Sunday, August 7, 2011

8/7 - 5:15pm - More Storms in Our Future

Did the storms in Louisville wake you up this morning? I slept through them, which is probably a good thing because those that couldn't sleep through them early this morning sure looked tired today. Locations near Downtown Louisville saw rainfall amounts exceed one inch this morning, but most of the suburbs and outlying areas received under an inch. Click the image on the left from NWS Louisville to see a complete map of the rainfall totals from this morning. More storms are possible this afternoon and especially tomorrow as a cold front to our north provides a focus for development.

I've been watching the radar and satellite image for the past couple hours and it appears that ongoing storms dropping southeastward near Indianapolis may send out a some outflow boundaries toward Louisville over the next few hours. Outflow boundaries are like miniature cold fronts created by the cool air flowing out from a thunderstorm's downdraft. They also can cause storms to develop because they are a source of lift and that's why they're so important when forecasting short-term storm development. Since we have a little bit of wind shear and a very unstable atmosphere over the Louisville area right now, a kick from one of these southward-moving outflow boundaries may cause a few isolated storms to develop this evening. Storms may also form without the boundary if another small-scale feature or surface heating gets things going first. So, a vast majority of the area will stay dry, but if you happen to get under one of these wildcard isolated storms get ready for some heavy rain and wind.

There's a much better chance for storms tomorrow as a shortwave disturbance moves through the region. These storms will likely cluster together into an MCS (Mesoscale Convective System - complex of storms) and severe weather is possible. These scattered or MCS storms will roll through Louisville sometime tomorrow late afternoon or evening. Damaging winds, frequent lightning, and small hail will be the main threats from these storms. If they cluster together in a line, wind damage probabilities will be higher. The Storm Prediction Center has placed much of Kentucky, including Louisville, in a 30% Slight Risk area for severe weather tomorrow due to these factors.

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