The National Weather Service says the Southeastern part of South Central Illinois is in the marginal area for severe thunderstorm activity on Sunday night and early Monday morning. South of Mt. Vernon the chance of severe weather is labeled as slight. A portion of southeast Missouri has an enhanced chance of severe weather. Some of the thunderstorm activity could produce heavy rainfall.
Temperatures will drop to 38 by Monday morning and will remain in the 30s throughout the day on Monday before falling to 28 Monday night. It will be partly sunny and 46 on Tuesday.