Lecture 11: Mid-Latitude Cyclones

Question 1

____ is the leading edge of a cold air mass and a ____ is the leading edge of a warm air mass.

Answer 1

Cold front, warm front

Question 2

True or False:

A day or two ahead of a cold front’s arrival, high cirrus clouds appear.

Answer 2

True

Question 3

True or False: When a could front appears, precipitation usually is heavy, containing large droplets, and can be accompanied by hail, lightning, and thunder.

Answer 3

True

Question 4

True or False: The aftermath of a cold front’s passage usually brings southerly winds in the Northern Hemisphere and northerly winds in the Southern Hemisphere as anticyclonic high pressure advances.

Answer 4

False, northerly winds in the Northern Hemisphere and southerly winds in the Southern Hemisphere as anticyclonic high pressure advances.

Question 5

True or False: As a cold front approaches, the density difference between them the dense cold air mass displaces the less dense warm air mass forcing it to rise vertically

Answer 5

True

Question 6

______ is a zone slightly ahead of a fast-advancing cold front, where wind patterns are rapidly changing and blustery and precipitation is strong.

Answer 6

Squall line

Question 7

____ is a low pressure system that forms when a cool air mass (cP) collides with a warm, moist air mass (mT).

Answer 7

Midlatitude cylone

Question 8

What are the four stages of a midlatitude cyclone?

Answer 8

Cyclogenesis
Open Stage
Occluded Stage
Dissolving Stage

Question 9

Describe the cyclogenesis stage of a midlatitude cyclone

Answer 9

Disturbance begins to develop along polar front. Warm air near surface begins to rise, creating instability.

Question 10

Describe the open stage of a midlatitude cyclone

Answer 10

counterclockwise flow, moist air from the south into low-pressure centre while cold air advances southeard west of centre

Question 11

Describe the occluded stage of a midlatitude cycle

Answer 11

faster moving cold front wedges underneath slower warm front, cold air pushes warm air upwards causing precipitation

Question 12

Describe the dissolving stage of a midlatitude cyclone.

Answer 12

dissolves when the cold air mass cuts off the warm air mass from its source of energy and moisture

Question 13

A Midlatitude cyclone is also known as what?

Answer 13

A wave cyclone

Question 14

____ are maps depict the distribution of air pressure, fronts, centres of high and low pressure and present data from climate stations.

Answer 14

Weather maps

Question 15

What happens to temperature, moisture, wind direction, air pressure and clouds/precipitation when a warm front approaches?

Answer 15

Temperature: increases after warm front passes

Moisture: humidity and dew point temp increase with passage of warm front

Wind Direction: SE (E) winds before front, SW winds after front

Air Pressure: decrease in air pressure as the centre of low approaches

Clouds and Prec: gradual increase in cloud cover, precipitation near front, then partial clearing

Question 16

What happens to temperature, moisture, wind direction, air pressure and clouds/precipitation when a cold front approaches?

Answer 16

Temperature: decreases after cold front passes

Moisture: humidity and dew point temp decrease with passage of cold front

Wind Direction: north winds winds after front

Air Pressure: decrease in air pressure as the centre of low approaches

Clouds and Prec: abrupt increase in cloud cover, precipitation near front, then partial clearing

Question 17

A tropical cyclone is otherwise known as?

Answer 17

Hurricane, typhoon, or cyclone dependant on its location

Question 18

____ is a very intense vortex

Answer 18

Tornado