1. What Is a Thunderstorm?  Produce Rain, Lightning, and Thunder  2000 Thunderstorms Occur Every moment

2. Conditions Necessary For Thunderstorms  1). Lots of water in the atmosphere  2). Release of Latent Heat: Makes air warm Occurs by Condensation  3). Unstable Atmosphere

3. What’s Latent Heat?  Heat released when objects change states  Everything takes energy  Allows clouds to be warmer then the air around them Fuels thunderstorms

4. Types of Thunderstorms  Air Mass Thunderstorms  Happens because of convection  Only one air mass is involved Differences in heat within one air mass

5. Air Mass Thunderstorm Cont..  Sea Breeze Thunderstorms  Type of air mass thunderstorm  Differences in temp over land and over water

6. Air Mass Thunderstorm  Occur in Maritime Tropical Air Only Already Warm and Wet Perfect for Making Thunderstorms  Do NOT produce severe thunderstorms  Last 30-60 min  Happen in the afternoon  Most common

7. Types of Thunderstorms  Frontal Thunderstorms  Produced mainly by cold fronts  Last for long periods of time

8. Frontal Thunderstorm  Capable of producing severe thunderstorms  US has about 10,000 severe thunderstorms annually  Last several hours

9. What’s a Severe Thunderstorm  Severe Winds of 50mph or more Hailstones measuring 0.75 inches Produce a tornado  10,000 in the US every year

10. Thunderstorms Have Lifecycles  Today, we are going to make a cloud story book.

11. Cumulus Stage  Warm wet air rises Creates Updrafts  As it rises, it begins to cool Until it hits its dew point  Clouds form  Latent heat causes air to keep rising Creates tall cumulonimbus clouds

12. Mature Stage  Rain begins  Rain creates strong downdrafts  At this stage heavy rain and/or hail is possible.

13. Dissipation Stage  No warm wet air is rising Clouds energy supply is cut off Only Downdrafts remain  Very Light Rain  Clouds Evaporate

14. Supercell Thunderstorm  2,000-3,000 a year  Single HUGE thunderstorm  Do the most damage  Whole cloud is rotating  Entire center of cloud= updrafts

15. Severe Thunderstorm Hazards  1). Lightning  2). Tornadoes  3). Flash Flooding

16. Lightning When there is lightning it is not safe to be outside; you could be struck. 80% of victims are males between the ages of 15-40.

17. Lightning Myths  1). It can’t occur without rain  2). Rubber soles of shoes or car tires can protect you  3). People can carry an electrical charge  4). Heat lightning means the thunderstorm is far away so you cannot be struck by lightning.  5). All lightning strikes the ground.

18. How does lightning work?  During a thunderstorm, particles at the bottom of clouds take on a negative charge.  More positive by the Earth.  Electrical current, in the form of lightning, passes down to the ground Picks up a positive charge (Like a hand) Returns to cloud.

19. Tornadoes  Begin with air moving on the surface.  Storm updrafts pick this air up  Air begins to stretch out More stretching = Faster air -Mesocyclone

20. Profile of a Tornado  Form in front of cold fronts  Form in southwest winds  Travel to the northeast

21. Record Breakers  Longest Touch- Down Tri-State Tornado Deadliest Longest Path On the ground for 219 miles (3.5 hours)  Most Tornadoes Super Outbreak of 1974 148 tornadoes 315 fatalities 5,000 injured

22. Fujita Tornado Intensity Scale  Used after the tornado has occurred  Based upon damage caused  Old version = misleading Doesn’t differentiate between structures  Enhanced: Differentiates between structures

23. Flash Flooding  Causes the most deaths out of all thunderstorm hazards 3 Ways for Flash- Flooding to Occur  1). Heavy Rains in a small area  2). Great volume of rain in a short time  3). Urban areas receiving lots of rain in a short time

24. Hurricanes  Require Warm Ocean Water  Occur in Late Summer  Coriolis Force Causes Rotation

25. Hurricanes Stages  1). Tropical Disturbance  2). Tropical Depression  3). Tropical Storm  4). Hurricane

26. Tropical Disturbance  Band of thunderstorms  Located in the tropics  Air rises because It is warm Waves

27. Next Stages Tropical Depression  When a tropical disturbance reaches warm ocean water  Wind speeds = 37 mph  Tropical Storm Wind is moving up to 74mph  Hurricane Wind is traveling faster then 74mph

28. Parts of a Hurricane  Eye: Center of the rotating storm Calm High Pressure: Air is sinking  Eyewall: Location of the fastest winds Air is rising

29. Hurricane Death  How do hurricanes lose energy? Move over land → lose moisture Move over colder water → lose heat supply

30. Saffir-Simpson Hurricane Scale  Rates hurricanes based upon current conditions  A hurricane moves through different levels throughout its life.  1-5 scale  Based upon storm surge and pressure

31. Hurricane Destruction  1). Storm Surge  2). Wind Damage  3). Flash Flooding

32. Storm Surge  Rise in sea level  Caused by hurricane force winds  Looks like a wall of water rushing in  Causes 90% of all hurricane deaths

33. Instant Flooding  Hurricanes produce a lot of rain Causes Flash Flooding A lot of rain in a small amount of time  Worse if combined with storm surge

34. Wind Damage  75-150 mph winds  These change in intensity depending on your location and the path of the hurricane

35. Watches vs Warnings  Watch Specific Area Possibility of coastal areas being struck 36 hour notice  Warning More Severe Hurricane force winds are expected to arrive Less then 24 hr notice

36. Reoccurring Weather  Floods: Abundance of water When storms hang around  Droughts: Lack of rainfall Extended period with no rain or below average rainfall Result of high pressure systems

37. Temperature Extremes  Heat Waves Extended Period of Above Normal Temperature Associated with High Pressure Systems High Humidity  Cold Waves Extended Period of Below Normal Temperature High Pressure System of Polar Origin Wind Chill: How cold does it feel ○ Combo of cold air and wind