A tropical cyclone tracking chart is used by those within hurricane-threatened areas to track tropical cyclones worldwide. In the north Atlantic basin, they are known as hurricane tracking charts. New tropical cyclone information is available at least every six hours in the Northern Hemisphere and at least every twelve hours in the Southern Hemisphere. Charts include maps of the areas where tropical cyclones form and track within the various basins, include name lists for the year, basin-specific tropical cyclone definitions, rules of thumb for hurricane preparedness, emergency contact information, and numbers for figuring out where tropical cyclone shelters are open.
In paper form originally, computer programs were developed in the 1980s for personal home and use by professional weather forecasters. Those used by weather forecasters saved preparation times, allowing tropical cyclone advisories to be sent an hour earlier. With the advent of the internet in the 1990s, digitally-prepared charts began to include other information along with storm position and past track, including forecast track, areas of wind impact, and related watches and warnings. Geographic information system (GIS) software allows end users to underlay other layered files onto forecast storm tracks to anticipate future impacts.
Tropical cyclone tracking charts were initially used for tropical cyclone forecasting and towards the end of the year for post season summaries of the season's activity. Their use led to a north Atlantic-based term still in use today: Cape Verde hurricane. Prior to the early 1940s, the term Cape Verde hurricane referred to August and early September storms that formed to the east of the surface plotting charts in use at the time. [1] By October 1955, charts used for tropical cyclone tracking and forecasting operationally, such as United States Weather Bureau Form 770-17 and National Weather Service Chart HU-1, extended eastward to the African coast. [2]
Within the United States since at least 1956, [3] during the Atlantic hurricane season, those within threatened states were provided hurricane tracking charts in order to follow tropical storms and hurricanes during the season for situational awareness. This was more popular along sections of the southern Eastern Seaboard and Gulf Coast of the United States than the coast of California due to their increased danger of a landfalling tropical cyclone. The maps would include place names, latitude and longitude lines, [4] names of the storms on that year's list, [5] along with hurricane preparedness information. [6] Newspapers, [3] television stations, [4] radio stations, [7] banks, [4] restaurants, [8] grocery stores, insurance companies, [5] gas stations, the American Red Cross, the Federal Emergency Management Agency, state departments of emergency management, [9] the National Weather Service, [4] and its subagency the National Hurricane Center were the main suppliers of these charts. Companies would distribute these for free as they were considered good advertising. [4] Some would have a table where you could enter data prior to plotting the storm's position, [10] usually using an associated tropical cyclone symbol: open circle for tropical depression, open circle with curved lines on opposite sides of the circle for tropical storms, and a closed circle with curved lines on opposite sides of the circle for hurricanes. [11] The Vanuatu Meteorology and Geo-Hazards Department started preparing special tropical cyclone tracking charts for its archipelago in the 1980s. [12]
Initially, the charts were in paper form. Magnetic charts appeared in 1956. [13] By 1974, laminated paper was used, and by 1977 maps were placed under glass, [4] so that grease pencil, washable marker, or dry erase marker could be used and that the map could be used for multiple seasons. [14] Starting in the 1980s with the increasing popularity of personal computers, programs were available to track the storms digitally, [15] and databases of past storms could be maintained. However, computational space requirements did not allow access to the entire hurricane database for a related basin until the 1990s, with the advent of more powerful computers with megabytes of storage and file quantities became less limited in computer directory structures. Starting in the mid 1990s, with the popularity of the World Wide Web, web sites kept images of old hurricane tracks and interactive web sites allowed you to specify parameters for the storms you wished to display. [16] Ongoing storms have tracking charts with forecast track overlaid. [17] Since 2004, GIS software has been available for hurricane tracking. [18]
Historically, tropical cyclone tracking charts were used to include the past track and prepare future forecasts at Regional Specialized Meteorological Centers and Tropical Cyclone Warning Centers. The need for a more modernized method for forecasting tropical cyclones had become apparent to operational weather forecasters by the mid-1980s. At that time the United States Department of Defense was using paper maps, acetate, grease pencils, and disparate computer programs to forecast tropical cyclones. [19] The Automated Tropical Cyclone Forecasting System (ATCF) software was developed by the Naval Research Laboratory for the Joint Typhoon Warning Center (JTWC) beginning in 1986, [20] and used since 1988. During 1990 the system was adapted by the National Hurricane Center (NHC) for use at the NHC, National Centers for Environmental Prediction and the Central Pacific Hurricane Center. [20] [21] This provided the NHC with a multitasking software environment which allowed them to improve efficiency and cut the time required to make a forecast by 25% or 1 hour. [21] ATCF was originally developed for use within DOS, before later being adapted to Unix and Linux. [20] Despite ATCF's introduction, into the late 1990s, a National Hurricane Center forecaster stated that the most important tools available were "a pair of dividers to measure distance, a ruler, a brush for eraser dirt, three sharp pencils colored red, black, and blue, and a large paper plotting chart". [22]
