"Rainfall amounts in northeastern Illinois already have established this as the wettest August and wettest summer since regional records began in 1895. As of the morning of August 24, rainfall for northeastern Illinois (including those counties from Boone to LaSalle and eastward) averaged 11.32 inches, 8.10 inches above normal, and beating the 1987 record of 11.02 inches. Totals for JuneAugust thus far in this area averaged 20.02 inches, 8.91 inches above normal, and beating the 1972 record of 19.26 inches," says State Climatologist Jim Angel of the Illinois State Water Survey (http://www.sws.uiuc.edu), a division of the Illinois Department of Natural Resources.
"Many individual stations also have set all-time August records, noteworthy because climate records for these locations go back more than 50 years. The list includes Freeport (11.88 inches), Rockford (13.82 inches), Antioch (11.31 inches), Elgin (15.05 inches), Joliet (10.18 inches), Morris (11.42 inches), Peotone (14.00 inches), and Peru (8.89 inches). Several other stations with much shorter records also reported impressive rainfall totals, including Genoa (15.66 inches), Chicago Botanic Garden (12.44 inches), McHenry (12.52 inches), Streamwood (11.51 inches), and Yorkville (10.81 inches)," says Angel.
"Parts of southern and west-central Illinois, however, have struggled with a lack of rainfall in August and are classified as either abnormally dry or in moderate drought according to the U.S. Drought Monitor. For example, Waterloo (east of St. Louis) reported only 0.15 inches for August so far, 100 times less than rainfall that fell in Elgin this month," says Angel.
The National Weather Service forecast includes more chances of rain on Friday before a cold front finally passes through the state by Saturday. "Additional rains today and next week will push many of these extraordinary rainfall totals upward by the end of the month," concludes Angel.
Disclaimer: Data used for all statistics provided herein are from the Midwestern Regional Climate Center and are based on preliminary data.