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Isolated Waterspouts Possible On Lake Michigan

Posted at 5:29 PM, Jul 27, 2013
and last updated 2013-07-27 17:29:14-04

WEST MICHIGAN — We don’t often hear about the chance of waterspouts (tornadoes) over Lake Michigan in the summer, but it will certainly be possible on Sunday!

Typically, we expect (or anticipate) waterspouts when the warm waters of Lake Michigan meet the cold air masses from the north/west in the fall. That said, this weekend may set the stage for the formation of a few isolated waterspouts thanks to a strong upper level low pressure system (cold air aloft) and the relatively warm waters of the lake.

While it’s impossible to forecast exactly where they will form, we as meteorologists know the environment that is favorable to these tornadoes over water. While conditions this weekend won’t be ideal, it will still be possible that a few may form. Scattered lake-effect rain showers and thunderstorms are likely throughout Sunday as well thanks to the upper low and daytime heating that will take place.

Waterspouts generally occur over water, but I can recall one time a few years back where one of these briefly came onshore and did some damage. The NWS had to issue an immediate tornado warning, but it wasn’t the type that’s spawned from severe thunderstorms…and it is rare that they live to make it ashore. These waterspouts require the temperature difference and instability between the lake and the temperatures aloft. Take away the indifference and you basically shut it down.

Take a look here at one of our forecast models (valid for Sunday morning) that show the atmosphere at about 18,000 feet (or for you pilots 500 MB) above the surface. This is the level where we examine the trough/ridge pattern and look for upper level low pressure systems. Note the giant “low” over the Great Lakes and the energy, power, spin, and vorticity around the low. This is why our temperatures are cold this weekend and why we have the chance at seeing a few waterspouts.

If you click here you’ll see another computer forecast model (valid for Sunday morning) from about 5,000 feet above the surface (or 850 MB). Note the cooler colors/tones over the Great Lakes as temperatures at this level dip to about 4 degrees Celsius. Normal temps at this level for summer would be around 14 to 18 degrees Celsius…quite the difference!

Make sure to snap a photo or take some video if you happen to catch anything on the lake. Send it to weather@fox17online.com or post it to our FOX 17 Facebook page and we’ll use it on air. Thanks in advance. Get the complete forecast by going to www.fox17online.com/weather