068
FXUS66 KPDT 081123
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
323 AM PST SAT NOV 8 2025
DISCUSSION
KEY MESSAGES:
1. DRY AND NEAR NORMAL TEMPERATURES THROUGH WEEKEND.
2. BREEZY WINDS ACROSS THE GRANDE RONDE VALLEY SUNDAY.
3. MOUNTAIN PRECIPITATION MONDAY, WIDESPREAD ON THURSDAY.
CURRENT RADAR AND INFRARED SATELLITE IMAGERY SHOWING DRY
CONDITIONS AS RIBBONS OF HIGH LEVEL CLOUDS PASS THROUGH THE AREA
FROM THE NORTHWEST. THIS IS IN RESPONSE TO AN UPPER LEVEL RIDGE
OF HIGH PRESSURE THAT IS BUILDING OVER THE PACIFIC NORTHWEST TODAY
INTO SUNDAY MORNING, PROVIDING DRY CONDITIONS, MOSTLY SUNNY
SKIES, AND NEAR NORMAL TEMPERATURES AS HIGHS REACH INTO THE LOW TO
MID-50S ACROSS THE COLUMBIA BASIN TODAY AND TOMORROW. WARMER HIGH
TEMPERATURES ARE EXPECTED ACROSS CENTRAL OREGON, WITH VALUES IN
THE UPPER 50S TO LOW 60S TODAY AND IN THE LOW TO MID-60S SUNDAY AS
THE RIDGE RIDGE PUSHES IN FROM THE SOUTH. COOLER MORNING
TEMPERATURES WILL ALSO RESULT FROM CLEAR SKIES AND A DRIER
AIRMASS, WITH LOWS DIPPING INTO THE LOW TO MID-30S ACROSS THE
COLUMBIA BASIN, AND IN THE UPPER 20S TO LOW 30S THROUGH CENTRAL
OREGON.
THE UPPER LEVEL RIDGE WILL BEGIN TO FLATTEN SUNDAY AFTERNOON AS A
WEAK UPPER LEVEL SHORTWAVE APPROACHES THE COAST. THE RIDGE AXIS
WILL SHIFT EAST WITH SURFACE HIGH PRESSURE OVER SOUTHERN IDAHO
RESULTING IN A PRESSURE GRADIENT DEVELOPING ALONG THE BLUE
MOUNTAINS SUNDAY MORNING. THE NAM AND SREF ADVERTISE A PRESSURE
GRADIENT OF 5.7-6.5 MB BETWEEN MEACHAM (KMEH) AND BAKER CITY
(KBKE) SUNDAY MORNING THROUGH THE EVENING, RESULTING IN SUSTAINED
SOUTH WINDS OF 20-25 MPH WITH GUSTS UP TO 35 MPH POSSIBLE (85-95%
CHANCE VIA HREF) OVER LADD AND PYLES CANYONS. AT THIS TIME, WINDS
ARE EXPECTED TO PEAK BETWEEN 8 AM AND 1 PM BEFORE SLOWLY
SUBSIDING LATE SUNDAY EVENING. THERE IS A LOW LIKELIHOOD (10%
CHANCE) OF ADVISORY LEVEL WINDS BEING REACHED.
ENSEMBLE GUIDANCE IS IN GOOD AGREEMENT REGARDING THE UPPER LEVEL
RIDGE SHIFTING EAST LATE SUNDAY AND SUPPRESSING AS A WEAK UPPER
LEVEL SHORTWAVE PASSES THE AREA ON MONDAY. THIS FEATURE WILL BRING
A RETURN TO MOUNTAIN SHOWERS OVER THE CASCADES BEGINNING MONDAY
MORNING AND EXTENDING THROUGH MUCH OF THE DAY. SNOW LEVELS WILL
HOVER BETWEEN 7000-8000 FEET AS 0.05-0.15" OF RAINFALL IS EXPECTED
ALONG THE CENTRAL CASCADES OF WASHINGTON (65-75% CHANCE VIA NBM).
A MORE SUBSTANTIAL SYSTEM WILL APPROACH LATE WEDNESDAY THROUGH
FRIDAY, BRINGING MOUNTAIN SHOWERS WEDNESDAY THROUGH FRIDAY AND
WIDESPREAD SHOWERS ACROSS LOWER ELEVATIONS ON THURSDAY. HOWEVER,
ENSEMBLE MEMBERS ARE STILL IN DISAGREEMENT WITH THE OVERALL
STRENGTH, LOCATION, AND SPEED OF THE INCOMING UPPER LEVEL TROUGH.
CURRENTLY, THE FORECAST REFLECTS 0.30-0.50" OF RAINFALL OVER THE
CASCADE CREST, 0.25-0.40" OF RAIN OVER THE NORTHERN BLUE
MOUNTAINS AMD ELKHORNS, 0.10-0.20" OF RAIN THROUGH THE BLUE
MOUNTAIN FOOTHILLS, AND 0.01-0.10" OF RAINFALL ACROSS THE LOWER
ELEVATIONS OF THE COLUMBIA BASIN AND ACROSS CENTRAL OREGON. SNOW
LEVELS WILL BE DROPPING FROM 5000-6000 FEET THROUGH THE EVENT,
RESULTING IN HIGHER ELEVATIONS OF THE CASCADES AND ELKHORNS
RECEIVING 1-5 INCHES OF SNOWFALL THURSDAY AND FRIDAY. AT THIS
TIME, 54% OF ENSEMBLE MEMBERS HINT AT SLIGHTLY LOWER PRECIPITATION
AMOUNTS THURSDAY DUE TO A LATER ARRIVING TROUGH AND FRONTAL
SYSTEM. THIS SCENARIO IS REFLECTED IN 71% OF ENSEMBLE MEMBERS
SUGGESTING A SLIGHTLY WETTER OUTCOME THAN THE CURRENT FORECAST ON
FRIDAY. THUS, THERE IS SIGNIFICANT UNCERTAINTY REGARDING TIMING
AND OVERALL RAIN AMOUNTS THIS FAR IN ADVANCE OF THE MID-WEEK
SYSTEM. ABOVE NORMAL TEMPERATURES WILL PERSIST THROUGH MIDWEEK AS
A COOLING TREND IS EXPECTED FOLLOWING THE SYSTEM INTO NEXT
WEEKEND. 75
AVIATION...12Z TAFS
VFR CONDITIONS WILL PERSIST THROUGHOUT THE
TAF PERIOD. KBDN WILL BE BRIEFLY IN MVFR AS LOW CLOUDS PASS THROUGH.
OTHERWISE, WINDS WILL BE LESS THAN 12KTS WITH SCT-BKN HIGH CLOUDS AT
10-25KFT PREVAILING ACROSS ALL SITES. FEASTER/97
PRELIMINARY POINT TEMPS/POPS
PDT 56 34 53 37 / 0 0 0 0
ALW 55 37 52 40 / 0 0 0 0
PSC 54 33 52 34 / 0 0 0 0
YKM 53 33 54 37 / 0 0 0 0
HRI 54 34 52 36 / 0 0 0 0
ELN 50 30 52 34 / 0 0 0 0
RDM 59 30 63 35 / 0 0 0 0
LGD 56 36 60 42 / 0 0 0 0
GCD 60 35 66 38 / 0 0 0 0
DLS 56 38 55 40 / 10 0 0 0
PDT WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
SHORT TERM...75
LONG TERM....75
AVIATION...97
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