* WHAT...Very hot daytime temperatures combined with warm overnight lows will produce cumulative heat stress.
* WHERE...Portions of south central and southeast Montana.
* WHEN...Until midnight MDT Tuesday Night.
* IMPACTS...Heat related illnesses increase significantly during extreme heat events.
* ADDITIONAL DETAILS...Dangerously hot conditions with high temperatures of 98 to 105 today and Tuesday. Overnight lows will remain well above normal providing only limited relief.