Which is it, Hurricane or Typhoon or Cyclone?
“Cyclone” is a powerful word in meteorology. It has come to refer to an area of winds that are rotating in a counter-clockwise manner in the Northern Hemisphere or clockwise in the Southern Hemisphere. The word “Hurricane” used in the North Atlantic and Northeast Pacific, is derived from huracán, the Spanish word for the Carib/Taino storm god, Juracán. The word “Typhoon” is used in the Northwest Pacific, originates from Greek Typhon, a monster from Greek mythology associated with storms. The word is also similar to Chinese "táifēng". An English merchant skipper studied tropical storms from Calcutta in the 1800’s and coined the term cyclone, meaning the coil of a snake.
A tropical cyclone is a rapidly rotating storm system characterized by a low-pressure center, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain. Tropical refers to the geographical origin of these systems, which form almost exclusively over tropical seas. Cyclone refers to their cyclonic nature, with wind blowing counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere. The opposite direction of circulation is due to the Coriolis effect.
Tropical cyclones typically form over large bodies of relatively warm water. They derive their energy through the evaporation of water from the ocean surface. This energy source differs from that of mid-latitude cyclonic storms, such as nor'easters and European windstorms, which are fueled primarily by horizontal temperature contrasts. The strong rotating winds of a tropical cyclone are a result of the Earth's rotation as air flows inwards toward the axis of rotation. As a result, they rarely form within 5° of the equator.
What’s With The Scales?
The “Scales” refers to the Saffir-Simpson Hurricane Wind Scale. This ranges from 1 to 5 and is based on a hurricane's sustained wind speed. This scale estimates potential property damage. Hurricanes reaching Category 3 and higher are considered major hurricanes because of their potential for significant loss of life and damage. Category 1 and 2 storms are still dangerous and require preventative measures. In the western North Pacific, the term "super typhoon" is used for tropical cyclones with sustained winds exceeding 130KTS. Below here is a relative timeline of storm development.
Tropical Disturbance, A discrete tropical weather system of apparently organized convection originating in the tropics or subtropics, having a non-frontal migratory character, and maintaining its identity for 24 hours or more.
Tropical Depression, A tropical cyclone in which the maximum sustained surface wind speed of <33KTS
Tropical Storm, sustained surface wind speed ranges from 34-63KTS. This is the stage were names are applied.
Category 1 Hurricane, surface wind speed ranges from 64-82KTS. Very dangerous winds will produce extensive damage to power lines and poles likely will result in power outages that could last a few to several days.
Category 2 Hurricane, surface wind speed ranges from 83-95KTS. Winds will cause extensive damage. Many shallowly rooted trees will be snapped or uprooted and block numerous roads.
Category 3 Hurricane, surface wind speed ranges from 96-112KTS This begins the “Major” level. Devastating damage will occur. Well-built framed homes may incur major damage or removal of roof decking and gable ends. Electricity and water will be unavailable for several days to weeks after the storm passes.
Category 4 Hurricane, surface wind speed ranges from 113-136KTS
Catastrophic damage will occur. Well-built framed homes can sustain severe damage with loss of most of the roof structure and/or some exterior walls. Most trees will be snapped or uprooted and power poles downed. Power outages will last weeks to possibly months. Most of the area will be uninhabitable for weeks or months.
Category 5 Hurricane, >137KTS. Catastrophic damage will occur. A high percentage of framed homes will be destroyed, with total roof failure and wall collapse. Fallen trees and power poles will isolate residential areas. Power outages will last for weeks to possibly months. Most of the area will be uninhabitable for weeks or months.
So Why Make-Up Names?
The idea here is to provide positive identification of severe weather systems in a brief form, which is readily understood and recognized by the public and across hurricane track centers worldwide. The first usage of personal names for weather systems is generally accredited to an Australian Meteorologist from the late 1800’s. During World War II, storms in the Western Pacific were named after wives or girlfriends of the US Navy meteorologist first identifying the storm. Formal naming schemes have subsequently been introduced for the North and South Atlantic, Eastern, Central, Western and Southern Pacific basins as well as the Australian region and Indian Ocean. At present tropical cyclones are officially named by one of eleven meteorological services and retain their names throughout their “lifetime”. Unusually destructive storm names are “Retired” from active use.
