From NWS:
...FLOOD WATCH IN EFFECT FROM LATE MONDAY NIGHT THROUGH TUESDAY
EVENING...
* WHAT...Flash flooding caused by excessive rainfall is possible.
* WHERE...Portions of southern Illinois, western Kentucky and
southeast Missouri.
* WHEN...From late Monday night through Tuesday evening.
* IMPACTS...Excessive runoff may result in flooding of rivers,
creeks, streams, and other low-lying and flood-prone locations.
* ADDITIONAL DETAILS...
- Heavy rain is forecast to fall on already saturated ground
across southeast Missouri, far southern Illinois and western
Kentucky. Rainfall in excess of two inches is expected, with
higher amounts possible in thunderstorms.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
You should monitor later forecasts and be prepared to take action
should Flash Flood Warnings be issued.