The return of heavy rainfall is likely for some beginning Wednesday night, and then again Friday as a strong fall storm system moves across the country. No rain showers are expected Tuesday night, just another chilly night, as temperatures once again dip into the low 30s. Sunshine will start the day Wednesday but by the afternoon cloud cover will be on the increase.
Moisture in the atmosphere remains low until early afternoon, limiting the initial threat for rainfall during that time. By late afternoon, around 3pm/4pm, we should begin to see showers lift in from the south. These will remain focused across our southern counties of Whiteside, Lee, and DeKalb during that time, but gradually lift north into the overnight. With a little elevated instability there may be some rumbles of thunder Wednesday night. The increase in moisture will also lead to periods of heavy rainfall, especially in areas where west to east bands of rain set up. These showers will last through Thursday morning. Localized flooding may occur in some low-lying and poor drainage areas during that time.
We will likely see a break from the precipitation during the afternoon Thursday as a brief ridge of high pressure moves in. Rain and thunderstorm chances increase Thursday night and Friday as both low pressure and a warm front lift closer to the Stateline. This should help temperatures warm into the low 60s Friday, but also increase the risk for heavy rainfall during the afternoon and evening.
The placement of low and warm front will also be key in whether or not we see a low-end risk for strong/severe storms Friday afternoon. Right now, both look to remain to our south, but a shift to the north could place some of the area under the risk for a strong storm or two into Friday afternoon.
Localized flooding will also be possible Friday with rainfall totals coming close to a couple inches through Friday night. Scattered wind-driven showers will continue into Saturday before slowly coming to an end Sunday. Highs through the weekend will remain in the low to mid 50s.