1. National Weather Service Shreveport Working Together to Save Lives Understanding Severe Storms

2. Topics Global Circulations Thunderstorm Ingredients Lightning Hail Tornadoes and Downbursts Flooding

3. Global Circulations

4. Jet Stream

5. Thunderstorm Ingredients

6. Thunderstorm Ingredients Moisture - Preferably in the lower or mid levels of the atmosphere

7. Thunderstorm Ingredients Source of lift – Agent which lifts the warm, moist air starting the thunderstorm

8. Another Source of Lift

9. Thunderstorm Ingredients Instability – Ability for air to accelerate upward/downward when started up/down

10. Thunderstorm Life Cycle Cumulus Stage Mature Stage Dissipating Stage

11. Multicell Thunderstorm

12. motion (Cross section) Squall Lines

13. downdraft N Tornado Supercell Thunderstorms

14. Shear Rotation Shear vs. Rotation

15. Lightning

17. Lightning Formation

19. Thunder

20. Hail

21. Weather Related Hazards Hail Baseball size hail can do severe damage

22. Hail Formation

23. Tornadoes and Downburst

25. Tornadoes Fujita Scale F0-F1 Winds 60 - 115 mph F2-F3 Winds 115 - 205 mph F4-F5 Winds > 205 mph

26. Damaging Wind Cold air ‘bursts’ down from cloud Spreads on ground contact Accelerates on outwash Can reach 150 mph Tornado-like damage Cold air ‘bursts’ down from cloud Spreads on ground contact Accelerates on outwash Can reach 150 mph Tornado-like damage

27. Downbursts and Aircraft

28. Flooding

29. Weather Related Hazards Flash Flooding Safety Tips  Do not drive across a flooded roadway or low water crossing  If your vehicle stalls in high water, leave it and seek higher ground  Be especially careful at night when it is harder to recognize the dangers of flash flooding

30. Acknowledgments Jetstream website – Southern Region Headquarters, National Weather Service www.srh.noaa.gov/srh/jetstream

31. The End