Lightning, Thunder, Freezing Rain, and Sleet. Oh My.

Today's winter storm brought a mixed bag of winter weather to Texas, Missouri, and Oklahoma. Many residents of these states witnessed the unusual phenomenon of thundersleet, which is sleet associated with convective bands. The thunder and lightning cause intensified precipitation rates within a convective band. Residents in some parts of southwest Missouri awoke to thunder, lightning, sleet, AND freezing rain. And the weather got even weirder from there. While already under a Winter Storm Warning for accumulating sleet and freezing rain, two counties also were issued a Severe Thunderstorm Warning by NWS Springfield. In Ozark and Taney counties, not only was there thunder, lightning, and sleet, it was also HAILING. Hail the size of quarters to be exact.

ky3moIcy road conditions after thundersleet passed through the area led to numerous accidents along I-44 in Missouri. Photo: Steve Lock

Later on in the day, some Oklahoma residents saw heavy thunderstorms as well. Surface temperatures were in the low teens, with heavy sleet, thundersleet, and some light freezing rain occurring. An inversion allowed these thunderstorms to form. This radar image shows a strong thunderstorm located near Norman, OK this afternoon, which was ongoing during the winter storm.

norman, ok

 

How can a thunderstorm, a warm weather occurrence, happen during such cold temperatures? The answer lies in the warmer air that was aloft over the colder air at the surface. It was within this warmer elevated layer that the thunderstorms formed. So while there were thunderstorms and hail ongoing in an upper layer, precipitation took the form of sleet as it descended from a cold layer, melted as it hit warmer air, and refroze into sleet as it reached the cold air at the surface. Thundersnow works on the same principle, the only difference being that it falls through a deeper layer cold air before reaching the surface.

thundersnow