January 30, 2013 Cheatham Tornadoes

Analysis of the Wednesday, January 30, 2013, early morning Tornadoes
On the morning of January 30, 2013, a squall line came through Cheatham bringing with it two brief tornadoes, strong winds, and rain.  The system entered the county at approximately 2:37 A.M.  Figure 1 shows the line as it entered  the county.  If you look due south of Charlotte, there is a "notch" which shows where the winds are spinning counter-clockwise indicating rotation. 

Figure 1: Radar valid for 2:37 A.M. on January 30, 2013.

A problem with this type of severe weather event is picking up on the "notches" because they are embedded and the line itself is moving fast.  One product that meteorologist use to pick out if true rotation is taking place is Base Velocity.  Base velocity shows winds moving toward and away from the radar, and if winds are confined and moving toward and away from the radar rotation is taking place.  Figure 2 shows the Base Velocity for 2:37 A.M. (same as Figure 1).  Notice the light counter-clockwise spin of the "notch" within the line of storms indicated by the red circle.

Figure 2: Base Velocity valid for 2:37 A.M. on January 30, 2013.

The importance of focusing on this notch is that it goes on to produce the tornado that goes through Dickson and into Cheatham effecting Kingston Springs.  At 2:46 A.M. the line officially enters Cheatham and at 2:51 A.M. it enters Kingston Springs.  Figure 3 shows the radar signature and you can clearly see the notch with impressive rotation.

Figure 3: Radar (left) and Base Velocity (right) valid for 2:51 A.M. on January 30, 2013.

The overall length of the tornado path was 6 miles and the width was 100 yards.  For more info on the logistics go here.  The second tornado occurred in Ashland City, however was not as long as the Kingston Springs tornado.  An analysis of the radar focusing on Ashland City shows a small "notch" to the northeast of Charlotte (Figure 4).  Base velocity was not that great at this time.

Figure 4: Radar (left) and Base Velocity (right) valid for 2:41 A.M. on January 30, 2013.

  As the radar progressed through time, the notch became very defined over Ashland City indicating rotation.  At 2:51 A.M. the storm moved into Ashland City the same time as the Kingston Springs (Figure 5)

Figure 5: Radar (left) and Base Velocity (right) valid for 2:51 A.M. on January 30, 2013.

  The path of the Ashland City tornado was 0.25 miles long and the width was 50 yards wide.  For more info on the logistics go here.  The overall name of this system is known as a QLCS or Quasi-Linear Convective System.  QLCS' have the ability to maintain small updrafts overtime and are multi-cellular.  The reason these tornadoes were not powerful like most, is the set up of the system.  If these storms had been in the form of super cells, the outcome would have been different.  The biggest problem associated with this system was the timing.  This occurred during the early morning while most people were asleep.  This is why it is important to invest in a NOAA Weather Radio so that if a system like this ever comes through, you will be alerted of the threat.

Forecaster: Tyler Binkley