A large storm system that moved from the Central Great Plains to the Upper Midwest and Upper Great Lakes during Monday and Monday Night produced precipitation across the region. This included significant amounts of rain across Northern Illinois and Northwest Indiana with much of this area receiving between 1/2 to 3/4 of an inch of rain.
Precipitation - Multi Sensor
The multi-sensor precipitation maps are based on National Weather Service (NWS) NEXRAD radar data and hourly gage data processed by 12 NWS River Forecast Centers. The data are combined into a 4-km resolution national grid and archived by the NWS. The 24-hour, 7-day and 30-day precipitation fields are valid for the morning (1200 GMT) of the indicated date. The fields are updated at 8:00 a.m. (yesterday’s data) and 2:30 p.m. (today’s data). For more information on this precipitation analysis, visit the NWS Advanced Hydrologic Prediction Service web site....http://water.weather.gov/precip/about.php