Funnel Cloud Spotted Across Central Trinidad

Funnel cloud spotted in Caroni at 3:42 PM (Neela Motilal)

Shortly after 3:40 PM Saturday 14th August 2021, a funnel cloud was spotted moving northwestward across Central Trinidad. Sightings were reported from Valsayn, Caroni, Spring Village, and Carapichaima.

There were no reports of the funnel touching down, hence no tornado.

Through Sunday, as Tropical Storm Grace moves across the Leewards, near calm winds with southeasterly steering may allow for additional funnel clouds to develop during the late mornings through the afternoon, favoring Trinidad. Waterspouts are also possible across Trinidad and Tobago’s coastal areas, favoring southern and western parts of both islands. If either a funnel cloud touches land or a waterspout moves onshore, it could become a tornado.

The Origin of Funnel Clouds, Tornadoes and Waterspouts

Within showers and thundershowers (all convective showers), there is an updraft, where warm air rises.

Structure of a thunderstorm. (Credit: Encyclopedia Britannica, Inc.)

However, when there is a change of wind speed or direction as the air rises (wind shear), this updraft begins to rotate. This rotating updraft is called a mesocyclone. As this mesocyclone, or rotating air, moves closer to the surface of the earth, this may cause a this cloud to form.

If this rotating updraft touches the surface of the earth (land), a tornado is formed. Alternatively, if the updraft touches the surface of the ocean or a waterbody, it is considered a waterspout.

A diagram showing how an updraft of a thunderstorm can become a rotating updraft. (Credit: Wikipedia)

A diagram showing how an updraft of a thunderstorm can become a rotating updraft. (Credit: Wikipedia)

Classic Funnel Clouds

Similar to the formation of a tornado or waterspout, a rotating column of air draws in water droplets – making a region of intense low-pressure visible. This rotating column of air can be found at the base of cumulonimbus clouds, where the updraft is located. Note that funnel clouds that are produced from cumulonimbus clouds are typically associated with supercell thunderstorms, a rare thunderstorm type in T&T.

A true funnel cloud rotates, but has no ground contact or debris, and does not produce damage.

There is some disagreement over the definition of a funnel cloud and a condensation funnel. According to the Glossary of Meteorology, a funnel cloud is any rotating cloud pendant from a cumulus or cumulonimbus, and thus most tornadoes are included under this definition.

Types of cumuliform clouds, or convective clouds. Small: cumulus humilis, also called "fair weather cumulus"; Medium: cumulus mediocris; Large: cumulus congestus, also known as towering cumulus; Extra large: cumulonimbus, also called thunderstorms (University of British Columbia/Roland Stull)
Types of cumuliform clouds, or convective clouds. Small: cumulus humilis, also called “fair weather cumulus”; Medium: cumulus mediocris; Large: cumulus congestus, also known as towering cumulus; Extra large: cumulonimbus, also called thunderstorms (University of British Columbia/Roland Stull)

Among many meteorologists, the ‘funnel cloud’ term is strictly defined as a rotating cloud that is not associated with strong winds at the surface, and condensation funnel is a broad term for any rotating cloud below a cumuliform (convective) cloud.

Note: The term condensation funnel may refer to either a tornadic cloud or a funnel cloud aloft, but the term funnel cloud exclusively refers to a rotating condensation funnel not reaching the surface. If strong cyclonic winds are occurring at the surface and are connected to a cloud base, regardless of condensation, then the feature is a tornado.

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