Another potential severe weather event and how it compares to Thursday's severe weather

As things have started to settle down from Thursday night's severe weather episode and most folks power is now restored, I thought it necessary to at least start talking about the next potential severe weather event to impact the Mid-South.

We experienced a very cool and cloudy day today with high temperatures about 30 degrees colder than Thursday, when the Mid-South was in a warm sector ahead of the line of storms that blasted through Thursday evening. Temperatures will drop only a little overnight, reaching the mid 30s as clouds hang tight. By Saturday afternoon, a warm front will again move through, scouring out the clouds and sending temperatures back into the lower 60s. Sunday is "setup" day once again as the Mid-South remains firmly entrenched in the warm sector ahead of yet another strong weather system. We could see scattered showers and perhaps a few thunderstorms during the day as high temperatures will be similar to Thursday - in the lower to mid 70s - with fairly muggy and breezy conditions.

The potential severe weather event will occur late Sunday night or early Monday morning. A couple of differences from the Thursday evening system:

1) The low pressure center that is forcing a strong cold front through the region will be much further north this time - moving from Kansas into the southern Great Lakes rather than across northern Arkansas into the Ohio Valley.
2) The timing of the storms will be early morning versus early evening, which could play a key role in available instability, as it will be during the "coolest" part of the day versus the warmest, and thus potentially limiting one of the factors necessary.

On the other hand, even given the typically less-favorable low pressure track well to our north, jet stream dynamics at all levels will be favorable for the development of high winds and isolated tornadoes, very similar to the Thursday night event. While any tornado activity would again be more likely in supercells ahead of a squall line, these storms would have to form during the overnight hours Sunday night rather than during peak heating. While this is certainly not uncommon, it seems less likely at this time of year and given the recent history of a lack of pre-squall line supercells on Thursday afternoon.

My expectation is that we will see scattered showers and isolated non-severe thunderstorms on Sunday, followed by a somewhat "quiet" period much of Sunday night, then a fast-moving squall line containing high wind and an isolated tornado threat sometime around dawn on Monday morning (a very similar scenario to Thursday evening).  It should be noted that one of the short-range models (the NAM) is beginning to push the timing of the line into the mid-morning hours Monday. Given the potential for a fast-moving squall line and the models typically underplaying forward propagation in this type of system, I believe it could be quicker than that. Stay tuned and begin reviewing those severe weather safety tips once again!

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