912
FXUS66 KPDT 232342
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
442 PM PDT THU OCT 23 2025
.UPDATED AVIATION DISCUSSION.
AVIATION...00Z TAFS
VFR CONDITIONS CONTINUE THROUGH THE PERIOD,
WITH NO EXPECTED SUB-VFR CONDITIONS EXPECTED. THERE IS SOME SMALL
CHANCE (5-15%) THAT SUB-VFR CONDITIONS CAN TEMPORARY DEVELOP FOR
RDM/BDN/YKM TOWARDS THE TAIL END OF THE PERIOD WITH THE WEATHER
SYSTEM PUSHING THROUGH THE AREA. SOME OF THE HEAVIER RAIN BANDS
CAN PRODUCE <6 MILE VISIBILITY AND/OR LOWER CLOUD DECKS. WASN'T
HIGHLY CONFIDENT THAT THE RAIN WILL ARRIVE IN SOME SITES, NOTABLY
RDM/BDN, BY THE END OF THE PERIOD BUT WENT A HEAD AND PUT A PROB30
FOR THE LAST THREE HOURS OF THE PERIOD. WILL MORE THAN LIKELY
(>90% CHANCE) OF PUTTING IN A PRELIMINARY LINE OF RAIN FOR THE 06Z
TAFS ONCE THE SYSTEM PUSHING EVEN FURTHER INTO THE AREA. WINDS
WILL BE LIGHT BUT WILL BEGIN TO PICK-UP GOING INTO THE LATE
MORNING/EARLY AFTERNOON HOURS OF TOMORROW WITH SOME SITES
(BDN/RDM) GETTING BREEZIER WINDS OF 20-30 KNOTS BY THE LATE
MORNING/EARLY AFTERNOON.
DISCUSSION
KEY MESSAGES:
1. WIDESPREAD RAIN FRIDAY AND SATURDAY,
2. MOUNTAIN SNOWFALL SATURDAY THROUGH MONDAY.
3. BREEZY WINDS FRIDAY TURNING WINDY SATURDAY INTO SUNDAY MORNING.
THE WEAK UPPER RIDGE OVER THE REGION WILL BECOME BROKEN DOWN THIS
WEEKEND AS A COLD POOL ALOFT MOVES INLAND WITH AN ATTENDANT
ATMOSPHERIC RIVER, BRINGING OROGRAPHIC LIFT, RAINS AND HIGH
ELEVATION SNOW AS EARLY AS FRIDAY, AND MORE WIDESPREAD RAINS TO
THE LOWLAND REGIONS AGAIN SATURDAY. ADDITIONAL HEAVY SNOW AMOUNTS
WILL AGAIN COMPOUND THE HIGHER ELEVATION SNOW AMOUNTS FOR THE
ENTIRE 3 DAY EPISODE.
THE INITIAL LEAD SHORTWAVE MOVES ONSHORE FRIDAY MORNING AND
OVERSPREADS THE INTERIOR NORTHWEST THROUGH FRIDAY EVENING. THIS
INITIAL WAVE CAN BRING SNOW TO THE HIGHEST ELEVATIONS OF THE
CASCADES FRIDAY AND FRIDAY NIGHT AS THE SNOW LEVELS HOVER AROUND
6500-8000 FT, AND DROPPING SHARPLY FRIDAY EVENING ACROSS THE
WASHINGTON CASCADES TO THE 4-5KFT LAYER. AS THE COLDER AIR ARRIVES
WITH THE SECOND, MORE LARGE SCALE SHORTWAVE AND WITH WESTERLY
MOISTURE TRANSPORT SATURDAY, THESE MORE EFFICIENT SNOWS WILL BE
LARGELY CONFINED TO WA523 LOWER SLOPES OF THE EASTERN WASHINGTON
CASCADE CREST, AND OR509 EAST SLOPES OF THE OREGON CASCADES. RAIN
FARTHER EAST IN THE LOWLAND AREAS ARE LIMITED TO THE WASHINGTON
CASCADES AND EASTERN SLOPES FRIDAY EVENING, HOWEVER THE NEXT 24
HOURS THROUGH SATURDAY EVENING, A WIDESPREAD NEAR TWO TENTHS TO
AROUND A THIRD OF AN INCH QPF IS PROJECTED BY THE NBM 50TH
PERCENTILE OF MEMBERS. ASSUMING A LESS ROBUST EPISODE DEVELOPS
WITH RESPECT TO MOISTURE, THE 25TH PERCENTILE WOULD STILL SUGGEST
AT LEAST CLOSE TO A WETTING RAIN OF NINE OR TEN HUNDREDTHS OF AN
INCH ACROSS THE COLUMBIA BASIN AND CENTRAL OREGON WITH MORE LIKE A
QUARTER OF AN INCH ACROSS THE EASTERN MOUNTAINS. LOWLANDS PRECIP
SHOULD WANE OR BECOME MORE INTERMITTENT IN NATURE BY SUNDAY WITH
ONGOING OROGRAPHIC LIFT PROMOTING ADDITIONAL SNOWS IN THE CASCADES
AND WALLOWAS. FIRE WEATHER WILL BE ENHANCED, FOR A SHORT PERIOD
ON FRIDAY AFTERNOON WHERE COMBINED PROBABILITIES FOR RED FLAG
CONDITIONS ARE RUNNING ABOUT 20 PERCENT ACROSS DESCHUTES,
JEFFERSON AND CROOK COUNTIES IN THE AFTERNOON. RUSSELL/71
PRELIMINARY POINT TEMPS/POPS
PDT 43 69 44 61 / 0 10 80 100
ALW 47 70 46 61 / 0 10 90 100
PSC 41 65 41 61 / 0 20 60 90
YKM 43 62 36 54 / 0 60 70 90
HRI 42 64 43 62 / 0 20 70 90
ELN 39 58 31 50 / 10 70 80 90
RDM 39 68 37 55 / 0 40 80 90
LGD 41 66 44 57 / 0 0 80 100
GCD 42 70 44 57 / 0 0 80 100
DLS 47 64 44 59 / 0 80 90 100
PDT WATCHES/WARNINGS/ADVISORIES
OR...NONE.
WA...NONE.
SHORT TERM...71
LONG TERM....71
AVIATION...95
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