Warm, humid week ahead with storms likely

Yesterday, Midway hit 90° for the fifth time this month, and it looks like three more 90° days will be added to that total by midweek. Humidity will also slowly be on the rise. Showers and thunderstorms appear in the forecast each day starting Wednesday through next weekend. While the core of the jet stream still resides far to the north across southern and central Canada, light westerly winds aloft at this latitude allow low-level southerly flow to feed warm, moist air into northern Illinois. A cool front will sag south through Wisconsin, drifting through Chicago on the heels of a thunderstorm-producing low pressure center Friday. From that point on, the front will become quasi-stationary, with the potential to fluctuate north or south of the metro area. Current computer model projections have the front situated just south of Interstate 80 next weekend, but a slight repositioning to the north could radically change temperature and rainfall forecasts.