HUNTSVILLE, Ala. — The ingredients were there and the stage was set for what could have potentially been a significant severe weather outbreak across North Alabama and Southern Middle Tennessee.
When the day was done and the all-clear was given, there were just three tornado warnings in the Tennessee Valley with two confirmed EF1 tornadoes in Cullman County. One of the tornadoes actually did not have a warning associated with it. It began at 9:36 PM and had a maximum path width of 50 yards. Its path length was right around 4.94 miles. It did mostly minor structural damage.
Without discounting the confirmed tornadoes in Cullman County, it is a safe assumption to say that the St. Patrick's Day Severe Weather didn't exactly come to fruition.
Why didn't that happen? Why didn't we see the same event that was seen in central and south Alabama? There are a couple of things at play.
First, there was a strong capping inversion in place that was essentially non-existent in Central and South Alabama. A capping inversion is a "lid" that acts as a cap on our atmosphere. This cap prevents air at the surface from rising through the atmosphere. With that inability for air to rise through the atmosphere, we lack the ability to get strong thunderstorm development.
We may have been able to break the cap if we would have had a more unstable air mass at the surface.
Remember this warm front? We talked about this warm front for several days. It was a key player in our threat for severe weather across the Tennessee Valley. When this warm front lifted north of the Tennessee Valley it would usher in an insanely unstable air mass that would have been favorable for the development of some significantly severe thunderstorms.
That warm front "drug its feet" and never lifted north of the Tennessee Valley. With that lack of movement, our air was never able to destabilize. The stable air was never able to break the cap mentioned above.
These two factors basically killed our chance for widespread severe weather. Not to mention all the rain. At the end of the day, that is a good thing. The damage was limited and no lives were lost.
The storms did come through the Tennessee Valley, but instead of bringing significant severe weather, they brought incredibly heavy rain which has lead to flooding across many locations in the Tennessee Valley.
It is important to remember that March is just the beginning of the severe weather season in the Tennessee Valley. The season peaks in April and runs through about the middle part of May. Consider this an opportunity to practice your severe weather plan, and now you can adjust for next time.