Heavy rain this weekend, flood watches in effect for Northern Illinois

 [10PM UPDATE] Things are still on track for some spots to see 1-3" totals tonight and early Saturday morning. As of 10PM, the heaviest rain is beginning to develop in far Northern Iowa and Southern Minnesota. That will be slow to progress Southward, likely not reaching the Stateline until after 2AM. If things keep up this track, the highest totals may end up *just* North of the Stateline, with best confidence on 2-3" totals in Southern Wisconsin. For everyone, the heaviest rain still looks likely between 3-10AM with most areas picking up at least an inch or two by midday Saturday. Additional rainfall could add onto those totals through Saturday afternoon and again overnight.

Multiple rounds of heavy rain will be possible this weekend, with main waves arriving Friday night and Saturday night. At the heaviest, rainfall rates may push 1-2" per hour, resulting in quickly piling up rainfall totals. The first wave of heavy rain is centered between 3-10AM Saturday morning. The afternoon will feature a few scattered showers and storms, before another round of heavy widespread rain will be possible Saturday evening and overnight.

The first axis of showers and embedded storms will arrive after 2-3AM, pushing across the Stateline from North to South. The rain itself will be slow-moving, with intense rainfall rates lingering over some spots for a couple hours at a time. If any embedded storms track over the same spots over and over, rainfall will add up rather quickly. The severe threat with these storms does not appear to be very high.

The heaviest of the rain will wind down after 10AM-12PM, but a few scattered showers and embedded storms may be possible through the daytime. Any storms that develop will add to rainfall totals, but this would be rather sparse in nature.

Another round of heavy rain may be possible Saturday night into Sunday, but the placement of this round is far less certain. If this round of heavy rain tracks over the Stateline region again, flash flooding will again be a concern with another 1-2" possible over already saturated soils.

All told between both rounds, up to 2-5" of rain may come down between Southern Wisconsin and around I-88/I-80 regions through Sunday evening. The highest confidence on flash flooding will be with heavier rainfall Friday night, but Saturday evening's round may also produce some flooding concerns if it follows the same path as the storms from the night before.

A flood watch is in effect area-wide from Friday night through Saturday. Heavy rainfall could cause flooding in low-lying areas, and rivers could rise to flood stage over the coming days with the heavy rain on the way. Remember to turn around, don't drown when you come across flooded roadways.