FNUS75 KBOI 211009

FWSBOI



Spot Forecast for Cold Rx - Scirius...USFS

National Weather Service Boise ID

409 AM MDT Tue Apr 21 2026



Forecast is based on ignition time of 0713 MDT on April 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.



...STRONG COLD FRONT TO ARRIVE THIS EVENING WITH SHOWERS AND 

THUNDERSTORMS...

...WIDESPREAD RAIN AND SNOW ON WEDNESDAY...



.DISCUSSION...

Today will be warm and dry with breezy afternoon winds ahead of a

cold front. The front will move through this evening, bringing 

showers, isolated thunderstorms, and shifting winds. Rain will 

increase late tonight with isolated thunderstorms continuing. 

Cooler temperatures will allow rain to mix with or change to snow 

by Wednesday morning, but little to no snow accumulation is 

expected at the burn site. Much cooler temperatures will arrive on

Wednesday. Lighter rain and snow will linger into Thursday. 

Temperatures will remain cool through the weekend with lower 

chances of rain and snow.



.TODAY (TUESDAY)...



Sky/weather.........Sunny in the morning with increasing clouds

                    in the afternoon. 

Max temperature.....66 to 71. 

Min humidity........20 to 25 percent. 

CWR.................0 percent. 

Wind - 20 foot......North 2 to 5 mph in the morning, becoming south 

                    3 to 8 mph after 1000L. Gusts up to 15 mph in the 

                    afternoon. 

Mixing height.......6000 ft AGL. 

Transport winds.....South around 15 mph. 

Ventilation Index...900 excellent. 



.TONIGHT...



Sky/weather.........A 25% chance of thunderstorms in the evening and 

                    overnight. Storms capable of erratic gusty winds,

                    small hail, heavy downpours, and isolated lightning 

                    strikes. Scattered rain showers in the evening, 

                    then widespread rain after 0300L. Chance of 

                    precipitation 40 percent in the evening, increasing

                    to 90 percent after 0300L. 

Min temperature.....35 to 40. 

Max humidity........95 to 100 percent. 

CWR.................60 percent. 

Wind - 20 foot......North to northeast 3 to 6 mph with in the evening 

                    shifting to the south 5 to 10 mph with gusts to 

                    around 20 mph overnight. Gusty and erratic winds 

                    expected near thunderstorms. 

Mixing height.......500 ft AGL. 

Transport winds.....Northeast around 15 mph. 

Ventilation Index...75 poor. 



.WEDNESDAY...



Sky/weather.........Rain and snow showers. A slight chance of 

                    thunderstorms in the afternoon. Chance of 

                    precipitation near 100 percent. Snow level 5300 feet.

                    Snow accumulation less than 1 inch. 

Max temperature.....37 to 42. 

Min humidity........85 to 90 percent. 

CWR.................90 percent. 

Wind - 20 foot......Southwest around 4 to 8 mph. Gusts up to 14 mph in 

                    the afternoon. Gusty and erratic winds expected 

                    near thunderstorms. 

Mixing height.......2500 ft AGL. 

Transport winds.....West around 15 mph. 

Ventilation Index...375 fair. 



$$

Forecaster...Tangen

Requested by...Jonathan Miller

Type of request...PRESCRIBED

.TAG 2610807.1/BOI

.DELDT 04/21/26

.FormatterVersion 2.0.0

.EMAIL jonathan.miller@usda.gov,will.woods@usda.gov