ATHENS/SIGEL, Ill. (WCIA) – Multiple cold air funnels were spotted in Central Illinois on Sunday.
Cold air funnels are different than traditional tornadic funnels in that they form in certain conditions.
A funnel cloud coming from a tornadic storm has a rotating updraft, or a mesocyclone. When they touch down, they are called a tornado and can cause damage as they pass along the ground. There were at least five of these in Central Illinois on Saturday.
But cold air funnels are different. They often form beneath showers or weak thunderstorms when there is cold air aloft. Once sunshine breaks through and helps generate instability at the surface, the contrast between warm surface conditions and a cold atmosphere is a key factor. This helps bubble up convection, and when coupled with an upper level low pressure providing subtle wind shear, can be a breeding ground for cold air funnels.
Cold air funnels are relatively harmless, but they can look scary. They rarely touch the ground, and if they do, they rarely cause much damage with EF-0 type damage. That means winds are less than 85 mph, many times much less than that.
Cold air funnels are common in Central Illinois in the late Spring and Summer months. The National Weather Service generally does not issue tornado warnings for these, but sometimes can issue special weather statements, just like they did Sunday afternoon. But, if one touches down, they sometimes will issue a warning.
Cold air funnels are hard to detect on radar. Often they are so small that doppler radar and velocity don’t indicate they are there. That’s why viewer reports and reports from emergency management officials and local storm spotters are key on days like Sunday was.
If you have a report of a funnel cloud, you can send them to WCIA on Facebook, or email email@example.com.