It’s not often that a forecast includes the phrase “Thunder Sleet,” but that’s exactly what we’re experiencing right now. However, what exactly is “Thunder Sleet” and what makes this natural occurrence of the weather so uncommon?
What precisely is Thunder Sleet, then?
Well, it certainly sounds like it! This natural phenomenon occurs when thunder and lightning strike simultaneously with sleet, also known as freezing rain. According to Scientific America, “less than 1% of observed snowstorms unleash Thunder Snow or Sleet.” This is a weather phenomenon that occurs very infrequently.
Formation of Thunder Sleet
Thunder Sleet forms in a similar fashion as a traditional Thunder Storm, but with a minor difference. Thunderstorms traditionally form when warm, moist air rises into cold air. The warm air will become cooler which will cause the water droplets to form. This repetitive circuit of rising and falling air is called a convection cell which thunderstorms are formed.
Thunder Sleet is formed when rain falls from the cloud and the ground temperature is below freezing (32 degrees), the droplets will starts to freeze. Some times they will not freeze until they are closer to the surface. Conditions have to be just right for Thunder Sleet to form which is why this weather phenomenon is so rare to see!.
Different from Hail?
Sleet is very round and light. It’s snow that falls and melts in a warm layer then refreezes in a colder lower layer.
Hail is going to have a lot of imperfections since it (rain) gets thrown way up in the atmosphere in severe storms, freezes then falls down.
Is It A Rare Phenomenon?
“While thundersnow is rare, it can be considered even rarer when sleet and freezing rain are accompanied by thunder and lightning,” FOX Weather senior digital meteorologist Brian Donegan said.
“First, in order for sleet to form, you need a so-called ‘warm nose’ in the atmosphere that causes snowflakes to melt into raindrops after they fall from the clouds, but a layer of subfreezing air in place near the surface causes those liquid drops to freeze into ice pellets before they reach the ground,” Donegan said.