• Hurricane Irma: 9 weather terms you should know

    By: WFTV Web Staff


    As Florida braces for Hurricane Irma, there are several terms Channel 9 viewers will be hearing a lot from our meteorologists. Here are common ones you should know as you keep your eye on the storm’s path:  


    Lines or bands of low-level clouds that move (feed) into the upper region of a thunderstorm, usually from the east through south.

    This term also is used in tropical meteorology to describe spiral-shaped bands of convection surrounding, and moving toward, the center of a tropical cyclone.

    Read: Community still rebuilding after Hurricane Matthew braces for Irma


    When the wind speed increases at least 16 knots and is sustained at 22 knots or more for at least one minute.

    Storm Surge

    An abnormal rise in sea level accompanying a hurricane or other intense storm. The height is the difference between the normal level of the sea surface and the level that would have occurred in the absence of the cyclone. Storm surge is usually estimated by subtracting the normal or astronomic high tide from the observed storm tide.




    An organized band or ring of clouds that surround the eye, or light-wind center of a tropical cyclone. Eyewall and wall cloud are used synonymously.

    Sustained winds

    Wind speed determined by averaging observed values over a two-minute period.

    Computer Models

    Meteorologists use computer models to figure out a storm’s path and its potential path. The models are dictated based on typical weather patterns.

    Watch: Powerful winds during Hurricane Irma in St. Thomas


    Official information describing all tropical cyclone watches and warnings in effect along with details concerning tropical cyclone locations, intensity and movement, and precautions that should be taken.

    Hurricane Watch

    An announcement that sustained winds of 74 mph or higher are possible. Because hurricane preparedness activities become difficult once winds reach tropical storm force, the hurricane watch is issued 48 hours in advance of the anticipated onset of tropical storm force winds.

    Hurricane Warning

    An announcement that sustained winds of 74 mph or higher are expected somewhere within the specified area in association with a cyclone. Because hurricane preparedness activities become difficult once winds reach tropical storm force, the warning is issued 36 hours in advance. The warning can remain in effect when dangerously high water or high water and waves continue, even though winds may be less than hurricane force.

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