387
FNUS75 KBOI 211126
FWSBOI

Spot Forecast for Lake Fire...USFS
National Weather Service Boise ID
526 AM MDT Fri Aug 21 2026

Forecast is based on forecast start time of 0600 MDT on August 21.
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.

...UNSTABLE ON SATURDAY...
...THUNDERSTORM THREAT INCREASES TONIGHT INTO SATURDAY...

.DISCUSSION...
Southwest flow aloft continues as a ridge remains over the area
with a trough off the OR coast. Breezy southwest winds expected
during the afternoon Saturday with unstable conditions. Monsoon
moisture will bring a slight chance of thunderstorms tonight into
Saturday with gusty and erratic winds possible from showers and
thunderstorms. A weak cold front will bring drier air to the area
on Sunday.


.TODAY...

Sky/weather.........Partly sunny.
Max temperature.....77 to 84.
Min humidity........16 to 21 percent.
CWR.................0 percent.
Wind - 20 foot......East-southeast 3 to 6 mph.
Mixing height.......10000 ft AGL.
Transport winds.....Southeast around 10 mph.
Ventilation Index...1000 excellent.

.TONIGHT...

Sky/weather.........Cloudy with a 20 percent chance of showers and
                    thunderstorms. Some thunderstorms may produce
                    gusty winds.
Min temperature.....59 to 64.
Max humidity........44 to 51 percent.
CWR.................10 percent.
Wind - 20 foot......northeast 4 to 9 mph in the evening shifting to the
                    southwest-southeast 5 to 11 mph overnight. Gusts up to 20
                    mph. Gusty and erratic winds expected near
                    thunderstorms.
Mixing height.......300 ft AGL.
Transport winds.....South around 5 mph.
Ventilation Index...15 poor.

.SATURDAY...

Sky/weather.........Partly sunny with a slight chance of showers. A
                    slight chance of thunderstorms. Some
                    thunderstorms may produce gusty winds in the
                    afternoon. Chance of precipitation 20 percent.
Max temperature.....71 to 76.
Min humidity........24 to 29 percent.
CWR.................10 percent.
Wind - 20 foot......Southwest 7 to 13 mph with gusts to around 20
                    mph. Gusty and erratic winds expected near
                    thunderstorms in the morning. Gusty and erratic
                    winds expected near thunderstorms in the
                    afternoon.
Mixing height.......9000 ft AGL.
Transport winds.....Southwest around 15 mph.
Ventilation Index...1350 excellent.

$$
Forecaster...Anderson
Requested by...Justin Aleshire
Type of request...WILDFIRE
.TAG 2619812.4/BOI
.DELDT 08/21/26
.FormatterVersion 2.0.0
.EMAIL justin.aleshire@usda.gov