.gif)
Hurricane Cleo (1958)
Encyclopedia
Hurricane Cleo was the strongest Atlantic hurricane of the 1958 Atlantic hurricane season. It remains one of only three Category 5 hurricanes to avoid land in the historical database
–the others were Dog of 1950
and Easy of 1951
. The third tropical cyclone
, first hurricane, and first major hurricane
of the season, Cleo developed from a tropical wave
off the coast of Africa
. It intensified to a tropical storm 300 miles (480 km) southeast of Praia
, Cape Verde
. It moved steadily westward, and it intensified to a hurricane on August 12. On August 14, the cyclone turned northward, and its forward motion decelerated. Later, the hurricane strengthened to its peak intensity of 160 mph (260 km/h) on August 15. On August 16, its movement increased, and the cyclone moved around the periphery of an upper-level anticyclone
. Its northwest path was halted on August 18, and it turned northeast in response to a shortwave trough
. The hurricane transitioned to an extratropical cyclone
on August 20, causing no casualties in its path.
was detected via weather reports near the Cape Verde islands. Wind observations suggested the possibility of a low-level circulation, and a tropical storm is believed to have formed on the same day. Operationally, lack of data prevented the classification of Cleo until August 14. On August 12, Tropical Storm Cleo quickly strengthened, and several ships reported the presence of an expansive circulation. On August 13, it intensified to a Category 1 hurricane with maximum sustained winds of 75 mph (120 km/h). It continued to rapidly strengthen, and it attained major hurricane status on August 14. Hurricane Hunters
located the cyclone as it attained peak winds of 140 mph (225 km/h); the planes reported that the storm's pressure dropped to 962 mbar
(28.41 inHg
). At the time, the cyclone's motion slowed, and an adjacent upper trough near 50°W
allowed the cyclone to gradually turn north. On August 15, the hurricane's minimum central pressure
was measured by reconnaissance aircraft, and it reached its estimated maximum sustained winds of 160 mph (260 km/h). The hurricane's strongest winds were not documented, so it is assumed that the cyclone reached its peak strength during the day.
On August 16, the upper-level trough weakened, and a ridge of high pressure
forced Cleo to turn northwest. Recurvature was not completed because of the storm's southerly latitude and climatological time of year. The storm slowly weakened to a strong Category 3 hurricane, and it passed within 450 miles (725 km) of Bermuda
on August 18. Its speed slowed during the day, and a strong shortwave trough exited the Northeastern United States
. In response, the cyclone accelerated northeast, and its winds diminished below major hurricane status. On August 19, its motion increased to 29 mph (45 km/h), and the weakening cyclone remained southeast of the Canadian Maritimes
. On August 20, it became extratropical, and its remnants moved east-southeast on August 21. It dissipated west of Portugal
.
issued a hurricane watch
for the Lesser Antilles
, and caution was advised for watercraft in the cyclone's path. Later, reconnaissance data indicated the cyclone continued to move northward, reducing the threat. The precautionary watch was discontinued on August 15. The Radio Station NSS Washington informed ships about the cyclone's location in the Atlantic Ocean. Although the hurricane transversed several shipping routes, no deaths or severe damages were reported over the ocean. The extratropical remnants of Cleo eventually affected Europe
, but damages are unknown. The cyclone's effects were minimal, and the name Cleo was not retired. It was eventually retired due to the effects of another Cleo
in 1964
. Cleo was one of only four Category 5 hurricanes whose names were not retired (six if counting Dog and Easy which were named using the phonetic alphabet).
Cleo became a Category 5 hurricane at 49.8 W, farther east than any other storm.
Atlantic hurricane reanalysis
Atlantic hurricane reanalysis is an ongoing project within the National Oceanic and Atmospheric Administration which seeks to correct and add new information about past Atlantic tropical cyclones...
–the others were Dog of 1950
Hurricane Dog (1950)
Hurricane Dog was the most intense hurricane in the 1950 Atlantic hurricane season. The fourth named storm of the season, Dog developed on August 30 to the east of Antigua; after passing through the northern Lesser Antilles, it turned to the north and intensified into a Category 5 hurricane...
and Easy of 1951
Hurricane Easy (1951)
Hurricane Easy was the strongest tropical cyclone of the 1951 Atlantic hurricane season. It was a Cape Verde-type hurricane that recurved away from land masses. The fifth tropical cyclone, fourth hurricane, and fourth major hurricane of the season, Easy formed 1,000 miles west of Cape Verde...
