TORNADIC WATERSPOUTS VS. NON-TORNADIC WATERSPOUTS… We had a tornado warning for much of central Baldwin County earlier today due to a tornado that threatened to move in from Mobile Bay. Thanks to Wendy Armstrong for this view (original video here). While technically still a “waterspout,” this is actually a tornado over water. There is quite a bit of confusion about the term, “waterspout.” I’d like to share some insight about this…
WATERSPOUTS ARE WEAKER… Non-tornadic waterspouts can happen on both good weather days and bad weather days. They form within the updraft of a maturing cumulus cloud and have winds of 30-60mph. They’re very common around our coastline, especially in the summer months. Usually, these “fair weather waterspouts” are weak and dissipate before ever reaching the shore.
TORNADOES HAPPEN OVER WATER TOO… The tornado warning this morning was triggered because of a large tornadic waterspout that happened to form over Mobile Bay. The key difference in waterspouts versus a tornado over water is the presence of a detectable, parent mesocyclone in the atmosphere. This morning when we showed you the rotation in the velocity product on radar, we actually were seeing the large mesocyclone above what was a tornado that formed over the waters of Mobile Bay. Thankfully, the tornado dissipated before making moving onshore. Unlike fair weather waterspouts, tornadoes (even over water) can have winds of 60-200+ mph. Tornadoes form in much more complex environments.
MESSAGING IS KEY… In order to keep things simple during times of a potential disaster, you’ll hear me say, “tornado over water” whenever we have a tornadic waterspout moving onshore. Using the word “waterspout” seems to convey this sense of a weak, brief spin-up vortex that is not likely to do much damage. Tornadoes (whether on land or over water) are dangerous, period.
MORE RAIN & STORMS OVERNIGHT AND FRIDAY… Rain and thunderstorms will continue to intermittently happen over the next 24 hours across south Alabama and northwest Florida. Widespread severe weather is not expected. If we happen to have any storms that ramp up to strong levels, they’re most likely to happen near the immediate coastline. I’ll have updates for you in the RedZone Weather app.
APP ALERTS… If you have not already, be sure to download the RedZone Weather app and set up your customized app alerts. redzoneweather.com/app is the link for the free download. Once you have the app downloaded to your iOS or Android device, be sure to visit the Alerts tab (lower right corner) and tap on the large, yellow Alert Settings button to customize the alerts you’d like to receive straight from me.
Special thanks to our local National Weather Service office in Mobile, AL for highlighting this issue at the recent Integrated Tropical Workshop meeting. Thanks also to NWS Mobile for some of the specific language used in this post from the specific presentation about this issue.
Have a nice evening!