561
FNUS75 KBOI 220047
FWSBOI

Spot Forecast for Cold Rx...US Forest Service
National Weather Service Boise ID
647 PM MDT Mon Sep 21 2026

Forecast is based on forecast start time of 0600 MDT on September 22.
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.

...MILD WEATHER THROUGH THURSDAY...
...COLD FRONT LATER THIS WEEK...

.DISCUSSION...
A slight warming trend through Thursday, peaking Thursday and
then cooling down Friday/Saturday as a cold front moves through.
RHs will follow a similar pattern, with 50-60% overnight RH
recoveries and afternoon minimum RHs near 25-30% through Thursday.
Wind are mostly mild each day, prevailing out of the south each
day and out of the North/East each night. Winds pick up ahead of
the late week cold front, with gusts up to 20 mph possible and a
steady southwesterly wind direction. Precipitation chance climbs
to 20% Friday night as the front moves through, though timing is
still uncertain.

.TUESDAY...

Sky/weather.........Partly sunny.
Max temperature.....71 to 76.
Min humidity........28 to 33 percent.
CWR.................0 percent.
Wind - 20 foot......Northeast 3 to 5 mph in the morning shifting to
                    the southwest 3 to 5 mph in the afternoon.
Mixing height.......9000 ft AGL.
Transport winds.....West around 10 mph.
Ventilation Index...900 excellent.

.TUESDAY NIGHT...

Sky/weather.........Mostly cloudy in the evening, then clearing.
Min temperature.....46 to 51.
Max humidity........64 to 69 percent.
CWR.................0 percent.
Wind - 20 foot......North around 7 mph.
Mixing height.......200 ft AGL.
Transport winds.....Northeast around 5 mph.
Ventilation Index...10 poor.

.WEDNESDAY...

Sky/weather.........Mostly sunny.
Max temperature.....70 to 75.
Min humidity........29 to 34 percent.
CWR.................0 percent.
Wind - 20 foot......Northeast 3 to 6 mph in the morning shifting to
                    the south around 6 mph in the afternoon.
Mixing height.......5000 ft AGL.
Transport winds.....South around 10 mph.
Ventilation Index...500 good.

$$
Forecaster...Smith
Requested by...Rose Carey
Type of request...WILDFIRE
.TAG 2622291.0/BOI
.DELDT 09/22/26
.FormatterVersion 2.0.0
.EMAIL rose.carey@usda.gov,jonathan.miller@usda.gov,idpac@firenet.gov