. The third tropical cyclone
Tropical cyclone
A tropical cyclone is a storm system characterized by a large low-pressure center and numerous thunderstorms that produce strong winds and heavy rain. Tropical cyclones strengthen when water evaporated from the ocean is released as the saturated air rises, resulting in condensation of water vapor...
, first hurricane, and first major hurricane
Saffir-Simpson Hurricane Scale
The Saffir–Simpson Hurricane Scale , or the Saffir–Simpson Hurricane Wind Scale , classifies hurricanes — Western Hemisphere tropical cyclones that exceed the intensities of tropical depressions and tropical storms — into five categories distinguished by the intensities of their sustained winds...
of the season, Cleo developed from a tropical wave
Tropical wave
Tropical waves, easterly waves, or tropical easterly waves, also known as African easterly waves in the Atlantic region, are a type of atmospheric trough, an elongated area of relatively low air pressure, oriented north to south, which move from east to west across the tropics causing areas of...
off the coast of Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
. It intensified to a tropical storm 300 miles (480 km) southeast of Praia
Praia
Praia , is the capital and largest city of Cape Verde, an island nation in the Atlantic Ocean west of Senegal. It lies on the southern coast of Santiago island in the Sotavento Islands group. It is the island's ferry port and is home to one of the nation’s four international airports...
, Cape Verde
Cape Verde
The Republic of Cape Verde is an island country, spanning an archipelago of 10 islands located in the central Atlantic Ocean, 570 kilometres off the coast of Western Africa...
. It moved steadily westward, and it intensified to a hurricane on August 12. On August 14, the cyclone turned northward, and its forward motion decelerated. Later, the hurricane strengthened to its peak intensity of 160 mph (260 km/h) on August 15. On August 16, its movement increased, and the cyclone moved around the periphery of an upper-level anticyclone
Anticyclone
An anticyclone is a weather phenomenon defined by the United States' National Weather Service's glossary as "[a] large-scale circulation of winds around a central region of high atmospheric pressure, clockwise in the Northern Hemisphere, counterclockwise in the Southern Hemisphere"...
. Its northwest path was halted on August 18, and it turned northeast in response to a shortwave trough
Trough (meteorology)
A trough is an elongated region of relatively low atmospheric pressure, often associated with fronts.Unlike fronts, there is not a universal symbol for a trough on a weather chart. The weather charts in some countries or regions mark troughs by a line. In the United States, a trough may be marked...
. The hurricane transitioned to an extratropical cyclone
Extratropical cyclone
Extratropical cyclones, sometimes called mid-latitude cyclones or wave cyclones, are a group of cyclones defined as synoptic scale low pressure weather systems that occur in the middle latitudes of the Earth having neither tropical nor polar characteristics, and are connected with fronts and...
on August 20, causing no casualties in its path.
Meteorological history
On August 11, an area of low pressureLow pressure area
A low-pressure area, or "low", is a region where the atmospheric pressure at sea level is below that of surrounding locations. Low-pressure systems form under areas of wind divergence which occur in upper levels of the troposphere. The formation process of a low-pressure area is known as...
was detected via weather reports near the Cape Verde islands. Wind observations suggested the possibility of a low-level circulation, and a tropical storm is believed to have formed on the same day. Operationally, lack of data prevented the classification of Cleo until August 14. On August 12, Tropical Storm Cleo quickly strengthened, and several ships reported the presence of an expansive circulation. On August 13, it intensified to a Category 1 hurricane with maximum sustained winds of 75 mph (120 km/h). It continued to rapidly strengthen, and it attained major hurricane status on August 14. Hurricane Hunters
Hurricane Hunters
The Hurricane Hunters are aircraft that fly into tropical cyclones in the North Atlantic Ocean and Northeastern Pacific Ocean for the specific purpose of directly measuring weather data in and around those storms. In the United States, the Air Force, Navy, and NOAA units have all participated in...
located the cyclone as it attained peak winds of 140 mph (225 km/h); the planes reported that the storm's pressure dropped to 962 mbar
Bar (unit)
The bar is a unit of pressure equal to 100 kilopascals, and roughly equal to the atmospheric pressure on Earth at sea level. Other units derived from the bar are the megabar , kilobar , decibar , centibar , and millibar...
(28.41 inHg
Pascal (unit)
The pascal is the SI derived unit of pressure, internal pressure, stress, Young's modulus and tensile strength, named after the French mathematician, physicist, inventor, writer, and philosopher Blaise Pascal. It is a measure of force per unit area, defined as one newton per square metre...
