A scale, developed in the early 1970s by Herbert Saffir, a consulting engineer, and Robert Simpson, then Director of the National Hurricane Center, to measure the intensity of a hurricane from 1 to 5. The scale categorizes potential damage based on barometric pressure, wind speeds, and storm surge. Scale numbers are available to public safety officials when a hurricane is within 72 hours of landfall. Scale assessments are revised regularly as new observations are made. Public safety organizations are kept informed of new estimates of the hurricane's disaster potential. In practice, sustained surface wind speed (1-minute average) is the parameter that determines the category since storm surge is strongly dependent on the slope of the continental shelf.

An advisory issued for marine interests, especially for operators of small boats or other vessels. Conditions include wind speeds between 37 kph (23 mph) and 63 kph (39 mph). Issued up to 12 hours ahead of conditions.

An individual low-pressure disturbance, complete with winds, clouds, and precipitation. Examples include thunderstorms, tornadoes, or even tropical cyclones. The name is associated with destructive or unpleasant weather

An abnormal rise in sea level accompanying a hurricane or other intense storm, and whose height is the difference between the observed 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. Note: waves on top of the storm surge will create an even greater high-water mark.

The actual level of seawater resulting from the astronomic tide combined with the storm surge. If the storm comes ashore during astronomical low tide, the surge will be decreased by the amount of the low tide. If the storm makes landfall during astronomical high tide, the surge will be that much higher.

The region between the tropical and temperate regions, an area between 35 and 40 degrees North and South latitude. This is generally an area of semi-permanent high pressure that exists and is where the Azores and North Pacific Highs may be found.

A low pressure system that develops over subtropical waters that initially has a non-tropical circulation but in which some elements of tropical cyclone cloud structure are present. Subtropical cyclones can evolve into tropical cyclones.

A subtropical cyclone in which the maximum sustained surface wind speed (using the U.S. 1-minute average) is 61 kph (38 mph) or less.

A semi-permanent high-pressure region near 30 degrees latitude.

A subtropical cyclone in which the maximum sustained surface wind speed (using the U.S. 1-minute average) is 63 kph (39 mph) or more.