Temperatures were quick to warm Wednesday afternoon, reaching the upper 80s and low 90s once again. Dew point temperatures were also quick to rise pushing the heat index in a few places over 100 degrees. The heat did take a break as thunderstorms were quick to develop shortly before 2pm, producing torrential downpours for some and wind gusts 40-50 mph. While the severe risk was very low locally, some of the stronger thunderstorms did produce funnel clouds – and even a reported landspout just north of Sterling in Whiteside County.
Here are a few photos of those funnel clouds from Wednesday afternoon.
Funnels that form in this type of environment rarely touch the ground, but so far this week we’ve have two reported landspouts from such funnels. One Saturday, July 4th, in Lee County and the second one this afternoon in Whiteside County.
Landspouts form differently than tornadoes. A tornado forms from a thunderstorm with a rotating updraft, or what meteorologists refer to as a meso-cyclone. These form most often in supercell thunderstorms, where a wall cloud is present.
A landspout, however, develops from the rotation originating near the ground and requires a towering cumulus cloud (sometimes a thunderstorm) to form over a boundary where there are converging winds near the surface. Quickly rising air into that towering cumulus cloud can sometimes ‘catch’ that circulation near the surface, stretching it in the vertical causing the formation of the landspout. Often times landspouts are mistaken for tornadoes, because they can sometimes look similar. But remember, the formation of them are different from each other.