|
Term | Definition |
---|---|
Gale Warning |
A warning of 1-minute sustained surface winds in the range 63-87 kph (39 to 54 mph) inclusive, either predicted or occurring not directly associated with tropical cyclones. |
Geostationary Operational Environmental |
Family of NWS weather satellites, which orbit 22,300 miles above the earth and maintain a velocity that allows it to remain over a fixed place above the equator. Images are available to forecasters every 30 minutes. Aliases (separate with |): GOES
|
Greenwich Mean Time |
The name of the twenty-four hour time scale that is used throughout the scientific and military communities. Standard Time begins at Greenwich, England, which is the Prime Meridian of Longitude. The globe is divided into twenty-four (24) time zones of 15 degrees of arc, or one hour in time apart. To the east of this meridian, time zones are numbered 1 to 12 and prefixed with a minus (-), while to the west, the time zones are also numbered 1 through 12 but prefixed with a plus (+). Other names for this time measurement are Universal Time Coordinate (UTC) and Zulu (Z). Aliases (separate with |): GMT
|
High Pressure System |
An area of relative pressure maximum that has diverging winds and a rotation opposite to the earth's rotation. This is clockwise in the Northern Disaster Information Kit for the Caribbean Media Page 29 Hemisphere and counterclockwise in the Southern Hemisphere. Also known as an anticyclone, it is the opposite of an area of low pressure or a cyclone. |
Humidity |
The amount of water vapor in the air. |
Hurricane |
A tropical cyclone in the Northern Hemisphere with sustained winds of at least 119 kph (74 mph) or greater in the North Atlantic Ocean, Caribbean Sea or Gulf of Mexico. These winds blow in a large spiral around a relatively calm center of extremely low pressure known as the eye. Around the rim of the eye, winds may gust to more than 200 miles per hour. The entire storm, which can be up to 550 kilometers (340 miles) in diameter, dominates the ocean surface and lower atmosphere over tens of thousands of square miles. Hurricanes draw their energy from the warm surface water of the tropics (usually above 27 Celsius) and latent heat of condensation, which explains why hurricanes dissipate rapidly once they move over cold water or large land masses. |
Hurricane Advisory |
Notice, issued by the local meteorological office or national disaster management office, numbered consecutively for each storm, describing the present and forecasted position and intensity. Advisories are issued at six-hour intervals at midnight, 5 am, 11 am, 5 pm and 11 pm Eastern Caribbean Time. Bulletins provide additional information. Each message gives the name, eye position, intensity and forecast movement of the storm. Advisories will be issued every three hours if the hurricane is close to land. |
Hurricane Eye |
The relatively calm area near the center of the storm. In this area, winds are light and the sky is often partly covered by clouds. |
Hurricane Eye Landfall |
When the eye, or physical center of the hurricane, reaches the coastline from the hurricane's approach over water. |
Hurricane Hunters |
The 53rd Weather Reconnaissance Squadron of the U.S. Air Force Reserve, based out of Keesler Air Force Base in Biloxi, Mississippi. As a part of the 403rd Air Wing, the crew flies Lockheed WC-130 aircraft into tropical storms and hurricanes to gather meteorological data for the National Hurricane Center. |
Hurricane Season |
The portion of the year having a relatively high incidence of hurricanes. The hurricane season in the Atlantic, Caribbean, and Gulf of Mexico runs from June 1 to November 30. |
Hurricane Track |
Line of movement (propagation) of the eye through an area. Aliases (separate with |): Hurricane Path
|
Hurricane Warning |
A warning added to a hurricane advisory that sustained winds of 119 kph (74 mph) or higher associated with a hurricane are expected in a specified coastal area within 24 hours or less. A hurricane warning can remain in effect when dangerously high water or a combination of dangerously high water and exceptionally high waves continue, even though winds may be less than hurricane force. A warning is used to inform the public and marine interests of the storm's location, intensity, and movement. |
Hurricane Watch |
An announcement added to a hurricane advisory that hurricane conditions pose a possible threat to a specified coastal area within 36 hours. A watch is used to inform the public and marine interests of the storm's location, intensity, and movement. |
Instability |
Occurs when a rising air parcel becomes less dense than the surrounding air. Since its temperature will not cool as rapidly as the surrounding environment, it will continue to rise on its own. Contrasts with stable air. |