A subtropical cyclone is a weather system that has some characteristics of both tropical and extratropical cyclones.
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.
The Central Pacific Hurricane Center (CPHC) of the United States National Weather Service is the official body responsible for tracking and issuing tropical cyclone warnings, watches, advisories, discussions, and statements for the Central Pacific region: from the equator northward, 140°W–180°W, most significantly for Hawai‘i. It is the Regional Specialized Meteorological Center (RSMC) for tropical cyclones in this region, and in this capacity is known as RSMC Honolulu.
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 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.
The Dvorak technique is a widely used system to estimate tropical cyclone intensity based solely on visible and infrared satellite images. Within the Dvorak satellite strength estimate for tropical cyclones, there are several visual patterns that a cyclone may take on which define the upper and lower bounds on its intensity. The primary patterns used are curved band pattern (T1.0-T4.5), shear pattern (T1.5–T3.5), central dense overcast (CDO) pattern (T2.5–T5.0), central cold cover (CCC) pattern, banding eye pattern (T4.0–T4.5), and eye pattern (T4.5–T8.0).
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.
The Hurricane Databases (HURDAT), managed by the National Hurricane Center (NHC), are two separate databases that contain details on tropical cyclones that have occurred within the Atlantic Ocean and Eastern Pacific Ocean since 1851 and 1949 respectively.
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 2010 Pacific typhoon season, with 14 named storms, was the least active Pacific typhoon season on record. Seven of them strengthened into typhoons while one reached super typhoon intensity. All of the 14 named storms developed west of 150°E.
Typhoon Oliwa was one of a record eleven super typhoons in the 1997 Pacific typhoon season. Oliwa formed in the central Pacific Ocean on September 2 to the southwest of Hawaii, but it became a typhoon in the western Pacific. Oliwa explosively intensified on September 8, increasing its winds from 85 mph to 160 mph in a 24‑hour period. Afterward, it slowly weakened, and after passing east of Okinawa, Oliwa turned northeast and struck Japan with winds of 85 mph (137 km/h). There, it affected 30,000 people and killed 12; thousands of houses were flooded, and some were destroyed. Offshore South Korea, the winds and waves wrecked 28 boats, while one boat went missing with a crew of 10 people. Oliwa dissipated on September 19 in northern Pacific Ocean near the International Date Line.
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 1951 Pacific hurricane season ran through the summer and fall of 1951. Nine tropical systems were observed during the season.
Hurricane Genevieve, also referred to as Typhoon Genevieve, was the first tropical cyclone to track across all three northern Pacific basins since Hurricane Dora in 1999. Genevieve developed from a tropical wave into the eighth tropical storm of the 2014 Pacific hurricane season well east-southeast of Hawaii on July 25. However, increased vertical wind shear caused it to weaken into a tropical depression by the following day and degenerate into a remnant low on July 28. Late on July 29, the system regenerated into a tropical depression, but it weakened into a remnant low again on July 31, owing to vertical wind shear and dry air.
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.
During 1991, tropical cyclones formed within seven different tropical cyclone basins, located within various parts of the Atlantic, Pacific and Indian Oceans. During the year, a total of 100 systems formed with 75 of these developing further and were named by the responsible warning centre. The strongest tropical cyclone of the year was Typhoon Yuri, which was estimated to have a minimum barometric pressure of 895 hPa (26.43 inHg). The deadliest tropical cyclone was Cyclone BOB 01, which caused 138,866 fatalities in Bangladesh, Northeastern India, Myanmar, Yunnan, while the costliest was Typhoon Mireille, which caused an estimated $10 billion USD in damage after striking Japan. Four Category 5 tropical cyclones formed in 1991.
