032
FXUS66 KPDT 210602
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
1002 PM PST SAT DEC 20 2025
AVIATION...06Z TAFS
VFR CONDITIONS ARE PRESENT ACROSS ALL SITES
THIS EVENING. HOWEVER, AN INCOMING WEATHER SYSTEM WILL FACILITATE
LOWERING CIGS AND PRECIPITATION CHANCES WHICH WILL SPREAD FROM
SOUTH TO NORTH BEGINNING AROUND MIDNIGHT AT BDN/RDM, REACHING
PDT/ALW BY 11-15Z. CONFIDENCE IN PRECIPITATION IS LOWEST FOR YKM
(30 PERCENT LATE IN THE PERIOD), WITH PROB30 GROUPS AT DLS/PSC
INDICATIVE OF 30-50 PERCENT CONFIDENCE IN LIGHT RAIN STRETCHING
THAT FAR NORTH AND WEST IN THE MORNING AND AFTERNOON HOURS.
ELSEWHERE, PRECIPITATION TYPE IS A BIT MESSIER AT BDN/RDM WHERE A
MIX OF RAIN AND SNOW IS FORECAST THROUGH THE MORNING HOURS BEFORE
TURNING OVER TO ALL RAIN BY AFTERNOON.
WINDS WILL BE MOSTLY 10 KTS OR LESS FOR THE NEXT 24 HOURS. SOME
NWP GUIDANCE HINTS AT GUSTS AND RAIN SHOWERS TOWARDS THE END OF
THE PERIOD, BUT CONFIDENCE IN MAGNITUDE/TIMING WAS TOO LOW TO
INCLUDE IN THE 06Z TAFS.
PREV DISCUSSION
/ISSUED 249 PM PST SAT DEC 20 2025/
DISCUSSION...MOUNTAIN SNOW SHOWERS CONTINUE THROUGH THE WASHINGTON
CASCADES WITH A WINTER STORM WARNING STILL IN EFFECT THROUGH
MIDNIGHT TONIGHT. PREPARE FOR SOME WINTER WEATHER DRIVING GOING
THROUGH THE WASHINGTON PASSES AS SNOW/WINTRY MIX WILL CONTINUE
OVER THE NEXT FEW HOURS. ELSEWHERE, DRY CONDITIONS PREVAIL WITH
LIGHT AND LOCALLY BREEZY WINDS ACROSS THE REGION. OUR NEXT ROUND
OF UNSETTLED WEATHER COMES THROUGH TOMORROW AS A LOW PRESSURE
PUSHES FROM THE GULF OF ALASKA, BRINGING SOUTHWEST FLOW ALOFT INTO
THE REGION. SNOW LEVELS WILL INCREASE NEAR CENTRAL OREGON AND THE
BLUE MOUNTAINS TO 4500 TO 5500 FEET GOING THROUGH TOMORROW
MORNING, WITH THE WASHINGTON CASCADES AND KITTITAS VALLEY NEARING
2500 TO 3500 FEET (>80% CHANCE). SNOW RATES WILL INCREASE ACROSS
THE MOUNTAIN REGIONS SUNDAY MORNING THROUGH THE REST OF THE DAY
WITH THE OR AND WA CASCADES NEARING 2 TO 5 INCHES AN HOUR BY THE
MID TO LATE MORNING HOURS. WILL MORE THAN LIKELY CONSIDER WINTER
WEATHER ADVISORY TONIGHT WITH 24-HOUR ACCUMULATIONS FOR BOTH
REGIONS FALLING BETWEEN 4 AND 8 INCHES. IN THE LOWER VALLEYS,
WE'LL CONTINUE TO SEE PERIODS OF LIGHT RAIN SHOWERS OVER THE NEXT
FEW DAYS, BECOMING MORE LIGHT TO MODERATE HEADING INTO THE MIDWEEK
WITH 3-HOUR QPF AMOUNTS BETWEEN A TENTH AND A QUARTER OF AN INCH
(60-80% CHANCE).
GOING THROUGH CHRISTMAS EVE AND CHRISTMAS DAY, WE'LL SEE WHAT WILL
BE THE BEST CHANCES OF SNOW FLURRIES FOR PARTS OF CENTRAL OR AND
PARTS OF THE FOOTHILLS OF THE BLUES WITH PROB CHANCES OF SEEING
MEASURABLE SNOW (>0.1 INCHES) GO UP TO 5 TO 15 PERCENT (HIGHER END
PROBABILITIES ARE IN CENTRAL OREGON AREA). ALTHOUGH CHANCES AND
CONFIDENCE REMAIN LOW FOR SNOW WEDNESDAY AND THURSDAY, WINTER
WEATHER CONDITIONS PERSIST IF TRAVELING THROUGH MOUNTAIN PASSES AS
LIGHT TO MODERATE SNOW CONTINUES. A DRIER PATTERN IS CURRENTLY
FORECASTED TO EMERGE BY NEXT WEEK WITH ZONAL FLOW TRANSITIONING
INTO A WEAK RIDGE WHICH WILL GIVE THE LOWER COLUMBIA BASIN A
BREAK WITH CLEARER CONDITIONS. TEMPS REMAIN SOMEWHAT STABLE
THROUGH THE WEEK WITH HIGHS IN THE LOW TO MID 40S IN MOST
POPULATED AREAS WITH LOWS DROPPING BELOW OR NEAR FREEZING
OVERNIGHT.
PRELIMINARY POINT TEMPS/POPS
PDT 32 43 33 50 / 10 60 70 10
ALW 35 44 36 51 / 10 60 80 20
PSC 33 43 32 48 / 0 40 50 0
YKM 28 40 26 43 / 0 20 40 10
HRI 32 42 32 49 / 10 50 60 0
ELN 24 35 23 37 / 20 30 60 20
RDM 27 45 27 47 / 50 80 60 0
LGD 27 41 32 43 / 30 90 90 30
GCD 30 46 30 45 / 60 100 70 20
DLS 35 42 35 46 / 10 50 90 30
PDT WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...WINTER STORM WARNING UNTIL MIDNIGHT PST TONIGHT FOR WAZ522.
DISCUSSION...95
AVIATION...86
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