Half of Indiana (shaded in dark green on the map, above-left) has a marginal risk of severe thunderstorms between 9 a.m. EDT today and 8 a.m. EDT tomorrow, according to the “Day 1 Convective Outlook” that the National Weather Service Storm Prediction Center (SPC) issued at 8:52 a.m.
The primary risks are damaging straight-line thunderstorm winds of 58 mph or stronger and hail of one inch or more in diameter. The probability of either occurring within 25 miles of any point in the slight risk area is five percent.
The normal wind probability for any May 12 is about two percent, according to climatology data from the National Severe Storms Laboratory. Today’s probability, therefore, is roughly twice the normal probability for this date.
The normal hail probability for any May 12 is about one percent, so today’s probability is roughly five times normal.
There’s no reason to be alarmed by a marginal risk, but if you live in that half of Indiana, it’s wise to remain weather-aware today, especially if you’ll be involved in any outdoor activities (e.g. baseball games, etc.). Remember that all thunderstorms, severe or not, bring lightning, which kills people who are outdoors.
The SPC plans to update its outlook for today by 12:30 p.m. EDT.