QLCS Tornadoes develop quickly

The Ohio Valley region along with the Miami Valley has the highest frequency of Quasi Linear Convective System (QLCS) Tornadoes in the United States.

According to a tornado environment study by the Storm Prediction Center, the cold season is between Oct 15th and Feb 15th.

Tornadoes develop within the updraft of a storm. This area is difficult to locate when the storms form a line.

One thing meteorologists look for in a line of convection is a bow in the direction of storm motion.

Bow Echo

Strong straight-line winds are pushing the storm forward in this area of the line.

Sometimes at the top of the bow wind flowing into the storm from the opposite direction. An inflow notch can be spotted on radar.

Inflow Notch

The change in wind direction will create shear. This is where a Tornado can form.

Many times the rotating winds cannot be seen on the radar image until after the tornado has already formed.

Rotation couplet

In Troy on Jan. 11, 2019 the rotation was spotted at 10:12 p.m. The tornado formed at 10:11 p.m.

The tornado was only on the ground for 2 minutes.

QLCS tornadoes are different from the tornadoes we see on Memorial Day in 2019.

QLCS tornadoes are rarely ranked higher than EF-2 but can be very dangerous because of the short lead time.

The tornadoes on Memorial Day were produced in a supercell thunderstorm.

The updraft is rotating before a tornado ever develops. The rotating updraft can be spotted early on radar and lead to warning lead times up to 30 minutes before the tornado ever develops.

Location of rotating updraft in supercell

Supercell tornadoes create the classic hook echo image seen on the radar.

Hook Echo Reflectivity on Memorial Day 2019