869
FXUS66 KPDT 020608
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
1008 PM PST THU JAN 1 2026
EVENING UPDATE
TEMPERATURES REMAIN NEAR OR BELOW FREEZING
ACROSS THE MAJORITY OF THE COLUMBIA BASIN AND SURROUNDING
LOWLANDS. WHILE THE STEADIEST FREEZING RAIN HAS ENDED OR IS
TAPERING OFF IN THE AREAS UNDER A WINTER WEATHER ADVISORY, AFTER
COLLABORATION WITH SURROUNDING OFFICES, OPTED TO EXTEND THE
ADVISORIES UNTIL 7 AM PST FRIDAY MORNING DUE TO ADDITIONAL
INTERMITTENT PRECIPITATION THAT IS FORECAST TO CONTINUE OVERNIGHT
INTO THE EARLY MORNING HOURS.
AVIATION...06Z TAFS
THE STEADIEST PRECIPITATION (FZRA FOR ALL
BUT RDM/BDN/DLS) HAS ENDED OR IS TAPERING OFF FOR TAF SITES.
INTERMITTENT PRECIPITATION IS FORECAST TO CONTINUE OVERNIGHT INTO
THE MORNING HOURS, ESPECIALLY AT ALW, WITH MOSTLY DRY CONDITIONS
RETURNING BY FRIDAY AFTERNOON. CONFIDENCE IS VERY HIGH (80-100
PERCENT) IN AT LEAST PERIODS OF SUB-VFR CONDITIONS DUE TO LOW CIGS
AND/OR VSBYS AT ALL SITES EXCEPT RDM/BDN WHERE CONFIDENCE IN SUB-
VFR CONDITIONS IS 40-60 PERCENT OVERNIGHT. SUSTAINED WINDS OF 10
KTS OR LESS ARE FORECAST AT ALL SITES.
PREV DISCUSSION
/ISSUED 233 PM PST THU JAN 1 2026/
KEY MESSAGES...
- FREEZING RAIN RISK CONTINUES TONIGHT BEFORE ENDING SOUTH TO
NORTH EARLY FRIDAY MORNING
DISCUSSION...
AIR STAGNATION ADVISORY WAS ALLOWED TO EXPIRE AS PRECIPITATION
BECOMES ONSET THIS AFTERNOON INTO TONIGHT, FOLLOWED BY A MARKED
EASTWARD SHIFT OF THE MID LEVEL RIDGE FROM THE INTERIOR NW INTO
THE NRN ROCKIES. THE CONSENSUS OF SHORT TERM MODELS HAS A
SLIGHTLY COOLER TREND FOR TODAY’S HIGHS AND WAS USED FOR SHORT
TERMS UPDATES, ACTUALLY UNDERCUTTING THE HRRR BY ABOUT A DEGREE IN
SOME AREAS OF SOUTH CENTRAL WA. THE LIFTING WARM FRONT HAS WARMED
TEMPERATURES SUFFICIENTLY ACROSS THE BEND AND REDMOND AREAS TO
ALLOW THE WINTER WEATHER ADVISORY TO EXPIRE ON TIME. AT THE SAME
TIME FREEZING RAIN HAS BECOME ESTABLISHED AT PDT WITH EARLY
AFTERNOON TEMPERATURE REMAINING STEADY AT 30F. LAMP GUIDANCE KEEPS
THE TEMPS BELOW FREEZING THOUGH 11Z SATURDAY, MAINTAINING THE
FREEZING RAIN THREAT, ALTHOUGH PRECIPITATION MIGHT END WELL
BEFORE THEN. FREEZING RAIN ACCUMULATION MODEL AND NBM EXPECTED ICE
ACCUMULATIONS ARE AVERAGING FROM AROUND A LIGHT GLAZE TO ABOUT
0.05” OF ICE ACROSS A LARGE PORTION OF THE LOWER COLUMBIA BASIN
AND EASTERN COLUMBIA RIVER GORGE, INTO THE KITTITAS AND YAKIMA
VALLEYS. ENHANCED EXPECTED AMOUNTS ARE SEEN OVER THE BLUE MOUNTAIN
FOOTHILLS WHERE CLOSER TO ONE TENTH OF AN INCH IS MORE COMMON,
WHILE HIGHEST AMOUNT ARE EXPECTED IN THE WA CASCADE UPPER SLOPES.
TRENDS ON HREF CONTINUE TO SHOW THE LAST OF THE LIGHT FZRA
ACCUMULATIONS EXITING THE SOUTH CENTRAL/SOUTHEAST WA BEFORE 18Z
SATURDAY. THE SURFACE PRESSURE GRADIENT IS FORECAST TO INCREASE
DRAMATICALLY SATURDAY NIGHT INTO SUNDAY ACROSS THE GRANDE RONDE
VALLEY, POINTING TO A PERIOD OF POTENTIALLY STRONG GUSTY WINDS TO
50 MPH. THE DETERMINISTIC NAM PEAKS AT AROUND 10 MPH MIDNIGHT
SATURDAY WHILE SREF (ENSEMBLES ) LEAVE A LITTLE MORE UNCERTAINTY
IN THE STRENGTH OF THIS GRADIENT. FRIDAY LIKEWISE WILL BRING A
BUMP IN TEMPERATURES TO THE 40S ACROSS THE LOWLANDS AND LOW 50S AT
CREST WHERE BETTER WIND MIXING WILL BE PRESENT. THE REST OF THE 7
DAY FORECAST PERIOD IS RELATIVELY MILD IN TERMS OF IMPACTS.
SATURDAY INTO SUNDAY MIGHT BRING SOME MOUNTAINS SNOWS AND BREEZY
WINDS IN ADDITION TO LOWLAND SHOWERS. ANOTHER SIGNAL POINTS TO WA
CASCADE UPPER SLOPES SNOWS BY TUESDAY AND WEDNESDAY.
PRELIMINARY POINT TEMPS/POPS
PDT 29 48 34 50 / 80 40 10 40
ALW 30 44 36 48 / 90 70 10 60
PSC 27 41 31 45 / 80 30 10 50
YKM 28 41 32 43 / 60 20 20 50
HRI 28 42 32 46 / 80 30 10 40
ELN 27 38 31 40 / 60 40 40 70
RDM 34 52 36 53 / 60 0 10 20
LGD 35 45 38 48 / 90 70 0 50
GCD 38 50 36 50 / 90 30 10 50
DLS 32 44 37 45 / 90 50 40 60
PDT WATCHES/WARNINGS/ADVISORIES
OR...WINTER WEATHER ADVISORY UNTIL 7 AM PST FRIDAY FOR ORZ041-044-507-
508-510.
WA...WINTER WEATHER ADVISORY UNTIL 7 AM PST FRIDAY FOR WAZ024-026>029-
521>523.
EVENING UPDATE...86
DISCUSSION...71
AVIATION...86
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