Potential Tropical Cyclone Ten was a damaging storm that was the tenth

tropical disturbance Tropical cyclones are ranked on one of five tropical cyclone intensity scales, according to their maximum sustained winds and which tropical cyclone basins they are located in. Only a few classifications are used officially by the meteorologica ...

designated by the

National Hurricane Center 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 IERS Reference Meridian, Prime Meridian and the 140th meridian ...

(NHC) during the

2017 Atlantic hurricane season The 2017 Atlantic hurricane season was a devastating and extremely active Atlantic hurricane season that became the costliest tropical cyclone season on record worldwide, with a damage total of at least $294.92 billion (USD). It was the second c ...

. The disturbance was deemed to have a very high chance of becoming a tropical cyclone while posing a threat to populated areas and was designated a "

Potential Tropical Cyclone The following is a glossary of tropical cyclone terms. A ;Advisory: Official information issued by tropical cyclone warning centers describing all tropical cyclone watches and warnings in effect along with details concerning tropical cyclone loc ...

". The storm caused flooding and brought

tropical storm A tropical cyclone is a rapidly rotating storm system with a low-pressure area, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain and squalls. Depending on its lo ...

-force winds to parts of the

Southeastern United States The Southeastern United States, also known as the American Southeast or simply the Southeast, is a geographical List of regions in the United States, region of the United States located in the eastern portion of the Southern United States and t ...

and the

Mid-Atlantic states The Mid-Atlantic is a region of the United States located in the overlap between the nation's Northeastern and Southeastern states. Traditional definitions include seven U.S. states: New York, New Jersey, Pennsylvania, Delaware, Maryland, Virg ...

, particularly Florida and the

Carolinas The Carolinas, also known simply as Carolina, are the U.S. states of North Carolina and South Carolina considered collectively. They are bordered by Virginia to the north, Tennessee to the west, and Georgia (U.S. state), Georgia to the southwes ...

, before it affected parts of

Atlantic Canada Atlantic Canada, also called the Atlantic provinces (), is the list of regions of Canada, region of Eastern Canada comprising four provinces: New Brunswick, Newfoundland and Labrador, Nova Scotia, and Prince Edward Island. As of 2021, the landma ...

. Potential Tropical Cyclone Ten was the tenth storm that had advisories issued on it by the NHC in 2017, and the only such system that failed to fully develop into a tropical cyclone during that Atlantic hurricane season. Potential Tropical Cyclone Ten originated from a

tropical wave A tropical wave (also called easterly wave, tropical easterly wave, and African easterly wave), in and around the Atlantic Ocean, is a type of atmospheric trough, an elongated area of relatively low air pressure, oriented north to south, which ...

that moved off the coast of

West Africa West Africa, also known as Western Africa, is the westernmost region of Africa. The United Nations geoscheme for Africa#Western Africa, United Nations defines Western Africa as the 16 countries of Benin, Burkina Faso, Cape Verde, The Gambia, Gha ...

on August 13. The disturbance slowly tracked its way westward across the Atlantic Ocean, before reaching Florida in late August. The disturbance came close to developing into a tropical storm while it was situated off the coast of the Carolinas; however, strong

wind shear Wind shear (; also written windshear), sometimes referred to as wind gradient, is a difference in wind speed and/or direction over a relatively short distance in the atmosphere. Atmospheric wind shear is normally described as either vertical ...

and

outflow Outflow may refer to: *Capital outflow, the capital leaving a particular economy *Bipolar outflow, in astronomy, two continuous flows of gas from the poles of a star * Outflow (hydrology), the discharge of a lake or other reservoir system *Outflow ...

from

Hurricane Harvey Hurricane Harvey was a devastating tropical cyclone that made landfall in Texas and Louisiana in August 2017, causing catastrophic flooding and more than 100 deaths. It is tied with 2005's Hurricane Katrina as the costliest tropical cy ...

prevented the storm from organizing into a tropical cyclone. The system transitioned into an

extratropical cyclone Extratropical cyclones, sometimes called mid-latitude cyclones or wave cyclones, are low-pressure areas which, along with the anticyclones of high-pressure areas, drive the weather over much of the Earth. Extratropical cyclones are capable of p ...

instead, and became a strong hurricane-force low to the south of

Newfoundland Newfoundland and Labrador is the easternmost province of Canada, in the country's Atlantic region. The province comprises the island of Newfoundland and the continental region of Labrador, having a total size of . As of 2025 the population ...

