Thursday, July 7, 2016 11 A.M.
Looking at this morning’s forecast models and actual forecasts is almost a case of “What’s going on?” Everything you look at has a different story to tell. First, the NWS forecast includes a scant 20% chance for rain/t-storms today and another 20% chance tonight. The backbone of our forecast system, the GFS produces a 1% chance today and about 40% tonight (LAMP) and a 4% chance today, 45% tonight (MOS). Meanwhile, the NAM model output is also low…11% today and 53% tonight. By the way, all of the “tonight” forecasts call for the rain after midnight.
On the other hand, the Storm Prediction Center gives us a 40% chance for thunderstorms today and just 10% tonight. Then, the two primary short-term forecasts chime in with a slight different story. Both the RAP and the HRRR predict a line of thunderstorms to reach the Louisville area between roughly 8 P.M. and Midnight. Earlier today I saw WAVE TV’s in house model project a line of storms between 6 and 8 P.M..
What’s one to believe? Good question! First of all the GFS has been terrible lately as evidenced by a lot of forecasts we’ve heard recently. Second, the short-term forecasts are better at picking up on the “outflow boundaries” created by previous storm systems, so they should be more reliable. As a result, I’d lean toward the RAP/HRRR/WAVE forecast expecting a line of thunderstorms this evening. We’ll see how it plays out.