An invest in meteorology (short for investigative area, alternatively written 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.
Meteorology is a branch of the atmospheric sciences which includes atmospheric chemistry and atmospheric physics, with a major focus on weather forecasting. The study of meteorology dates back millennia, though significant progress in meteorology did not occur until the 18th century. The 19th century saw modest progress in the field after weather observation networks were formed across broad regions. Prior attempts at prediction of weather depended on historical data. It was not until after the elucidation of the laws of physics and more particularly, the development of the computer, allowing for the automated solution of a great many equations that model the weather, in the latter half of the 20th century that significant breakthroughs in weather forecasting were achieved. An important domain of weather forecasting is marine weather forecasting as it relates to maritime and coastal safety, in which weather effects also include atmospheric interactions with large bodies of water.
A tropical cyclone is a rapidly rotating storm system characterized by a low-pressure center, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain. Depending on its location and strength, a tropical cyclone is referred to by different names, including hurricane, typhoon, tropical storm, cyclonic storm, tropical depression, and simply cyclone. A hurricane is a tropical cyclone that occurs in the Atlantic Ocean and northeastern Pacific Ocean, and a typhoon occurs in the northwestern Pacific Ocean; in the south Pacific or Indian Ocean, comparable storms are referred to simply as "tropical cyclones" or "severe cyclonic storms".
The United States of America (USA), commonly known as the United States or America, is a country composed of 50 states, a federal district, five major self-governing territories, and various possessions. At 3.8 million square miles, the United States is the world's third or fourth largest country by total area and is slightly smaller than the entire continent of Europe's 3.9 million square miles. With a population of over 327 million people, the U.S. is the third most populous country. The capital is Washington, D.C., and the largest city by population is New York City. Forty-eight states and the capital's federal district are contiguous in North America between Canada and Mexico. The State of Alaska is in the northwest corner of North America, bordered by Canada to the east and across the Bering Strait from Russia to the west. The State of Hawaii is an archipelago in the mid-Pacific Ocean. The U.S. territories are scattered about the Pacific Ocean and the Caribbean Sea, stretching across nine official time zones. The extremely diverse geography, climate, and wildlife of the United States make it one of the world's 17 megadiverse countries.
Invests (also called areas of interest) are designated by three separate forecast centers located in the United States: the National Hurricane Center in Miami, Florida, overseeing the North Atlantic and North Eastern Pacific basins (east of the 140°W meridian); the Central Pacific Hurricane Center in Honolulu, Hawaii, monitoring the North Central Pacific basin (between the International Date Line and the 140°W meridian); and the Joint Typhoon Warning Center in Pearl Harbor, Hawaii (formerly located in the island of Guam), serving U.S. government interests elsewhere (like, i.e. the North Western Pacific basin west of the International Date Line). The designation of a system as an invest does not necessarily correspond to any particular likelihood of development of the system into a tropical cyclone (tropical depression, tropical storm, or hurricane/typhoon).
The National Hurricane Center (NHC) is the division of the United States' 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, Florida.
Miami, officially the City of Miami, is the cultural, economic and financial center of South Florida. Miami is the seat of Miami-Dade County, the most populous county in Florida. The city covers an area of about 56.6 square miles (147 km2), between the Everglades to the west and Biscayne Bay on the east; with a 2017 estimated population of 463,347, Miami is the sixth most densely populated major city in the United States. The Miami metropolitan area is home to 6.1 million people and the seventh-largest metropolitan area in the nation. Miami's metro area is the second-most populous metropolis in the southeastern United States and fourth-largest urban area in the U.S. Miami has the third tallest skyline in the United States with over 300 high-rises, 80 of which stand taller than 400 feet.
Florida is the southernmost contiguous state in the United States. The state is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Atlantic Ocean, and to the south by the Straits of Florida. Florida is the 22nd-most extensive, the 3rd-most populous, and the 8th-most densely populated of the U.S. states. Jacksonville is the most populous municipality in the state and the largest city by area in the contiguous United States. The Miami metropolitan area is Florida's most populous urban area. Tallahassee is the state's capital.
|INVEST Numbering (NHC/CPHC/JTWC)|
| NE Pacific |
(E of 140°W)
| NC Pacific |
(E of IDL, W of 140°W)
| NW Pacific |
(W of IDL)
| N Indian O. |
(Bay of Bengal)
| N Indian O. |
| SW Indian O. & Australian reg. |
(W of 135°E)
| Australian reg. & S Pacific |
(E of 135°E)
|S Atlantic||NRL , NHC||Q||Invest-98Q|
Invests are numbered from 90 to 99, followed by a suffix letter "L" in the North Atlantic basin, "E" and "C" in the Eastern and Central Pacific basins (respectively), or "W" in the Western Pacific basin.