, before being absorbed by another extratropical system near

Iceland Iceland is a Nordic countries, Nordic island country between the Atlantic Ocean, North Atlantic and Arctic Oceans, on the Mid-Atlantic Ridge between North America and Europe. It is culturally and politically linked with Europe and is the regi ...

on September 3. The storm caused flooding across Florida, especially around

Fort Myers A fortification (also called a fort, fortress, fastness, or stronghold) is a military construction designed for the defense of territories in warfare, and is used to establish rule in a region during peacetime. The term is derived from Lati ...

and other areas in southwestern Florida, forcing the evacuation of more than 200 people. The disturbance dropped a maximum total of rainfall in excess of of rain in Ten Mile Canal and

Six Mile Cypress Slough Preserve The Six Mile Cypress Slough Preserve is a 3,500 acre wetland, located in Fort Myers, Florida, which filters rainwater on its way towards Estero Bay. The preserve contains a 1.2-mile boardwalk trail, interpretive center, and amphitheater. The sl ...

, in southwestern Florida, in addition to of rain in the western parts of

. The flooding was the worst seen in western Florida in at least 20 years. Overall, the storm killed two people and caused more than $1.923 million (2017

USD The United States dollar (symbol: $; currency code: USD) is the official currency of the United States and several other countries. The Coinage Act of 1792 introduced the U.S. dollar at par with the Spanish silver dollar, divided it int ...

) in damages. Less than two weeks after the storm,

Hurricane Irma Hurricane Irma was an extremely powerful and devastating tropical cyclone that was the first Category 5 hurricane to strike the Leeward Islands on record, followed by Hurricane Maria, Maria two weeks later. At the time, it was considered ...

made landfall in southwestern Florida, which further compounded the damage in the region.

Background

Beginning in 2017, the

(NHC) decided to issue advisories, and thus allow watches and warnings to be issued on disturbances that are not yet tropical cyclones but have a high chance to become one, and are expected to bring tropical storm or hurricane conditions to landmasses within 48 hours. Such systems are termed " Potential Tropical Cyclones". Advisories on these storms contain the same content as typical tropical cyclone advisories, including track forecasts, and cyclone watches and warnings, similar to advisories that the NHC issues on active tropical cyclones. This was first demonstrated on June 18 with the designation of Potential Tropical Cyclone Two, which later developed into

Tropical Storm Bret The name Bret has been used for eight tropical cyclones in the Atlantic Ocean The Atlantic Ocean is the second largest of the world's five borders of the oceans, oceanic divisions, with an area of about . It covers approximately 17% of Earth ...

, east-southeast of the

Windward Islands The Windward Islands are the southern, generally larger islands of the Lesser Antilles of the Caribbean islands or the West Indies. Located approximately between latitudes 10° and 16° N and longitudes 60° and 62° W, they extend from D ...

. In addition, the numbering that a potential tropical cyclone receives would be retained for the rest of the hurricane season, meaning that the next tropical system or disturbance would be designated with the following number, even though potential tropical cyclones are not treated as tropical cyclones. This was first demonstrated with Potential Tropical Cyclone Ten, which failed to develop into a tropical cyclone. After that storm's formation and dissipation, one of the following tropical systems, which would eventually become Hurricane Katia, was designated as "Tropical Depression Thirteen", even though the Atlantic hurricane season had a total of only 12 tropical cyclones at that point. Potential Tropical Cyclone Ten was the first system so designated not to become an organize as a tropical cyclone.

Meteorological history

At the beginning of August 13, the

(NHC) began monitoring a

on the western coast of

Africa Africa is the world's second-largest and second-most populous continent after Asia. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surfac ...

