Extreme Weather

Question 1

What are the layers of the atmosphere, from top to bottom?

Answer 1

Thermosphere.

Mesosphere.

Stratosphere.

Troposphere.

Question 2

In what layers do weather and temperature, respectively, occur?

Answer 2

Weather: troposphere.

Temperature: mesosphere.

Question 3

Pressure refers to atmospheric mass. What is the energy source and what is it responsible for?

Answer 3

Gravity.

Weather systems.

Question 4

Pressure relates to what two things?

Answer 4

Altitude and latitude.

Question 5

Atmospheric mass decreases with _____.

Answer 5

Altitude.

Question 6

Describe the following air masses:

• cP (Continental Polar) / cA (Continental Arctic)
• mP (Maritime Polar)
• mT (Maritime Tropical)
• cT (Contintental Tropical)

Answer 6

cP/cA: cold, dry, stable.

mP: cold, moist, unstable.

mT: warm, moist, usually unstable.

cT: hot, dry, unstable at low levels/stable at high.

Question 7

What is it wind? How is it named (provide example)?

Answer 7

Air moving horizontally over surface of Earth.

Based on direction it comes from (e.g., westerly winds travel west to east).

Question 8

Which weather instrument measures direction? Which measures speed?

Answer 8

Direction: wind vane.

Speed: anemometer.

Question 9

How is atmospheric pressure measured? What does 1 bar equal? What is Canada’s normal sea level pressure?

Answer 9

Barometer.

1000mb.

1013.2mb.

Question 10

Wind direction and velocity are controlled by what four things?

Answer 10

Gravitation.

Pressure Gradients.

Coriolis Effect.

Friction.

Question 11

How do pressure gradients drive air?

Answer 11

Drives air from areas of higher pressure (more dense air) to areas of lower pressure (less dense air).

Question 12

Why does the Coriolis Effect make wind that travels in a straight path appear to be deflected in relation to Earth’s rotating surface?

Answer 12

Earth is rotating eastward.

Question 13

What is friction? When does it decrease?

Answer 13

Drags on the wind as it moves over Earth’s surface.

Decrease with height from surface.

Question 14

Describe the balance of forces between friction, gradients, and the Coriolis effect.

Answer 14

Coriolis acts at right angles to direction of motion.

Pressure gradient forces parcel to lower pressure.

Frictional force exerted from surface is proportional to wind speed, always acts in opposite direction to direction of motion.

Question 15

A cyclone that coverges aloft (aka downward wind) is known as what?

Answer 15

Anticyclone.

Question 16

Describe the difference between cloudy weather and sunny weather with regards to pressure and temperature.

Answer 16

Cloudy: low pressure, rising warm and moist air.

Clear weather: high pressure, descending cool and dry air.

Question 17

Rising air is known as _____ flow.

Answer 17

Cyclonic.

Question 18

Large area of air with similar temperature and humidity throughout.

Answer 18

Air mass.

Question 19

Invisible boundaries between two air masses.

Answer 19

Front.

Question 20

Describe warm weather fronts with regards to cold air, speed, weather.

Answer 20

Pushes cold air masses, warm air moves over cold.

Moves slowly, clouds thinner and spread out.

Steady light rain that can last a day or so.

Question 21

Describe cold weather fronts with regards to warm air, speed, weather.

Answer 21

Pushes warm air mass, cold air denser so warm air pushed up quickly, cools and condenses.

Move faster, clouds form cumulus, size depending on humidity.

Heavy precipitation, increased wind speed, sudden drop in temperature.

Question 22

Describe stationery weather fronts with regards to speed, weather.

Answer 22

Doesn’t move.

Overcast weather with drizzle.

Question 23

Describe occluded weather fronts with regards to cold/warm air, speed, weather.

Answer 23

Cold/cool push warm front up.

Thick clouds and rain, larger difference in temp/humidity and more drastic weather.

Question 24

List three conditions for thunderstorms.

Answer 24

Water vapour available in lower atmosphere.

Temperature gradient, rising air cools rapidly.

Updraft must force moist air up to colder levels.

Question 25

Describe the three components of a thunderstorm’s developing stage.

Answer 25

Moist air moves upwards, cools and water condenses to form cumulus cloud.

Continuing updraft and moisture supply causes cloud to grow upward.

Cloud grows above freezing level, precipitation begins to form.

Question 26

Describe the four components of a thunderstorm’s mature stage.

Answer 26

Downdraft, falling precipitation leave base of cloud.

Has both updraft and down draft.

Continues to grow until encounters top of unstable air.

Updrafts may continue to grow outward, forming anvil shape.

Question 27

During a thunderstorm’s dissipative stage, the supply of moisture is blocked by _____ at lower levels.

Answer 27

Downdrafts.

Question 28

How does less moisture affect a thunderstorm?

Answer 28

Weakens it, decreases precipitation, dissipates cloud.

Question 29

Dsecribe the three types of severe thunderstorm.

Answer 29

Mesoscale convective complexes (MCC): most common, very large cluster of storms. Downdraft of one cell leads the formation of a new cell.

Squall lines: long lines (500km) of individual cells along a cold front.

Supercells: smaller than other two, but spawn tornadoes.

Question 30

What is hail?

Answer 30

Concentric rings of ice formed as the hailstone moves up and down in the thunderstorm.

Question 31

Describe the four steps to lightning.

Answer 31

Electrical charge separation in the cloud.

Invisible step-leader branches downward.

Spark surges up to meet leader.

Electrons flow back up to the cloud, producing lightning.

Question 32

What is a tornado? When does it occur?

Answer 32

Rapidly rotating column of air descending from a large thunderstorm, making contact with the ground.

Large differences in atmospheric pressure over short distances.

Question 33

Describe the five steps of a tornado’s evolution.

Answer 33

Wind sheer causes rotation to develop (mesocyclone).

Updrafts lower portion of cumulonimbus cloud to form wall cloud.

May begin to rotate and produce short funnel clouds.

Dust and debris on ground swirl around.

If the two columns connect, then funnel is a tornado.

Question 34

In the mature stages of a tornado, what is seen? What happens to air?

Answer 34

Visible funnel extending from the cloud to the ground.

Moist air is drawn up.

Question 35

What three things happen in the shrinking stage of a tornado?

Answer 35

Warm moist air reduced, funnel thins and tilts, decreased size can increase speeds.

Question 36

Describe the rope/decay stage of a tornado.

Answer 36

Upward spiralling air contacts downdrafts, tornado moves erratically.