Heavy downpours shift south…for now. Flash flood watch remains in effect.
Radar imagery indicates that heavier showers and thunderstorms have shifted south, extending from near Streator, in southern LaSalle county, northeastward to Gary, and NW Indiana. The southward shift of heavier rainfall is due to southbound outflow from rain-cooled air to the north, and the passage of a weak disturbance aloft, which was moving into SW Michigan at 2 PM. Lighter, fairly steady rain can be expected across most of the Chicago area the rest of the afternoon.
Temperatures in the orange-shaded area on the map below are in the mid and upper 80s, with dew points in the mid and upper 60s. Thjs very warm, humid air south of the metro area is forecast to lift northward as low pressure to our west deepens and moves across Wisconsin tonight. This is likely to spawn more thunderstorms across northern Illinois later this evening, bringing a threat of additional heavy rain.