, which quickly emerged into the eastern Atlantic. Amid favorable environmental conditions, the wave was expected to merge with a broad

area of low pressure In meteorology, a low-pressure area (LPA), low area or low is a region where the atmospheric pressure is lower than that of surrounding locations. It is the opposite of a high-pressure area. Low-pressure areas are commonly associated with inclem ...

southwest of

Cape Verde Cape Verde or Cabo Verde, officially the Republic of Cabo Verde, is an island country and archipelagic state of West Africa in the central Atlantic Ocean, consisting of ten volcanic islands with a combined land area of about . These islands ...

and gradually organize thereafter. Instead, the two disturbances remained separate, with the broad

trough Trough may refer to: In science * Trough (geology), a long depression less steep than a trench * Trough (meteorology), an elongated region of low atmospheric pressure * Trough (physics), the lowest point on a wave * Trough level (medicine), the l ...

to the west continuing westward and the tropical wave moving farther north. The system farther to the west accelerated further and eventually developed into Tropical Storm Harvey on August 17 (which later became a hurricane), while the tropical wave to the east lagged behind. On August 18, the disturbance behind Harvey became increasingly organized and was given a 70% chance of developing into a tropical cyclone within 2 days; however, increased wind shear weakened the system and prevented it from attaining full tropical characteristics. The disturbance remained disorganized while moving northwestward over the next several days, reaching the

Bahamas The Bahamas, officially the Commonwealth of The Bahamas, is an archipelagic and island country within the Lucayan Archipelago of the Atlantic Ocean. It contains 97 per cent of the archipelago's land area and 88 per cent of its population. ...

on August 21. The disturbance crossed south Florida on August 23, and stalled to the west of the peninsula for the next two days. On August 25, the storm moved over central Florida and stalled there for two days, before emerging off the east coast of Florida on August 27. Late on August 27, the system organized significantly off the coast of

Georgia Georgia most commonly refers to: * Georgia (country), a country in the South Caucasus * Georgia (U.S. state), a state in the southeastern United States Georgia may also refer to: People and fictional characters * Georgia (name), a list of pe ...

; as the system was expected to develop into a tropical cyclone within 2 days and posed a hazard to the

, the NHC designated the storm as ''Potential Tropical Cyclone Ten'' and initiated advisories on the storm. At the time of its designation on August 27, Potential Tropical Cyclone Ten was given a 90% chance of becoming a tropical storm within the next 2 days. Due to the storm's organization and its proximity to land, Tropical Storm Watches and Warnings were issued for the coasts of

North North is one of the four compass points or cardinal directions. It is the opposite of south and is perpendicular to east and west. ''North'' is a noun, adjective, or adverb indicating Direction (geometry), direction or geography. Etymology T ...

and

South Carolina South Carolina ( ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders North Carolina to the north and northeast, the Atlantic Ocean to the southeast, and Georgia (U.S. state), Georg ...

. However, the storm remained disorganized and lacked a closed low-level circulation. On August 28, Potential Tropical Cyclone Ten's

central pressure Atmospheric pressure, also known as air pressure or barometric pressure (after the barometer), is the pressure within the atmosphere of Earth. The standard atmosphere (symbol: atm) is a unit of pressure defined as , which is equivalent to 1,013.2 ...

reached , and the storm had 1-minute sustained winds of 40 mph (65 km/h), equivalent to that of a minimal tropical storm. However, the system still lacked a closed low-level circulation center, and increasing wind shear from the southeast and outflow from Hurricane Harvey (which was now a tropical storm) was beginning to inhibit the system's chances of tropical development. As the system accelerated to the northeast, the storm expanded in size, though it grew increasingly disorganized. As the storm moved past the

, on August 29, the disturbance brought

thunderstorm A thunderstorm, also known as an electrical storm or a lightning storm, is a storm characterized by the presence of lightning and its acoustics, acoustic effect on the Earth's atmosphere, known as thunder. Relatively weak thunderstorm ...

s to the region, in addition to tropical storm-force winds. The NHC noted that the disturbance had "very cold, but extremely deep asymmetric convection", with all of the thunderstorms around the center displaced to the east, due to strong wind shear. Around that time, the disturbance began interacting with a baroclinic zone, causing the disturbance to begin transitioning into an

. Late on August 29, at 18:00

UTC Coordinated Universal Time (UTC) is the primary time standard globally used to regulate clocks and time. It establishes a reference for the current time, forming the basis for civil time and time zones. UTC facilitates international communica ...

