GRAND RAPIDS (WWJ) -- The severe weather that hit Michigan over Memorial Day weekend spawned a "gustnado" near Grand Rapids, according to the National Weather Service.
The NWS said while most of lower Michigan had heavy rain, lightning and wind gusts of 30 to 40 miles per hour, a "gustnado" carrying winds of around 60 miles per hour hit an area between Forest Hills, Caledonia and Middleville, southeast of Grand Rapids.
Along portions of the leading edge of the storm's front -- several whirlwinds formed and enhanced the wind speeds on a smaller scale to severe levels around 60 mph, NWS said.
There was some tree damage and power outages reported in the area, but no major damage beyond that.
What exactly is a "gustnado"? The NWS explained it like this:
"Short answer: It's not a tornado in the official sense, as most of the gusty wind was due to a several mile wide surge in the thunderstorm's downdraft and outflow (very common). However, along portions of the leading edge of the storm's gust front, several whirlwinds did form and enhanced the wind speeds on a smaller scale to severe levels around 60 mph. These are sometimes called 'gustnadoes' (less common but not as rare as you might think).
"They are not fully like tornadoes, meteorologically, but do live in gray area since they aren't really 'straight-line winds' either.
"Long answer: The NOAA Glossary defines a gustnado as 'a small whirlwind which forms as an eddy in thunderstorm outflows.' They do not connect with any cloud-base rotation and are not tornadoes. Since their origin is associated with cumuliform clouds, gustnadoes will be classified as Thunderstorm Wind events. Like dust devils, some stronger gustnadoes can cause damage.
"So a key difference between gustnadoes and tornadoes is how deep the circulation extends above ground: mainly whether it stays shallow and generally below the cloud base, or if it connects deeper into the storm cloud's main updraft. Nature doesn't always draw a clear line in the sand, but in the case of Sunday, a combination of factors makes us lean toward the idea that this was more of a gustnado."
There was some tree damage and power outages reported in the area.
For more about gustnados from the NWS, visit this link.
