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.
History
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. 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. Within the United States since at least 1956, 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, names of the storms on that year's list, along with hurricane preparedness information. Newspapers, television stations, radio stations, banks, restaurants, grocery stores, insurance companies, gas stations, the American Red Cross, the Federal Emergency Management Agency, state departments of emergency management, the National Weather Service, 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. Some would have a table where you could enter data prior to plotting the storm's position, 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. The Vanuatu Meteorology and Geo-Hazards Department started preparing special tropical cyclone tracking charts for its archipelago in the 1980s. Initially, the charts were in paper form. Magnetic charts appeared in 1956. By 1974, laminated paper was used, and by 1977 maps were placed under glass, so that grease pencil, washable marker, or dry erase marker could be used and that the map could be used for multiple seasons. Starting in the 1980s with the increasing popularity of personal computers, programs were available to track the storms digitally, 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. Ongoing storms have tracking charts with forecast track overlaid. Since 2004, GIS software has been available for hurricane tracking.
Move away from paper use operationally
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. 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, 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. 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. ATCF was originally developed for MS-DOS, before being adapted to Unix and Linux. 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".
Markings used
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