The National Weather Service placed a broad stretch of the Central Plains and Midwest under severe-weather advisories on Thursday, warning that multiple rounds of thunderstorms will sweep from Nebraska to Illinois and continue into early Friday. The Storm Prediction Center elevated parts of Iowa and eastern Nebraska to an Enhanced Risk, citing the likelihood of damaging straight-line winds that could exceed 75 mph, large hail and a few tornadoes. A flash-flood watch is in effect for central and western Iowa from 7 p.m. Thursday until 7 a.m. Friday, with forecasters calling for one to three inches of rain overnight and isolated totals of five to ten inches. Near and north of Interstate 80, storms are expected to produce rainfall rates above two inches an hour, raising concerns about rapid runoff and river rises. Chicago is under an Accuweather Alert, with the metropolitan area facing a Level 1 severe-weather risk Thursday and a Level 2 risk on Friday; heavy downpours could trigger localized flooding as storms move east across northern Illinois this evening. Additional thunderstorm clusters are forecast across Minnesota, Wisconsin and the Corn Belt through Saturday, and meteorologists urge residents across the region to monitor updated watches and warnings, have multiple ways to receive alerts and be prepared to seek shelter if conditions deteriorate.