As mentioned earlier, a Flash Flood Watch will go into effect at 9pm for Winnebago, Boone, McHenry, Ogle, Lee, DeKalb and Whiteside counties. It's appears as if the flooding potential may be a bit further south than where it was located late Tuesday night. Which will be good news for those who are suffering from the significant flooding.
As the front begins to shift south it will turn more parallel with the winds that are moving above in the atmosphere. This type of set up is ideal for 'training' thunderstorms and typically is the cause of heavy rain events. Like Tuesday night, it won't be a widespread event but for locations that do receive thunderstorms, rainfall rates of nearly one inch per hour are possible. Right now, that highest risk looks to be over west-central Illinois and for some of our southern counties - Whiteside, Lee, Ogle and DeKalb.
Thunderstorm coverage should begin to increase towards 9pm/10pm over western/northwestern Illinois. It's important to remember that not everyone will experience heavy rain producing thunderstorms. But those that do could see high rainfall rates. So be prepared.