676
FNUS75 KBOI 201653
FWSBOI

Spot Forecast for Gerdie Fire...BOI
National Weather Service Boise ID
1053 AM MDT Thu Aug 20 2026

Forecast is based on forecast start time of 1000 MDT on August 20.
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.

...HOT AND DRY THROUGH TOMORROW...
...STORM/SHOWER CHANCE FRIDAY NIGHT AND SATURDAY EVENING...
...COOLER TEMPS AND BREEZY WINDS DUE TO A COLD FRONT THIS WEEKEND...

.DISCUSSION...
Hot temperatures today and tomorrow with low relative humidity
and poor overnight recovery. Each afternoon 10 to 15 mph winds
develop. Wind directions shift each day, out of the north-
northwest this afternoon, switching from east to southwest
tomorrow afternoon, and remaining out of the southwest Saturday.
An increasing chance of thunderstorms and showers Friday night and
Saturday afternoon could also produce erratic gusty outflow winds
up to 45 mph. Saturday has the higher risk for severe weather,
with storms lasting from noon through the evening. Storms could
produce gusty winds, abundant lightning, small hail, and heavy
rainfall. Storms arrive alongside a cold front, set to cool temps
down and bring gusty 15 to 25 mph winds this weekend.


.REST OF TODAY...

Sky/weather.........Sunny late in the morning then becoming partly
                    sunny in the afternoon.
Max temperature.....86 to 91.
Min humidity........15 to 20 percent.
CWR.................0 percent.
Wind - 20 foot......Northwest to north 4 to 7 mph. Gusts up to 14
                    mph in the afternoon.
Mixing height.......8000 ft AGL.
Transport winds.....Southwest around 15 mph.
Ventilation Index...1200 excellent.

.TONIGHT...

Sky/weather.........Mostly cloudy.
Min temperature.....68 to 73.
Max humidity........20 to 25 percent.
CWR.................0 percent.
Wind - 20 foot......Downslope 3 to 7 mph. Gusts up to 14 mph in the
                    evening weakening overnight.
Mixing height.......300 ft AGL.
Transport winds.....East around 5 mph.
Ventilation Index...15 poor.

.FRIDAY...

Sky/weather.........Partly sunny.
Max temperature.....87 to 92.
Min humidity........15 to 20 percent.
CWR.................0 percent.
Wind - 20 foot......East to southeast 3 to 7 mph. Gusts up to 14 mph
                    in the afternoon.
Mixing height.......9500 ft AGL.
Transport winds.....South around 10 mph.
Ventilation Index...950 excellent.

$$
Forecaster...Macfarlane
Requested by...Max Maeda (IC)
Type of request...WILDFIRE
.TAG 2619958.1/BOI
.DELDT 08/20/26
.FormatterVersion 2.0.0
.EMAIL max.s.maeda@gmail.com