METEOROLOGICAL SERVICES

GRENADA, CARRIACOU & PETITE MARTINIQUE

Tropical Cyclones

Terms and Definitions

Tropical wave

A migratory wavelike (trough or cyclonic curvature) disturbance in the tropical easterlies. Tropical waves occasionally intensify into tropical cyclones. They are also called easterly waves.

Tropical Storm

An organized system of strong thunderstorms with a well-defined circulation and maximum sustained winds of 39 to 73 mph (34 to 63 knots)

Tropical Disturbance

A discrete system of organized convection, originating in the tropics or sub-tropics, having a non-frontal unitary character and having maintained its identity for 24 hours or more. It’s the basic generic designation, which in successive stages of intensification, may be subsequently classified as a tropical wave, depression, storm or hurricane.

Hurricane Watch

An announcement for specific areas that hurricane conditions (maximum sustained winds of 74 mph or greater) are possible generally within 48 hours.

Hurricane Warning

n announcement for specific areas that hurricane conditions (maximum sustained winds of 74 mph) are possible generally within 36 hours. Action to protect life and property should be rushed to completion after the warning is issued.

Flood

Rise, usually brief, in the water level in a stream to a stream to a peak from which the water level recedes at a slower rate; relatively high flow as measured by stage height or discharge. (Source: WMO No. 1072)

Flooding

Overflowing by water of the normal confines of a stream or other body of water, or accumulation of water by drainage over areas that are not normally submerged (Source: WMO No. 1072)

Storm surge

an abnormal rise of water generated by a storm, over and above the predicted astronomical tides.

Landslide

Down slope movement of soil mass under the influence of precipitation, ground water and other causes.

Tropical Depression

An organized system of persistent clouds and thunderstorms with a closed low-level circulation and maximum sustained winds of 38 mph (33 knots) or less.

Hurricane

An intense tropical weather system with a well-defined circulation and maximum sustained winds 74 mph (64 knots) or higher.

Advisory

A formal message from the Meteorological Office issued every six hours and giving warning information along with details on tropical cyclone location, intensity and movement.

Tropical Storm Watch

An announcement for specific areas that tropical storm conditions (maximum sustained winds of 39 to 73 mph) are possible generally within 48 hours.

Tropical Storm Warning

An announcement for specific areas that tropical storm conditions (maximum sustained winds of 39 to 73 mph) are possible generally within 36 hours.

Hurricane Center or Eye

The relatively calm area near the center of the tropical cyclone. In this area, winds are light and the sky is often only partly covered by clouds.

Flash Flood:

A flood that rises and falls quite rapidly, in general, six hours from the onset of torrential rainfall and confined to relatively small and poorly drained areas. There is little or no advance warning as it often results from intense rainfall over a relatively small area.

Climate Change

A change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods. (Source: UNFCCC)
Top
This is for alerts and notifications
This is default text for notification bar