1. CAE Tornado Cases Hunter Coleman Anthony Petrolito Michael Cammarata
HSLC Event March 2010
CAE Tornado Cases
Hunter Coleman
Anthony Petrolito
Michael Cammarata

2. Tornadoes Analyzed Lexington County , SC Edgefield County, SC
McCormick County/Edgefield Counties, SC
Guilford County, NC
Tornado Tracks from the HSLC Event March 2010

3. Synoptic and Mesoscale Overview
Positively tilted upper trough with 120+ kt 300 mb jet
80+ kt 500 mb jet streak rounding base of upper trough
50-55 kt 850 mb low level jet over Carolinas
Surface low in mid Mississippi Valley approaching
Cold front extending to the Gulf Coast in MS pushing through Carolinas after 29/0000 UTC
Stationary wedge front across western Piedmont of NC into Upstate SC
sbCAPE < 400 J/kg in vicinity of tornado reports
mlCAPE values were higher and increased with time over SC
muCAPE also higher than sbCAPE and became maximized over SC by 0300 UTC with values > 1000 J/kg
30-40 kts 0-1 km shear and kts of 0-6 km shear
m2s km SRH and m2s km SRH

4. Surface Analysis and Regional Radar
29/0000 UTC Surface Analysis
Regional Radar Image at 28/2348 UTC
Stationary wedge front likely contributed to locally higher SRH
EF-3 damage associated with tornado in High Point, NC

5. Significant Tornado Parameter
28/2100 UTC
29/0000 UTC
29/0300 UTC
29/0400 UTC

6. SHERB Composite
(a) 28/2100 UTC, (b) 29/0000 UTC, (c) 29/0300 UTC, (d) 29/0400 UTC

7. Lexington County EF2
A tornado formed along a quasi-linear convective line near a “Broken S” feature over Lexington County in central South Carolina on 29 March The tornado touched down at 0225 UTC as an EF2 with winds of 109 kts. Around 40 homes were damaged along with numerous trees and power lines down from near Ridge Road northeast to Lake Murray. There was also damage to several vehicles and one minor injury was reported.

8. Vr-Shear
25-35 kts Vr-shear appears to be a signal several minutes prior to tornadogenesis.
Strengthening noted aloft just prior to tornadogenesis.
Decrease in Vr-Shear after tornadogenesis.
0.5 elevation at 2311 EST = 1700 FT
0.9 elevation at 2311 EST = 2600 FT
1.4 elevation at 2311 EST = 3700 FT
1.9 elevation at 2311 EST = 5000 FT
Time-Series plot of Vr-Shear at the lowest elevation angles from the Columbia, SC (KCAE) WSR-88D. Shaded area depicts the time period of the tornado.

9. Normalized Rotation 0.5-1.0 NROT values prior to tornadogenesis.
Strengthening at all levels prior to tornadogenesis.
Decrease in NROT after tornadogenesis.
0.5 elevation at 2311 EST = 1700 FT
0.9 elevation at 2311 EST = 2600 FT
1.4 elevation at 2311 EST = 3700 FT
1.9 elevation at 2311 EST = 5000 FT
Time-Series plot of Normalized Rotation (NROT) at the lowest elevation angles from the Columbia, SC (KCAE) WSR-88D. Shaded area depicts the time period of the tornado.

10. Rotational Shear
Increase in rotational shear in the lowest elevation angles several minutes prior to tornadogenesis.
Increase in rotational shear aloft just prior to tornadogenesis.
0.5 elevation at 2311 EST = 1700 FT
0.9 elevation at 2311 EST = 2600 FT
1.4 elevation at 2311 EST = 3700 FT
1.9 elevation at 2311 EST = 5000 FT
Time-Series plot of rotational shear at the lowest elevation angles from the Columbia, SC (KCAE) WSR-88D. Shaded area depicts the time period of the tornado.

11. Edgefield County EF2
The Edgefield Thunderstorm was a mini-supercell embedded within a quasi-linear convective line. It was the same thunderstorm that produced the EF2 damage at 0225 UTC in Lexington County. This EF2 tornado touched down on state highway 230 near Stevens Creek and took down numerous trees and power lines. Two homes had moderate damage. A mobile home lost half of its roof. Another mobile home was crushed from a tree.

