Weather Alert Day: Severe storms possible by Wednesday afternoon

The ABC 17 Stormtrack Weather Team has issued a Weather Alert Day for the potential of severe thunderstorms on Wednesday afternoon into the evening.

A low-pressure system will track across the Upper Midwest or the Great Lakes between Tuesday and Wednesday, allowing winds to shift to the south across Mid-Missouri. Late Tuesday night, a complex of storms near the warm front could develop and track across northeast Missouri into central Illinois, bringing the potential of severe weather. This will likely miss Mid-Missouri.

Wednesday afternoon will be hot and humid ahead of the evening cold front, allowing the atmosphere to become increasingly unstable and provide energy for storms to sustain severe limits as they develop.

We'll also have strong low-level winds increasing moisture across the region starting late Tuesday night. Wind shear will be sufficient at the low and mid-levels for storms to quickly become severe.

Storms are expected to fire along a trailing cold front between 3 and 5 p.m. These initial storms could be discrete supercells capable of producing large hail and tornadoes.

From here, we'll have to watch to see if storms congeal into a line, or remain somewhat supercellular. It's possible that some, if not all, congeal into a line along the front, but there is some uncertainty regarding this. Whether a line or individual cells, storms will generally move north to south, exiting and weakening after midnight.

All hazards will be possible with these storms, but the main concern going into the evening will be damaging winds and heavy rain. Moisture levels in the atmosphere will be high, meaning storms could have high rainfall rates, leaving another 1-2"+ through Thursday morning. Almost all of Mid-Missouri is in a level 3/5 severe risk from the Storm Prediction Center on Wednesday.

There remains uncertainty in timing and severity from morning to evening. While it looks likely that morning rain will miss the region, and allow for abundant storm energy for the cold front to use in the late afternoon and evening, one of the main questions remaining is exactly what mode these storms take on. There appears to be some potential for both line segments and/or individual cells. Differences in storm mode will mean differences in what severe threats we can expect. The main threat appears to be damaging wind, as we expect this with both individual supercells and line segments.

Individual supercells would favor a higher threat for tornadoes and larger hail. In either scenario, wind will likely be the most common impact, but this keeps the potential for strong tornadoes (up to EF-2) on the table for now. Stay tuned for details on how this forecast evolves.