What we expect:
If you don’t want to read everything about this round of storms and just want to know what to expect, this part is for you.
Storms could be strong at times Wednesday night, but widespread severe weather looks unlikely for now. Our main concern with these storms is heavy rain producing some flooding, gusty winds of around 40-50 mph, and frequent lightning and thunder.
High pressure that’s been in place for the past several days slides east Wednesday evening as a line of storms ahead of an advancing cold front moves into Alabama.
This line of storms will be moving into an environment Wednesday night that isn’t overly supportive of severe storms, but an environment that could support some strong storms and perhaps a few storms that could cause some severe weather. Winds about 3/4 mile above our heads will be blowing at about 40-60 mph as storms move through.
It’s certainly possible that some of these storms could push some of that wind energy down to the ground, causing some wind issues overnight. The biggest limiting factor for storms will be the amount of energy they can tap in to. CAPE will be quite meager as storms move through despite decent warm air advection at the surface keeping temperatures in the mid 60s.
The reason for the relatively low amount of energy storms can tap in to is because the lapse rates (temperatures decreasing with height) are pretty low.
Basically, temperatures aloft aren’t cold enough. If the upper level low were closer to us, we’d probably have colder air aloft and a more substantial severe weather threat. We don’t have that, so most of these storms probably won’t have “the juice” to become severe. As it stands now, the Storm Prediction Center has a Marginal Risk (their lowest risk of severe weather) in place for Wednesday night into Thursday morning across North Alabama.
Of course, it’s April, and you should keep an eye on any storms coming through in the middle of the spring severe weather season. Small scale features in the atmosphere that we aren’t very good at forecasting sometimes make events like this more impactful than we forecast. It’s always a good idea to be prepared.