Eastern Grayson County flooded this morning, an area about an hour southwest of Louisville, just to the southeast of Leitchfield and Clarkson, near Nolin River Lake. About 3-5" of rain fell over a period of a couple hours early this morning. Here's the estimates per Stormtracker 3D Doppler Radar...

The unstable air that produced this heavy rain is pretty unique. It's a pocket of air surrounded by stable air. It's only a hundred miles or so in diameter and not moving. It originates from a chilly pocket of air above about 10,000 feet. You can see the cool pocket in this graphic, which the RUC weather model picked up on, it's the blue area in western Kentucky, and southern Illinois.

This area created a spin in the atosphere (called a VORT MAX, or shorwave), which in turn caused these showers and storms to spin up. The small scale spin could easily be seen this morning on our radar loops. The VORT is easily seen in this image, again, picked up by the RUC...

You can see a larger shortwave, or vorticity maximum (VORT MAX), to the northwest over the Missouri River Valley, or eastern Nebraska and western Iowa, this mid-level spin also produced morning showers and storms in that location. The VORT is just one of many features we have to watch for, which kicks up showers and storms. It is not associated with an organized storm system or large scale fronts, but it can produce a bullseye of some heavy downpours, which we saw today. The cool air aloft creates an environment of unstable air with warmer air at the surface, this created convection - like holding a beach ball underwater - the air wants to shoot up and does in the form of thunderstorms.

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