404
FXUS66 KPQR 101042
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
342 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 AFOREMENTIOEND 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 FRIDAY
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 06Z SUNDAY
MAINLY VFR CONDITIONS WITH
SCATTERED LOW AND MID LEVEL CLOUDS STREAMING IN ALONG NORTHWEST
FLOW. SCATTERED RAIN SHOWERS HAVE POPPED UP AND WILL CONTINUE TO
MOVE ACROSS THE AREA IN THE POST FRONTAL ENVIRONMENT. GUIDANCE
SUGGESTS LOW STRATUS REMAINS AWAY FROM THE TERMINALS WITH LOW
(10-20%) CHANCES FOR MVFR CIGS AT ANY GIVEN TERMINAL. STRATUS
ALONG THE WESTERN SLOPES OF THE CASCADES AND COAST RANGE ARE
POSSIBLE. BRIEF SUB-VFR CONDITIONS ARE POSSIBLE IF ANY LIGHT
SHOWER PASSES DIRECTLY OVER A TERMINAL. LIGHT NORTHWEST WINDS LESS
THAN 5 KT OVERNIGHT BECOMING SOUTHERLY INLAND LATE SATURDAY
MORNING AND STAYING NORTHWEST ALONG THE COAST.
KPDX AND APPROACHES...VFR CONDITIONS THROUGH THE PERIOD. THERE IS
A 10-20% CHANCE FOR LIGHT RAIN SHOWERS THROUGH SATURDAY AFTERNOON.
ANY SHOWER THAT PASSES DIRECTLY OVER THE TERMINAL MAY BRING
SUB-VFR CONDITIONS. LIGHT WEST WINDS SHIFT SOUTHERLY DURING THE
DAY. -19
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.
FROST ADVISORY UNTIL 9 AM PDT THIS MORNING FOR ORZ121.
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.
WWW.WEATHER.GOV/PORTLAND
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