Monday, March 12, 2012

I-80 Supercell Threat

Somewhat of a surprise event today (surprise, because I haven't been paying attention) in NE Illinois. I just came back down to Champaign yesterday evening, so I'm actually in decent position for this. Current target right now is around the Kankakee area, so I'm perhaps just a jaunt up Interstate 57 away from some fun later this evening.

A compact upper level wave is currently swinging through the region, and has already sparked off a line of elevated thunderstorms in NW Illinois. Surface reflection of this upper level wave is pretty weak, and that is my main concern at the moment.

It feels like a chase day when stepping outside here in Champaign, with temperatures already warming into the lower to middle 60s, and dew points approaching the upper 50s. Low level moisture can be seen screaming northward in the rapidly moving low level clouds racing from south to north overhead. This should continue through the afternoon as the atmosphere slowly begins to prime. 0-3 km cape values of 50-100 k/jg are already in place north of Interstate 74 in northern Illinois, and this should continue to increase toward evening.

It looks like as we may see an increase in surface convergence as evening approaches, and this may be enough to squeeze out an isolated strong storm or two near Interstate 80 in northeast Illinois. Upper level support will be there to support organized severe storms.

These best risk for more widespread storms this evening seems to be in Michigan, but that obviously is not something I'm considering doing. With increasing surface convergence toward sunset, and the potential for a lingering boundary or two, I am hoping for the development of one or two strong to severe storms on the tail end, near Interstate 80. That being said, I'm not sure if this isn't more of a wish-cast than a forecast. Trying to avoid that mindset. There are a lot of things going against me seeing a storm south of Interstate 80 today.

It'll be play it by ear time, so go ahead and just follow the old twitter for my back and forth, hot and cold updates. For now we'll call my target a Dwight to Kankakee line, an hour or two before sunset.!/PStormImagery

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