Limited risk of severe thunderstorms mainly tonight in the Chicago area
Update 12:30PM CDT…
With a band of showers/thunderstorms moving east out of our area early this afternoon, the next risk of strong to severe thunderstorms appears to be this evening into the overnight hours as a warm front lifts north out of central Illinois, moving through our area into southern Wisconsin by Thursday morning. The latest update (see highlighted map) of the severe weather outlook by the National Storm prediction center has the entire Chicago area now in a Marginal Risk of Severe storms from this afternoon through tonight.
Update 8:15AM CDT…
The National Storm Prediction Center has made a minor adjustment to the severe weather risk in our area, shifting the Slight Risk area a little to the west of Chicago with the remainder of the area including the city of Chicago in a Marginal Risk (dark-green-shaded area on the highlighted map depicting a 5% risk of severe storms within 25 miles of a given location). The primary risk in our area will be damaging winds and large hail. The Enhanced Risk of severe storms now includes most of Iowa.
A band of showers/thunderstorms looks like it will move east, moving through northeast Illinois, northwest Indiana and southeast Wisconsin later this morning into the afternoon. A better chance of severe storms here still remains late this afternoon into the overnight hours as warmer, moist and more unstable air associated with the northward-moving warm front approaches from the south and moves through the area into southern Wisconsin.
A “back-door” cold front is forecast to sag south through the Chicago area this morning, then reverse course and move back north as a warm front triggering showers and possible severe thunderstorms later this afternoon and tonight. The National Storm Prediction Center has determined that much of the Chicago area will be under a Slight Risk of Severe thunderstorms during this period (yellow-shaded area on the highlighted map depicting a 15% chance of severe storms within 25 miles of a given location).
While we rest in the cooler northeast flow today, a center of low pressure is expected to intensify over Iowa and move northeast. This in turn will force the cold front that moved through our area this morning to reverse course, approaching our area from the south this afternoon and moving north through our area overnight, bringing a return or milder, moist and more unstable air and triggering a round of potentially severe storms. The greatest risk of severe storms looks to be in eastern Iowa.
Colder air will swing across our area from the northwest Thursday, as the center of low pressure moves to the north and east across Wisconsin.