More rain's coming, but don't panic yet
Meteorologists said thunderstorms packing the potential to dump heavy rain is most likely headed to Illinois overnight Wednesday into Thursday.
However, they said, the heaviest rain should fall on the Iowa-side of Illinois and, at this time, should not add more problems to the recently receding Des Plaines River.
Mike Bardou, a meteorologist from the National Weather Service, said pinpointing the actual location of the forecast heaviest rainfall is sometimes difficult, specifically when that rainfall is more than 24 hours away.
However, he said, if the models used by meteorologists to forecast the weather hold true, then only an inch of rain will fall over the Des Plaines River, and that precipitation is expected to be spread out over an 18-hour period from Wednesday to Thursday.
Those totals will not be enough to make the river rise and overflow again, he said.
“But, again, it's only a prediction at this point,” he said. “Depending on where this storm sets up, it could change where and how much rain will fall, and in turn, could affect the height of the river.”
In the interim, the Des Plaines River dropped below flood stage early Tuesday morning, and is expected to keep receding until overnight Wednesday, before the latest storms hit.
Bill Morris, a hydraulist for the National Weather Service, said an additional inch of rain over a long period of time will not cause a problem on the Des Plaines.
“Getting an inch or two in an hour could be a problem, but over the course of 18 hours, there shouldn't be any problems at all,” he said.
He said the latest flooding on the Des Plaines was because about 5 inches of rain fell over the Des Plaines watershed in about two hours, causing the river to rise faster than water was flowing downstream.
“But, that won't happen if the forecast models remain the same,” he said. “A lot of this hinges on how this latest storm shapes up in the next 24 hours.”