Updated May 24, 2007

 All Cases
(32 cases)

 ML CAPE
(Lowest 100 mb)
J/kg (Mean)

 Bulk Shear
(0 - 3 km)
m /s (Mean)


 Bulk Shear
(0 - 5 km)
m /s (Mean)

 Weak Shear 
( < 12 m s-1)
(8 cases)

3162 J/Kg  

 9.2 m s-1

 12.8 m s-1

 Moderate Shear
 (13 - 19 m s-1)
(18 cases)

 3299 J/Kg

 15.2 m s-1

 18.4 m s-1

Strong Shear
(20 m s-1>) 
(6 cases)

 2957 J/kg

 20.7 m s-1

 25.8 m s-1


Non-Supercell tornadoes occurred: 
 -in two 
of the eight weak shear cases 
- in twelve of the eighteen moderate shear cases 
- in two of the six strong shear cases


Fig. 1.  (Left Side)

Plot of the range of Mixed Layer Convective Available Potential Energy (CAPE) (J/Kg) for32 cases generated by lifting the mean- mixed parcel through the lowest 100 mb.  ML CAPE values are compared to each shear category.  Boxes denotes the 50% of values between the 25th and 75th percentile with thin vertical line extending to the 10th and 90th percentiles. (Right Side) Plot of the range of CAPE for tornadic and non-tornadic cases for all three shear cases.  Very little if any signal in MLCAPE between tornadic and non-tornadic events is noted.
(Click on image for a larger image).


Fig 2 - (Left Side)

Plot of the range of magnitudes for Bulk Shear (0 - 3 km) (m s-1) for each of the three shear categories (32 cases). We used Weisman's definition for 0-3 km moderate shear as 13-19 m s-1 and strong shear above 20 ms-1. The dot within the box represents the median value of shear for each category.  Values below each box and whisker plot show the number of tornadic cases compared to the total number of cases.   Eighteen of the thirty-two cases fell under the moderate shear category and twelve of the eighteen cases were tornadic.  The dot within each box represents the median value of 0 - 3 km bulk shear (Right side)  Plot of the range of magnitudes for Bulk Shear (0 - 3 km) for tornadic verses non-tornadic cases for all shear categories.  Tornadic cases show a slightly stronger magnitude of shear compared to non-tornadic cases.  However there still remains some overlap between the two box plots.
(Click on image for a larger image)

 

 

 


Fig. 3 -
 Same as Fig. 2 except for 0 - 5 km Shear.
 


Other parameters including 0 - 1 km and 0 - 6 km Bulk Shear; 0 - 1 km and 0 - 3 km Storm-relative helicity plots and other parameters will be forthcoming. 



Back to the COMET - Damaging Wind Studies Page


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.