Heavy rains caused the National Weather Service to issue a Flash Flood Warning on Sunday evening that expired at 11:15 p.m. for Cole and Moniteau counties, as well as the southern tip of Boone County and southern Callaway County.
However, a Flash Flood Watch issued by the NWS on Sunday evening continued until an expiration of 1 a.m. Monday in a larger section of Mid-Missouri. The Flash Flood Watch, which indicates flash flooding is still possible, was issued for a wider area that included all of Boone, Callaway, Cole, Gasconade, Moniteau and Osage counties.
An area of slow moving thunderstorms developing along a nearly stationary front in a very moist and unstable atmosphere produced heavy rains beginning late Sunday afternoon.
Very heavy rainfall amounts of 2 to 4 inches in an hour or two in parts of this area was the cause for the threat of flash flooding.
The risk was for flooding of low lying or poor drainage areas and ultimately dangerous flash flooding on smaller creeks and streams. Significant rises on larger streams and rivers were possible.