Risk of severe storms/flood-producing downpours continues Thursday through Friday and Saturday
The National Storm Prediction Center has the Chicago area in a Marginal Risk of severe thunderstorms Thursday/Thursday night and a higher Slight Risk Friday and Saturday (see highlighted Thursday/Thursday night severe weather outlook map and the Friday/Saturday maps below.
A cluster of showers and thunderstorms will move east across our area this Thursday morning with the primary threat locally heavy rains that could exasperate current flooding on the Des Plaines and Fox Rivers. Isolated storms could develop again later this afternoon into the overnight hours.
For the remainder of the week Chicago will be under the influence of a very warm humid atmospherically-unstable air mass. Complicating matters will be a west-east-oriented frontal boundary that will vacillate north-south over northern Illinois and northwest Indiana and a 110 mile-per-hour jet stream aloft over Wisconsin.
More widespread storm activity is expected later Friday into Saturday as the embedded impulses in the jet stream look to intensify and combined with the frontal boundary will trigger periodic lines/clusters of thunderstorms capable of producing damaging winds, large hail, torrential flood-producing downpours and even a few tornadoes.
Additional/enhanced flooding is s very real concern in the coming days north of Interstate-80 with flooding on the Des Plaines and Fox in progress and flows high on the Kishwaukee, Rock and North Branch of the Chicago Rivers. With temperatures in the 90s and dew points in the 70s, Heat will also be a continuing concern south of Interstate-80 with daily heat Indexes expected to exceed 100-degrees.
Severe Weather outlook map for Friday/Friday night…
Severe Weather Outlook Map for Saturday/Saturday night…