Sunshine, as Friday gets underway, will contribute to daytime heating expected to de-stabilize the atmosphere, allowing a re-eruption of possibly gusty showers and thunderstorms in the afternoon.
The best indications we have at the moment suggest storm formation is to take place beyond the Blackhawks outdoor rally, occurring Friday afternoon and evening instead.
Chicago headed for cool June close and July open; 4 days of north/northeast winds get underway Saturday
The warm spell, which has been in place more than a week here, has yielded eight consecutive 80-degree or higher daytime highs. A ninth is likely Friday.
But North America’s weather pattern is undergoing impressive changes which involve the westward drift of a blisteringly hot air mass which is predicted to produce near record temps across the Southwest. That pattern realignment will prove a game-changer for Chicago.
The jet stream which runs around the hot air mass’ periphery is to buckle farther north then dive into the United States from Canada. It’s a set-up expected to allow cooler Canadian air to sink southward into the Lower 48. As that happens, late May-level temperatures are replace recent 80s in each of the next 4 days beginning Saturday. The cool-down is to coincide with the closing days of June and July 2013’s open on Monday.