Journal of Operational Meteorology Article The 5 June 2012 Central Montana Tornado Event

During the afternoon and evening of 5 June 2012, central Montana experienced a rare tornado event for that region, with three confirmed tornadoes from two supercell thunderstorms. While the background environment supporting this event was generally consistent with that corresponding to a severe thunderstorm and tornado event in the midlatitudes, particular factors supporting this event in central Montana were seasonally anomalous. In support of future pattern recognition and forecasting of such an event—for which large potential impact could exist—the synoptic and mesoscale environment evolution, and the radar evolution associated with this event, are investigated. We present climatological anomalies, with midlevel lapse rates and deep moisture content being particularly high for this case. Impact-based decision support services and detailed tornado assessments from the National Weather Service in Great Falls also will be discussed.