1. Life Cycle Classification Location Severe Thunderstorms Hazards

2. What is a thunderstorm?
A thunderstorm is a storm accompanied by lightning and thunder
Affects a relatively small area for a short amount of time
Product of vigorous convection extending into troposphere

3. Thunderstorm life cycle
3 stages to the life cycle of a thunderstorm
Towering cumulus stage
Mature stage
Dissipating stage

4. Thunderstorm life cycle towering cumulus stage
The build up stage
Can build vertically and horizontally
Neighboring cumulus clouds can merge together making the lateral dimension 6-9 miles long

5. Towering cumulus stage
Caused by updrafts in the air
An updraft is an upward moving current of air
This forces all water droplets and ice crystals in the cloud
Precipitation does not occur during the towering cumulus stage

6. Mature Stage Middle stage when exciting stuff starts to happen
Precipitation begins to fall
Lasts minutes

7. Mature Stage
During this time an accumulation of water droplets and ice crystals are sent up in the cloud
The weight of these begins too much and they begin to work their way down the cloud carrying the wind as well
This produces a downdraft alongside the updraft

8. Dissipating Stage
Subsiding air replaces the updraft which effectively cuts off the supply of moisture delivered by the updraft

10. Classifying thunderstorms
4 types of thunderstorms
Single cell
Multicell cluster
Multicell line
supercell

11. Single Cell Weakest of thunderstorms Weak updraft (non severe)
Strong updraft
Slight threat

12. Multi cell cluster
Weak updraft
Strong updraft
Moderate threat

13. MultiCell line
Weak updraft
Strong updraft
Moderate threat

14. Super Cell Intense updraft Mesocyclone present High threat
Vertical column of cyclonically rotating air
High threat

16. Severe Thunderstorms
In order to be a severe thunderstorm, it needs to have
58 mph winds
Hailstones 1 inch or longer in diameter (penny size)

17. What is needed to cause a sever thunderstorm?
Wind shear- change in horizontal wind speed or direction
High vertical wind shear
High developing clouds
Carries more moisture to feed the storm

18. Hazards Lightning Down Bursts
Strong down draft which hits the ground and spreads

19. Hazards
Flash flooding
Hail