908
FXUS66 KPDT 242049
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
149 PM PDT SAT OCT 24 2026
KEY MESSAGES
1. DRY AND COOL CONDITIONS THROUGH SUNDAY
2. PATTERN SHIFT AT THE BEGINNING OF THE WEEK WILL BRING
SLIGHTLY BELOW SEASONAL TEMPERATURES
3. INCREASED CHANCES OF PRECIPITATION AT THE START OF THE WEEK
DISCUSSION
CURRENT SATELLITE IS SHOWING MID TO HIGH LEVEL CLOUDS MOVING IN OVER
THE WA CASCADES WITH HIGH LEVEL CLOUDS MOVING IN OVER THE OR
CASCADES. TEMPERATURES TODAY WILL REMAIN IN THE MID TO UPPER 50S
WITH SOME ISOLATED 60S IN CENTRAL OR AND THE COLOMBIA BASIN/GORGE.
OVERNIGHT TEMPERATURES WILL BE SUB-FREEZING ALONG A FEW AREAS IN
CENTRAL OR, THE COLUMBIA BASIN AND YAKIMA VALLEY AS WELL AS THROUGH
THE COLD PRONE AREAS OF SENECA AND WALLOWA VALLEY.
A WEAK UPPER LEVEL RIDGE IS OVER THE REGION THROUGH THE DAY TODAY
AND MOST OF TOMORROW. THIS WILL KEEP THE REGION UNDER DRY CONDITIONS
AND COOL CONDITIONS. IN HOUSE CALCULATIONS SHOW THE REGION TO BE AT
OR SLIGHT BELOW NORMAL SEASONAL TEMPERATURES FOR TODAY WITH THE NBM
SHOWING TEMPERATURES IN THE MID TO UPPER 50S ACROSS MUCH OF THE
REGION. A FEW ISOLATED LOCATIONS IN CENTRAL OR AND THE JOHN DAY
BASIN COULD SEE LOW 60S. OVERNIGHT TEMPERATURES WILL BE SUB-FREEZING
ALONG A FEW AREAS IN CENTRAL OR, THE COLUMBIA BASIN AND YAKIMA
VALLEY AS WELL AS THROUGH THE COLD PRONE AREAS OF SENECA AND WALLOWA
VALLEY.
A CHANGE IN THE SYNOPTIC PATTERN WILL LEAD TO BELOW SEASONAL AVERAGE
TEMPERATURES CONTINUING WITH THE COOLEST DAY BEING MONDAY.
DETERMINISTIC GUIDANCE MODELS SHOW AN UPPER LEVEL LOW MOVING INTO
THE PACNW FROM THE GULF OF ALASKA BY SUNDAY NIGHT. MODELS ARE IN
GOOD AGREEMENT WITH THE INITIAL LOW MAKING ITS WAY ONSHORE BY MONDAY
AFTERNOON. THIS WILL BRING WITH IT BELOW SEASONAL AVERAGE
TEMPERATURES WITH IN HOUSE CALCULATIONS SHOWING NEARLY 5-10 DEGREES
BELOW NORMAL ACROSS CENTRAL OR, EASTERN MOUNTAINS AND THE FOOTHILLS
OF THE BLUES WHILE THE GORGE BASIN AND ADJACENT VALLEYS WILL SEE
TEMPERATURES 1-5 DEGREES BELOW SEASONAL NORMAL. MONDAY NBM RAW
ENSEMBLES SHOW 60-80% CHANCES OF THESE AREAS SEEING MID TO UPPER
50S. TEMPERATURES WILL STEADILY TREND DOWNWARD THROUGH MIDWEEK.
NOT ONLY WILL THIS UPPER LEVEL LOW BRING COOLER TEMPERATURES, BUT
MODELS ARE ALSO SHOWING INCREASED CHANCES OF PRECIPITATION. LOOKING
AT THE MEAN 24 HOUR PRECIPITATION STATISTIC, RAIN/SNOW WILL BE ALONG
THE CASCADES AS EARLY AS SUNDAY NIGHT. THE RAIN WILL CONTINUE TO
SPREAD ACROSS THE REGION THROUGH MONDAY BECOMING WIDESPREAD BETWEEN
11 AM AND 5 PM. LOOKING AT THE NBM RAW ENSEMBLES FOR THE 24 HOUR
PERIOD, THE ENSEMBLES SHOW A 50-80% CHANCE THE EASTERN MOUNTAINS,
BLUES, FOOTHILLS AND THE EASTERN SLOPES OF THE CASCADES WILL SEE
NEAR 0.05 INCHES OF RAIN. THE REMAINING LOCATIONS WILL SEE 0.01-0.04
INCHES OF RAIN. AS THE LOW CONTINUES TO MOVE TO THE EAST, CLUSTERS
AND DETERMINISTIC MODELS BEGIN TO DIVERGE. NBM SHOWS RAIN SHOWERS
CONTINUING ON WEDNESDAY WHILE THE VARIANCE BETWEEN THE MODELS
DIFFER IN TIMING AND AMOUNTS.
AVIATION /18Z TAFS THROUGH 18Z SUNDAY/
VFR CONDITIONS WILL PERSIST THROUGH THE FORECAST PERIOD WITH
GENERALLY LIGHT WINDS. CIGS WILL CONTINUE TO INCREASE OVER THE
REGION FROM WEST TO EAST. NO CIG OR VIS ISSUES WILL OCCUR.
PRELIMINARY POINT TEMPS/POPS
PDT 32 59 33 56 / 0 0 20 40
ALW 38 61 38 56 / 0 0 10 30
PSC 29 58 33 58 / 0 0 20 20
YKM 32 58 36 58 / 0 10 20 20
HRI 30 58 32 57 / 0 0 20 20
ELN 25 54 30 54 / 0 10 30 40
RDM 28 64 27 51 / 0 0 30 60
LGD 34 61 37 57 / 0 0 10 80
GCD 30 64 34 55 / 0 0 10 60
DLS 36 60 38 59 / 0 10 40 60
PDT WATCHES/WARNINGS/ADVISORIES
WA...NONE.
OR...NONE.
DISCUSSION...90
AVIATION...90
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