1. Tornado Events Associated With Supercells and Quasi- linear Convective Systems Sara Jupin EAS4480 4/28/2011 Sara Jupin EAS4480 4/28/2011

2. Introduction  Supercell: thunderstorm characterized by the presence of a mesocyclone.  Quasi-linear Convective System (QLCS): line of thunderstorms that form along or ahead of a cold front.  Both can produce tornadoes, however Supercell tornadoes are the most common, and often the most dangerous.  Issuing warnings for QLCS tornodoes is more problematic. Don’t have the strong precursor signatures seen with SC tornadoes.  Objective: Compare data between SC and QLCS data in order to increase future knowledge of QLCS tornadoes.  Supercell: thunderstorm characterized by the presence of a mesocyclone.  Quasi-linear Convective System (QLCS): line of thunderstorms that form along or ahead of a cold front.  Both can produce tornadoes, however Supercell tornadoes are the most common, and often the most dangerous.  Issuing warnings for QLCS tornodoes is more problematic. Don’t have the strong precursor signatures seen with SC tornadoes.  Objective: Compare data between SC and QLCS data in order to increase future knowledge of QLCS tornadoes.

3. Methodology  GA, AL, TN, MS tornado events from 11/15/2007-4/25/2010.  Probability of detection for QLCS vs. SC tornado events.  T-test and F-test to determine if effects of SC vs. QLCS tornadoes are statistically significant.  Magnitude, Deaths, Injuries, Property Damage(K), Path Length(Miles), Path Width(Yards), and Lead Time (Hours).  Determine any correlations between factors for each type of event.  GA, AL, TN, MS tornado events from 11/15/2007-4/25/2010.  Probability of detection for QLCS vs. SC tornado events.  T-test and F-test to determine if effects of SC vs. QLCS tornadoes are statistically significant.  Magnitude, Deaths, Injuries, Property Damage(K), Path Length(Miles), Path Width(Yards), and Lead Time (Hours).  Determine any correlations between factors for each type of event.

4. Background Info Supercells  65 events (71%)  59 warned, 6 unwarned  POD: 0.91  Deaths: 0.82  Injuries: 7.08  Damage Cost: 16,521  Path Length: 15.38  Path Width: 588.23  Lead Time: 3:05 Supercells  65 events (71%)  59 warned, 6 unwarned  POD: 0.91  Deaths: 0.82  Injuries: 7.08  Damage Cost: 16,521  Path Length: 15.38  Path Width: 588.23  Lead Time: 3:05 QLCS’s  26 events (29%)  21 warned, 5 unwarned  POD: 0.81  Deaths: 0.23  Injuries: 1.88  Damage Cost: 1,975  Path Length: 8.11  Path Width: 326.35  Lead Time: 3:11 QLCS’s  26 events (29%)  21 warned, 5 unwarned  POD: 0.81  Deaths: 0.23  Injuries: 1.88  Damage Cost: 1,975  Path Length: 8.11  Path Width: 326.35  Lead Time: 3:11 91 Total Events

5. Student’s T-test Results Null hypothesis: means of the two distributions are identical

6. F-Test Results Null hypothesis: variances of the two distributions are identical

7. Correlation Results

8. Conclusions  SC vs. QLCS results were not statistically significant at 5% convidence interval. Majority of the data did not have identical means or variances.  Not enough evidence in the correlations to suggest a difference between SC vs. QLCS causality.  Tornadoes from SC and QLCS have different results. Therefore, need to research how atmospheric conditions are different between the two. Very long and tedious task.  SC vs. QLCS results were not statistically significant at 5% convidence interval. Majority of the data did not have identical means or variances.  Not enough evidence in the correlations to suggest a difference between SC vs. QLCS causality.  Tornadoes from SC and QLCS have different results. Therefore, need to research how atmospheric conditions are different between the two. Very long and tedious task.

9. Sources  NWS verification website  MATLAB  NWS verification website  MATLAB