UPDATE: A SEVERE THUNDERSTORM WATCH has just been issued for Lee and Whiteside counties until 1am Friday morning. Storm coverage is expected to increase after 8pm/9pm with strong gusty winds possible through the overnight.
Thunderstorms are increasing in coverage in Iowa this evening and will continue to spread east and northeast into Illinois later tonight. Parts of Iowa and Illinois may need a severe storm watch as storms grow over the next hour or two. Instability has gone up in northern Illinois as breaks in the cloud cover development, warming temperatures into the low 70s. A stationary boundary draped across northern Illinois and southern Iowa will be the focal point for storm development later this evening.
Expect storm coverage to increase over the next couple of hours, with the heaviest rain/storm activity coming after 9pm. Rainfall totals over two inches will be possible in some spots, especially where repeated rounds of rain occur. Strong to severe storms will be possible, but may be focused a little more over central Illinois this evening. Parts of southeast Iowa and west-central Illinois are currently being monitored for a severe weather watch later this evening.