Stormy Fourth of July?

If you got outside for any period of time yesterday, you probably instantly noticed the comfortable feel. Dew points yesterday remained in the 50's for most of the area, which meant a comfortable air mass as highs climbed into the low 80's. It's been a pleasant morning, but dew points are already on the rise. It will begin to feel a bit muggy later today as dew points climb into the upper 60's.

We'll really feel the heat and humidity for the 4th of July, and Thursday too, with highs climbing into the upper 80s to near 90°. However, with dew points in the 70's our heat index values will make it feel like the mid and upper 90's to 100° for both of those days. Unfortunately, we also have a threat for storms both of those days.

Looking at the mid levels of the atmosphere, a few disturbances will lift north through Illinois, following upper level winds. These vorticities or 'disturbances' will bring enough lift in our unstable environment, to allow for a few scattered showers and storms. Right now the timing with the highest chance for rain and thunder, will be between about noon and 5pm. So if you have plans outside for the fourth, you'll want to keep your eyes on a radar through the afternoon. The good news is, if we do get storms through the afternoon, it could essentially 'work over' the atmosphere, which would keep the forecast dry for the fireworks display.

A cold front will come through Thursday, which brings another and higher threat for storms on Thursday. Any storm that develops will bring the potential for locally heavy downpours.

The good news here, is that behind the front we will get to experience a cooler and more comfortable air mass Friday and into the weekend with much lower dew points.