587
FXUS66 KPDT 180634
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
1034 PM PST WED DEC 17 2025
.UPDATED AVIATION DISCUSSION.
AVIATION...06Z TAFS
VFR CONDITIONS CURRENTLY ACROSS ALL SITES,
BUT CONDITIONS ARE EXPECTED TO DEGRADE TO IFR FOR ALL SITES BETWEEN
LATE MORNING TO MID-AFTERNOON ASSOCIATED WITH REDUCED VISIBILITIES
OF 1-2 SM AND CEILINGS OF 700-1500 FEET. THESE CONDITIONS ARE A
RESULT OF AN INCOMING SYSTEM SUPPLIED BY AN ATMOSPHERIC RIVER THAT
WILL ALSO BRING LIGHT RAIN ACROSS ALL TERMINALS EARLY MORNING
ONWARD. THE COLD FRONT ASSOCIATED WITH THIS SYSTEM WILL ELEVATE
WINDS ACROSS THE REGION, WITH SUSTAINED WINDS OF 15-25KTS AND GUSTS
OF 20-30KTS. HIGHEST WINDS ARE EXPECTED FOR KRDM/KBDN WITH SUSTAINED
WINDS OF 25-35KTS AND GUSTS OF 35-45KTS THAT PEAK TOWARD THE END OF
THE PERIOD. 75
PREV DISCUSSION
/ISSUED 408 PM PST WED DEC 17 2025/
UPDATE...WINDS HAVE SUBSIDED BELOW EITHER WARNING OR ADVISORY
CRITERIA ACROSS THE AREA, AND WILL CONTINUE TO DECREASE THROUGH
THE REMAINDER OF THE EVENING. AS A RESULT, THE HIGH WIND WARNINGS
AND WIND ADVISORIES EXPIRED AT 4 PM PST.
PREV DISCUSSION... /ISSUED 254 PM PST WED DEC 17 2025/
DISCUSSION...CURRENT CONDITIONS ARE STILL RELATIVELY BREEZY
THROUGHOUT THE REGION, WITH THE HIGH WIND WARNING STILL IN EFFECT
FOR MOST OF THE REGION UNTIL 4 PM TODAY. WILL LET IT EXPIRE SINCE
WINDS HAVE WEAKENED SINCE THIS MORNING AND MOST OF THE OBSERVING
WINDS ARE CURRENTLY SETTLING JUST BELOW ADVISORY CRITERIA. OUR
ASOS AT THE AIRPORT RECORDED A PRELIMINARY RECORDING OF AN 81 MPH
GUST THAT WAS OBSERVED AT 3:53 AM THIS MORNING. WINDS SUSTAIN
AROUND 45 TO 55 MPH THROUGH AROUND 5:30 AM WITH CURRENT GUSTS AT
THE OFFICE NOW AROUND 35 TO 40 MPH. WINDS WILL CONTINUE TO WEAKEN
THROUGH THE MORNING HOURS UNTIL THE LATE MORNING TO EARLY
AFTERNOON TOMORROW WHEN WINDS WILL RE-STRENGTHEN UP TO 30 TO 40
MPH, WITH A PEAK EXPECTED THURSDAY EVENING TO FRIDAY MORNING.
CURRENTLY NOT SETTLING FOR WIND ADVISORY CRITERIA, ALTHOUGH
CONFIDENCE IS INCREASING (40 TO 60 PERCENT CHANCE ACROSS PARTS OF
CENTRAL OR THROUGH THE COLUMBIA BASIN) WE CROSS CRITERIA OVER THE
NEXT 48-HOURS.
ELEVATED RIVER LEVELS TO LOCALLY MINOR FLOODING THROUGH THE
YAKIMA, NACHES, AND KLICKITAT (NEAR PITT, WA) WILL CONTINUE TO BE
A CONCERN GOING THROUGH THE NEXT COUPLE OF DAYS. ADDITIONAL
PRECIPITATION WITH THE NEXT SET OF FRONTS WILL KEEP SOME OF THE
RIVERS ELEVATED IN 'ACTION' STAGE THROUGH THE WEEKEND. MOST RIVERS
HAVE ALREADY CRESTED (WITH THE EXCEPTIONS OF THE YAKIMA AT KIONA
AND KLICKITAT NEAR PITT, WA) AND WILL SEE SLIGHT IMPROVEMENTS IN
RIVER LEVELS OVER THE NEXT 48-HOURS.