2017 Atlantic Hurricane Season
The season officially began on June 1, 2017, and will end on November 30, 2017. These dates historically describe the period each year when most tropical cyclones form in the Atlantic basin. This year is unusual in that, Tropical Storm Arlene formed on April 19, nearly a month and a half before the official start of the season. It is only the second named storm on record to exist in the month in April.
The first forecast for the year was issued in December 2016. They anticipated that the 2017 season would be a near-average season, with a prediction of 14 named storms, 6 hurricanes, and 3 major hurricanes. On May 26, this prediction was updated to around the same numbers as its December 2016 prediction.The following list of names will be used for named storms that form in the North Atlantic in 2017. Arlene, Bret, Cindy, Don, Emily, Franklin, Gert, Harvey, Irma, Jose, Katia, Lee, Maria, Nate, Ophelia, Philippe, Rina, Sean, Tammy, Vince, Whitney.
2017 Pacific Hurricane Season
Based on tropical cyclones formed in the northeastern Pacific Ocean, the season officially started on May 15 in the eastern Pacific, and started on June 1 in the central Pacific. Both of these seasons will end on November 30. The formation of tropical cyclones is possible at any time of the year. For example, Tropical Storm Adrian, was named on May 10 and became the earliest-known tropical storm in the East Pacific since the advent of satellite imagery. On May 25, 2017, the National Oceanic and Atmospheric Administration released its annual forecast for this region. NOAA is predicting a 80% chance of a near- to above-average season in both the Eastern and Central Pacific basins, with a total of 14–20 named storms, 6–11 hurricanes, and 3–7 major hurricanes.
The following names will be used for named storms that form in the northeastern Pacific Ocean during 2017. Adrian, Beatriz, Calvin, Dora, Eugene, Fernanda, Greg, Hilary, Irwin, Jova, Kenneth, Lidia, Max, Norma, Otis, Pilar, Ramon, Selma, Todd, Veronica, Wiley, Xina, York, Zelda.
2017 Pacific Typhoon Season
Based on tropical cyclones formed in the western Pacific Ocean, there is no specific season. Most tropical cyclones typically develop into Typhoons between May and October. The season's first named storm, Muifa, developed on April 26. This region is limited to the Pacific Ocean to the north of the equator between 100° E to the 180th meridian. There are two separate agencies that assign names to tropical cyclones here that can result in a cyclone having two names. The Japan Meteorological Agency, JMA will name a tropical cyclone should it be judged to have 10-minute sustained wind speeds of at least 40 mph anywhere in the Pacific basin. The Philippine Atmospheric, Geophysical and Astronomical Services Administration, PAGASA assigns names to tropical cyclones which move into or form as a tropical depression in their area of responsibility located between 115°E–135°E and between 5°N–25°N regardless of whether or not a tropical cyclone has already been given a name by the JMA.
The JMA selected the names from a list of 140 names, that had been developed by the 14 members nations and territories of the ESCAP/WMO Typhoon Committee: Merbok, Nanmadol, Talas, Noru, Kulap, Roke, Sonca, Nesat, Haitang, Nalgae, Banyan Hato, Pakhar, Sanvu, Mawar, Guchol, Talim, Doksuri, Khanun, Lan, Saola, Damrey
2017 North Indian Ocean Cyclone Season
The North Indian Ocean cyclone season has no official bounds. Tropical cyclones tend to form between April and December, with the two peaks in May and November. There are two main seas in the North Indian Ocean. The Arabian Sea to the west of the India and the Bay of Bengal to the east. On average, three to four cyclonic storms form in this basin every season. The next six available names from the List of North Indian Ocean storm names are here: Maarutha, Mora, Ockhi, Sagar, Mekunu, Daye.
So How Do I Predict And Track These Storms?
Two big players in Atlantic hurricane predictions are the National Oceanic and Atmospheric Administration, NOAA and Colorado State University’s Tropical Meteorology Project.
NOAA maintains a National Hurricane Center website. This provides 30-Day and closer forecasts of potential and actually forming storms in the Atlantic and Pacific regions, here is a link
NOAA also produces a Global Tropics Benefits/Hazards 1 and 2 Week forecasts. Here is a link
United States Joint Typhoon Warning Center, JTWC . Here’s a link:
My favorite apps for you iPhone and Hurricane tracking are:
Hurricane Tracker, By EZ Apps, Inc. and Hurricane Tracker By HurricaneSoftware.com