thunderstorms

What type of cloud contains thunderstorm activity?

CB

A thunderstorm is a _______ produced by a ______.

weather phenomenon, cumulonimbus cloud

Thunderstorms tend to develop in clusters of __ or more.

2

CBs associated with thunderstorms may extend vertically as high as _______.

70,000 feet

Precipitation occurs at the cumulus stage

False

The mature stage of the thunderstorm is characterized by _____ and is where the _____ incidence of precipitation occurs.

the onset of precipitation, highest

What other weather can occur at the mature stage?

• Lightning

• Microbursts

• Gust fronts

• Hail

• Tornadoes

Updrafts within a mature cumulonimbus cloud may attain ______ feet per minute (FPM)

6,000

As the water droplets grow, they start dragging the air down with them, producing downdrafts in the _____ range.

2,000 FPM

What shape does a dissipating stage cloud form?

An anvil

What are the 3 basic requirements for the formation of thunderstorms?

Unstable air, lifting action, and high moisture content

What are the two types of thunderstorms?

Air mass and Frontal

Air mass thunderstorms usually form as the result of ____.

convection, advection, or orographic lift

What time of day do convection thunderstorms usually occur?

Afternoon or early evening

Over land, advection thunderstorms usually occur in the _____ and dissipate in the _____. Clouds are scattered over a large area, and the storm has a _____ flow.

afternoon, late evening or overnight, northerly

Over water, advection thunderstorms usually occur in the ____ and dissipate with a ____ flow. Clouds tend to be ____

morning, southerly, close together

Orographic storms occur ____, and dissipate with ____. Clouds form ____.

day or night, change in wind direction, in a stationary line

Individual air mass thunderstorms are called _____, while large clusters are collectively known as _____.

single-cell thunderstorms, supercells

Frontal thunderstorms only occur with cold fronts

False

Cold front thunderstorms occur _____, and they dissipate ____. Clouds are in a line _____ to the front.

day or night, with the movement of the front, parallel

Warm front thunderstorms are often ______ and are not as visible as cold front thunderstorms

embedded in stratiform clouds

In which stage of a thunderstorm can you find hail?

Mature

Where does the strongest turbulence in a cloud occur?

During the mature stage in the transition zone

Above the cumulonimbus cloud, turbulence is also possible ________ and outward up to ________

up to several thousand metres, 30 km

Hail occurs most from the surface up to around _____

10,000 to 15,000 feet

What are the types of lightning?

• In-cloud (aka sheet lightning)

• Cloud-to-cloud

• Cloud-to-ground

• Distant

Severe clear icing is most likely to occur in the _____ of a thunderstorm cloud in the mature stage, especially when temperatures are between ____.

upper half, 0° and -25°C

Squall lines are non-frontal, narrow bands of highly active thunderstorms that generally develop ahead of a _____ in ______.

cold front, moist and unstable air

Tornadoes occur most frequently with supercell thunderstorms (those associated with cold fronts and squall lines)

True

What type of cloud is often an indication of tornadoes and violent turbulence?

Cumulonimbus mammatus, or mamma clouds

How can heavy rain showers affect flight?

• Contaminate the wing surface

• Reduce visibility

• Cause hydroplaning

A microburst is a sudden and powerful downdraft ____. Can cause sudden and dangerous _____.

within a thunderstorm, low-level wind shear

Which of the following scenarios is likely to result in icing?

An aircraft flying at or below freezing temperatures and encountering supercooled water droplets

Squall lines are narrow bands of highly active thunderstorms and generally develop ahead of a _____ front in moist and ____ air.

cold, unstable

What are squall lines?

Narrow bands of highly active thunderstorms

Which type of air mass thunderstorm has the potential of forming supercells?

Advection thunderstorms

Strongest turbulence in a cloud occurs during the _____ in the transition zone between the updrafts and downdrafts, generally between ______.

mature stage, 12,000 - 20,000 feet

Icing is possible in all stages of a thunderstorm.

True