National Weather Service United States Department of Commerce

Mississippi Valley Summer Heat Wave; Severe Thunderstorms and Flooding Possible to the North

A dangerous summer heat wave will continue much of the Plains, Mid/Lower Mississippi Valley, Southeast U.S. today and Thursday. Areas of severe thunderstorms may occur today and again on Thursday from parts of the northern/central Rockies and High Plains into the Ohio Valley and Carolinas. Excessive rainfall over similar areas may bring flash flooding today and Thursday. Read More >


Fast Facts:

  • Flash flooding, some significant, was observed across numerous locations in the Chicago Metropolitan Area on Sunday night May 17, especially downtown near the Chicago River.  The Chicago River rose high enough that the Metropolitan Water Reclamation District, which manages the river, was able to reverse the flow to Lake Michigan.
  • The 3.11" ranks as the 5th wettest May calendar day ever in Chicago.
  • While flooding was the significant hazard, two reported brief/weak tornadoes also occurred in NWS Chicago’s Warning Area, one along the LaSalle / Kendall Co. border, second near Grundy / Will Co. border. There was no significant damage.
  • Two of the five wettest days ever recorded during any May in Chicago have happened in the past week!  Last Thursday's 3.53" of rain broke the record for the wettest calendar day ever in May in Chicago.
Widespread flash flooding across the Chicago metro area Sunday, May 17, 2020.
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Additional recaps can be found on the NWS Chicago Past Events Page
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