Weather Alert Day: Greatest severe thunderstorm threat on Monday after a few storm chances over the weekend

Monday is an ABC17 Stormtrack Weather Alert Day, as severe storms look increasingly possible with a more favorable pattern taking shape early next week.

SETUP

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

These are embedded in the upper-level jet stream, which is strongest to our north. If there's one limiting factor for severe storms this weekend, it's that a northern jet stream may keep our overall wind shear and support relatively low with each event until 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 from Friday through Tuesday.

This lower-level flow from the south will supply moisture and instability. This flow includes our low-level jet, which aids in storm development and supports Friday night into Saturday morning.

This field of winds from the south will intensify each evening, serving as a focus for storms each evening near the warm front. Given mid-Missouri's position in relation to the front and greater support aloft, any chance for severe weather appears low through the weekend.

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.

Instability will build overhead on Monday, alongside increasing wind shear through the atmosphere ahead of an approaching cold front on Monday evening. Exact timing and details remain to be worked out, but signals indicate a greater threat of severe storms in this window than what we expect through the weekend.

TIMING

We're mostly dry on Friday, before the same mechanisms drive another chance for storms Friday night. Dewpoints and temperatures will increase on Friday, driving higher instability across the region. With just enough shear to organize severe storms in the northwest, storms may support severe hail and damaging winds in the evening. Then, rain chances look to linger well into Saturday morning, mostly as showers and weak storms.

Similarly, on Saturday, another intensification of our low-level jet will drive more thunderstorms, with the greatest combination of ingredients for strong storms north of I-70 in the evening.

The warm front and low-level jet are forecast to lift north on Sunday, which should take the focus for storms north of our region, leaving us warmer and drier.

Monday may start with chances for showers and storms after remnant Sunday night activity drifts in from the west. If this happens, it could end up being a limiting factor in an evening severe threat, but the focus for Monday's severe chances revolves around the approaching cold front and upper-level wind shear, which are both expected late in the day. It's largely uncertain exactly how Monday unfolds, but given the ingredients expected, Monday could be the greatest threat for severe storms out of this active pattern. Stay tuned to the forecast for updates over the weekend.

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

Hail and damaging winds are the primary impacts expected from storms over the weekend. The best chance for strong storms in our region will be on Monday and Tuesday, as the upper trough moves closer. At an early glance, we are monitoring for damaging winds, large hail, and tornadoes.