Weather SCOTT HANDEL National Oceanic and Atmospheric Administration Photo: Courtesy NOAA

Outline Thunderstorms Hail/Lightning Tornadoes Tsunamis Hurricanes (Time Permitting)

Thunderstorm Formation

Lightning

How Lightning Forms The connection is made and the protons rush up to meet the electrons. It is at that point that we see lightning and hear thunder. A bolt of lightning heats the air along its path causing it to expand rapidly. Thunder is the sound caused by rapidly expanding air.

Hail

How does Hail Form? Strong updrafts of warm air and down- drafts of cold air are in a thunderstorm. If a water droplet is picked up by the updrafts...it can be carried well above the freezing level. With temperatures below 32°F...our water droplet freezes. As the frozen droplet begins to fall...carried by cold downdrafts...it may thaw as it moves into warmer air toward the bottom of the thunderstorm But...it may also get picked up again by another updraft...carrying it back into very cold air and re-freezing it. With each trip above and below the freezing level our frozen droplet adds another layer of ice. Finally...our frozen water droplet...with many layers of ice - much like the rings in a tree...falls to the ground - as hail!

What can hail do?

Tornadoes What is a tornado? "a violently rotating column of air, pendant from a cumuliform cloud or underneath a cumuliform cloud, and often (but not always) visible as a funnel cloud."

HOW DO TORNADOES FORM?

WHERE DO TORNADOES FORM?

WHY DO TORNADOES LIKE THE CENTRAL U.S.? WHY DO TORNADOES LIKE THE CENTRAL U.S.?

Fujita Tornado Damage Scale Scale Wind Estimate (MPH) Typical Damage F0 < 73 Light – Some damage to chimneys, branches broken, signs damaged. F Moderate – Peels surface off roofs; mobile homes pushed off foundations or overturned. F Considerable – Roofs torn off frame houses, mobile homes demolished, large trees snapped F Severe – Roofs and some walls torn off well constructed homes, trains overturned F Devastating – Well-constructed homes leveled; cars thrown and large missiles generated F Incredible – Strong frame houses leveled off foundation and swept away, trees debarked

F0 Damage

F1 Damage

F2 Damage

F3 Damage

F4 Damage

F5 Damage

Tornado Embeds

Rate the Tornado

F2

Rate the Tornado

F4

Rate the Tornado

F1

Rate the Tornado

F2

Rate the Tornado

F4

Rate the Tornado

F3

Rate the Tornado

F5

Rate the Tornado

F2

Rate the Tornado

F2

HURRICANES! …An overview of tropical cyclones Princeton University Quest Science Workshop July, 2007

Why are the winds so strong in a hurricane? Winds always move from areas of higher pressure to areas of lower pressure. The bigger the difference between the high and low pressure, the stronger the winds. HL The winds from Hurricane Fabian battering Bermuda on September 5, 2003.

What causes the winds to rotate around a hurricane? Hurricane Isabel making landfall on September 18, 2003 H HH H L The Coriolis Effect: A change in the direction of moving objects due to those objects moving on a rotating, spherical planet.

The hurricane heat engine: how it works 3. Having lost most of its heat and energy, the air is now expelled outward away from the center of the storm in the cooler hurricane outflow at high levels. In mature hurricanes, an eye forms in the center. Here, the air is descending and the region is generally cloud-free. 2. The warm, moist air rises in thunderstorms surrounding the eye, supplying the fuel that helps strengthen the storm and intensify the winds. 1. As air rushes into the hurricane’s low pressure center, the air picks up heat and moisture (fuel) from the warm ocean surface. H H L

- Atlantic and Eastern Pacific Oceans (hurricanes) - Western North Pacific Ocean (typhoons) - South Pacific and Indian Oceans (cyclones) Where do tropical cyclones form? (10) (26) (14) (15) (5) (9) (nn) Number of storms per year

Saffir Simpson Scale

Wind Damage examples A 1x4 board of wood was pierced through a palm tree by Hurricane Andrew’s winds in August, A mobile home park near Miami, FL was completely destroyed by Hurricane Andrew in August, An historic home along the Gulf Coast before and after the passage of Category 5 Hurricane Camille in August, 1969.

Storm Surge