Tropical Revolving Storm

What actions to take?

You should know….

Referred as TRS. Rotating low-pressure on surface. Consists of warm and humid air. Brings thunderstorms, strong winds flooding

rains, high waves and damaging storm.

How to Detect it?

•Appears smaller than a temperature depression

•Form a zone of Inter Tropical Convergence Zone /instability.

•Circular isobars

•Steep pressure gradient

•Intense

Warnings 1: On-Board Equipment

Set-up radio and navigation equipment; warnings about known storms would be broadcasted with coordinates.

Though coast meteorological stations are useful; ship’s equipment is more reliable as they sometimes, are unable to detect the storm.

Barometer; if corrected reading falls below 3mb a TRS is expected.

Warnings 2: Environment

Swells generated at sea below area of storm.

Tropical wind is normally constant, any anomalies (variations of speed, strength and direction) are signs of storm.

Clouds; Red sunrise/sunset before storm. Cirrus clouds visible 300 to 600 miles from the storm. Altostratus clouds, lower and covering bigger area, seen closer. Cumulus seen closest

Altostratus

Cirrus

Skyline before storm Cumulus

Course of Action: Officer’s Approach

Obtain bearing of the eye. Observe path followed by the storm. Facing the wind; eye will be 100 t0 125 degrees right

hand; in Northern Hemisphere. While the storm is 200 miles away.

General assumption is that the storm is not moving towards the Equator; Eastern constituent if latitude is lower than 20 degrees.

Storm with unusual course is likely to be slower.

Course of Action: Avoidance

Maintain distance of 50 miles from center of the storm. Optimal distance is 200 miles to avoid possible danger altogether.

Maintain speed; a vessel pulling 20 knots and following a course away from the eye can outstrip an approaching TRS, which move slow until winds build up, restricting the vessel’s movement.