Now that Storm Season is officially underway, we wanted to help you refresh your memory on specific terms we'll be throwing around in our Tropical Updates and forecasts.
Advisory: Bulletins from the National Hurricane Center, which are issued at the following times: 5 a.m., 11 a.m., 5 p.m., and 11 p.m. When there are watches or warnings, then intermediate advisories are issued at 2 a.m., 8 a.m., 2 p.m., 8 p.m. When a hurricane is close to shore, an advisory might be issued hourly.
Cone of Uncertainty: The cone is not a forecast. The cone is a graphical representation of historical error at various time periods. The cone will have the exact same width for every storm during a hurricane season as it isn’t based on a forecast.
Eye: The circular area of comparatively light winds that encompasses the center of a severe tropical cyclone. The eye is either completely or partially surrounded by the eye-wall.
Eye-wall: An organized band or ring of very high winds and heavy rain that surround the eye of a hurricane. This is the most dangerous part of the hurricane with the highest winds.
Hurricane: A tropical cyclone in which the maximum sustained surface winds are 74 mph or more.
Hurricane Season: The Atlantic hurricane season runs from June 1 to November 30 with a peak around Sept 14.
Hurricane Warning: An announcement that hurricane conditions (sustained winds of 74 mph or higher) are expected somewhere within the specified area. Because hurricane preparedness activities become difficult once winds reach tropical storm force, the hurricane warning is issued 36 hours in advance of the anticipated onset of tropical-storm-force winds.
Hurricane Watch: An announcement that hurricane conditions (sustained winds of 74 mph or higher) are possible within the specified area. 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.
Invest: A tropical weather system which meteorologists are interested in investigating with computer models. Most INVESTs do not turn into named storms. They are numbered 90-99, and the numbers repeat through the season.
Major Hurricane: A hurricane that is classified as Category 3 or higher.
Rapid Intensification: An increase in the maximum sustained winds of a tropical storm or hurricane of at least 30 kt in a 24-hr period.
Saffir-Simpson Hurricane Wind Scale: The Saffir-Simpson Hurricane Wind Scale is a 1 to 5 categorization based on the hurricane's intensity.
Spaghetti Plot: A single graphical display showing various computer models forecast for the track of the tropical cyclone. The lines represent the computer model’s forecast of where the center of the storm is estimated to be 3-5 days in the future. The Spaghetti Plot does not forecast intensity, only track.
Storm Surge: An abnormal rise in water accompanying a hurricane or other intense storm. Storm surge has nothing to do with rainfall. This is the most dangerous part of a hurricane. Historically, most fatalities are caused by surge. Storm Surge Warnings are now issued, they may or may not be in the same coastal area as the Hurricane Warning.
Tropical Depression: A tropical cyclone in which the maximum sustained surface wind speed is 38 mph or less.
Tropical Storm: A tropical cyclone in which the maximum sustained surface wind speed ranges from 39 to 73 mph.
Tropical Storm Warning: Tropical storm conditions (sustained winds of 39 to 73 mph) are expected 36 hours.
Tropical Storm Watch: Tropical storm conditions (sustained winds of 39 to 73 mph) are possible within 48 hours.
Tropical Wave: An open wave in the deep tropics that does not yet have a closed circulation. Some gusty winds and increased shower chances typically accompany tropical waves.
PLEASE NOTE: You can also find this information in the glossary section of our Storm Season 2017 page.