The Joint Typhoon Warning Center also issues unofficial warnings for U.S. government interests (predominantly military) in the Southern Hemisphere, designating tropical invests with the "S" suffix when they form west of 135°E (this spans the whole South Indian Ocean, including the South-Western Indian Ocean basin and the western half of the Australian-region basin), and the "P" suffix when they form east of 135°E (spans both the eastern half of the Australian region and the South Pacific basin). In addition, invests in the North Indian Ocean cyclone basin are also labelled by the JTWC, and are suffixed with "A" if they form in the Arabian Sea and with "B" if they form in the Bay of Bengal.
The Joint Typhoon Warning Center (JTWC) is a joint United States Navy – United States Air Force command located 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 for the protection of primarily military ships and aircraft as well as military installations jointly operated with other countries around the world.
The Indian Ocean is the third largest of the world's oceanic divisions, covering 70,560,000 km2 (27,240,000 sq mi). It is bounded by Asia on the north, on the west by Africa, on the east by Australia, and on the south by the Southern Ocean or, depending on definition, by Antarctica.
In the south-west Indian Ocean, tropical cyclones form south of the equator and west of 90° E to the coast of Africa.
The Naval Research Laboratory's Marine Meteorology Division also uses the "Q" suffix to designate invests which form in the South Atlantic Ocean,even though it is not recognized as an official tropical cyclone basin by the World Meteorological Organization.
South Atlantic tropical cyclones are unusual weather events that occur in the Southern Hemisphere. Strong wind shear, which disrupts the formation of cyclones, as well as a lack of weather disturbances favorable for development in the South Atlantic Ocean make any strong tropical system extremely rare, and Hurricane Catarina in 2004 is the only recorded South Atlantic hurricane in history. South Atlantic storms have developed year-round, with activity peaking during the months from November through May in this basin. Since 2011, the Brazilian Navy Hydrographic Center has assigned names to tropical and subtropical systems in the western side of the basin, near Brazil, when they have sustained wind speeds of at least 65 km/h (40 mph), the generally accepted minimum sustained wind speed for a disturbance to be designated as a tropical storm in the North Atlantic basin. Below is a list of notable South Atlantic tropical and subtropical cyclones.
The World Meteorological Organization (WMO) is an intergovernmental organization with a membership of 192 Member States and Territories. Its current Secretary-General is Petteri Taalas and the President of the World Meteorological Congress, its supreme body, is David Grimes. The Organization is headquartered in Geneva, Switzerland.
These suffix letters (with the usual exception of "L") are also used with the tropical cyclone numbers (TC numbers for short) assigned to tropical and subtropical depressions (and potential tropical cyclones) monitored by the NHC & CPHC (North Atlantic systems are usually designated by TC numbers without a suffix letter; the "L" is still used, however, by the NRL for this basin) and all tropical, subtropical, and potential tropical cyclones tracked by the JTWC.
Numbers are rotated within the season and are re-used as necessary (the next invest after 99 would be numbered 90). In contrast, TC numbers (which start each year/season with 01 and run upwards, usually up to 30 in NHC and CPHC-monitored basins;the hard-coded limit imposed by the Automated Tropical Cyclone Forecasting System is 49) assigned to proper cyclones (tropical, subtropical, and potential tropical) are not recycled until the following year/season. If the invest system develops into a (sub)tropical cyclone, it is reclassified as the next name/number on the list (a TC number if evolving into a depression or JTWC cyclone; or a name if evolving quickly into a tropical or subtropical storm, bypassing the depression stage).
Tropical cyclones and subtropical cyclones are named by various warning centers to provide ease of 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. Generally once storms produce sustained wind speeds of more than 33 knots, names are assigned in order from predetermined lists depending on which basin they originate. However, standards vary from basin to basin: some tropical depressions are named in the Western Pacific, while tropical cyclones must have a significant amount of gale-force winds occurring around the centre 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.
