BOZEMAN – Southwesterly flow aloft will help produce stronger thunderstorms over Montana Tuesday afternoon and evening.
A shortwave disturbance, strong surface heating, and a very unstable atmosphere will produce possible damaging thunderstorms Tuesday afternoon especially east of the divide.
The Storm Prediction Center thunderstorm outlook for Tuesday over Montana shows a “marginal” (green) or low risk of damaging thunderstorms along the Continental Divide. A “slight” (yellow) risk for damaging storms from Bozeman to Helena to Great Falls. An “enhanced” (brown) risk for damaging storms for central and eastern counties.
In the enhance areas of the state there will likely be very large hail Tuesday afternoon up to or over 2” in diameter and some forecast models have 2.5” to 4.5” in diameter.
There is a 5% chance for tornadoes Tuesday across central and eastern counties of Montana.
Thunderstorms will develop over SW Montana early in the day Tuesday and as these storms lift to the NE they will mature and become very strong before diminishing after sunset.