689
FNUS76 KPDT 172139
FWSPDT
SPOT FORECAST FOR STEHEKIN FLOODING ASSESSMENT...NPS
NATIONAL WEATHER SERVICE PENDLETON OR
139 PM PST WED DEC 17 2025
FORECAST IS BASED ON FORECAST START TIME OF 0600 PST ON DECEMBER 18.
***THUNDERSTORMS IMPLY GUSTY AND ERRATIC WINDS***
***WINDS ARE 20 FOOT 10-MINUTE AVERAGES***
***CWR-CHANCE OF WETTING RAIN 0.10 OR GREATER***
***VENTILATION INDEX IS DERIVED FROM THE
TRANSPORT WIND MULTIPLIED BY THE MIXING
HEIGHT IN 100'S OF FEET. INDEX CATEGORIES
ARE A GENERALIZED INDICATOR ONLY.***
IF YOU HAVE QUESTIONS OR CONCERNS WITH THIS FORECAST, PLEASE
CONTACT OUR OFFICE AT (541) 276-8134.
DISCUSSION
SNOW IS EXPECTED ACROSS THE WA CASCADES THROUGH THE
WEEKEND. THURSDAY SNOW AMOUNTS ARE 75% PROBABILITIES OF 5 INCHES.
MOVING ONTO FRIDAY THERE IS A 75-95% PROBABILITY FOR 5-7 INCHES.
SATURDAY AN 85-95% PROBABILITY OF BETWEEN 8-10 INCHES. SUNDAY
THE PROBABILITY OF ANOTHER 5 INCHES OF SNOW DROPS TO BELOW 60%
PROBABILITIES WITH SNOW ACCUMULATIONS OF 3-5 INCHES SUNDAY AND
ANOTHER 4-8 INCHES MONDAY WITH 75-95% PROBABILITIES. TOTAL SNOW
ACCUMULATIONS OVER SNOQUALMIE PASS IS 15-27 INCHES. WINDS WILL
CONTINUE TO BE BREEZY THROUGH FRIDAY WITH SOUTHERLY WINDS 6-10
MPH WITH GUSTS NEARING 25 MPH (70-80% CONFIDENCE). WINDS WILL
BEGIN TO DECREASE FRIDAY AFTER 4 PM RETURNING TO MORE DIURNALLY
DRIVEN.
THURSDAY
SKY/WEATHER.........CLOUDY (90-100 PERCENT). RAIN LIKELY IN THE
MORNING. SNOW THROUGH THE DAY. RAIN IN THE
AFTERNOON.
CHANCE OF PCPN......100 PERCENT.
CHANCE OF LIGHTNING.9 PERCENT.
MAX TEMPERATURE.....41-44.
MIN HUMIDITY........92-97 PERCENT.
SURFACE WINDS (MPH).LIGHT WINDS BECOMING SOUTHEAST 6 TO 10 MPH WITH
GUSTS TO AROUND 21 MPH IN THE LATE MORNING AND
EARLY AFTERNOON, THEN SHIFTING TO THE SOUTHWEST
WITH GUSTS TO AROUND 22 MPH LATE IN THE
AFTERNOON.
MIXING HEIGHT.......2400 FT AGL.
TRANSPORT WINDS.....SOUTHEAST 9 TO 15 MPH INCREASING TO WEST AROUND
22 MPH LATE IN THE AFTERNOON.
TIME (PST) 6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM
CHC OF LTNG (%).0 0 0 0 10 10 10 10 10 10 10 10
TEMP............32 31 31 31 32 33 33 34 37 38 39 40
RH..............100 99 99 100 99 98 100 98 97 100 100 100
SURFACE WND DIR.SE SE SE SE SE SE SE SE SE SE SW SW
SURFACE WND SPD.4 5 5 5 9 9 9 10 10 10 10 10
SURFACE WND GST.10 13 13 13 16 16 16 21 21 21 22 22
THURSDAY NIGHT
SKY/WEATHER.........CLOUDY (85-95 PERCENT). RAIN IN THE EVENING.
SNOW THROUGH THE NIGHT. SLIGHT CHANCE OF RAIN
OVERNIGHT.
CHANCE OF PCPN......100 PERCENT.
CHANCE OF LIGHTNING.9 PERCENT.
MIN TEMPERATURE.....AROUND 30.
MAX HUMIDITY........92-97 PERCENT.
SURFACE WINDS (MPH).WEST WINDS 6 TO 10 MPH. GUSTS UP TO 25 MPH IN
THE EVENING AND OVERNIGHT.
MIXING HEIGHT.......2400 FT AGL.
TRANSPORT WINDS.....WEST 18 TO 26 MPH.
FRIDAY
SKY/WEATHER.........MOSTLY CLOUDY (75-85 PERCENT). SNOW.
CHANCE OF PCPN......100 PERCENT.
CHANCE OF LIGHTNING.9 PERCENT.
MAX TEMPERATURE.....31-34.
MIN HUMIDITY........88-93 PERCENT.
SURFACE WINDS (MPH).WEST WINDS AROUND 6 MPH EARLY IN THE MORNING
BECOMING LIGHT, THEN BECOMING WEST 6 TO 10 MPH
IN THE LATE MORNING AND AFTERNOON.
MIXING HEIGHT.......3000 FT AGL.
TRANSPORT WINDS.....WEST 15 TO 21 MPH.
FORECAST DAYS 3 THROUGH 5
SATURDAY
SNOW. LOWS IN THE UPPER 20S. HIGHS IN THE MID 30S. LIGHT WINDS.
SUNDAY
RAIN AND SNOW. LOWS IN THE UPPER 20S. HIGHS IN THE MID 30S. LIGHT
WINDS.
MONDAY
SNOW AND RAIN. LOWS IN THE UPPER 20S. HIGHS IN THE MID 30S. LIGHT
WINDS.
FORECASTER...BENNESE
REQUESTED BY...T. CAVENDISH
TYPE OF REQUEST...OTHER
.TAG 2527891.0/PDT
.DELDT 12/17/25
.FORMATTERVERSION 2.0.0
.EMAIL KEVIN_DILLON@NPS.GOV
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