610
FNUS76 KOTX 211941
FWSOTX
SPOT FORECAST FOR UPPER SMITH SOUTH...UPPER SMITH
NATIONAL WEATHER SERVICE SPOKANE WA
1241 PM PDT FRI AUG 21 2026
FORECAST IS BASED ON FORECAST START TIME OF 0600 PDT ON AUGUST 22.
..HEAT ADVISORY IN EFFECT UNTIL 10 PM PDT THIS EVENING
...RED FLAG WARNING IN EFFECT FROM 4 PM SATURDAY TO 11 AM PDT
SUNDAY...
DISCUSSION
209:
ON FRIDAY, WARM AND DRIER CONDITIONS WERE OBSERVED OVER THE FIRE
WITH HIGH TEMPERATURES IN THE LOW TO MID 890S ON SOUTH ASPECTS
WITH HUMIDITY IN THE UPPER TEENS TO LOW 20 PERCENT RANGE. FAIR
OVERNIGHT HUMIDITY RECOVERY OCCURRED FRIDAY MORNING. SMOKE FROM
REGIONAL FIRES RESULTED IN HAZY CONDITIONS. WINDS WERE GENERALLY
LIGHT AND TERRAIN DRIVEN.
THE AIRMASS WILL TREND COOLER AND WETTER SATURDAY AND SUNDAY WITH
THE PASSAGE OF COLD FRONT. THIS WILL BRING INCREASED EASTERLY
WINDS TO THE FIRE THROUGH EARLY SATURDAY AFTERNOON BEFORE SHIFTING
TO THE SOUTHWEST DURING THE AFTERNOON AND EVENING. THERE IS A 40%
CHANCE FOR LIGHT SHOWERS OR SPRINKLES EARLY SATURDAY MORNING. THIS
BRIEFLY DECREASES TO A 15% CHANCE IN THE LATE MORNING AND EARLY
AFTERNOON, BEFORE INCREASING AGAIN TO A 40% CHANCE OF SHOWERS AND
A 20% CHANCE OF THUNDERSTORMS AROUND 1600 HOURS OVER THE FIRE. ANY
THUNDERSTORMS OVER OR NEAR THE FIRE WILL BRING A THREAT FOR GUSTY
OUTFLOW WINDS UP TO 50 MPH AND ISOLATED RAINFALL RANGING FROM A
TRACE TO A QUARTER OF AN INCH.
SPOT DISCUSSION:
WEATHER WILL TREND COOLER AND WETTER ON SATURDAY AND SUNDAY WITH
HIGH TEMPERATURES COOLING BY 2-5 DEGREES ON SATURDAY AND THEN
ANOTHER 15 DEGREES ON SUNDAY. MINIMUM HUMIDITIES WILL TREND ABOUT
10 PERCENT WETTER EACH DAY. PRECIPITATION WILL FALL AS ISOLATED
LIGHT RAIN SHOWERS AND SPRINKLES EARLY SATURDAY MORNING AND
SCATTERED SHOWERS AND THUNDERSTORMS AFTER 1600 HOURS SATURDAY
AFTERNOON AND EVENING. ANY STORMS OVER OR NEAR THE FIRE WILL BRING
A THREAT FOR GUSTY OUTFLOW WINDS UP TO 50 MPH. GENERAL WINDS WILL
BE BREEZY OUT OF THE EAST SATURDAY MORNING BEFORE SHIFTING TO THE
SOUTHWEST WITH AND BEHIND A COLD FRONT. WINDS WILL REMAIN BREEZY
OUT OF THE SOUTHWEST THROUGH SUNDAY.
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).
***************************************************************
SATURDAY
SKY/WEATHER.........MOSTLY CLOUDY THEN BECOMING SUNNY. PATCHY SMOKE.
40% CHANCE OF SHOWERS/SPRINKLES IN THE MORNING, THEN
A 15% CHANCE OF SHOWERS AND THUNDERSTORMS THROUGH
1600 HOURS. INCREASING TO A 40% CHANCE OF SHOWERS
AND A 20% CHANCE OF THUNDERSTORMS AFTER 1600 HOURS.
CWR.................0 PERCENT IN THE MORNING AND AFTERNOON.
CHANCE OF LIGHTNING.15 PERCENT IN THE EARLY AFTERNOON, INCREASING TO 20
PERCENT AFTER 1600 HOURS.
MAX TEMPERATURE.....90-92.
MIN HUMIDITY........25-30 PERCENT.
WIND (20 FT)........EAST 2-6 MPH INCREASING TO EAST-NORTHEAST 7-11 MPH
AROUND 1000 HOURS. WINDS SHIFTING TO THE SOUTHWEST
4-8 MPH AROUND 1600 HOURS. GUSTY AND ERRATIC WINDS
EXPECTED NEAR THUNDERSTORMS IN THE AFTERNOON.
MIXING HEIGHT.......6000 FT AGL IN THE AFTERNOON.
TRANSPORT WINDS.....NORTHEAST AROUND 7 MPH SHIFTING TO THE SOUTH
AROUND 9 MPH IN THE AFTERNOON.
VENTILATION INDEX...MODERATE (262) INCREASING TO HIGH (533) IN THE
AFTERNOON.
SATURDAY NIGHT
SKY/WEATHER.........MOSTLY CLOUDY. 15% CHANCE OF THUNDERSTORMS
IN THE EVENING. 50% CHANCE OF RAIN SHOWERS THROUGH
THE NIGHT.
CWR.................10 PERCENT IN THE LATE AFTERNOON AND EVENING.
CHANCE OF LIGHTNING.20 PERCENT.
MIN TEMPERATURE.....AROUND 51.
MAX HUMIDITY........85-90 PERCENT.
WIND (20 FT)........SOUTHWEST WINDS 3-6 MPH. GUSTY AND ERRATIC WINDS
EXPECTED NEAR THUNDERSTORMS IN THE EVENING.
MIXING HEIGHT.......3000 FT AGL FALLING TO NEAR SURFACE BETWEEN
1900-2000 HOURS.
TRANSPORT WINDS.....SOUTHWEST 8 TO 11 MPH.
VENTILATION INDEX...MODERATE (292) DECREASING TO LOW (58)
OVERNIGHT.
SUNDAY
SKY/WEATHER.........SUNNY BECOMING MOSTLY SUNNY. 15% CHANCE OF
SHOWERS AND THUNDERSTORMS IN THE AFTERNOON.
CWR.................0 PERCENT.
CHANCE OF LIGHTNING.15 PERCENT IN THE AFTERNOON.
MAX TEMPERATURE.....AROUND 75.
MIN HUMIDITY........40-45 PERCENT.
WIND (20 FT)........SOUTHWEST WINDS 5-10 MPH WITH GUSTS UP TO 20 MPH.
MIXING HEIGHT.......7000 FT AGL IN THE AFTERNOON.
TRANSPORT WINDS.....SOUTHWEST 14 TO 19 MPH.
VENTILATION INDEX...HIGH (689) INCREASING TO VERY HIGH (1184) IN
THE AFTERNOON.
FORECASTER...VT
REQUESTED BY...NOELLE
TYPE OF REQUEST...WILDFIRE
.TAG 2620106.1/OTX
.DELDT 08/21/26
.FORMATTERVERSION 2.0.0
.EMAIL DAVID_PEARSON@FIRENET.GOV,2026.UPPERSMITHPLANS@FIRENET.GOV,IDCDC@FIRENET.GOV
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