BIRMINGHAM, Ala. (WBRC) - On Saturday the WBRC FOX6 First Alert Weather Team broke into programming for multiple tornado warnings that were issued for Cullman County. In total, there were five tornado warnings, and some were issued based on tornado sightings from trained storm spotters. There was no tornado watch in place and tornadoes were not expected on Saturday. So I know there are lots of questions: Why did this happen? And, what changed to cause so many storms to produce tornado warnings?
What happened yesterday is very rare for late June. In fact, I’ve only seen that sort of setup two or three times in my twenty years of covering weather in Alabama. I remember a summer afternoon storm producing a brief tornado in Northport, AL in the early 2000′s. Most warm season tornadoes are often associated with tropical systems, and sometimes organized complexes of thunderstorms (called mesoscale convective systems). When it comes to heat activated afternoon thunderstorms, or pulse thunderstorms, we don’t see many tornadoes, due to a lack of wind shear. There is often weak upper level support, so as storms intensify, they soon collapse. We see most tornadoes in the late fall, winter, and spring because of increased wind shear caused by stronger winds aloft. This causes storms to rotate.
However, this event serves as a good reminder that tornadoes can happen in Alabama during any time of the year. Sometimes local scale processes unfold during a very short period of time that can totally change the storm environment. Our thoughts are that the severe event yesterday was likely caused by storm interaction with a thermal boundary. This boundary likely developed as a result of rain from earlier in the day.
Many times in the summer, the rising motions associated with thunderstorms, and the humid environment, causes fractus clouds or scud clouds to develop. These clouds can be quite deceiving and often appear irregular shaped, low to the ground, and underneath the base of storms. We call them tornado look-alikes because they can sometimes resemble a funnel shape. You may hear us refer to these cloud types when we receive storm photos in the summer. However, yesterday we received several videos of rotating wall clouds and funnel clouds, which clearly showed storms of significant concern. Thankfully, there was no loss of life or property.
The good news is the weather should be much calmer for Sunday evening but we will need to monitor radar in the days ahead for the possibility of strong to severe storms. And while the primary threats will include damaging wind gusts, lightning, and hail, always remember the non-zero tornado risk. Always be ready to take action if you hear a First Alert, and have multiple ways to receive severe weather alerts like the WBRC First Alert Weather App. You can download the app for free by searching WBRC in your app store.