Temperatures above 90° isn't uncommon but this will be the first time of the season with mid/late summer heat. Most people aren't used to this kind of heat just yet. And you know the old saying, "It's not the heat, it's the humidity.", it will be true this weekend. Dew points are expected to get above 70°. This could push the heat index to 100° or higher.
It's all about the upper levels of the atmosphere and compressional heating. We are going to see an early season HOT DOME settle in over the Mississippi Valley. The area of high pressure will remain relatively stationary or drift slightly to the east through the weekend.
If you think about it, high pressure means there is a lot of pressure. When you squeeze air under high pressure, air temperature will increase. That will be in play this weekend.
Let's take a look at what various computer models are showing. Here is a look at temperatures forecast by last night's run of the computer models (0z runs).
Canadian Forecast Agency Model for 1pm CT Sunday afternoon:
European Forecast Agency Model 1pm CT Saturday afternoon:
European Forecast Agency Model 1pm CT Sunday afternoon:
As I mentioned, the humidity will play a big factor. Humidity is a look at how much moisture is in the air. A more accurate measure of the moisture in the air is the dew point. The higher the dew point, the higher the moisture content.
Here is the latest run of NOAA's Global Forecast model showing dew points at 7pm CT Sunday.
If you go through and do the calculation for the heat index (feels like temperature), a temperature of 96° and a dew point of 71° results in a heat index of 103°. A temperature of 94° and a dew point of 70° results in a heat index of 100°.
Needless to say, it is going to be hot around the Ohio Valley this weekend.
Of note, there is a HUGE race going on that will draw hundreds of thousands of spectators going on Sunday. The Indianapolis 500. Temperatures in the mid-90°s and high humidity could be dangerous for people attending the race. If you are going, be sure to drink lots of water and/or sports drinks. (Yes, I know lots of liquids will be consumed, that is why I suggested water/sports drinks. haha)
It is looks like this could be the hottest Indy 500 ever. The hottest Indy 500 was in 1937 when the high temperature was 92°. In fact, it is rare that the mercury reads 90° or higher for the race. It has only happened five previous times (5.2% of the time).
Previous Indianapolis 500's with temperatures over 90°:
- 1937 - 92°
- 1953 - 91°
- 1919 - 91°
- 1978 - 90°
- 1977 - 90°