National Weather Service says 3 tornadoes touched down in Metro Detroit on Tuesday night

Tornadoes touched down in Monroe, Wayne counties

By Paul Gross - Meteorologist

DETROIT - The national weather service has confirmed that damage in Monroe and Wayne Counties Tuesday night was caused by three tornadoes.

The first tornado touched down at around 8:23 p.m. near Frenchtown Township in Monroe County.  The twister started with weak EF-0 damage, mainly to trees, until near Reinhardt and Heiss Roads where it became a solid EF-0.

The tornado reached EF-1 strength near Toben and South Stony Creek Roads, where roofing material was removed leaving exposed trusses and windows that were blown out of homes in the area. Garage doors were also blown in and many trees were damaged and uprooted. EF-0 damage to siding and tree limbs was noted before the tornado dissipated around 8:32 P.M. near North Stoney Creek Road and the railroad tracks.

The tornado’s path length was 4.3 miles, had a maximum estimated wind speed of 95 to 100 mph, and its maximum width was 400 yards.

The same storm then generated another tornado that caused damage in the Gibraltar and Berlin Township areas in extreme southeast Wayne County. This tornado was generated by the same storm that produced the Monroe County tornado.The National Weather Service also says that a third tornado touched down shortly thereafter in the Gibraltar area, and this had EF1 strength…similar to the strength of the Frenchtown Township tornado.  We’ll add details here as we get them.

An EF-0 tornado touched down at 8:45 p.m. in Berlin Township in Monroe County just south of Sigler Road on North Dixie Highway. The tornado remained at EF-0 strength throughout the entire path length, before dissipating around 8:52 p.m. near the intersection of Meadow Lane and Ostreich Road in Wayne County near the border of Brownstown Charter Township and the city of Gibraltar. Damage included multiple limbs and large trees downed, along with missing shingles to a house near the end of the tornado path.

The tornado was on the ground for 4.0 miles, had an estimated maximum  wind speed of 65 mph, and a maximum width of 100 yards.

A third tornado touched down shortly thereafter in the Gibraltar area, and strengthened to EF1 status…similar to the strength of the Frenchtown Township tornado…at 95 to 100 mph.  This twister began just to the west of West Jefferson Avenue and south of Gibraltar Road.  The tornado remained at EF1 strength up to the Navarre Street and Young Drive area, before weakening to EF0 strength for the remainder of the path.  The tornado then crossed the Detroit River before dissipating at the north end of Elba Island in Grosse Ile Township.  Damage included multiple large limbs and trees downed, a roof partially blown off and powerlines downed. 

 

 

We explained in great detail Tuesday afternoon why we were so concerned about the Tuesday night tornado threat, and three tornadoes did indeed touch down and cause quite a bit of damage. Allow me to now show you some of what Ben Bailey and I were seeing on radar in the Local 4 weather office as the event unfolded, and how this technology undoubtedly saved lives.

First of all, here’s the “usual” radar image we typically show you on TV as an average looking heavy thunderstorm moved across Monroe County.

This radar product is called Base Reflectivity -- all you get to see here is rain. Yes, the red colors indicate torrential downpours, but this gives you no additional information about what’s going on inside the storm.

Now take a look at this radar image:

This is called Storm Relative Velocity. You see, Doppler Radar not only sees those raindrops, it also sees the wind inside of the storm. How? Because the wind blows those raindrops around.

So here’s what happens:  the radar sends out a beam, and it knows the frequency of that beam. When the beam hits raindrops being blown toward the radar, the part of the beam reflected back to the radar has a higher frequency. Wind blowing away from the radar is reflected back to the radar with a lower frequency.

The radar computes the difference in frequency between the beam that left the radar and the beam reflected back, and knows not only if it’s wind blowing toward or away from it, but also the wind speed.  Now take a look again at the above image. The radar in White Lake is directed about fifty miles to the upper left of this image.

Green colors are blowing toward the radar, and red colors are blowing away from the radar. At the time of this image, we were noticing some greens right next to some reds, which we call a couplet and, at 8:19 p.m., the National Weather Service issued a tornado warning for Monroe County.

It is important to understand that this warning was what is called a Radar Based Warning. Radar indicated solid rotation, but there was no reports of a tornado, yet.

Now take a look at these three radar images:

The official title of this product, used by meteorologists all around the country, is Correlation Coefficient (“CC”).  But that’s such a complicated term that we title this radar product “Debris Potential” when we show it to you on TV. Here’s how it works: The radar also looks at the consistency of the targets that its beam is detecting.

For example, raindrops are relatively uniform in their shape and size. So are snowflakes. Hail starts to show some differences, and this product indicates that. But the biggest use for this product is during a tornado event, because tornadoes lift debris of very different shapes and sizes into the air, and this usually shows up as a little “ball” on the CC image.

We meteorologists call that a Debris Ball.  If you look at these three images, I’ve circled a Debris Ball that developed in association with the Monroe County tornado. Later, a weaker one developed near Gibraltar following that touchdown.

The most important morel to this story is that the National Weather Service’s tornado warning was issued minutes before the first tornado touchdown. That’s the power of Doppler Radar, and meteorologists who know how to interpret its data. The people in Monroe County affected by the first tornado had warning before the tornado actually touched down.

Ben and I were keenly aware that a lot of people were upset about interrupting programming during NBC Premier Week, and we weren’t happy about it, either. However, lives were in danger, and the Local4Casters will always put your safety first.

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