107
FNUS76 KOTX 242356
FWSOTX
SPOT FORECAST FOR NORTH SIWASH UNIT 30B...USFS
NATIONAL WEATHER SERVICE SPOKANE WA
456 PM PDT THU SEP 24 2026
FORECAST IS BASED ON IGNITION TIME OF 1800 PDT ON SEPTEMBER 24.
DISCUSSION
DRY WEATHER CONTINUES THROUGH FRIDAY MORNING WITH INCREASING
CLOUDS AHEAD OF A COLD FRONT. THE COLD FRONT MOVES INTO NORTH
IDAHO LATE FRIDAY MORNING BRINGING GUSTY WINDS, RAIN, AND A SMALL
CHANCE FOR THUNDERSTORMS IN THE AFTERNOON. PRECIPITATION CHANCES
INCREASE AFTER 1100 HOURS FIRST FALLING AS LIGHT CONTINUOUS RAIN
BEFORE TRANSITIONING TO SHOWERS AROUND 1500. EXPECTED RAINFALL
TOTALS ARE BETWEEN 0.12 AND 0.50 INCHES. IF THUNDERSTORMS MOVE
OVER THE PROJECT, THEN THE TOTALS WOULD BE NEAR THE HIGHER END.
SHOWER CHANCES LINGER THROUGH THE NIGHT ON FRIDAY THEN WEATHER
TRENDS DRIER AND COOLER FOR SATURDAY.
IF CONDITIONS BECOME UNREPRESENTATIVE, CONTACT THE NATIONAL WEATHER
SERVICE.
***************************************************************
FORECASTS FOR 20 FOOT WIND SPEEDS (VALLEYS AND RIDGE TOPS) ARE
10 MINUTE AVERAGES REFLECTING RAWS WIND.
***VENTILATION INDEX IS DERIVED FROM TRANSPORT WIND
MULTIPLIED BY THE MIXING HEIGHT DIVIDED BY 100.
CATEGORIES: LOW (< 200), MODERATE (200-500),
HIGH (500-800), AND VERY HIGH (> 800).
***************************************************************
TONIGHT
SKY/WEATHER.........MOSTLY CLOUDY.
CWR.................0 PERCENT.
CHANCE OF LIGHTNING.0 PERCENT.
MIN TEMPERATURE.....53.
MAX HUMIDITY........55-60 PERCENT.
WIND (20 FT)........SOUTH-SOUTHEAST WINDS 2 TO 6 MPH.
MIXING HEIGHT.......FALLING TO NEAR SURFACE BETWEEN 1700-1800.
TRANSPORT WINDS.....SOUTH 8 TO 12 MPH.
VENTILATION INDEX...LOW (50).
FRIDAY
SKY/WEATHER.........PARTLY SUNNY THEN BECOMING CLOUDY. RAIN
IN THE LATE MORNING AND AFTERNOON.
CWR.................30 PERCENT.
CHANCE OF LIGHTNING.10 PERCENT.
MAX TEMPERATURE.....56.
MIN HUMIDITY........45-50 PERCENT.
WIND (20 FT)........SOUTH 1 TO 4 MPH IN THE MORNING BECOMING WEST
2 TO 5 MPH AROUND 0800 THEN INCREASING TO WEST
8 TO 12 MPH WITH GUSTS TO AROUND 20 MPH AFTER 1100.
MIXING HEIGHT.......3000 FT AGL IN THE AFTERNOON.
TRANSPORT WINDS.....WEST-SOUTHWEST 12 TO 19 MPH.
VENTILATION INDEX...MODERATE (409) INCREASING TO HIGH (575) IN THE
AFTERNOON.
FRIDAY NIGHT
SKY/WEATHER.........MOSTLY CLOUDY. 50% CHANCE OF RAIN SHOWERS
THROUGH THE NIGHT.
CWR.................10 PERCENT.
CHANCE OF LIGHTNING.5 PERCENT.
MIN TEMPERATURE.....38.
MAX HUMIDITY........95-100 PERCENT.
WIND (20 FT)........SOUTHWEST WINDS 8 TO 12 MPH WITH GUSTS TO
AROUND 25 MPH THROUGH THE EVENING.
MIXING HEIGHT.......500 FT AGL.
TRANSPORT WINDS.....SOUTHWEST 14 TO 17 MPH.
VENTILATION INDEX...MODERATE (354).
FORECASTER...VT
REQUESTED BY...JUSTIN COLVIN
TYPE OF REQUEST...PRESCRIBED
.TAG 2622210.3/OTX
.DELDT 09/24/26
.FORMATTERVERSION 2.0.0
.EMAIL MARSHALL.MYHRE@USDA.GOV,RACHAEL.MIDDLEKOOP@USDA.GOV,JUSTIN.L.COLVIN@USDA.GOV,MEGAN.PRIMMER@USDA.GOV
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