Wednesday, May 2nd:

A couple of different scenarios may unfold across mainly the northern and central sections of the state on Wednesday. This would be this areas first chance at severe weather in 2018 so we want to make sure you all have brushed off those weather radios, know where to get information, as well as making sure you are in a safe place should a severe storm approach your region. Overall the threat for Wednesday is “Conditional” meaning a couple of widely scattered severe storms will be possible with mainly a hail and wind threat. Tornado threat is not high, but the atmosphere at least conditionally supports a small tornado threat across mainly northwestern Illinois.  Showers and thunderstorms may form overnight tonight and move across northern Illinois by late morning. These storms are not expected to be severe and *may* have an impact on the atmosphere later on in the day. Overall the threat is contingent on how much “good” moisture advects into the region as well as when the best forcing arrives.



The most likely scenario is that scattered severe storms will develop across Iowa and sweep into northwest Illinois later in the evening or overnight with an associated risk for large hail and damaging winds. An isolated tornado is possible mainly west of the state. Another very conditional scenario is for a couple of thunderstorms to form across north-central Illinois tomorrow afternoon. The environment here would be more supportive of supercells and/or a small tornado threat. However, dew points being way overdone on the models would lead to instability values being overdone as well which would mitigate an otherwise good looking environment. Another caveat is the lack of focus for storm development. If morning convection does form overnight and drops a boundary south across central Illinois, it would be worth monitoring tomorrow to see if any cumulus begin to mature on it. Overall it could be a wet morning across portions of the area tomorrow with a potentially storm evening and overnight.

Counties with highest threat: Jo Daviess, Stephenson, Carroll, Whiteside, Rock Island and points north and west.


Stay tuned.

Northwest Illinois: 


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