OCT 10 2026
SYNOPSIS
WEAK LOW PRESSURE OVER THE REGION WILL MAINTAIN
COOL TEMPERATURES WITH LIGHT SCATTERED SHOWERS TODAY. HIGH
PRESSURE RE-BUILDS SUNDAY TO MONDAY, RETURNING DRY AND SUNNY
CONDITIONS. COOL NIGHTS WILL BRING CHANCES FOR MORNING FROST IN
RURAL VALLEYS AWAY FROM URBAN CORES THIS WEEKEND INTO EARLY NEXT
WEEK. NEXT CHANCES FOR LIGHT RAIN ARRIVE TUESDAY TO WEDNESDAY.
TEMPERATURES TREND WARMER LATE IN THE WEEK AS AN UPPER-LEVEL
RIDGE AMPLIFIES OVER THE REGION.
SHORT TERM...TODAY THROUGH MONDAY NIGHT
RADAR IMAGERY AS OF
EARLY SATURDAY MORNING DEPICTS LIGHT, SCATTERED SHOWERS ACROSS
NORTHWEST OREGON AND SOUTHWEST WASHINGTON AS UPPER-LEVEL
TROUGHING REMAINS OVER THE REGION FOLLOWING A FRONTAL PASSAGE
YESTERDAY. THE UPPER TROUGH WILL DEVELOP INTO A CLOSED UPPER-
LEVEL LOW TODAY AND PROGRESS SOUTHWARD, BRINGING WRAP-AROUND
MOISTURE ON THE RELATIVELY COOLER BACKSIDE OF THE LOW OVER
WESTERN OR/WA. THIS WILL MAINTAIN CHANCES FOR LIGHT SHOWERS
THROUGHOUT THE DAY WITH RAIN TOTALS LESS THAN WHAT WE SAW
YESTERDAY. THERE IS HIGH CONFIDENCE (80-90% CHANCE) THAT RAIN
TOTALS TODAY WILL BE LESS THAN 0.10 INCH ACROSS THE REGION.
EXPECT ANOTHER COOL DAY WITH TEMPERATURES PEAKING IN THE LOW 60S
ACROSS INTERIOR VALLEYS AND 50S ALONG THE COAST.
A FROST ADVISORY REMAINS IN EFFECT THIS MORNING FOR THE UPPER
HOOD RIVER VALLEY. HOWEVER, LOW-LEVEL CLOUD COVER IS KEEPING
CONDITIONS MUCH WARMER IN THE MID TO UPPER 40S AS OF 3 AM
SATURDAY. HIGH-RESOLUTION REFS GUIDANCE SUGGESTS THAT LOW CLOUDS
WILL REMAIN THROUGH THE REST OF THE MORNING, WHICH WOULD
PREVENT RADIATIONAL COOLING. WILL CONTINUE TO MONITOR
TEMPERATURES OF THE NEXT FEW HOURS, AND IF CLOUDS DON'T CLEAR
OUT, FROST DEVELOPMENT WILL BE LESS LIKELY AND THE FROST
ADVISORY MAY BE CANCELED EARLY.
ON THE CONTRAST, CHANCES FOR MORE WIDESPREAD AND IMPACTFUL FROST
INCREASE TONIGHT INTO SUNDAY MORNING AS THE AFOREMENTIONED UPPER
LOW DROPS SOUTHWARD AND HIGH PRESSURE BUILDS OVERHEAD, RETURNING
CLEAR SKIES AND CALM WINDS. THERE IS HIGH CONFIDENCE FOR FROST
AND MORNING LOWS BETWEEN 33-36 DEGREES OVER THE UPPER HOOD RIVER
VALLEY, CASCADE FOOTHILLS, NORTH OREGON COAST RANGE VALLEYS,
BATTLE GROUND/BRUSH PRAIRIE AREA, AND PORTIONS OF THE
CENTRAL/SOUTHERN WILLAMETTE VALLEY TO THE EAST OF THE I-5
CORRIDOR NEAR THE FOOTHILLS (E.G. LEBANON, SCIO, ALBANY, HALSEY,
BROWNSVILLE, SWEET HOME, MARCOLA, MOHAWK, JASPER). SUB-FREEZING
TEMPERATURES LESS THAN 32 DEGREES ARE LIKELY IN DEE AND
PARKDALE (70-90% CHANCE). THEREFORE, FROST ADVISORIES REMAIN IN
EFFECT FOR TONIGHT WHERE CONFIDENCE IN FROST FORMATION IS
HIGHEST. ANYONE GROWING OUTDOOR PLANTS THAT ARE SUSCEPTIBLE TO
FROST DAMAGE SHOULD COVER PLANTS OR MOVE PLANTS INDOORS IF
POSSIBLE.
