A warm and sunny Tuesday, much like Monday, will give residents a chance to dry out from the weekend’s storms. The break will be short lived, with the potential for thunderstorms and very heavy rainfall Wednesday night into Thursday.
High pressure that has dropped in from Canada will continue to push to the east of the area. Light easterly winds will allow dry air to filter in off Lake Michigan and keep dewpoints in the lower to middle 60’s, giving the air a comfortable feel. Temperatures will warm into the upper 80’s once again. Although still very warm, this is the most comfortable the air will feel all week.
The heat wave that moved east will shift back west across the center of the country in a pattern known as retrograding. This will develop an ominous situation in which a warm frontal boundary pushes back north into the area. Northern Illinois will sit on the northern edge of a heat dome and the southern edge of an upper level jet stream.
This will fire thunderstorms across parts of the area Wednesday night through Thursday as the ring of fire pattern sets up once again. Temperatures will move back into the lower 90’s, with dewpoints climbing to the middle 70’s. Temperatures may remain lower Thursday if there are thunderstorms to cool the air, or else a heat advisory may be needed.
Levels of moisture typically only found in tropical storms or hurricanes will pile along the warm front in the area. This could make the storms incredible rainfall producers, like the ones that struck last weekend. This situation will be closely watched, and the National Weather Service may need to issue a flash flood watch considering how wet the grounds already are.