50 08 Non-Frontal Depressions

Question 1

Why don’t TRS form in the South Atlantic and South Pacific Seas?

Answer 1

Water is too cold

Question 2

At what latitudes do RTS form at?

Answer 2

Between 10 degrees and 20 degrees North and South

Question 3

What is the number of TRS in NE. Australia?

Answer 3

9

Question 4

What temperature must the sea be for a RTS to form?

Answer 4

26.5 degrees C or more

Question 5

What kind of weather would you find flying towards a TRS?

Answer 5

• Very choppy sea
• Lots of precipitation
• Poor visibility
• Ci clouds further out

Question 6

Describe Orographic / Lee Depressions and the possible weather associated to them

Answer 6

• Form on the lee side of a mountain range when the air flow is blocked by and forced to go around a ridge of mountains
• Significant weather can form when a cold front moves over the ridge
• Lower air mass gets blocked by mountains but higher part moves over the warm air mass
• Causes great instability and TS, Cb’s
• Lasts until all of the warm air has been replaced with cold

Question 7

Describe the following regarding Cold Air Pools:

• AKA
• How they form
• Where they can reach
• How big they are
• What altitudes are they found at
• How long they last
• How they effect the weather
• What latitudes do they effect

Answer 7

• Aka Polar Vortices or Cut Off Lows
• Due to the rotation of the Earth, Polar Outbreaks can be cut off from the Polar air mass
• Can reach as far as the Sahara Desert
• 300 to 1000nm
• 10,000 to 30,000ft
• A few days to a few weeks
• Bring unseasonable weather
• 30 degrees N to 50 degrees N

Question 7

What is the size range and average size of a TRS?

Answer 7

• 300km to 2000km

- Avg. 500km

Question 9

What is the number of TRS in Madagascar?

Answer 9

10 to 11

Question 10

In a TRS how large can the Eye be?

Answer 10

100km

Question 11

What is the number of TRS in W. Australia?

Answer 11

7

Question 12

What directions do TRS travel in the NH and SH?

Answer 12

• NH: East to West and turn right

- SH: East to West and turn left

Question 13

What is the number of TRS in the NE. Pacific

Answer 13

16 - 17

Question 14

What are the 4 stages of development of a TRS and the wind speeds associated with each?

Answer 14

• Tropical Disturbance: Weak circulation
• Tropical Depression: Wind Speeds: 20 - 33kts
• Tropical Storm: Wind Speeds: 34 - 63kts
• Tropical Rotating Storm: Wind Speeds: 64kts +

Question 15

Where in a TRS are the fastest wind speeds found?

Answer 15

At the Eye Wall

Question 16

What are TRS known as in:

• North Americas
• Australia and Africa
• Japan and Asia

Answer 16

• Hurricanes
• Cyclones
• Typhoons

Question 17

What is the number of TRS in N. India?

Answer 17

5 - 6

Question 18

What sort of Depression (Low) is a TRS?

Answer 18

Massive Thermal Low

Question 20

Describe the different types of temperature depressions and anti-cyclones

Answer 20

• Thermal Low: Isohypes curve down at the surface and up at the tropopause
• Thermal High: Isohypes curve up from surface to tropopause
• Cold Low: Isohypes curve down from surface to tropopause
• Cold High: Isohypes curve up at the surface and down at the tropopause

Question 21

Describe a Polar Outbreak

Answer 21

• Very cold Polar air moves very far south

- Can lead on to form a Cold Air Pool

Question 21

What is the number of TRS in N. Australia?

Answer 21

2

Question 21

What is the number of TRS in the S. China Sea?

Answer 21

20 - 25

Question 22

What are the minimum wind speeds required to be classified a TRS?

Answer 22

64kts

Question 24

What is the number of TRS in the N. Atlantic

Answer 24

<= 10

Question 25

What times of year are TRS found in:

• NH
• SH

Answer 25

• NH: Aug to Sep

- SH: Jan to Feb

Question 26

How fast so TRS travel over the sea?

Answer 26

15kts