Symbols used within the charts vary by basin, by center, and by individual preference. Simple dots or circles can be used for each position. The National Hurricane Center uses a variety of symbols composed of overlapping 6's and 9's for tropical storms and hurricanes to emulate their circulation pattern, and a circle for tropical depressions. [23] Other Northern Hemisphere centers used the overlapping 6 and 9 symbols for all tropical cyclones of tropical storm strength, with L's reserved for tropical depressions or general low pressure areas in the tropics. Southern Hemisphere versions would use backward overlapping 6's and 9's. The World Meteorological Organization uses an unfilled symbol to depict tropical storms, a filled symbol to depict systems of cyclone/hurricane/typhoon strength, and a circle to depict a tropical low or tropical convective cluster. [24] Colors of the symbols may be representative of the cyclone's intensity. [25]
Lines or dots connecting symbols can be varying colors, solid, dashed, or symbols between the points depending on the intensity and type of the system being tracked. [26] Different colors could also be used to differentiate storms from one other within the same map. [27] If black and white markings are used, tropical depression track portions can be indicated by dots, with tropical storms indicated by dashes, systems of cyclone/hurricane/typhoon strength using a solid line, intermittent triangles for the subtropical cyclone stage, and intermittent plus signs for the extratropical cyclone phase. [28] Systems of category 3 strength or greater on the Saffir–Simpson scale can be depicted with a thicker line. [29]
In order to use a hurricane tracking chart, one needs access to latitude/longitude pairs of the cyclone's center and maximum sustained wind information in order to know which symbol to depict. New tropical cyclone information is available at least every twelve hours in the Southern Hemisphere and at least every six hours in the Northern Hemisphere from Regional Specialized Meteorological Centers and Tropical Cyclone Warning Centers. [30] [31] [32] [33] [34]
In decades past, newspaper, television, and radio (including weather radio) were primary sources for this information. Local television stations within threatened markets would advertise tropical cyclone positions within the morning, evening, and nightly news during their weather segments. The Weather Channel includes the information within their tropical updates every hour during the Atlantic and Pacific hurricane seasons. Starting in the mid 1990s, the World Wide Web allowed for the development of ftp and web sites by the Bureau of Meteorology in Australia, [35] Canadian Hurricane Centre, [36] Central Pacific Hurricane Center, [37] the Nadi Tropical Cyclone Centre/Fiji Meteorological Service, [38] Japan Meteorological Agency, [39] Joint Typhoon Warning Center, [40] Météo-France La Réunion, National Hurricane Center, [33] and the Philippine Atmospheric, Geophysical and Astronomical Services Administration which allows the end user to get their information from their official products. [41]
The maps either use a mercator projection if restricted to the tropics and subtropics, but can use a Lambert conformal conic projection if the maps reach towards the arctic for the North Atlantic basin where tropical cyclones move more poleward. Meteorologists use these maps to estimate a system's initial position based on aircraft, satellite, and surface data within surface weather analyses. The data is then analyzed to determine recent storm motion and create and convey forecast tracks, wind swaths, uncertainty, related watches, and related warnings to end users of tropical cyclone forecasts.
Hurricane tracking charts allow people to track ongoing systems to form their own opinions regarding where the storms are going and whether or not they need to prepare for the system being tracked, including possible evacuation. This continues to be encouraged by the National Oceanic and Atmospheric Administration and National Hurricane Center. [11] Some agencies provide track storms in their immediate vicinity, [42] while others cover entire ocean basins. One can choose to track one storm per map, use the map until the table is filled, or use one map per season. Some tracking charts have important contact information in case of an emergency or to locate nearby hurricane shelters. [9] Tracking charts allow tropical cyclones to be better understood by the end user. [43]
A number of Hurricane tracker apps are also available online to install directly over a smartphone. By using these apps, one can easily track the current activity of the Hurricanes. Red Cross has also launched several applications for this purpose. [44]
The National Hurricane Center (NHC) is the division of the United States' NOAA/National Weather Service responsible for tracking and predicting tropical weather systems between the Prime Meridian and the 140th meridian west poleward to the 30th parallel north in the northeast Pacific Ocean and the 31st parallel north in the northern Atlantic Ocean. The agency, which is co-located with the Miami branch of the National Weather Service, is situated on the campus of Florida International University in University Park, Miami, Florida.
