Tornado or No Tornado? - 05/29/13
Tuesday night was certainly active in the state of Michigan. First, there were powerful thunderstorms rolling through the Lansing area between 8 and 9 o'clock, damaging a lumber yard and rolling a tractor-trailer in Delta Township, northwest of the city. The National Weather Service says a storm survey of the damage indicates wind speeds of 75 to 80 mph, but no circulation; not tornadic,
As the cluster of storms moved east, they intensified, becoming tornadic around Flint. Storm survey teams from the National Weather Office in Detroit confirm six tornadoes on the east side of the state, two of them causing EF2 damage, with max wind speeds of 115-130 mph.
Closer to home, a cluster of intense thunderstorms (which brought torrential rainfall to central/eastern Illinois) moved across southern Lake Michigan and into our neighborhood at about 10 p.m. As the area moved across West Michigan, meteorologists at the National Weather Service office in Grand Rapids detected possible rotation in a cell just east of Kalamazoo at about 11:15. A Tornado Warning was issued for NE Kalamazoo County, NW Calhoun County, and much of southern/western Barry County.
There were a couple of possible sightings of a funnel cloud by emergency services personnel NW of Battle Creek and NE of Augusta (northeasternmost Kalamazoo County), but nothing was ever verified. The Tornado Warning was for "radar indicated" circulation, meaning the radar returns indicating velocities within the storm showed some rotation. When National Weather Service radar indicates rotation within a thunderstorm, and the rotation is noted in successive "scans" of the storm (in each scan, or revolution, the radar is tilted slightly higher, to get a vertical profile), the Warning is issued.
However, in the case of last night's storm, there were several factors that made "calling" the event difficult. First, the cell in question was about 45 miles away from the Weather Service radar site, which sits adjacent to the Gerald R. Ford International Airport. The data returning to the radar can be degraded somewhat at that distance, which of course might negatively affect the reliability of the information. Additionally, as the radar beam is tilted slightly above the horizon, at a distance of 45 miles, the effect of the earth's curvature places the center of the beam a few thousand feet above the surface. In other words, the data returning to the radar showing what might be happening in the thunderstorm east/northeast of Kalamazoo was taken from about 4,000 feet high in the cell. So, even if the data suggesting rotation were accurate, whether the circulation was happening at ground level or was suspended high into the storm was unknown.
In a case like this you can easily see why it is essential to supplement radar data with "ground truth," which comes in the form of eyewitnesses. That's the vital link that trained SkyWarn spotters provide in severe weather. There were a couple of reports of possible funnel clouds coming from emergency fire/rescue personnel in the area; one from NW of Battle Creek, and another from NE of Augusta. However, there were no damage reports from that area -- in fact, reports from the area suggested the wind was relatively calm as the thunderstorms moved through. Of course, the fact that it was the dead of night when the storms moved through didn't help. One could only see storm clouds aided by split-second flashes of lightning.
An interesting video from downtown Kalamazoo shows what seems to be a funnel cloud, illuminated by lightning (you can find it on our website, or on the WWMT Facebook page, or on my WWMT Facebook page). The video, shot (and shared with us) by Derrick Jones, was taken from the rooftop of a building downtown at about 11 o'clock. Derrick says he was shooting toward the NNW as the storms approached from the west. It sure seems as though the lightning is illuminating a funnel cloud, stretching down from the thunderstorm!
But I don't think that's what we're seeing, for a few reasons: first, if the image was indeed a funnel cloud, its signature would have likely been detected on Doppler Radar, and though the National Weather Service did spot possible rotation in the storm as it moved ENE of Kalamazoo, Derrick's video is looking to the NW of Kalamazoo. Second, if the image in the video was indeed a tornado, there would have certainly been damage, and likely plenty of it. There was very little damage reported from last night's thunderstorms in West Michigan, and nothing reported from the NW side of Kalamazoo. Third, such a distinct funnel would have been seen by numerous people, even though it happened in the dead of night; the phone lines in our newsroom should have been ringing off the hook! But no one called with such a report last night.
Despite my reasons for believing the image in the video was not a tornado, I can't explain what it might be. It surely looks like a twister, and who knows, maybe it was!