Flash Flood Watch this afternoon and tonight across Chicago area; severe t-storms possible

Update 12:15PM CDT…

The threat of severe thunderstorms with damaging winds, large hail and flood-producing downpours continues this afternoon and evening. There is still a risk of isolated tornadoes associated with the strongest storms. The Flash Flood Watch for the area along and north of Interstate-80 remains in effect until later tonight.

Because of extensive cloudiness and earlier-morning showers/thunderstorms, the National Storm Prediction Center has reassessed our severe storm risk to Marginal over most of the Chicago area for this afternoon and tonight (see latest severe weather outlook map below). However with a cold front approaching from the west, clusters of severe thunderstorms could still develop along the Mississippi River this afternoon and track east-northeast into the Chicago area later this afternoon/evening.

____________________________________________________________________________________________________________

CHICAGO — A good portion of the Chicago area is under a Flash Flood Watch this afternoon and tonight (dark-green-shaded area on the headlined map). At the same time severe thunderstorms may produce damaging winds, large hail and even a tornado in a few cases, as well as heavy flood-producing downpours.

While the greatest risk is along and north of Interstate-80, severe storms and flooding could also occur in any part of our area south of Interstate-80 into northwest Indiana.

Clusters and bands of strong thunderstorms are expected to move across our area today with the most intense storms this afternoon and evening as warm moist unstable air sweeps into our area ahead of a deepening center of low pressure approaching from the west. Ingredients are in place to support not only severe storms, but also flash-flooding. Heavy rainfall of 1 to 3-inches-plus over saturated soils and already swollen rivers and streams will likely cause localized flooding.

The National Weather Prediction center has northern Illinois in Slight to Marginal outlook for Excessive Rainfall today and tonight (yellow and green-shaded area on the map below), while the National Storm Prediction Center has much of our area in the Slight Risk of severe thunderstorms this afternoon and tonight (yellow-shaded area on the second map below).

Excessive Rainfall outlook map Tuesday/Tuesday night…

Day 1 Excessive Rainfall Forecast

Severe Weather outlook map Tuesday/Tuesday night…