Weather Alert Day: Heavy rain increases flash flood risk Monday, severe storms remain possible overnight into Tuesday morning

Monday is an ABC17 Stormtrack Weather Alert Day, with multiple chances for thunderstorms. There will be a morning round that could linger through mid-late afternoon, with an additional overnight round that hangs into early Tuesday.

SETUP

Relatively flat west-to-east flow aloft has sent small disturbances and short-wave troughs of low pressure near our region this weekend.

A deeper dip in the jet stream drives higher storm chances by bringing a deeper trough and stronger wind support on Monday and Tuesday.

At the surface, and at the lower levels of the atmosphere, an area of low pressure will strengthen to our west, and draw warmth and moisture in from the Gulf through Tuesday.

The warm and muggy pattern remains Monday, ahead of a larger dip in the upper-level flow, which will push the more active pattern and greater support for strong storms into mid-Missouri.

TIMING

Monday began with widespread storms that were generally not severe, except for a storm that produced 67 mph winds at Columbia Regional Airport, and left some damage in Columbia, prompting a Severe Thunderstorm Warning for Callaway County.

These storms are expected to stall across the southern half of mid-Missouri, raising concern for flooding, including isolated flash flooding where heavy rain is the most persistent.

Warmth and storm energy are expected to lift north again through the afternoon and evening, restoring fuel for late-night storms. In fact, as this outflow boundary interacts with more instability lifting north, we may see an intensification of ongoing storms during the afternoon and early evening. The focus for Monday's greatest severe chance centers on the approaching cold front and upper-level wind shear, which are both expected late in the night, potentially overnight. It's still uncertain exactly how Monday unfolds, but given the ingredients expected, Monday night looks to be the greatest threat for severe storms out of this active pattern.

To a lesser extent, there is some potential for storms to redevelop locally on Tuesday, but this will greatly depend on the speed of the front, which may entirely clear the region of a severe threat.

IMPACTS

Storms during the day on Monday will primarily pose a flood risk, but an isolated severe storm remains possible in the south. This is where a training heavy rain threat will likley develop, increasing the flash flood risk. The best chance for strong storms in our region will be late Monday night into Tuesday morning, when hail, wind, and tornadoes will be possible. Severe storms may develop again on Tuesday afternoon before pushing east, but the threat is low.