Records set and rain still has 8 hours or so to go – Winter Weather later tonight/Flood Warnings to continue
Chicago’s 66-degree high temperatures fell just 4-degrees shy of the record for this date – 70-degrees set just last year, but the moisture this unseasonably warm air held provided the basis for record high rainfall totals. Rain started earlier at Midway and record rainfall was recorded at that site two days…Monday the 0.83-inch broke the old record 0.78-inch for February 19 set back in 1944 and as of this afternoon another 2.05-inches had been measured, easily exceeding the previous February 20th high of 1.35-inches set in 1997.
The record rainfall for February 20th was also set at O’Hare (Chicago’s official site) where 1.80-inch had been recorded by late afternoon and still raining, supplanting the old record 1.16-inches in 2014. At Rockford the 1.19-inches by late afternoon, exceeded the old record of 0.96-inch set back in 1911.
There is still more rain to come, especially south of Chicago, where another 2 to 3-inches could fall before the rain changes over to sleet/freezing rain and ends early Wednesday (see map below projecting expected overnight rainfall produced by the Chicago National Weather Service). Before this storm is over, some locations could end up with rainfall totals three times or more the normal for the entire month of February (1.79-inches is the February normal for O’Hare).
The area-wide Flood Watch continues tonight as does the Urban and Small Stream Flood Warning, and the many Moderate and Major River Flood Warnings will continue into the latter part of the work week. As cold air follows the departing cold front, rain will continue, and with temperatures dropping below freezing, sleet and freezing rain will likely develop, causing slick spots in many areas later tonight before precipitation ends.