In the tropics, Don quickly weakened the last 24 hours as the system hit the wall of shear across the Caribbean. The map below shows the wall of shear which ripped Don apart. This has been the issue in the tropics that any system that does develop moves west and hits the shear and quickly gets ripped apart. Also, the Atlantic High is very strong right now which is also suppressing the system fairly far south. So overall, until we see changes in the tropics, I would not expect any development unless something develops close to the U.S. coast.
We have issues in the for of nasty storms for the Upper Midwest today through tonight. A complex of storms over North Dakota this morning will move southeast and couple with the low level jet that will act as a spray nozzle of heat and humidity. Storms will enhance across Minnesota late this afternoon and we should see a Mesoscale Convective System (MCS) forming by late evening. That MCS will head southeast across Wisconsin producing wind damage and heavy rains. Typically these system will turn into the heat source so we may see the system move into northern Illinois and Indiana later tonight. Chicago will be close to getting that system tonight.
During the initial outbreak this afternoon, storms across Minnesota will produce hail, damaging winds and perhaps even a tornado. The simulated radars are below from the HRRR model.
Thursday, the severe threat moves to western New York, western Pennsylvania and Ohio as the remains of the MCS and a weak front move into the area. Impacts I expect area damaging winds and flash flooding rains, which seems to be the pattern the past couple of weeks as these fronts move into the muggy airmass.