(11/29/18 - 6:00PM) Another major storm system will be affecting the state this weekend, as it pushes through the region. This system will bring the chance for heavy rain, flooding, severe weather and snow to different portions of the state from Friday afternoon into Monday morning.
Things will start off Friday afternoon into Saturday evening, with heavy rain and flooding potential across a good portion of the state. Widespread rainfall amounts of 0.50-1.50" are likely across much of the state, with higher totals possible across portions of Southern Illinois. Minor flooding potential is likely across portions of Central and Southern Illinois, where conditions have been somewhat abnormally wet over the past several weeks. Additionally, minor to moderate flood potential is likely across portions of Northern and Western Illinois. Across this area, the combination of snow melt due to mild temperatures, frozen ground due to recently cold temps, and the expected heavy rainfall, will lead to an increased risk for flooding. Sewers/drains covered with ice and snow may lead to abnormal and increased flood potential on roads.
A thunderstorm and severe weather threat will likely exist across portions of the state on Saturday and Saturday night. In the wake of early heavy heavy rains, some clearing may occur, in addition to some destabilization. By mid-afternoon moderate instability and moisture will be in place for this time of year. With favorable upper level conditions and an approaching cold front, a broken line of thunderstorms will likely develop across far Eastern Missouri on into Southwest Illinois. This activity will push northeast, across a good portion of Central and Southern Illinois Saturday evening and early night. Given the environment in place, an isolated severe threat is likely. Further updates regarding the severe potential may be needed.
This storm system will end with rain showers turning to snow showers across portions of Northern and Central Illinois Sunday afternoon, continuing into Monday morning. Only minor accumulations of snow are likely, less than 1".