INDIANAPOLIS — We're making today and Thursday "Weather Aware" days with the potential of funnel clouds, rotating storms, and possibly a few tornadoes. This severe weather risk comes from the atmospheric spin around an approaching upper level low, noticeably more humid air that's pushed the Muggy Meter to the "miserable" range, low cloud bases, and increasing instability during peak heating hours between 2 - 9 p.m.
Watches and/ Warnings are possible this afternoon and again Thursday afternoon and we'll be updating as needed. It's no surprise to us that the Storm Prediction Center placed parts of central Indiana within a Level 2 (out of 5) risk for severe weather with tornado probabilities (within 25 miles of a point) ranging from 2% to 5% over the entire viewing area. In addition, severe wind gusts are also possible. Please have a way to get watches and warnings.
Central Indiana remains on the eastern side of the circulation of the upper low again on Thursday, which is the most favorable side for rotating storm/tornado potential. The probability of severe weather could rise for tomorrow, but either way you should expect scattered to numerous downpours/thunderstorms Thursday afternoon, some of which could become severe and rotate.
This slow-moving upper low lingers around the Ohio Valley on Friday and brings unsettled weather for Carb Day. We continue to forecast drizzle, showers, and possibility of thunderstorms at times on Friday. If no sun breaks emerge, temperatures likely stay in the 60s.
We'll finally lose the influence of the upper low just in time for Race Weekend, which currently looks rather pleasant. A big drop in the Muggy Meter from dewpoints in the 40s/50s brings pleasant air for the parade-goers Saturday in downtown Indianapolis. Clouds gradually decrease with mild temperatures in the 60s at the beginning of the parade to 70s to finish.
The weather for the 106th running of the Indy 500 looks mainly sunny, comfortable morning temps in the lower to mid-50s, and pleasantly warm afternoon highs in the lower to mid 80s – "pleasantly warm" because it appears the Muggy Meter doesn't climb until early next week.