The leading edge of cooler and drier high pressure nosed into the Chicago area from the north Monday. As the front sank south of Interstate-80 during the afternoon, showers and thunderstorms formed along and south of the frontal boundary. With the northern portions of our area entrenched in the increasingly cooler east to northeast flow behind the cold front, and southernmost sections still experiencing warm humid conditions, there ended up being a wide range in high temperatures from the upper 60s and lower 70s far north along the Lake Michigan shoreline to the upper 80s and lower 90s far south.
For the 4th of July holiday Tuesday, easterly winds will keep readings cool along and just inland of the lakefront, while temperatures will be able to warm into the 70s and lower 80s well inland. The evening fireworks look to be rain-free in most areas with the possible exception of far southern locations well to the south of Interstate-80 where a stray shower or thunderstorm could form along and north of the stationary front anchored across southern Illinois.