12. Vr-Shear
25-35 kts Vr-shear appears to be a signal several minutes prior to Tornadogenesis.
Some strengthening noted aloft just prior to tornadogenesis.
Decrease in Vr-Shear after Tornadogenesis.
0.5 elevation at 2111 EST = 4900 FT
0.9 elevation at 2311 EST = 7000 FT
1.4 elevation at 2311 EST = 9400 FT
1.9 elevation at 2311 EST = 11600FT
Time-Series plot of Vr-Shear at the lowest elevation angles from the Columbia, SC (KCAE) WSR-88D. Shaded area depicts the time period of the tornado.

13. Normalized Rotation 0.7-1.3 NROT values prior to tornadogenesis.
Some increase aloft just prior to tornadogenesis.
Slight decrease after touchdown.
0.5 elevation at 2111 EST = 4900 FT
0.9 elevation at 2311 EST = 7000 FT
1.4 elevation at 2311 EST = 9400 FT
1.9 elevation at 2311 EST = 11600FT
Time-Series plot of Normalized Rotation (NROT) at the lowest elevation angles from the Columbia, SC (KCAE) WSR-88D. Shaded area depicts the time period of the tornado.

14. Rotational Shear
Increase in rotational shear in the lowest elevation angles just prior to tornadogenesis.
Decrease in rotational shear after touchdown.
0.5 elevation at 2111 EST = 4900 FT
0.9 elevation at 2311 EST = 7000 FT
1.4 elevation at 2311 EST = 9400 FT
1.9 elevation at 2311 EST = 11600FT
Time-Series plot of rotational shear at the lowest elevation angles from the Columbia, SC (KCAE) WSR-88D. Shaded area depicts the time period of the tornado.

15. McCormick/Edgefield EF1
A developing convective line of thunderstorms moved into the Central Savannah River Area Georgia (CSRA) and the Piedmont of South Carolina during the late afternoon 28 March A mini-supercell thunderstorm developed over McCormick County and moved into Edgefield County. The storm produced an EF1 Tornado at 2106 UTC. The tornado took down several trees in the Sumter National Forecast to the southwest of downtown Edgefield.

16. Vr-Shear
25-35 kts Vr-shear appears to be a signal several minutes prior to tornadogenesis.
Some strengthening noted just prior to tornadogenesis.
Slight decrease in Vr-Shear after tornadogenesis.
0.5 elevation at 1547 EST = 5600 FT
0.9 elevation at 1547 EST = 8100 FT
1.4 elevation at 1547 EST = 10900FT
1.9 elevation at 1547 EST = 13900FT
Time-Series plot of Vr-Shear at the lowest elevation angles from the Columbia, SC (KCAE) WSR-88D. Shaded area depicts the time period of the tornado.

17. Normalized Rotation
NROT appears to be a signal prior to tornadogenesis.
Strengthening trend evident at all levels prior to tornadogenesis.
Decrease in NROT after tornadogenesis.
0.5 elevation at 1547 EST = 5600 FT
0.9 elevation at 1547 EST = 8100 FT
1.4 elevation at 1547 EST = 10900FT
1.9 elevation at 1547 EST = 13900FT
Time-Series plot of Normalized Rotation (NROT) at the lowest elevation angles from the Columbia, SC (KCAE) WSR-88D. Shaded area depicts the time period of the tornado.

18. Rotational Shear
Increase in rotational shear (especially lowest elevation angles) several minutes prior to tornadogenesis.
Increase in rotational shear aloft just prior to tornadogenesis.
0.5 elevation at 1547 EST = 5600 FT
0.9 elevation at 1547 EST = 8100 FT
1.4 elevation at 1547 EST = 10900FT
1.9 elevation at 1547 EST = 13900FT
Time-Series plot of rotational shear at the lowest elevation angles from the Columbia, SC (KCAE) WSR-88D. Shaded area depicts the time period of the tornado.

19. Guilford County, NC EF3
An EF3 tornado developed in Guilford County North Carolina during the evening on 28 March Twenty homes were damaged north of High Point. The radar sampling from the RAX radar for this case is less than optimal. At the 0.5 elevation slice, the mesocyclone was sampled above 8000 FT. Data not included for this presentation.

20. Summary
The storms analyzed generally had Vr shear values in the 25-35kt range in the lowest 4 elevation angles prior to tornadogenesis.
The storms analyzed generally had NROT values in the 0.5 to 1.3 range in the lowest 4 elevation angles prior to tornadogenesis.
General trend for both Vr shear and NROT was values increased before tornadogenesis and decreased after tornadogenesis.
For Rotational Shear, trends were most evident in lowest two elevation angles with some upward spiking prior to tornadogenesis.
SHERB Composite parameter appears to have coincided well with the location of the tornadoes