253
FXUS66 KPDT 222241
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
241 PM PST MON DEC 22 2025
KEY POINTS
1. WIDESPREAD LOW ELEVATION RAIN TUESDAY AFTERNOON
THROUGH WEDNESDAY MORNING
2. MOUNTAIN PASS SNOW THROUGH CHRISTMAS EVE
*SPS IN AFFECT*
3. BREEZY WINDS CHRISTMAS EVE
*SPS IN AFFECT 1 AM THROUGH 4 PM WEDNESDAY*
DISCUSSION
CURRENT SATELLITE SHOWS PARTLY SUNNY SKIES ACROSS
PORTIONS OF THE CWA. RADAR SHOWS A FEW RETURNS MOVING ACROSS
KLICKITAT, YAKIMA, BENTON AND FRANKLIN. GROUND OBSERVATIONS HAVE
RECORDED 0.01-0.04 INCHES OF PRECIPITATION HAS FALLEN IN THE LAST 3
HOURS BETWEEN KLICKITAT AND YAKIMA COUNTIES.
MODELS SHOW AN ACTIVE WEATHER PATTERN WITH AN ASSOCIATED ATMOSPHERIC
RIVER (AR) IS EXPECTED TO IMPACT THE CASCADES, MOST NOTABLY OVER THE
WASHINGTON CASCADES. MODERATE RAIN FAVORED, WITH AMOUNTS BETWEEN 0.5-
1 INCH (60-80% CONFIDENCE) AT THE CASCADE CREST WITH LESSER AMOUNTS
FOUND AT THE LOWER ELEVATIONS. LOWER ELEVATIONS WILL SEE UP TO 0.05
INCHES OF RAIN OVERNIGHT AND AGAIN INTO WEDNESDAY WITH 80-90%
CONFIDENCE.
MODELS SHOW THE UPPER LEVEL LOW WITH THE AR TO MOVE JUST ENOUGH TO
PUSH THE BAND OF PRECIPITATION ACROSS THE OR PORTIONS OF THE CWA
MOVING FORM THE SOUTHEAST TO THE NORTHWEST BEFORE BECOMING MOSTLY
FOCUSED OVER THE CASCADES BY TUESDAY NIGHT.
TONIGHT SNOW LEVELS WILL DECREASE TO BETWEEN 2000-3000 FEET ALLOWING
FOR PRECIPITATION TO TRANSITION OVER TO SNOW ALONG THE CASCADE
PASSES. HEAVIEST AMOUNTS OF PRECIPITATION WILL BE ALONG THE WA
CASCADES WITH 70-90% CONFIDENCE IN 2-3 INCHES OF SNOW OVERNIGHT. THE
OR CASCADES WILL REMAIN A LITTLE DRYER WITH 50-60% CONFIDENCE IN 2-3
INCHES OF SNOW OVERNIGHT. ALONG THE EASTERN MOUNTAINS AND THE CRESTS
OF THE BLUES WILL SEE LIGHT ACCUMULATIONS BELOW 0.5 INCHES WITH 80%
CONFIDENCE. EVEN WITH THE AR FOCUSED ON THE WA CASCADES THROUGH
WEDNESDAY AND THURSDAY, SNOW ACCUMULATION AMOUNTS WILL BE NEAR OR
SLIGHTLY ABOVE AND ADDITIONAL 2 INCHES EACH DAY (50-70% CONFIDENCE)
WITH THAT SAID, AND SPS HAS BEEN ISSUED FOR SNOW ACCUMULATIONS ALONG
THE PASSES AS THIS IS A HIGH TRAVEL WEEK AND WITH MANY DETOURS, THE
PASSES WILL SEE MORE THAN THE USUAL HOLIDAY TRAFFIC.
MODELS SHOW THE UPPER LEVEL LOW TO HAVE AN ASSOCIATED SURFACE LEVEL
LOW THAT WILL MOVE INTO THE REGION FROM THE SOUTH AND PUSH OFF
EASTWARDS. PRESSURE GRADIENT MODELS SHOW A TIGHTENING OF THE
GRADIENTS OF NEAR 15 MB FROM CENTRAL OR ALONG THE JOHN-DAY OCHOCO
HIGHLANDS AND THROUGH THE EASTERN MOUNTAINS. THIS WILL LEAD TO
BREEZY CONDITIONS ACROSS THE AFOREMENTIONED AREAS. THIS SURFACE LOW
WILL BRING SOUTHEAST WINDS OF 15 TO 25 MPH WITH GUSTS UP TO 30-35
MPH EXPECTED (60-80% CONFIDENCE). 90
AVIATION...00Z TAFS
VFR CONDITIONS CURRENTLY PREVAIL THROUGH THE
REGION. THE LOW DECK FROM THE DLS HAS SINCE LIFTED TO VFR LEVELS,
BUT WILL SEE A RETURN OF MVFR/IFR CONDITIONS HEADING THROUGH OUT THE
NEXT 24-HOURS. GUIDANCE HAS HINTED AT MVFR CONDITIONS TO DEVELOP AT
PDT, BDN, RDM, PSC AND ALW WITH 1500 TO 2500 CEILINGS TOWARDS THE
LAST FEW HOURS OF THE PERIOD, BUT WILL HOLD OFF INCORPORATING THEM
INTO THE TAFS UNTIL CONFIDENCE INCREASES (CURRENTLY AT 5 TO 15
PERCENT CHANCES).
PRELIMINARY POINT TEMPS/POPS
PDT 33 44 34 51 / 10 40 40 30
ALW 36 44 37 50 / 10 50 50 50
PSC 31 43 34 49 / 10 20 70 40
YKM 27 41 31 43 / 20 10 80 50
HRI 31 44 34 50 / 10 30 60 30
ELN 24 36 28 41 / 40 0 80 70
RDM 26 43 30 48 / 0 40 30 20
LGD 31 42 38 50 / 10 70 30 50
GCD 33 46 39 51 / 10 80 20 50
DLS 36 44 38 47 / 60 20 80 50
PDT WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
DISCUSSION...90
AVIATION...95
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