The weather Friday will be much different than what it’s been the past couple of days as thunderstorms are likely, first during the morning and then again late in the afternoon and evening. High pressure south of the Stateline Thursday evening will quickly shift to the southeast by Friday morning. This will cause winds to shift around to the south, which in many locations they already have, increasing into Friday morning.
The return of southerly winds will work to pull moisture northward into northern Illinois early Friday morning. Scattered showers with a few isolated thunderstorms will be possible during the morning, but should pick up a little more late morning and early afternoon. This first round of storms will be forming ahead of a warm front that will position itself across central Illinois. Warm, moist air lifting over top of the front will cause some heavier downpours into the early afternoon. The best area for those storms appear to be just to our south.
Isolated shower and storm activity will still be possible into the afternoon, but a gradual uptick in storm coverage is expected after 4pm Friday. A strong cold front to the northwest will begin to slowly inch its way southeast towards the Stateline Friday evening. Thunderstorms are expected to develop along and ahead of the front between 5pm and 9pm. Those storms are the ones that could have the heaviest rain and possibly some gusty winds and hail.
Much of the Stateline is outlined under a Slight Risk for strong to severe storms Friday afternoon and evening. Even though we likely won’t see much sunshine during the afternoon there appears to be enough energy in the atmosphere for the possibility of stronger storms. Wind and hail would be the greatest concerns. As storms develop along the front, they will most likely run parallel to the front leading to the possibly of very heavy rainfall. Anywhere from one to three inches of rain will be possible by Friday night.
Many of the area high school football games have been pushed up with start times either 5pm, 5:15pm or 5:30pm. I’m hopeful games will get in, but anytime after 4pm there is a chance for thunderstorms. If you’re heading out Friday, please make sure you have a way of receiving weather alerts on your phone and stay updated with the latest weather information, and know where to shelter should strong storms threaten your location.