948
FNUS75 KBOI 142000
FWSBOI

Spot Forecast for BIG GRASS...BLM
National Weather Service Boise ID
200 PM MDT Mon Sep 14 2026

Forecast is based on forecast start time of 1800 MDT on September 14.
If conditions become unrepresentative...contact the National Weather
Service.

Please contact our office at (208)334-9060, if you have questions
or concerns with this forecast.


...WARMING TREND THRU WEDNESDAY...
...UNSETTLED LATER THIS WEEK...

.DISCUSSION...
Colder temperatures tonight will allow good RH recovery,
supporting a chance for frost in the area. Temperatures warming to
near normal Tuesday and remain around normal into the weekend.
Tuesday through Wednesday winds shift out of the northeast 5 to 12
mph. Unsettled conditions later this week as a low pressures
system moves across the region. This will bring a 20% chance of
precipitation to the burn site Thursday and Friday.

.TONIGHT...

Sky/weather.........Mostly clear.
Min temperature.....37 to 47.
Max humidity........69 to 79 percent.
CWR.................0 percent.
Wind - 20 foot......North 3 to 7 mph in the evening shifting to the
                    east overnight.
Mixing height.......100 ft AGL.
Transport winds.....East around 5 mph.
Ventilation Index...5 poor.

.TUESDAY...

Sky/weather.........Mostly sunny.
Max temperature.....68 to 78.
Min humidity........14 to 24 percent.
CWR.................0 percent.
Wind - 20 foot......Southeast 3 to 7 mph in the morning shifting to
                    the west up to 6 mph in the afternoon.
Mixing height.......6000 ft AGL.
Transport winds.....Southwest around 5 mph.
Ventilation Index...300 fair.

.TUESDAY NIGHT...

Sky/weather.........Mostly cloudy in the evening then becoming
                    partly cloudy overnight.
Min temperature.....42 to 52.
Max humidity........51 to 61 percent.
CWR.................0 percent.
Wind - 20 foot......Northeast 6 to 12 mph.
Mixing height.......200 ft AGL.
Transport winds.....East around 10 mph.
Ventilation Index...20 poor.

.WEDNESDAY...

Sky/weather.........Mostly sunny.
Max temperature.....71 to 81.
Min humidity........15 to 25 percent.
CWR.................0 percent.
Wind - 20 foot......East 5 to 11 mph with gusts to around 18 mph.
Mixing height.......8500 ft AGL.
Transport winds.....Southeast around 10 mph.
Ventilation Index...850 excellent.

$$
Forecaster...Smith
Requested by...STEPHEN HAMMOND
Type of request...WILDFIRE
.TAG 2621735.3/BOI
.DELDT 09/14/26
.FormatterVersion 2.0.0
.EMAIL stephen_hammond@firenet.gov,2026.biggrass.plans@firenet.gov,ROBERT_EGGERT@FIRENET.GOV