Synoptic Features

Question 1

What are the two basic cloud forms?

Answer 1

1. Stratiform or stratus-type clouds
2. Cumuliform or cumulus-type clouds

Question 2

What are the four types of cumuliform clouds?

Answer 2

• Cumulus (CU)
• Towering cumulus (TCU)
• Cumulonimbus (CB)
• Altocumulus castellanus (ACC)

Question 3

What are CU clouds?

Answer 3

Cumulus clouds that develop vertically in form of rising mounds, domes, or towers

Question 4

What are TCU clouds?

Answer 4

Towering cumulus clouds is when the height of TCU exceeds the width with distinctive cauliflower top means showers below

Question 5

What are CB clouds?

Answer 5

Cumulonimbus clouds are thunderclouds that contain thunderstorm activity; appear heavy and dense with considerable vertical extent in form of mountain or tower

Question 6

What are ACC clouds?

Answer 6

Altocumulus castellanus clouds that are white, grey, or both; often a telltale sign of impending thunderstorm development

Question 7

What is a high-pressure area?

Answer 7

Region where atmospheric pressure greater than its surrounding environment with pressure values increasing towards centre; air circulates clockwise

Question 8

What is a low-pressure area?

Answer 8

Region where atmospheric pressure is lower than its surround environment, with pressure values decreasing towards centre; air circulates counter-clockwise

Question 9

What is Coriolis force?

Answer 9

Caused by Earth’s rotation which affects the direction of air movement

Question 10

How does the Coriolis force occur in southern hemisphere?

Answer 10

Coriolis force deflects moving air to left because rotating Earth has clockwise spin

Question 11

What is Buys Ballot’s Law?

Answer 11

Wind at your back in the northern hemisphere, area of lower pressure lies to your left

Question 12

What is veering?

Answer 12

When wind makes clockwise change in direction

Question 13

What is backing?

Answer 13

When wind makes a counter-clockwise change in direction

Question 14

What are the five lifting agents?

Answer 14

• Convection
• Orographic lift
• Frontal lift
• Mechanical turbulence
• Convergence

Question 15

What is convection?

Answer 15

Air is heated below by contact with Earth’s surface

Question 16

What is orographic lift?

Answer 16

Air is forced up sloping terrain by wind

Question 17

What is frontal lift?

Answer 17

Air is forced to rise by a wedge of colder and denser air

Question 18

What is mechanical turbulence?

Answer 18

Friction between air and ground causes air to be stirred up into series of areas of swirling motion known as eddies

Question 19

What is convergence?

Answer 19

Occurs at centre of low-pressure systems; air converges at this point and is forced to rise, resulting in cloud and precipitation

Question 20

What causes CB clouds to form?

Answer 20

• Lifting action
• Unstable air mass
• High moisture content

Question 21

What is air mass?

Answer 21

Large section of troposphere with relatively uniform properties of temperature and moisture in the horizontal

Question 22

What is a front?

Answer 22

Transition zone between two air masses

Question 23

What are the different types of fronts?

Answer 23

• Cold front
• Warm front
• Stationary front

Question 24

What is a cold front?

Answer 24

Transition between advancing cold air and warm air; identified by arrowhead

Question 25

What is a warm front?

Answer 25

Transition zone between warm air and retreating cold air; identified by half-circle

Question 26

What is stationary front?

Answer 26

Transition zone between two air masses that are not moving; identified by alternating arrowheads and half-circles

Question 27

What is turbulence?

Answer 27

It is disturbed air

Question 28

What is frontal turbulence?

Answer 28

Caused by lifting warm air by frontal surface leading to instability, or abrupt shifts in wind direction and speed between warm and cold air masses near frontal surface