Study Guide for Thunderstorms

Where do thunderstorms most commonly occur?

tropical places where there is abundant sunshine and moisture

What time of day do thunderstorms normally happen?

late afternoons in the summer

What region do thunderstorms mostly occur in?

regions with convergent winds and lifting like mountains or an land and sea boundary

How long do thunderstorms normally last?

half hour to an hour

What is the most common type of thunderstorm?

air-mass thunderstorm

Where do air mass thunderstorms occur and how long do they last?

locally and short lengths of times

When do cumulus clouds form?

when the warm air mass rises high enough that it cools to its dew point and water vapor condenses

How is the energy source due to heat released?

through condensation

When does rain happen?

when the mass of water/ice is too heavy for the updrafts to support

What does falling rain create?

downdrafts

What conditions must a thunderstorm meet to be considered severe?

wind >50 knots (58 mph)
hail 1 inch or larger in diameter
tornado

What do air masses do in a severe thunderstorm?

air masses collide and advancing front of cold air lifts the warm air

What is the most severe type of severe thunderstorm?

supercell

What is a supercell thunderstorm?

huge updraft of air that move laterally

What happens in a supercell?

they pick up fuel (warm, moist air) in the front and then dump the exhaust (cool, dry air) behind

How big can supercells get?

12-30 miles

How long do supercells last?

several hours

What does the rotation of the updraft create?

a vortex which is how tornadoes are formed

What part of the US do thunderstorms mostly affect?

the central and southern US

How big can a severe thunderstorm get?

60-600 mile long zone