, Potential Tropical Cyclone Ten completed its transition into an extratropical cyclone, even as it finished developing a closed low-level circulation, while situated off the coast of North Carolina; as such, the NHC issued their final advisory on the storm and cancelled the tropical storm warnings in the area. The storm strengthened as it became extratropical, with the disturbance's minimum central pressure reaching and the storm's sustained winds reaching 45 mph (75 km/h), just as it completed its transition. During the next couple of days, Ten's extratropical remnant quickly intensified, while accelerating to the northeast. On August 31, at 12:00 UTC, Potential Tropical Cyclone Ten's remnant reached a peak intensity of to the south of

, with hurricane-force sustained winds at 75 mph (120 km/h). Afterward, Ten's extratropical remnant weakened, and the system began to be drawn into another extratropical storm near

, on September 3. Later on the same day, Potential Tropical Cyclone Ten's remnant was fully absorbed by the larger extratropical cyclone, southwest of Iceland. This extratropical system was named ''Windstorm Perryman'' by the

Free University of Berlin The Free University of Berlin (, often abbreviated as FU Berlin or simply FU) is a public university, public research university in Berlin, Germany. It was founded in West Berlin in 1948 with American support during the early Cold War period a ...

on September 4; Windstorm Perryman subsequently impacted Ireland and the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Northwestern Europe, off the coast of European mainland, the continental mainland. It comprises England, Scotlan ...

Preparations and impact

Florida

During the system's time in Florida, the storm caused torrential rainfall and also triggered flooding across the state, especially in southwestern Florida. The floods were described as the worst that western Florida had seen in at least 20 years. Lee County was the hardest hit, particularly the Island Park neighborhood in the southern part of Fort Myers. The region experienced several days of rainfall, which caused Millet Creek and Ten Mile Canal to overflow, leading to widespread flooding in the area. A maximum total of rainfall in excess of was recorded in Ten Mile Canal and in

, which was equivalent to roughly 60% of the annual rainfall totals that those areas normally see. The western portions of

reported of rainfall, which was equivalent to about 55% of the city's annual rainfall total. On Monday, August 28, water levels peaked at a depth of on Island Park Road, on

US Route 41 U.S. Route 41, also U.S. Highway 41 (US 41), is a major north–south United States Numbered Highway that runs from Miami, Florida, to the Upper Peninsula of Michigan. Until 1949, the part in southern Florida, from Naples to Miam ...

. Flooding from the storm forced the rescue of more than 200 people and 37 animals, all of whom were evacuated. There was only one road leading into and out of more than a dozen gated communities along Island Park Road, which made it difficult for people to evacuate from the floods. Numerous homes were damaged by the floodwaters, including those in an

RV park A recreational vehicle park (RV park) or caravan park is a place where people with recreational vehicles can stay overnight, or longer, in allotted spaces known as "sites" or "campsites". They are also referred to as campgrounds, though a true ...

near the highway. Schools were closed across Lee and Collier Counties, and numerous roads were closed. Many roads were covered by more than of water, and several cars were stalled on Island Park Road. In Lee County, around the Fort Boca Grande area, over of rain fell across the area from August 26 to 27, with

Cape Coral Cape Coral is a city in Lee County, Florida, United States, on the Gulf of Mexico. Founded in 1957, the city's population had grown to 194,016 as of the 2020 census, a 26% increase from 154,309 at the 2010 census, making it the ninth-most p ...

recording of rain over a 72-hour period; this led to extreme flooding from August 27 to 28. Floodwaters entered 11 homes in Captiva and breached some trailer homes in the Coastal Estate Trailer Parks; another 30 trailers in the Tropical Trailer Park experienced waist-deep floodwaters. Numerous roads around Captiva, Cape Coral,

Sanibel Sanibel is an island and city in Lee County, Florida, United States. The population was 6,382 at the 2020 census, down from 6,469 at the 2010 census. It is part of the Cape Coral-Fort Myers, Florida Metropolitan Statistical Area. The island, al ...

