901
FXUS66 KPDT 012239
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
239 PM PST MON DEC 1 2025
UPDATED AVIATION DISCUSSION
AVIATION...00Z TAFS
VFR CONDITIONS EXPECTED THROUGH THE PERIOD,
WITH THE EXCEPTION OF PSC WHICH CONTINUES TO DEAL WITH LOW CIGS THIS
AFTERNOON, AND PDT/ALW, WHICH MAY SEE LIGHT RAIN SHOWERS EARLY
TUESDAY MORNING FROM AN ONCOMING FRONTAL SYSTEM. CONFIDENCE IN THE
LATTER TWO SITES SEEING MEASURABLE PRECIP IS ON THE LOWER END
(30-40%), SO OPTED TO MENTION THE CHANCE OF -RA VIA PROB30.
OTHERWISE, SKIES WILL GRADUALLY CLEAR ACROSS MOST SITES THIS
EVENING, WITH WINDS GENERALLY LESS THAN 10 KTS, BECOMING MORE W/NW
TUESDAY AS THIS ONCOMING FRONT MOVES THROUGH. 74
PREV DISCUSSION
/ISSUED 233 PM PST MON DEC 1 2025/
DISCUSSION...
LIGHT SNOW IS EXPECTED (40-90%) THIS EVENING THROUGH TONIGHT
ACROSS THE EASTERN COLUMBIA BASIN AND FOOTHILLS OF THE BLUE
MOUNTAINS THOUGH THE NORTHERN BLUES AND WALLOWAS, CREATING WINTER
WEATHER CONDITIONS. LOWER ELEVATIONS MIGHT ONLY GET A DUSTING OR
MORE OF SNOW BUT THE SNOW AMOUNTS QUICKLY RAMP UP WITH HIGHER
ELEVATIONS. A FRONTAL SYSTEM MOVING THOUGH THIS AFTERNOON AND
TONIGHT WILL BE THE INITIAL STRONG OROGRAPHIC FORCING IMPETUS,
FOLLOWED BY PERSIST NORTHWESTERLY MOMENTUM BEHIND THE SYSTEM
CONTINUING TO PROMOTE LIGHT PRECIPITATION IN THE DENDRITIC GROWTH
ZONE BEYOND 24 HOURS, DRIVING HIGH MOUNTAIN AREAS WELL ABOVE 6
INCHES OF SNOW WITH TIME. LATEST HREF ENSEMBLE MEAN HOURLY TRENDS
BEGIN NORTHERN BLUE MOUNTAINS SNOW IN EARNEST AROUND 8Z/OR LATE
EVENING, WITH SNOW CONTINUING THROUGH LATE AFTERNOON TUESDAY. FOR
WALLOWA COUNTY – WHERE 4 INCHES IS THE LOWER END FOR ADVISORY,
SNOW CHANCES FOR 4 INCHES OR MORE BELOW 5400 FT ARE QUITE LOW (20
PERCENT OR LESS ACROSS THE MAJORITY OF THAT AREA). THE NORTHERN
BLUE MOUNTAINS OF OREGON (OR502) HAVE A HIGHER MINIMUM REQUIREMENT
OF 6 INCHES FOR ADVISORIES. IN EITHER CASE THE PROBABILITIES FOR
THIS MAGNITUDE OF SNOW IS NOT MEETING IN 12 HOURS. ONE LOCAL
COMMUNITY WITH A GREATER RISK OF SOME SNOW IMP- ACTS IS TOLLGATE
WHERE THERE IS A 70% CHANCE OF 5 INCHES OF TOTAL SNOWFALL, AND
ABOUT A 50% CHANCE TO HIT OR EXCEED THE LOW END 6” THRESHOLD FOR
ADVISORIES.
FRIDAY THROUGH THE WEEKEND LOOK TO BE A WINDY PERIOD WITH
SOUTHWEST WINDS INCREASING FRIDAY EVENING, REMAINING WINDY
OVERNIGHT AND AND NOT APPRECIABLY DIMINISHING UNTIL SATURDAY
EVENING. WINDS WILL PICK UP AGAIN DIURNALLY SUNDAY, BASED ON NBM
TRENDS FOR THIS PERIOD. THIS CHANGE TO A DOWNSLOPE WINDY REGIME
WILL LEAD TO A MORE MARKED WARMUP ON FRIDAY WHERE NBM IS FORCING
LOW TO MID 50S ACROSS MUCH OF THE LOWER COLUMBIA BASIN, BLUE
MOUNTAIN FOOTHILLS, CENTRAL OREGON AND THE JOHN DAY BASIN.
RUSSELL/71
PRELIMINARY POINT TEMPS/POPS
PDT 29 40 27 40 / 20 60 10 0
ALW 30 38 29 38 / 40 70 10 10
PSC 25 39 24 37 / 20 30 0 0
YKM 24 45 24 38 / 10 0 0 0
HRI 27 41 26 38 / 20 40 0 0
ELN 25 44 22 37 / 10 10 0 0
RDM 26 46 21 46 / 0 10 0 0
LGD 31 41 27 41 / 40 90 20 0
GCD 30 42 27 43 / 10 50 10 0
DLS 34 51 34 43 / 10 20 0 0
PDT WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
DISCUSSION...71
AVIATION...74
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