EXPECT DRY AND SUNNY CONDITIONS SUNDAY TO MONDAY AS UPPER-LEVEL
RIDGING AMPLIFIES OVER THE PACIFIC NORTHWEST, WARMING
TEMPERATURES INTO THE MID TO UPPER 60S. WILL CONTINUE TO SEE
CHANCES FOR FROST DEVELOPMENT EACH NIGHT THROUGH MONDAY
NIGHT/TUESDAY MORNING AS CLEAR SKIES AND CALM WINDS SUPPORT
RADIATIONAL COOLING, ESPECIALLY IN RURAL AREAS AND SHELTERED
VALLEYS. THESE AREAS WILL LIKELY (50-60%) EXPERIENCE
TEMPERATURES INTO THE MID 30S EACH MORNING. -10/23
LONG TERM...TUESDAY THROUGH SATURDAY
HIGH PRESSURE WILL
MAINTAIN MOSTLY DRY CONDITIONS WITH SEASONABLE TEMPERATURES
TUESDAY TO WEDNESDAY FOR THE MAJORITY OF THE AREA. AN EXCEPTION
WOULD BE SOUTHWEST WASHINGTON AND THE NORTH OREGON COAST RANGE
AND CASCADES, WHERE CHANCES FOR LIGHT RAIN INCREASE TO 10-30% AS
A WEAK COLD FRONT OVER THE COASTAL WATERS ATTEMPTS PUSHING
INLAND. EVEN IF THIS FRONT IS ABLE TO MOVE INLAND, IT WOULD BE
DECAYING, WHICH SUGGESTS RAIN AMOUNTS WOULD LIKELY BE VERY
LIGHT. CHANCES FOR 48 HOUR RAIN TOTALS EXCEEDING 0.10 INCH FROM
5 AM TUESDAY TO 5 AM THURSDAY ARE 20-40% ACROSS SOUTHWEST
WASHINGTON AND THE NORTH OREGON COAST RANGE AND CASCADES, AND
5-15% ACROSS THE WILLAMETTE VALLEY. WILL ALSO SEE INCREASED
CLOUD COVER BY WEDNESDAY FROM THIS WEAK FRONT, WHICH WILL KEEP
OVERNIGHT TEMPERATURES WARMER AND REDUCE THE THREAT OF
WIDESPREAD FROST BY TUESDAY NIGHT/WEDNESDAY MORNING.
BY THURSDAY AND FRIDAY, THE MAJORITY OF ENSEMBLE MEMBERS ARE IN
AGREEMENT THAT UPPER-LEVEL RIDGING WILL AMPLIFY AGAIN OVER THE
WESTERN U.S., BRINGING ABOVE-AVERAGE 500 MB HEIGHTS. THIS WILL
RESULT IN TEMPERATURES REBOUNDING TO THE LOW TO MID 70S ACROSS
INTERIOR VALLEYS AT THE END OF THE WEEK. -10
AVIATION...THROUGH 18Z SUNDAY
RADAR IMAGERY CONTINUES TO SHOW
LIGHT, SCATTERED SHOWERS ACROSS THE AIRSPACE AS WEAK LOW PRESSURE
REMAINS OVER THE REGION. THESE SHOWERS ARE EXPECTED TO LINGER
THROUGH AROUND 00Z SUNDAY, BUT AM NOT EXPECTING ANY IMPACTS FROM
THESE SHOWERS. THEREFORE, EXPECT PREDOMINATELY VFR CONDITIONS
ACROSS THE AIRSPACE THROUGH THE MAJORITY OF THE TAF PERIOD. HIGH
PRESSURE WILL SLOWLY RE-BUILD THROUGH DAYTIME HOURS WHICH WILL
BRING A RETURN OF DRIER CONDITIONS ALONG WITH CLEARING SKIES.
