Hotter, Then Cooler From Chicago to Philadelphia

Tuesday morning

The temperature will soar toward 90 degrees in Chicago today and will be the same or higher from D.C. to Philadelphia tomorrow. These temperatures are well below all-time records for today. On this date in 1991, Chicago had a high temperature of 101. Three years ago today, Philadelphia sizzled with 103-degree heat. This video includes the forecast for the balance of the week.

The cold front that will cut off the heat will generate strong gusty thunderstorms as it moves southeastward today. The National Weather Service Storm Prediction Center highlights the most likely area for these severe thunderstorms today and tonight.

"Alarm clock thunderstorms" hit parts of the Pacific coast around San Francisco this morning. This is very rare for that area but was supported by unusually high water temperatures that have been noted near the California coast this summer. When thunderstorms rumble through any place around 4 or 5 in the morning, it can awaken people a long time before their alarm clocks sound off. This picture shows the thunderstorms at 5:20 a.m. PT: