Fronts

Question 1

What is the definition of a Front?

Answer 1

The transition zone between two air masses

Question 2

During the passing of a front, abrupt changes in temp, wind, moisture content, and humidity are dependent on:

Answer 2

• The stability and moisture content of the warmer air mass
• The speed of the front as determined by the cold air mass
• The slope of the front

Question 3

What does a cold front (where cold air is moving in to warm air) and a warm front (where warm air is filling in behind a passing cold front) look like on a weather map?

Answer 3

Cold Front: Spiky blue line with the spikes in the direction the cold front is moving

Warm Front: Red bubbles pointing in the direction into which the warm are is filling in

Question 4

How is a stationary front depicted on a weather map?

Answer 4

Alternating blue spikes and red bubbles. The red and blue spikes and bubbles are pointing in opposite directions.

Question 5

Where will frontal weather happen in a cold front vs warm front?

Answer 5

Cold Front: weather will happen behind the blue spiky line

Warm Front: weather will happen ahead of red bubble line

Question 6

What are the symbols on a weather map for cold, warm, and stationary fronts?

Answer 6

Question 7

An occluded front and a trowal are the same thing. Which one is American and which one is Canadian and what do their symbols look like on a map?

Answer 7

Question 8

If something is an ‘upper’ front, how are those depicted on weather maps?

Answer 8

Same symbols just not colored in

Question 9

What is a stationary front?

Answer 9

A warm, high pressure air mass, and a cold high pressure air mass trying to shove in to each other but neither will give

Question 10

What moves faster, a warm front or cold front?

Answer 10

Cold front

Question 11

How many degrees is a typical cold front’s slope and how fast can they move?

Answer 11

• 1 to 1.5°C
• 30KTS or more
• Depth is usually about 50NM

Question 12

What kind of clouds would indicate a warm front is coming?

Answer 12

Cirrus to start, then altostratus, then nimbostratus, then stratus

Question 13

How far in front of an advancing warm front can clouds and weather form?

Answer 13

250-600NM

Question 14

What is the typical slope of a warm front?

Answer 14

1:150 - 1:250

**For every 1NM of height, its 250NM across the ground

Question 15

If you are flying at 6000ft and 12000ft, what does height do in terms of where you will hit weather when flying towards a warm front?

Answer 15

The higher you are, the farther ahead of the front you will hit weather

Question 16

Fronts always cause the winds to ____

Answer 16

Veer

Question 17

Behind a cold front the warm air mass is warm but _____

Answer 17

Stable

Question 18

What signs indicate that a cold front is coming?

Answer 18

Wind: Starting in the south/southwest
Temp: Warm
Pressure: Falling
Cloud: Cumulus, TC, CB
Precip: Showery
Vis: Fair to poor, haze
Dew Point: High and steady

Question 19

What do the winds do as a cold front is passing?

Answer 19

Veer and increase

Question 20

Signs of a cold front as it passes

Answer 20

Question 21

What happens after cold front passage?

Answer 21

Question 22

The retreating edge of a cold front is known as a ____ ____

Answer 22

Warm front

Question 23

Warm front weather diagram

Answer 23

Question 24

What is an occluded/trowal front?

Answer 24

This happens when a cold front associated with a low ‘catches up’ to a warm front. It overtakes it and undercuts the warm front

Question 25

What is trowal an acronym for?

Answer 25

**Tr**ough **O**f **W**arm **A**ir A**l**oft

Question 26

Where can most of the weather be found in an occluded/trowal front?

Answer 26

In the trowal itself

Question 27

How many air masses are involved in a trowal?

Answer 27

3 Cold, cool (partially mixed), and warm

Question 28

What direction will the winds of each air mass be blowing along a stationary front?

Answer 28

Parallel

Question 29

What is frontogenesis?

Answer 29

The formation of a front due to a temp gradient becoming sharper/steeper

Question 30

What is frontolysis?

Answer 30

The dissipation of a front, which happens when the temperature difference between two air masses decreases

Question 31

In Canada, an upper front refers to...

Answer 31

A non-occlusion/trowal situation. (ie: an upper front is different from a trowal)

Question 32

How does an upper front differ from a trowal/occlusion?

Answer 32

With a trowal, two colder air masses converge and shove the warm are up With an upper front, warmer air moves up over cold air on its own. So the air below is still super cold but at altitude its nice and warm

Question 33

What is the only real indication of an upper front that is passing from the ground? What about at altitude?

Answer 33

From the ground, clouds and precip From the air, same as other fronts. Wind shift, temp shift, clouds, precip

Question 34

What is frontal fog?

Answer 34

Associated with weather at warmer fronts. Happens when frontal precip falls into the colder air ahead or below the warm air, causing the colder air to become saturated through evaporation

Question 35

What is a fast moving cold front?

Answer 35

* Mostly forms in summer * Very steep, cold, dense, air that moves fast * Warm air ahead of it is forced to rise violently * May produce a squall line is warm air is moist and unstable already * Very narrow band of violent weather * Winds veer with frontal passage and are strong, gusty, and turbulent well after passage

Question 36

Weather at a Trowal

Answer 36

* Cloud pattern **ahead of the approaching trowal** is similar to that of a **warm** front * Cold front cloud formations exist **behind** it * Cumulous buildup and TS likely, with continuous precip and low ceilings

Question 37

On the exam, if it asks 'at what level is the front', remember:

Answer 37

* Fronts on a GFA will be at the surface * Fronts on a SIGWX are also on the surface

Question 38

What kind of weather would you expect from an air mass that gets cooled from below?

Answer 38

Expect fog, layer cloud, and poor visibility

Question 39

What clouds are associated with stationary fronts?

Answer 39

Stratiform. (Stratus, nimbostratus, altostratus, cirrostratus)