, and Pine Island were covered by floodwaters deep, requiring 7 car rescues from first responders. The floods resulted in $300,000 (2017 USD) in property damage in the Fort Boca Grande area. In

Manatee County Manatee County is a county in the U.S. state of Florida. As of the 2020 U.S. Census, the population was 399,710. Manatee County is part of the North Port-Bradenton-Sarasota, Florida Metropolitan Statistical Area. Its county seat and largest ci ...

, up to of rain fell from August 26 to 28, causing numerous instances of street flooding, floating cars on State Road 70, and forcing the rescue of one person. In the Longbeach area, floodwaters entered numerous homes and businesses, with 67 homes experiencing over a foot (0.3 meters) of water, mostly in the Centre Lake Community, forcing the families living there to evacuate; water also entered homes along Manatee Avenue West around 38th Street West. On the evening of August 27, a 61-year-old man drowned in the Sara Palms neighborhood of the Longbeach area, when his wheelchair tipped over into the floodwaters. The flooding in Manatee County caused $1.34 million (2017 USD) in property damage. In Fort Myers Beach, in Lee County, heavy rainfall from August 27 to 28 resulting in localized flooding, with floodwaters breaching mobile homes in

Estero Estero ( Spanish for "estuary") is an incorporated village in Lee County, Florida, United States, located directly beside the first aquatic nature preserve established in Florida: The Estero Bay Aquatic Preserve, otherwise referred to as Estero ...

and

Bonita Springs Bonita Springs is a city in Lee County, Florida, United States. The population was 53,644 at the 2020 census, up from 43,914 at the 2010 census. It is part of the Cape Coral-Fort Myers, Florida Metropolitan Statistical Area, on the state's sou ...

. The floods forced the evacuation of 70 people from a mobile home park in Estero, and another 116 people were forced to evacuate from a mobile home park in Bonita Springs, due to rising floodwaters from the Imperial River. The floods in Fort Myers Beach caused $100,000 (2017 USD) in property damage. In the neighboring

Sarasota County Sarasota County is a county located in Southwest Florida. At the 2020 US census, the population was 434,006. Its county seat is Sarasota and its largest city is North Port. Sarasota County is part of the North Port–Bradenton–Sarasota, F ...

, a maximum total of of rain fell across the area from August 26 to 28, which caused numerous instances of street flooding, and resulted in $50,000 (2017 USD) in property damage. On the afternoon of August 27, a 73-year-old man in

Longboat Key A longboat is a type of ship's boat that was in use from ''circa'' 1500 or before. Though the Royal Navy replaced longboats with launches from 1780, examples can be found in merchant ships after that date. The longboat was usually the largest boa ...

drowned when his car was carried away by floodwaters into a drainage ditch, after he tried driving through a flooded parking lot at a

dog park A dog park is a park for dogs to exercise and play off-leash in a controlled environment under the supervision of their owners. Description Dog parks have varying features, although they typically offer a fence, separate double-gated entry an ...

. The disturbance was also responsible for

severe weather Severe weather is any dangerous meteorological phenomenon with the potential to cause damage, serious social disruption, or loss of human life. These vary depending on the latitude, altitude, topography, and atmospheric conditions. High ...

in Florida. From August 23 to 28, at least 21 storm reports were filed, including multiple instances of wind damage from severe thunderstorms. On August 24, at 10:05 a.m. EDT, a

funnel cloud A funnel cloud is a funnel-shaped cloud of condensed water droplets, associated with a rotating column of wind and extending from the base of a cloud (usually a cumulonimbus or towering cumulus cloud) but not reaching the ground or a water su ...

was reported in Hilolo, in

Okeechobee County Okeechobee County () is a county located in the Florida Heartland region of the state of Florida. As of the 2020 census, the population was 39,644. The county seat is Okeechobee. History Okeechobee County was incorporated in 1917. It was ...