Tropical cyclones and subtropical cyclones are named by various warning centers to simplify communication between forecasters and the general public regarding forecasts, watches and warnings. The names are intended to reduce confusion in the event of concurrent storms in the same basin. Once storms develop sustained wind speeds of more than 33 knots, names are generally assigned to them from predetermined lists, depending on the basin in which they originate. Some tropical depressions are named in the Western Pacific, while tropical cyclones must contain a significant amount of gale-force winds before they are named in the Southern Hemisphere.
Tropical cyclone warnings and watches are alerts issued by national weather forecasting bodies to coastal areas threatened by the imminent approach of a tropical cyclone of tropical storm or hurricane intensity. They are notices to the local population and civil authorities to make appropriate preparation for the cyclone, including evacuation of vulnerable areas where necessary. It is important that interests throughout the area of an alert make preparations to protect life and property, and do not disregard it on the strength of the detailed forecast track.
The Joint Typhoon Warning Center (JTWC) is a joint United States Navy – United States Air Force command in Pearl Harbor, Hawaii. The JTWC is responsible for the issuing of tropical cyclone warnings in the North-West Pacific Ocean, South Pacific Ocean, and Indian Ocean for all branches of the U.S. Department of Defense and other U.S. government agencies. Their warnings are intended primarily for the protection of U.S. military ships and aircraft, as well as military installations jointly operated with other countries around the world. Its U.S. Navy components are aligned with the Naval Meteorology and Oceanography Command.
A Pacific hurricane is a tropical cyclone that develops within the northeastern and central Pacific Ocean to the east of 180°W, north of the equator. For tropical cyclone warning purposes, the northern Pacific is divided into three regions: the eastern, central, and western, while the southern Pacific is divided into 2 sections, the Australian region and the southern Pacific basin between 160°E and 120°W. Identical phenomena in the western north Pacific are called typhoons. This separation between the two basins has a practical convenience, however, as tropical cyclones rarely form in the central north Pacific due to high vertical wind shear, and few cross the dateline.
A typhoon is a tropical cyclone that develops between 180° and 100°E in the Northern Hemisphere and which produces sustained hurricane-force winds of at least 119 km/h (74 mph). This region is referred to as the Northwestern Pacific Basin, accounting for almost one third of the world's tropical cyclones. The term hurricane refers to a tropical cyclone in the north central and northeast Pacific, and the north Atlantic. In all of the preceding regions, weaker tropical cyclones are called tropical storms. For organizational purposes, the northern Pacific Ocean is divided into three regions: the eastern, central, and western. The Regional Specialized Meteorological Center (RSMC) for tropical cyclone forecasts is in Japan, with other tropical cyclone warning centres for the northwest Pacific in Hawaii, the Philippines, and Hong Kong. Although the RSMC names each system, the main name list itself is coordinated among 18 countries that have territories threatened by typhoons each year.
A tropical cyclone forecast model is a computer program that uses meteorological data to forecast aspects of the future state of tropical cyclones. There are three types of models: statistical, dynamical, or combined statistical-dynamic. Dynamical models utilize powerful supercomputers with sophisticated mathematical modeling software and meteorological data to calculate future weather conditions. Statistical models forecast the evolution of a tropical cyclone in a simpler manner, by extrapolating from historical datasets, and thus can be run quickly on platforms such as personal computers. Statistical-dynamical models use aspects of both types of forecasting. Four primary types of forecasts exist for tropical cyclones: track, intensity, storm surge, and rainfall. Dynamical models were not developed until the 1970s and the 1980s, with earlier efforts focused on the storm surge problem.
James Louis Franklin is a former weather forecaster encompassing a 35-year career with National Oceanic and Atmospheric Administration (NOAA). He served as the first branch chief of the newly formed Hurricane Specialist Unit (HSU) before his retirement in 2017.
A tropical cyclone is a rapidly rotating storm system with a low-pressure center, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain and squalls. Depending on its location and strength, a tropical cyclone is called a hurricane, typhoon, tropical storm, cyclonic storm, tropical depression, or simply cyclone. A hurricane is a strong tropical cyclone that occurs in the Atlantic Ocean or northeastern Pacific Ocean. A typhoon occurs in the northwestern Pacific Ocean. In the Indian Ocean and South Pacific, comparable storms are referred to as "tropical cyclones". In modern times, on average around 80 to 90 named tropical cyclones form each year around the world, over half of which develop hurricane-force winds of 65 kn or more.
