Tornado in Blaine County, Montana

A supercell moved southeast across Blaine County early Tuesday

evening. This storm produced large hail of nearly two inches in

diameter along its path. As the severe storm approached Hays,

rotation strengthened slightly to where a brief tornado occurred.

The tornado occurred over open ranchland to the west of Montana

Highway 66 and, to our knowledge, no damage occurred. The

supercell then started to weaken as it move southeast between Hays

and Lodge Pole with the tornado likely lifting before it reached

Highway 66.

A shortwave trough over the Pacific Northwest began to compromise the ridge in place and introduced a more moist and unstable southwesterly flow to the Northern Rockies. This allowed daily rounds of afternoon and evening showers and thunderstorms to develop over Southwest and North-central MT. The period began with discrete supercell thunderstorms developing over the plains, producing severe wind gusts, large hail, and even a weak tornado. The strongest and most widespread activity occurred on July 7th as the Pacific trough and associated wind shear began to exert more of an influence on the region's weather and interacted with the moist and unstable environment already in place.