* WHAT...Areas of flooding caused by excessive rainfall. * WHERE...Along and north of the I-74 corridor, including the following counties, in central Illinois, Marshall, McLean, Peoria, Stark, Tazewell and Woodford. In east central Illinois, Champaign and Vermilion. In west central Illinois, Knox. * WHEN...Through Friday morning. * IMPACTS...Excessive runoff may result in flooding of rivers, creeks, and streams. Flooding may occur in poor drainage and urban areas. * ADDITIONAL DETAILS... - Rainfall of 2 to 3 inches has occurred over a large area since Wednesday morning. As thunderstorms develop in northern Illinois and sink southward overnight, another 1 to 2 inches of rain is possible, with local amounts of 3 to 4 inches. With the ground already saturated, heavy rain will run off quicker, causing areas of flooding.