Weather Exam 3 Pseudo Study Guide `2

What is lightning?

An electrical discharge that happens when electrical charges build up and separate in a storm.

What is cloud-to-cloud lightning?

Lightning between clouds. Much lightning also happens within a single cloud. Cloud-to-ground lightning connects a cloud and the ground.

What causes thunder?

Lightning heats the air very quickly. The air expands suddenly and makes a sound wave. 

Why do we see lightning before hearing thunder?

Light travels faster than sound. A longer delay usually means the lightning is farther away.

What is heat lightning?

Lightning from a distant storm whose thunder you cannot hear. Heat by itself does not make lightning. 

What is the main lightning safety rule?

When thunder roars, go indoors. Use a substantial building or enclosed hard-topped vehicle. Avoid trees, open fields, and water. Wait 30 minutes after the last thunder before returning outside.

What should I avoid indoors during a thunderstorm?

Plumbing, corded phones, plugged-in electrical equipment, and windows. Lightning can travel through wiring and pipes. 

What is a downdraft?

Air moving downward inside a storm.

What is a downburst, and what is a microburst?

A downburst is a strong downdraft that hits the ground and spreads outward, causing damaging winds. A microburst is a small downburst, less than about 2.5 miles across. 

How can downburst damage differ from tornado damage?

Downburst damage often spreads outward or lies in a similar direction. Tornado damage often shows a more converging or twisting pattern. Experts examine the whole damage path to tell them apart.

Why are microbursts dangerous to airplanes? 

They cause sudden changes in wind and strong sinking air, especially dangerous near the ground during takeoff or landing.

Where are thunderstorms especially common in the lecture?

Florida and the Gulf Coast, where warm, moist air and lifting are common.

What is a tornado?

A violently rotating column of air connected to a thunderstorm cloud and touching the ground. 

What is wind shear? 

A change in wind speed or direction with height. It helps storms develop rotation. 

What two tornado formation steps does the instructor describe? 

Tilting: a storm updraft turns horizontal spin upright. Stretching: the rising air stretches and narrows the rotating column, making it spin faster. Ground contact is needed for a tornado.

What is a mesocyclone?

The rotating updraft within a thunderstorm. A mesocyclone may produce a tornado, but many do not.

What is a wall cloud?

A lowered cloud base under a thunderstorm, sometimes rotating. It can signal tornado potential, but it is not itself a tornado.

How is a funnel cloud different from a tornado?

A funnel cloud is a rotating funnel-shaped cloud without ground contact by the circulation. A tornado has ground contact. The visible funnel does not have to reach the ground, so do not wait for that sign to take shelter.

What is a hook echo?

A hook-shaped radar pattern on a supercell that can signal rotation and a possible tornado. It does not prove a tornado is on the ground. 

Why does the central United States have favorable tornado conditions?

Warm, moist Gulf air can meet cold air from Canada and dry air from the Southwest. Strong wind shear and lifting can help create rotating storms.

Where and when does the lecture say tornadoes are common?

Traditional Tornado Alley includes Texas, Oklahoma, Kansas, and Nebraska. The Southeast also has major risk. The lecture gives May as the national peak month and April for Georgia. Tornadoes can occur in any month.

Which way do tornadoes usually rotate and travel in the lecture? 

Most U.S. tornadoes rotate counterclockwise. Many travel from southwest to northeast, but both rotation and travel can vary. Never use the usual direction to decide you are safe.

Why are tornado winds so strong?

Pressure changes greatly over a short distance, creating a very strong pressure gradient. 

What are suction vortices? 

Smaller areas of intense spin within a larger tornado. They can create narrow strips of especially severe damage.

What is a waterspout?

A rotating column of air over water. Some form with strong thunderstorms; fair-weather waterspouts are usually weaker. A waterspout that moves onto land is a tornado.

What is the Enhanced Fujita (EF) Scale?

