SKYWARN is the National Weather Service (NOAA) sponsored program enlisting weather spotters to assist NOAA meteorologists in observing and reporting severe weather conditions. These include trained volunteers in weather observation and reporting and Amateur (HAM) radio operators.
If you are see or especially are experiencing severe weather in the West-Central Montana area, please monitor HARC 147.04 MHz repeater and report observations to the NOAA-Missoula through amateur station, WX7MSO. You may also call their toll free number at 1-800-676-6975.
Please remember that your safety is first! Don't get yourself into trouble attempting to gather observations. Drive safe and stay clear of hazards.
National SKYWARN websites are found at http://www.crh.noaa.gov/hamradio/index.php,and http://www.skywarn.org/default.htm
This is a good site for information. It contains a good "spotter tools" publication detailing what to report to the NOAA.