6:20pm: NEW: SEVERE THUNDERSTORM WARNING for southwest Whiteside County until 7pm. The severe warned storm is north of Bettendorf, IA and capable of producing quarter sized hail. This storm was moving to the east at 30 mph.
Rain showers are beginning to move across northwest Illinois and will continue for the remainder of the afternoon and evening.
Dry air initially – dew points in the 30s – prevented the showers from impacting the region earlier today. But dew point temperatures have quickly warmed into the 50s allowing the steady to moderate rain reach the ground. A few thunderstorms have also been noted, mostly to the west and south where better instability resides. Showers should increase in coverage through the evening, especially after sunset, as the low-level jet increases and continues to fuel both warmth and moisture.
Heavy rainfall will be possible as west to east oriented rain bands develop north of I-80. Within these bands, localized flooding may occur within low-lying and poor drainage areas. Rainfall totals of 1-2 inches Wednesday night are possible. Hail may also occur with some of the stronger storms overnight, potentially reaching one inch in diameter. The heavy rain will lift north into Wisconsin by Thursday morning with scattered showers expected into Thursday afternoon.