Section 5C: TRS

Question 1

Briefly explain ‘Tropical Revolving Storm -TRS’ with respect to the following:
Origin
Movement
Life span
Structure

Answer 1

Origin
TRS originates from areas between 5°N and 30°N latitude and 5°S and 30°S latitude, where sea surface temperatures are typically 27°C or higher.
Warm, moist air rises from the ocean surface, creating an area of low pressure below. Surrounding air rushes in to fill this low pressure, causing the air to spin and form a rotating storm system.

Movement
In the Northern Hemisphere, TRS moves between west and west-northwest directions.
In the Southern Hemisphere, TRS moves between west and west-southwest directions.
The movement is influenced by the Coriolis effect and the surrounding wind patterns.

Lifespan
A TRS can continue as long as it remains over warm ocean waters (typically above 27°C) that provide the energy to sustain it.
Once a TRS moves over land or cooler waters, it begins to weaken and eventually dissipates due to the lack of warm, moist air supply.

Structure
Eye: A clear, calm area at the center with very low air pressure.
Eye Wall: A ring of tall thunderstorms surrounding the eye, producing heavy rains and the strongest winds (up to 150 knots).
Rain Bands: Curved bands of clouds and thunderstorms spiraling outward from the eye wall, capable of producing heavy rain, wind, and tornadoes.
The structure is divided into navigable and dangerous semicircles, with the strongest winds and heaviest seas in the dangerous semicircle.

Question 2

State the ideal conditions for the formation of a TRS.

Question 3

Define the following terms with the aid of a sketch:
Path
Track
Trough
Vertex
Dangerous semi-circle
Navigable semi-circle
Dangerous quadrant

Question 4

Briefly explain the weather associated with a TRS. Cover the following aspects in your answer:
Pressure
Wind
Clouds and precipitation
Visibility
Storm surges/swell/waves

Question 5

List and briefly explain the warning signs of an approaching TRS.

Question 6

List the actions to be taken when the approach of a TRS is confirmed and briefly explain how each action is executed (Hint: Semi-circle; bearing; avoiding action).