The average date of the last 90° day in Indianapolis is August 31st but Tuesday many area thermometers topped 90 and combined with unusually high levels of humidity for this time of the year, the heat index neared 100°.
Last September we suffered through the hottest weather of the season, with an extended spell of 7 days of 90° heat. While this heat is on the clock we potentially could equal or surpass the hottest so far this year on Wednesday. The forecast high of 93° will combine with high humidity levels to produce a heat index of 95° to 100°.
58% of all September's have produced at least 1 90° day, the most (12) in 1897 and 1891. The latest date of a 90° day in Indianapolis is actually in October. Most recently set October 8th 2007.
STORM CHANCES RISE SLOWLY
The front in the upper Midwest is stalled, the tropical traffic jam is still holding back west to east movement of weather systems. We will see the pattern free up soon.
Showers and thunderstorms will increase and reach peak coverage later this week, Friday when the cold front sags further south and into central Indiana. A refreshing brand of air will follow after the front departs early Saturday morning. The rain threat will diminish starting Saturday morning.