NORTHWESTERLY WINDS AROUND 3-7 KT FOR ALL TERMINALS TODAY.
TONIGHT, CLEARING SKIES AND CALM WINDS WILL SUPPORT TEMPERATURES
FALLING TOWARDS 33-36 DEGREES F FOR MORE RURAL AREAS AND
SHELTERED VALLEYS. AREAS THAT ARE ABLE TO COOL DOWN TO THESE
TEMPERATURES MAY SEE FROST DEVELOPMENT ON METAL SURFACES. COULD
ALSO SEE SOME IFR/LIFR CONDITIONS DEVELOPING BETWEEN KSLE AND KEUG
STARTING AROUND 12Z SUNDAY. ANY LOWERED FLIGHT CONDITIONS THAT DO
MANIFEST ARE EXPECTED TO IMPROVE TOWARDS VFR AROUND 17Z-19Z
SUNDAY.
KPDX AND APPROACHES...VFR WITH VERY LIGHT SHOWERS THROUGH AROUND
00Z SUNDAY. SKIES EXPECTED TO CLEAR THROUGH THE DAYTIME WHICH WILL
RESULT IN COOLER OVERNIGHT TEMPERATURES. NORTHWESTERLY WINDS 3-5
KT. /42
MARINE
BUOY OBSERVATIONS AS OF EARLY SATURDAY MORNING SHOW
NORTHWESTERLY WINDS AROUND 10-20 KT WITH GUSTS UP TO 25 KT, ALONG
WITH SEAS AROUND 8-10 FT AT 10 SECONDS. THE HAZARDOUS SEAS WARNING
FOR THE WATERS NORTH OF CAPE FALCON AND BEYOND 10 NM AS BEEN
CANCELLED GIVEN THAT SEAS HAVE NOW FALLEN BELOW 11-12 FT. HOWEVER,
SMALL CRAFT ADVISORIES REMAIN IN EFFECT FOR MOST OF THE WATERS
THROUGH THIS AFTERNOON FOR STEEP AND CHOPPY SEAS. WINDS WILL
GRADUALLY WEAKEN TODAY AND SEAS SUBSIDE TO 7-9 FT BY THIS EVENING.
TONIGHT INTO SUNDAY, WILL SEE A RENEWED ROUND OF SMALL CRAFT
CONDITIONS AS TIGHTENING PRESSURE GRADIENTS FROM A THERMAL TROUGH
RESULT IN BREEZY NORTH/NORTHEASTERLY WINDS WITH GUSTS UP TO 25 KT
FOR THE WATERS SOUTH OF CAPE FALCON. SEAS REMAIN STEEP AND CHOPPY
AROUND 7-10 FT AT 9 SECONDS DURING THIS TIME, STEEPEST AS YOU GO
BEYOND 10-20 NM. WINDS WEAKEN ON MONDAY AND REMAIN NORTHERLY
THROUGH EARLY TUESDAY MORNING, BEFORE TURNING MORE SOUTHWESTERLY
MID-WEEK AHEAD OF AN APPROACHING WEAK FRONT. -10
PQR WATCHES/WARNINGS/ADVISORIES
OR...FROST ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM PDT SUNDAY FOR
ORZ104-106-113-117-121-123>125.
WA...FROST ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM PDT SUNDAY FOR
WAZ205-208.
PZ...SMALL CRAFT ADVISORY UNTIL 8 PM PDT THIS EVENING FOR PZZ210.
SMALL CRAFT ADVISORY UNTIL 2 PM PDT THIS AFTERNOON FOR PZZ251-
252-271>273.
SMALL CRAFT ADVISORY FROM 2 PM TO 11 PM PDT SUNDAY FOR PZZ252-
253.
SMALL CRAFT ADVISORY FROM 2 AM TO 11 PM PDT SUNDAY FOR PZZ272-
273.
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