A Pacific hurricane is a mature tropical cyclone that develops within the eastern 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.
Tropical cyclones are unofficially ranked on one of five tropical cyclone intensity scales, according to their maximum sustained winds and which tropical cyclone basin(s) they are located in. Only a few scales of classifications are used officially by the meteorological agencies monitoring the tropical cyclones, but some alternative scales also exist, such as accumulated cyclone energy, the Power Dissipation Index, the Integrated Kinetic Energy Index, and the Hurricane Severity Index.
A Regional Specialized Meteorological Centre is responsible for the distribution of information, advisories, and warnings regarding the specific program they have a part of, agreed by consensus at the World Meteorological Organization as part of the World Weather Watch.
Traditionally, areas of tropical cyclone formation are divided into seven basins. These include the north Atlantic Ocean, the eastern and western parts of the northern Pacific Ocean, the southwestern Pacific, the southwestern and southeastern Indian Oceans, and the northern Indian Ocean. The western Pacific is the most active and the north Indian the least active. An average of 86 tropical cyclones of tropical storm intensity form annually worldwide, with 47 reaching hurricane/typhoon strength, and 20 becoming intense tropical cyclones, super typhoons, or major hurricanes.
Hurricane Ekeka was the most intense off-season tropical cyclone on record in the north-eastern pacific basin. The first storm of the 1992 Pacific hurricane season, Ekeka developed on January 28 well to the south of Hawaii. It gradually intensified to reach major hurricane status on February 2, although it subsequently began to weaken due to unfavorable wind shear. It crossed the International Date Line as a weakened tropical storm, and shortly thereafter degraded to tropical depression status. Ekeka continued westward, passing through the Marshall Islands and later over Chuuk State, before dissipating on February 9 about 310 miles (500 km) off the north coast of Papua New Guinea. The storm did not cause any significant damage or deaths.
Tropical cyclones of 2010 were spread across seven oceanic basins in their respective seasons; the strongest of these tropical cyclones was Typhoon Megi (2010), which strengthened to a minimum barometric pressure of 885 mbar before striking the east coast of Luzon in the Philippines. Regional Specialized Meteorological Centers (RSMC) and Tropical Cyclone Warning Centers (TCWC) designated names to 70 systems worldwide, of which 46 occurred in the northern hemisphere while 21 developed in the southern hemisphere. The most active basin in 2010 was the North Atlantic, which documented 19 named systems, while the North Indian Ocean, despite only amounting to five named systems, was its basin's most active since 1998. Conversely, both the West Pacific typhoon and East Pacific hurricane seasons experienced the least number of cyclones reaching tropical storm intensity in recorded history, numbering 14 and 8, respectively. Activity across the southern hemisphere's three basins—South-West Indian, Australian, and South Pacific—was spread evenly, with each region recording seven named storms apiece. That hemisphere's strongest tropical cyclone was Cyclone Edzani, which bottomed out with a barometric pressure of 910 mbar in the South-West Indian Ocean.
The following is a glossary of tropical cyclone terms.
The 2017–18 South Pacific cyclone season was a slightly below-average season that produced 6 tropical cyclones, 3 of which became severe tropical cyclones. The season officially began on November 1, 2017 and ended on April 30, 2018; however, a tropical cyclone could form at any time between July 1, 2017 and June 30, 2018 and would count towards the season total. During the season, tropical cyclones were officially monitored by the Fiji Meteorological Service, MetService and the Australian Bureau of Meteorology, while the United States Joint Typhoon Warning Center (JTWC) also monitored the basin and issued warnings for American interests. The FMS attaches a number and an F suffix to significant tropical disturbances that form in or move into the basin, while the JTWC designates significant tropical cyclones with a number and a P suffix. The BoM, FMS and MetService all use the Australian Tropical Cyclone Intensity Scale and estimate wind speeds over a period of ten minutes, while the JTWC estimates sustained winds over a 1-minute period, which are subsequently compared to the Saffir–Simpson hurricane wind scale (SSHWS).
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.
Hurricane Genevieve, also referred to as Typhoon Genevieve, was the fourth-most intense tropical cyclone of the North Pacific Ocean in 2014. A long-lasting system, Genevieve was the first one 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.
