331
FNUS76 KOTX 071219
FWSOTX
SPOT FORECAST FOR NORTH SIWASH UNIT 38C...USFS
NATIONAL WEATHER SERVICE SPOKANE WA
519 AM PDT THU MAY 7 2026
FORECAST IS BASED ON IGNITION TIME OF 0600 PDT ON MAY 07.
DISCUSSION
DRY CONDITIONS WILL OCCUR TODAY BUT RELATIVE HUMIDITY WILL BE
HIGHER COMPARED TO WEDNESDAY WITH MINIMUM READINGS ABOVE 40
PERCENT. ANOTHER INCREASE IN WINDS WILL OCCUR AGAIN ON FRIDAY AS
ANOTHER WEAK WEATHER SYSTEM PASSES THROUGH WITH WEST WINDS
GUSTING UP TO 20 MPH.
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).
***************************************************************
TODAY
SKY/WEATHER.........MOSTLY SUNNY IN THE MORNING THEN PARTLY CLOUDY.
CWR.................0 PERCENT.
CHANCE OF LIGHTNING.0 PERCENT.
MAX TEMPERATURE.....AROUND 62.
MIN HUMIDITY........43-48 PERCENT.
WIND (20 FT)........LIGHT WINDS BECOMING WEST 4 TO 9 MPH NEAR 1000.
GUSTS UP TO 15 MPH IN THE AFTERNOON.
MIXING HEIGHT.......NEAR SURFACE THROUGH 0800, INCREASING TO 4500 FT
AGL IN THE AFTERNOON.
TRANSPORT WINDS.....WEST AROUND 10 MPH.
VENTILATION INDEX...LOW (10) INCREASING TO MODERATE (370) IN THE
AFTERNOON.
TONIGHT
SKY/WEATHER.........PARTLY CLOUDY.
CWR.................0 PERCENT.
CHANCE OF LIGHTNING.0 PERCENT.
MIN TEMPERATURE.....AROUND 43.
MAX HUMIDITY........75-85 PERCENT.
WIND (20 FT)........SOUTHWEST 3 TO 6 MPH IN THE EVENING THEN
DOWNSLOPE/DOWNVALLEY 1 TO 3 MPH.
MIXING HEIGHT.......FALLING TO NEAR SURFACE NEAR 2000.
TRANSPORT WINDS.....SOUTHWEST 4 TO 8 MPH IN THE EVENING THEN
DOWNSLOPE/DOWNVALLEY LESS THAN 5 MPH.
VENTILATION INDEX...MODERATE (315) DECREASING TO LOW (8) OVERNIGHT.
FRIDAY
SKY/WEATHER.........MOSTLY CLOUDY.
CWR.................0 PERCENT.
CHANCE OF LIGHTNING.0 PERCENT.
MAX TEMPERATURE.....AROUND 62.
MIN HUMIDITY........35-40 PERCENT.
WIND (20 FT)........LIGHT WINDS THROUGH 0900 THEN BECOMING WEST 5 TO
12 MPH. GUSTS UP TO 20 MPH IN THE AFTERNOON.
MIXING HEIGHT.......NEAR SURFACE THROUGH 0800 INCREASING TO 5000 FT
AGL IN THE AFTERNOON.
TRANSPORT WINDS.....SOUTHWEST 5 TO 12 MPH IN THE MORNING THEN WEST
AROUND 15 MPH IN THE AFTERNOON.
VENTILATION INDEX...LOW (15) INCREASING TO HIGH (700) IN THE
AFTERNOON.
FORECASTER...JW
REQUESTED BY...JUSTIN COLVIN
TYPE OF REQUEST...PRESCRIBED
.TAG 2613020.0/OTX
.DELDT 05/07/26
.FORMATTERVERSION 2.0.0
.EMAIL MEGAN.PRIMMER@USDA.GOV,JUSTIN.L.COLVIN@USDA.GOV
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