The second round of downpour-generating thunderstorms in less than three
days threatens flooding and another outbreak of severe weather Friday
afternoon. Soils are saturated and the 1 to 2 inches or more of rain
expected to fall in sometimes-thundery deluges over the coming 24 hours
has nowhere to go but to run off. Flash flood guidance suggests sections
of Chicago's southern suburbs require less than an inch of rainfall to
initiate flooding.
A northbound warm front will be overrun by humid Gulf air producing
thunderstorms in waves Friday afternoon. As the front swings north and
introduces warm humid air into the Chicago area overnight, a squall line
may form and sweep the area. The Storm Prediction Center indicates a
slight risk of severe weather at that time.
Chilly weekend ahead
The chilliest weekend in five weeks follows Friday night's heavy rains
and thunderstorms. Highs Saturday will struggle to reach 60 degrees, and
Sunday will likely hold in the upper 50s.