. A trained weather spotter reported observing the funnel cloud near

Fort Drum Fort Drum is a U.S. Army military reservation and a census-designated place (CDP) in Jefferson County, near the western border of northern New York, United States. The population of the CDP portion of the base was 12,955 at the 2010 census. ...

, while he was driving northward on

U.S. Route 441 U.S. Route 441 (US 441) is a auxiliary route of U.S. Route 41. It extends from US 41 in Miami, Florida to US 25W in Rocky Top, Tennessee. Between its termini, US 441 travels through the states of Florida, Georgia, North ...

. On August 26, at 8:19 p.m. EDT, an

EF0 The Enhanced Fujita scale (abbreviated EF-Scale) is a scale that rates tornado intensity based on the severity of the damage a tornado causes. It is used in the United States and France, among other countries. The EF scale is also unofficially ...

tornado A tornado is a violently rotating column of air that is in contact with the surface of Earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. It is often referred to as a twister, whirlwind or cyclone, although the ...

touched down in

Samoset Samoset (also Somerset, – ) was an Abenaki sagamore and the first American Indian to make contact with the Pilgrims of Plymouth Colony in New England. He startled the colonists on March 16, 1621 by walking into Plymouth Colony and greeti ...

, in

, before lifting three minutes later, at 8:22 p.m. EDT. A couple of witnesses reported seeing a funnel cloud in the area around the time when the tornado touched down. The tornado left a narrow path of damage and caused minor damage at a County Public Works Facility, in addition to throwing around

aluminum Aluminium (or aluminum in North American English) is a chemical element; it has chemical symbol, symbol Al and atomic number 13. It has a density lower than that of other common metals, about one-third that of steel. Aluminium has ...

debris and downing multiple trees. The tornado caused $20,000 (2017

) in damage. Overall, the storm killed two people in Florida and caused more than $1.923 million (2017 USD) in damages. Less than two weeks later,

made landfall in southwestern Florida, which further compounded the damage in the region.

Elsewhere

On August 27, the NHC anticipated Potential Tropical Cyclone Ten to develop into a tropical storm within 48 hours, and as such, they issued Tropical Storm Watches and Warnings for the Carolinas on August 27. The disturbance was also expected to bring up to of rain to parts of coastal

and the

Outer Banks The Outer Banks (frequently abbreviated OBX) are a string of barrier islands and spits off the coast of North Carolina and southeastern Virginia, on the east coast of the United States. They line most of the North Carolina coastline, separatin ...

, along with a possible

storm surge A storm surge, storm flood, tidal surge, or storm tide is a coastal flood or tsunami-like phenomenon of rising water commonly associated with low-pressure weather systems, such as cyclones. It is measured as the rise in water level above the ...

. When Potential Tropical Cyclone Ten brushed the coastline of the Carolinas, the storm brought gale-force winds at tropical storm strength, flash flooding, and high surf to the area. However, the impacts in the Carolinas were rather minimal. The storm also brought rainfall and high surf to other states in the

Northeastern United States The Northeastern United States (also referred to as the Northeast, the East Coast, or the American Northeast) is List of regions of the United States, census regions United States Census Bureau. Located on the East Coast of the United States, ...

, as it moved northeastward. After Potential Tropical Cyclone Ten transitioned into an extratropical storm, the system brought tropical storm conditions to Atlantic Canada, including gusty winds and high surf, with the

Canadian Hurricane Centre The Canadian Hurricane Centre (CHC; ) is an organisation that monitors and warns of the threat of tropical cyclones such as hurricanes and tropical storms. CHC is a division of the Meteorological Service of Canada (MSC), which is in turn a branch o ...

(CHC) issuing an alert for the area.

Notes

References

External links

Potential Tropical Cyclone Ten storm activityPotential Tropical Cyclone Ten advisory archivesPotential Tropical Cyclone "Ten" storm watch information
{{2017 Atlantic hurricane season buttons

Ten Ten, TEN or 10 may refer to: * 10, an even natural number following 9 and preceding 11 * one of the years 10 BC, AD 10, 1910, 2010, 2110 * October, the tenth month of the year Places * Mount Ten, in Vietnam * Tongren Fenghuang Airport (IATA c ...

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