Hurricane Hector was a powerful and long-lived tropical cyclone that was the first to traverse all three North Pacific basins since Genevieve in 2014. The eighth named storm, fourth hurricane, and third major hurricane of the 2018 Pacific hurricane season, Hector originated from an area of low pressure that formed a couple hundred miles west-southwest of Mexico on July 28. Amid favorable weather conditions, a tropical depression formed a few days later on July 31. The depression continued strengthening and became Tropical Storm Hector on the next day. Hector became a hurricane on August 2, and rapidly intensified into a strong Category 2 hurricane later in the day. After weakening while undergoing an eyewall replacement cycle, Hector quickly strengthened into a Category 4 hurricane late on August 5. Over the next week, Hector fluctuated in intensity multiple times due to eyewall replacement cycles and shifting wind shear. Hector achieved its peak intensity on August 6, as a high-end Category 4 hurricane with winds of 155 mph (250 km/h). On the following day, the hurricane bypassed Hawaii approximately 200 mi (320 km) to the south. Increasing wind shear resulted in steady weakening of the storm, beginning on August 11. At that time, Hector accumulated the longest continuous stretch of time as a major hurricane in the northeastern Pacific since reliable records began. Eroding convection and dissipation of its eye marked its degradation to a tropical storm on August 13. The storm subsequently traversed the International Dateline that day. Hector later weakened into a tropical depression on August 15, before dissipating late on August 16.
Tropical cyclones in 2015 were spread out across seven different areas called basins; the strongest of these tropical cyclones was Hurricane Patricia, which strengthened to a minimum barometric pressure of 872 mbar before striking the east coast of Colima in Mexico. 133 tropical cyclones had formed this year to date. 92 tropical cyclones had been named by either a Regional Specialized Meteorological Center (RSMC) or a Tropical Cyclone Warning Center (TCWC).
Tropical cyclones in 2019 are spread out across seven different areas called basins and the Mediterranean Sea. Currently, 33 systems have formed during the year to date. 19 tropical cyclones have been named by either a Regional Specialized Meteorological Center (RSMC) or a Tropical Cyclone Warning Center (TCWC).
Tropical cyclones in 2014 were spread out across seven different areas called basins; the strongest of these tropical cyclones was Typhoon Vongfong, which strengthened to a minimum barometric pressure of 900 mbar before striking the east coast of Japan. 119 tropical cyclones had formed this year to date. 82 tropical cyclones had been named by either a Regional Specialized Meteorological Center (RSMC) or a Tropical Cyclone Warning Center (TCWC). The most active basin in 2014 was the Western Pacific, which documented 23 named systems, while the Eastern Pacific, despite only amounting to 22 named systems, was its basin's most active since 1992. Conversely, both the North Atlantic hurricane and North Indian Ocean cyclone seasons experienced the least number of cyclones reaching tropical storm intensity in recorded history, numbering 9 and 3, respectively. Activity across the southern hemisphere's three basins—South-West Indian, Australian, and South Pacific—was spread evenly, with each region recording seven named storms apiece.
Tropical cyclones in 2016 were spread out across seven different areas called basins; the strongest of these tropical cyclones was Cyclone Winston, which strengthened to a minimum barometric pressure of 884 mbar before striking Fiji. 139 tropical cyclones had formed this year to date. 84 tropical cyclones had been named by either a Regional Specialized Meteorological Center (RSMC) or a Tropical Cyclone Warning Center (TCWC). The most active basin in 2016 was the Western Pacific, which documented 26 named systems.
Tropical cyclones in 2004 were spread out across seven different areas called basins; the strongest of these tropical cyclones was Cyclone Gafilo, which strengthened to a minimum barometric pressure of 895 mbar becomes the most intense tropical cyclone ever recorded in the South-West Indian Ocean before striking the east coast of Madagascar. 130 tropical cyclones had formed this year to date. 81 tropical cyclones had been named by either a Regional Specialized Meteorological Center (RSMC) or a Tropical Cyclone Warning Center (TCWC). The most active basin in 2004 was the Western Pacific, which documented 29 named systems, while the North Atlantic, despite only amounting to 15 named systems, was its basin's hyperactive season since 1995. Conversely, both the Eastern Pacific hurricane and North Indian Ocean cyclone seasons experienced the least number of cyclones reaching tropical storm intensity in recorded history, numbering 12 and 4, respectively. Activity across the southern hemisphere's three basins—South-West Indian, Australian, and South Pacific—was spread evenly, with each region recording seven named storms apiece.