1. Thunderstorms and thunder observations Sven-Erik Enno Estonia 10.08.2005

2. Different types of thunderwinds Straight line winds Gustfronts Microbursts Tornadoes Mesocyclones

3. Structure of a thundercloud

6. Damaging winds occurr if... Air temperature and relative humidity values are high There are multicell / supercell thunderstorms Vertical windshear is strong enough Storng convectiv airflows occur Sharp temperature and air pressure contrasts under and around thunderclouds

7. Vertical airflows inside thundercloud

8. Microbursts / downbursts

9. Air temperature and pressure contrasts

10. Windsystem of a thundercloud

11. Straight line winds formation

12. Straight line winds between two thunderclouds

13. Damaging straight line winds in Estonia 16.07.2001 Air pressure Air temperature Windspeed m/s Wind direction

15. 16-th July 2001

17. Storm path in Notheastern Estonia

18. Supercell and mesocyclone

19. Supercell in USA

22. Supercells in Estonia

23. Supercell in Estonia

24. Thunder observations in Estonia Few meteorological stations Inserting lightning detectors Detailed observations and information from different places: over-Estonian volunteer thunderstorm observers network

25. Estonian thunderstorm observers network

26. Interactive European lightning maps

28. Contact information: Sven-Erik Enno seenno@ut.ee