A scale from EF0 to EF5 that rates tornadoes using damage to estimate wind speed. Larger numbers mean stronger estimated winds.

What are the Enhanced Fujita (EF) wind ranges?

EF0: 65–85; EF1: 86–110; EF2: 111–135; EF3: 136–165; EF4: 166–200; EF5: over 200 miles per hour.

Can I rate a tornado by how big or scary it looks?

No. Experts inspect its damage and consider how buildings were constructed. A thin tornado can be strong, and a large tornado can be weaker.

What does a tornado watch mean?

Conditions are favorable for tornadoes. Be ready, follow alerts, and know where to shelter. 

What does a tornado warning mean?

A tornado has been reported or radar indicates one may be developing or occurring. Take shelter immediately.

Where should I shelter from a tornado?

Use a storm shelter or safe room. Otherwise, go to a basement or small interior room on the lowest floor of a sturdy building. Stay away from windows and protect your head.

What places should I avoid during a tornado?

Mobile homes, vehicles, windows, and large rooms with wide roofs, such as gyms. Arrange a sturdy shelter before the storm arrives if you live in a mobile home.

What is El Niño Southern Oscillation (ENSO)?

A repeating ocean-and-atmosphere pattern in the tropical Pacific. Its warm phase is El Niño, its cool phase is La Niña, and neutral is between them.

What is El Niño?

Unusually warm surface water in the central and eastern equatorial Pacific, usually with weaker trade winds and less cold-water upwelling in the eastern Pacific.

What is La Niña?

Unusually cool surface water in the central and eastern equatorial Pacific, usually with stronger trade winds and stronger cold-water upwelling.

How can these patterns affect the southern United States? 

El Niño often favors cooler, wetter winters across the South. La Niña often favors warmer, drier winters. These are tendencies, not promises. 

How do I draw the four front symbols?

Draw a line for each front. Cold: blue triangles on one side. Warm: red semicircles on one side. Stationary: alternate blue triangles and red semicircles on opposite sides. Occluded: alternate purple triangles and semicircles on the same side. On moving fronts, the symbols point in the direction of movement. 

How do I sketch the Norwegian cyclone model?

1. Put an L near the center. 2. Extend a warm front east or northeast. 3. Extend a cold front south or southwest. 4. Label the area between them warm sector. 5. Add arrows turning counterclockwise and inward. 6. Mark colder air behind the cold front and cooler air ahead of the warm front.

How do I sketch the conveyor belts? 

Start with your low and fronts. Draw a warm arrow rising from the warm sector ahead of the cold front; label comma tail. Draw a cool arrow coming from the east and curving upward around the low; label comma head. Draw a dry arrow descending from high above into the gap; label dry slot. Label which arrows rise and which sink.

How do I sketch the thunderstorm life cycle? 

Draw three clouds side by side. Under developing, draw an up arrow. Under mature, draw up and down arrows plus rain. Under dissipating, draw mainly a down arrow. Label the stages: developing, mature, dissipating. 

How do I practice the global wind belts? 

Mark 0°, 30°, 60°, and 90° north and south. Label low pressure at 0° and near 60°; high pressure near 30° and 90°. Put trade winds between 0°–30°, westerlies between 30°–60°, and polar easterlies between 60°–90°. Add a Hadley loop rising near 0° and sinking near 30°. Check this against the missing lecture when available. 

What does the instructor specifically emphasize? 

Know air-mass letters and their meanings; front symbols; the mature cyclone and its fronts; conveyor-belt starting heights and paths; severe-storm wind and hail rules; the difference between watches and warnings; and damage-based tornado ratings.

What can I leave out or give less time to based on his comments?

Leave out detailed vorticity material, lightning leader stages and electrical physics, sprites and blue jets, and the potential-instability slide. Give less time to detailed cyclone life-cycle phases. He says the older Fujita-scale slide is outdated; use the Enhanced Fujita (EF) Scale instead.