PRECIPITATION WISE, IT WOULD SEEM WE'LL GO THROUGH A "WINDSHIELD
WIPER" EFFECT WITH THE TYPE OF PRECIPITATION WE WILL EXPECT THANKS
TO THE BACK-TO-BACK WARM AND COLD FRONTS THROUGH FRIDAY. CURRENT
RADAR SHOWS LIGHT MOUNTAIN SNOW SHOWERS MAINLY IN THE CASCADES
(WITH MORE COVERAGE IN THE WA SIDE) AND CAN EXPECT LIGHT TO
MODERATE SNOW TO CONTINUE THROUGH THURSDAY MORNING. WITH THE
APPROACHING WARM FRONT, SNOW LEVELS WILL RISE 7800 TO 8800 FEET,
WITH THE EXCEPTION NEAR THE KITTITAS VALLEY AND WA CASCADES, WHICH
WILL SIT AT 6000 TO 7000 FEET. THE APPROACHING WARM FRONT WILL
TRANSITION VIRTUALLY ALL OF THE MOUNTAIN SNOW IN THE OREGON
CASCADES INTO RAIN, WHILE LEAVING LIGHT SNOW/WINTRY MIX IN THE WA
CASCADES. DESPITE THIS, WE'VE ISSUED A WINTER WEATHER ADVISORY FOR
THE OREGON CASCADES AT 4 AM TO 10 AM THURSDAY, WITH MOST SNOWFALL
OCCURRING IN THE EARLIER HOURS. ON THE WASHINGTON CASCADE AND
NORTHERN BLUE MOUNTAINS SIDE, WINTER WEATHER ADVISORIES ARE
EXPECTED THROUGH 4 PM TOMORROW, WITH SLIGHT CHANCES (LESS THAN 30
PERCENT) OF A TRACE OR MORE OF FREEZING RAIN, MAINLY DURING THE
TRANSITION OF SNOW TO RAIN IN THE AFTERNOON HOURS THURSDAY. EXPECT
WINTER WEATHER DRIVING CONDITIONS WITH SOME SLIPPERY SPOTS ACROSS
HIGHWAYS AND INTERSTATE IN THE ADVISORY AREAS. FRIDAY SEES THE
RETURN OF A COLD FRONTAL PASSAGE WITH SNOW LEVELS DROPPING 2500 TO
3500 FEET, WITH LIGHT TO MODERATE MOUNTAIN SNOW AND VALLEY RAIN
CONTINUING.
A COOLING TREND WILL CONTINUE THROUGH THE WEEKEND THANKS TO THE
COLD FRONT PASSAGE AND MOST POPULATED AREAS WILL SEE A RETURN OF
BELOW FREEZING LOW TEMPERATURES BY THE WEEKEND.
PRELIMINARY POINT TEMPS/POPS
PDT 37 56 37 47 / 10 100 90 70
ALW 39 54 39 47 / 10 100 100 70
PSC 39 54 37 50 / 10 100 80 30
YKM 34 46 29 46 / 30 100 90 10
HRI 38 55 38 49 / 10 100 90 50
ELN 30 41 25 38 / 40 100 90 30
RDM 28 56 35 46 / 40 100 100 90
LGD 31 46 35 45 / 10 100 100 100
GCD 30 50 39 47 / 20 100 90 100
DLS 38 48 38 47 / 60 100 100 70
PDT WATCHES/WARNINGS/ADVISORIES
OR...WINTER WEATHER ADVISORY FROM 4 AM TO 4 PM PST THURSDAY FOR
ORZ502.
WINTER WEATHER ADVISORY UNTIL 10 AM PST THURSDAY FOR ORZ509.
FLOOD WATCH FROM 3 AM PST THURSDAY THROUGH LATE FRIDAY NIGHT FOR
ORZ509>511.
WA...WINTER WEATHER ADVISORY FROM 4 AM TO 4 PM PST THURSDAY FOR
WAZ030.
FLOOD WATCH THROUGH FRIDAY AFTERNOON FOR WAZ522-523.
WINTER WEATHER ADVISORY UNTIL 4 PM PST THURSDAY FOR WAZ522-523.
DISCUSSION....95
AVIATION...75
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