625
FXUS66 KPDT 281221
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
421 AM PST FRI NOV 28 2025
DISCUSSION
WIDESPREAD PRECIPITATION HAS ENVELOPED THE FORECAST
AREA AS AN UPPER-LEVEL TROUGH MOVES OVER THE REGION. WHILE
THE LOWER ELEVATIONS HAVE PREDOMINANTLY OBSERVED A COLD RAIN,
SNOW LEVELS HAVE DROPPED TO 2-3 KFT MSL IN WASHINGTON WITH
NOTEWORTHY SNOWFALL ACROSS WHITE AND SNOQUALMIE PASSES. THOUGH
SNOTEL DATA SUGGEST WE ARE APPROACHING LOW-END ADVISORY AMOUNTS
FOR THE WASHINGTON CASCADES, THE BULK OF THE PRECIPITATION WILL
TAPER OFF INTO THE EARLY MORNING HOURS, SO HAVE OPTED TO FORGO ANY
WINTER WEATHER HEADLINES AT THIS POINT. ELSEWHERE, SNOW LEVELS
ARE LOWERING IN THE BLUE MOUNTAINS, AND ARE EXPECTED TO REACH PASS
LEVELS OF 3.5-5 KFT MSL THROUGH MORNING. RAIN WILL TRANSITION TO
A RAIN/SNOW MIX THEN SNOW PRIOR TO PRECIPITATION ENDING LATE
MORNING THROUGH EARLY AFTERNOON. NO WINTER WEATHER HEADLINES ARE
IN EFFECT SINCE SNOWFALL IS UNLIKELY TO HIT OUR ADVISORY
THRESHOLD OF 6 INCHES (10 PERCENT CHANCE PER NBM GUIDANCE).
NORTHWEST FLOW ALOFT WILL USHER IN COLDER AIR AS WE HEAD INTO THE
WEEKEND, AND ENSEMBLE GUIDANCE IS IN REASONABLY GOOD AGREEMENT
THAT A SHORTWAVE TROUGH WILL PASS OVER THE FORECAST AREA LATE
SATURDAY INTO SUNDAY MORNING. WHILE THIS PATTERN FAVORS SNOWFALL,
EVEN FOR THE LOWLANDS, MOISTURE ACCOMPANYING THE SYSTEM IS
LACKING, SO CONFIDENCE IS LOW (5-25 PERCENT) IN OBSERVING
MEASURABLE SNOWFALL FOR THE LOWER COLUMBIA BASIN, LOW-MEDIUM
(15-40 PERCENT) ALONG THE BLUE MOUNTAIN FOOTHILLS, AND MEDIUM
(40-60 PERCENT) FOR THE BLUE MOUNTAIN BASINS SUCH AS THE GRANDE
RONDE AND WALLOWA VALLEYS. OF NOTE, NBM PROBABILITIES OF
ADVISORY-LEVEL SNOWFALL ARE VERY LOW (5 PERCENT OR LESS) AREA-WIDE.
DRIER WEATHER IS LIKELY SUNDAY INTO MONDAY, WITH ENSEMBLE NWP THEN
SHOWING ANOTHER SHORTWAVE TROUGH DIVING DOWN FROM THE NORTHWEST
BETWEEN LATE MONDAY AND WEDNESDAY. CONFIDENCE IN DETAILS WITH THIS
SYSTEM IS SHAKY, BUT THIS REPRESENTS ANOTHER CHANCE OF MOUNTAIN
AND LOWLAND SNOW.
AVIATION...12Z TAFS
LOW CEILINGS AND LOW VISIBILITIES CONTINUE
TO PREVAIL THROUGH THE TAF SITES, DELIVERING SUB-VFR CONDITIONS
THROUGHOUT. THE ONLY SITES THAT ESCAPE THE WORSE OF THE WEATHER
AND REMAIN IN VFR (AND ARE EXPECTED TO REMAIN SO FOR THE REMAINDER
OF THE PERIOD) WILL BE BDN AND RDM. MOST OF THE VIS WILL LIFT
GOING INTO THE LATE MORNING HOURS, BUT SUB-3000 FEET CEILINGS WILL
REMAIN IN ALW/PDT/DLS WILL REMAIN FARTHER INTO THE PERIOD, WITH
SOME SITES REMAINING MVFR/IFR THROUGHOUT THE TAF PERIOD. WINDS
REMAIN LIGHT AND VARIABLE WITH SOME BRIEF 15 TO 25 MPH GUST IN
BDN/PSC BUT WILL QUICKLY LOSE STRENGTH OVER THE NEXT FEW HOURS.
PRELIMINARY POINT TEMPS/POPS
PDT 44 28 40 25 / 100 0 10 30
ALW 44 31 39 27 / 100 0 10 40
PSC 49 28 41 23 / 80 0 10 20
YKM 49 27 41 22 / 50 0 10 10
HRI 47 29 41 25 / 90 0 10 20
ELN 45 25 38 20 / 20 0 10 10
RDM 49 24 46 23 / 20 0 0 20
LGD 44 26 44 25 / 90 0 10 40
GCD 46 27 48 26 / 70 0 0 30
DLS 50 35 45 33 / 90 0 10 30
PDT WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
DISCUSSION...86
AVIATION...95
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