Tropical cyclone observation has been carried out over the past couple of centuries in various ways. The passage of typhoons, hurricanes, as well as other tropical cyclones have been detected by word of mouth from sailors recently coming to port or by radio transmissions from ships at sea, from sediment deposits in near shore estuaries, to the wiping out of cities near the coastline. Since World War II, advances in technology have included using planes to survey the ocean basins, satellites to monitor the world's oceans from outer space using a variety of methods, radars to monitor their progress near the coastline, and recently the introduction of unmanned aerial vehicles to penetrate storms. Recent studies have concentrated on studying hurricane impacts lying within rocks or near shore lake sediments, which are branches of a new field known as paleotempestology. This article details the various methods employed in the creation of the hurricane database, as well as reconstructions necessary for reanalysis of past storms used in projects such as the Atlantic hurricane reanalysis.
Tropical cyclone forecasting is the science of forecasting where a tropical cyclone's center, and its effects, are expected to be at some point in the future. There are several elements to tropical cyclone forecasting: track forecasting, intensity forecasting, rainfall forecasting, storm surge, tornado, and seasonal forecasting. While skill is increasing in regard to track forecasting, intensity forecasting skill remains unchanged over the past several years. Seasonal forecasting began in the 1980s in the Atlantic basin and has spread into other basins in the years since.
In meteorology, an invest is a designated area of disturbed weather that is being monitored for potential tropical cyclone development. Invests are designated by three separate United States forecast centers: the National Hurricane Center, the Central Pacific Hurricane Center, and the Joint Typhoon Warning Center.
The following outline is provided as an overview of and topical guide to tropical cyclones:
The practice of using names to identify tropical cyclones goes back several centuries, with storms named after places, saints or things they hit before the formal start of naming in each basin. Examples of such names are the 1928 Okeechobee hurricane and the 1938 New England hurricane. The system currently in place provides identification of tropical cyclones in a brief form that is easily understood and recognized by the public. The credit for the first usage of personal names for weather systems is given to the Queensland Government Meteorologist Clement Wragge, who named tropical cyclones and anticyclones between 1887 and 1907. This system of naming fell into disuse for several years after Wragge retired, until it was revived in the latter part of World War II for the Western Pacific. Over the following decades, formal naming schemes were introduced for several tropical cyclone basins, including the North and South Atlantic, Eastern, Central, Western and Southern Pacific basins as well as the Australian region and Indian Ocean.
The following is a glossary of tropical cyclone terms.
The history of Atlantic tropical cyclone warnings details the progress of tropical cyclone warnings in the North Atlantic Ocean. The first service was set up in the 1870s from Cuba with the work of Father Benito Viñes. After his death, hurricane warning services were assumed by the US Army Signal Corps and United States Weather Bureau over the next few decades, first based in Jamaica and Cuba before shifting to Washington, D.C. The central office in Washington, which would evolve into the National Meteorological Center and the Weather Prediction Center, assumed the responsibilities by the early 20th century. This responsibility passed to regional hurricane offices in 1935, and the concept of the Atlantic hurricane season was established to keep a vigilant lookout for tropical cyclones during certain times of the year. Hurricane advisories issued every 12 hours by the regional hurricane offices began at this time.
The Automated Tropical Cyclone Forecasting System (ATCF) is a piece of software originally developed to run on a personal computer for the Joint Typhoon Warning Center (JTWC) in 1988, and the National Hurricane Center (NHC) in 1990. ATCF remains the main piece of forecasting software used for the United States Government, including the JTWC, NHC, and Central Pacific Hurricane Center. Other tropical cyclone centers in Australia and Canada developed similar software in the 1990s. The data files with ATCF lie within three decks, known as the a-, b-, and f-decks. The a-decks include forecast information, the b-decks contain a history of center fixes at synoptic hours, and the f-decks include the various fixes made by various analysis center at various times. In the years since its introduction, it has been adapted to Unix and Linux platforms.
{{cite book}}
: CS1 maint: multiple names: authors list (link){{cite web}}
: CS1 maint: multiple names: authors list (link){{cite web}}
: CS1 maint: multiple names: authors list (link){{cite book}}
: CS1 maint: multiple names: authors list (link)