The part of the surface of the Earth between the Tropic of Cancer (23.4° N latitude) and the Tropic of Capricorn (23.4° S latitude), characterized by a hot climate.

Stresses in plants that develop as temperatures rise more than 1°C (1.8°F) above the average expected in the hottest months of the year. Source: NOAA

Electrical resistance devices used in the measurement of temperature. Source: NOAA-NWS NHC

The boundary layer separating the near-surface warm waters from the colder, deeper layers of a body of water. Water temperature changes rapidly with depth within this layer. In the ocean, the thermocline also separates the fresher waters near the surface from the saltier waters below.

A local storm produced by cumulonimbus clouds. It is always accompanied by lightning and thunder. It is estimated that nearly 2,000 thunderstorms occur simultaneously around the Earth at any given instant. There are 3 types of thunderstorms: Single Cell, Multicell, and Severe Supercell. Source: NOAA Jetstream

Refers to the surface landscape of a geographic area, especially changes in elevation. Source: US NPS

A violent rotating column of air, in contact with the ground, pendant from a cumulonimbus cloud. A tornado does not require the visible presence of a funnel cloud. It has a typical width of tens to hundreds of meters and a lifespan of minutes to hours. Source: NOAA-NWS ERH

(Of a hurricane): The path a hurricane follows over a given period of time.

The belts of winds on either side of the equator, blowing from the northeast in the Northern Hemisphere and from the southeast in the Southern Hemisphere. In both hemispheres the winds become more easterly closer to the equator. Source: Canadian Hurricane Centre

A warm-core non-frontal synoptic-scale cyclone, originating over tropical or subtropical waters, with organized deep convection and a closed surface wind circulation about a well-defined center. Once formed, a tropical cyclone is maintained by the extraction of heat energy from the ocean at high temperature and heat export at the low temperatures of the upper troposphere. In this they differ from extratropical cyclones, which derive their energy from horizontal temperature contrasts in the atmosphere (baroclinic effects). Source: NOAA-NHC.

A tropical cyclone in which the maximum sustained surface wind speed (using the U.S. 1-minute average) is 62 km/h (38 mph) or less. Source: NOAA-NHC.

A discrete tropical weather system of apparently organized convection -- generally 184 to 552 km (145 to 345 mi) in diameter -- originating in the tropics or subtropics, having a nonfrontal migratory character, and maintaining its identity for 24 hours or more. It may or may not be associated with a detectable perturbation of the wind field. Source: NOAA-NHC.

(also known as The Tropics, Tropical Zone or Torrid Zone) The part of the surface of the Earth between the Tropic of Cancer (23°26 [23.4°] N latitude) and the Tropic of Capricorn (23°26 [23.4°] S latitude), characterized by a hot climate.

A tropical cyclone in which the maximum sustained surface wind speed (using the U.S. 1-minute average) ranges from 63 km/h (39 mph) to 118 km/h (73 mph). Source: NOAA-NHC.

An announcement that tropical storm conditions (sustained winds of 39 to 73 mph) are expected somewhere within the specified coastal area within 36 hours. Source: NOAA-NHC.

An announcement that tropical storm conditions (sustained winds of 39 to 73 mph) are possible within the specified coastal area within 48 hours. Source NOAA-NHC.

The usually slow development of an extratropically cold core vortex into a tropical cyclone. Although tropical cyclones generally weaken as they move poleward due to increased wind shear, lower sea surface temperatures and lower tropospheric humidities / landfall, some may develop explosively into extratropical depressions.

A trough or cyclonic curvature maximum in the trade-wind easterlies. The wave may reach maximum amplitude in the lower middle troposphere. Source NOAA-NHC.

The boundary between troposphere and the stratosphere. It is usually characterized by an abrupt change in temperature with height from positive (decreasing temperature with height) to neutral or negative (temperature constant or increasing with height). Source: NOAA- NWS ERH

The layer of the atmosphere from the surface of the earth up to the tropopause, characterized by decreasing temperature with height. It is the layer of the atmosphere where most of the weather occurs. Source: NOAA- NWS ERH

An elongated area of relatively low atmospheric pressure surface or aloft. Usually not associated with a closed circulation, and thus used to distinguish from a closed low. The opposite of ridge. Source: NOAA- NWS ERH

(in the ocean): Irregular motions of ocean waters. Turbulence increases ocean mixing, such as that at the edge of currents, which causes eddies to form.

A tropical cyclone with maximum sustained winds of 119 km/h (74 mph) or greater. The term “typhoon” is used for Pacific tropical cyclones north of the equator, west of the International Dateline. The term “hurricane” is used for Northern Hemisphere tropical cyclones east of the International Dateline to the Greenwich Meridian. Source NOAA-NHC.