). At the time, the cyclone's motion slowed, and an adjacent upper trough near 50°W
Longitude
Longitude is a geographic coordinate that specifies the east-west position of a point on the Earth's surface. It is an angular measurement, usually expressed in degrees, minutes and seconds, and denoted by the Greek letter lambda ....
allowed the cyclone to gradually turn north. On August 15, the hurricane's minimum central pressure
Atmospheric pressure
Atmospheric pressure is the force per unit area exerted into a surface by the weight of air above that surface in the atmosphere of Earth . In most circumstances atmospheric pressure is closely approximated by the hydrostatic pressure caused by the weight of air above the measurement point...
was measured by reconnaissance aircraft, and it reached its estimated maximum sustained winds of 160 mph (260 km/h). The hurricane's strongest winds were not documented, so it is assumed that the cyclone reached its peak strength during the day.
On August 16, the upper-level trough weakened, and a ridge of high pressure
Ridge (meteorology)
A ridge is an elongated region of relatively high atmospheric pressure, the opposite of a trough....
forced Cleo to turn northwest. Recurvature was not completed because of the storm's southerly latitude and climatological time of year. The storm slowly weakened to a strong Category 3 hurricane, and it passed within 450 miles (725 km) of Bermuda
Bermuda
Bermuda is a British overseas territory in the North Atlantic Ocean. Located off the east coast of the United States, its nearest landmass is Cape Hatteras, North Carolina, about to the west-northwest. It is about south of Halifax, Nova Scotia, Canada, and northeast of Miami, Florida...
on August 18. Its speed slowed during the day, and a strong shortwave trough exited the Northeastern United States
Northeastern United States
The Northeastern United States is a region of the United States as defined by the United States Census Bureau.-Composition:The region comprises nine states: the New England states of Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island and Vermont; and the Mid-Atlantic states of New...
. In response, the cyclone accelerated northeast, and its winds diminished below major hurricane status. On August 19, its motion increased to 29 mph (45 km/h), and the weakening cyclone remained southeast of the Canadian Maritimes
Maritimes
The Maritime provinces, also called the Maritimes or the Canadian Maritimes, is a region of Eastern Canada consisting of three provinces, New Brunswick, Nova Scotia, and Prince Edward Island. On the Atlantic coast, the Maritimes are a subregion of Atlantic Canada, which also includes the...
. On August 20, it became extratropical, and its remnants moved east-southeast on August 21. It dissipated west of Portugal
Portugal
Portugal , officially the Portuguese Republic is a country situated in southwestern Europe on the Iberian Peninsula. Portugal is the westernmost country of Europe, and is bordered by the Atlantic Ocean to the West and South and by Spain to the North and East. The Atlantic archipelagos of the...
.
Preparations and impact
A persistent trough enabled the recurvature of three tropical cyclones: Becky, Cleo, and Daisy remained over the ocean. The cyclone remained away from land masses, which reduced potential damages. On August 14, the Weather Bureau office in San Juan, Puerto RicoSan Juan, Puerto Rico
San Juan , officially Municipio de la Ciudad Capital San Juan Bautista , is the capital and most populous municipality in Puerto Rico, an unincorporated territory of the United States. As of the 2010 census, it had a population of 395,326 making it the 46th-largest city under the jurisdiction of...
issued a hurricane watch
Tropical cyclone warnings and watches
Warnings and watches are two levels of alert 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...
for the Lesser Antilles
Lesser Antilles
The Lesser Antilles are a long, partly volcanic island arc in the Western Hemisphere. Most of its islands form the eastern boundary of the Caribbean Sea with the Atlantic Ocean, with the remainder located in the southern Caribbean just north of South America...
, and caution was advised for watercraft in the cyclone's path. Later, reconnaissance data indicated the cyclone continued to move northward, reducing the threat. The precautionary watch was discontinued on August 15. The Radio Station NSS Washington informed ships about the cyclone's location in the Atlantic Ocean. Although the hurricane transversed several shipping routes, no deaths or severe damages were reported over the ocean. The extratropical remnants of Cleo eventually affected Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
, but damages are unknown. The cyclone's effects were minimal, and the name Cleo was not retired. It was eventually retired due to the effects of another Cleo
Hurricane Cleo
Hurricane Cleo was the third named storm, first hurricane, and first major hurricane of the 1964 Atlantic hurricane season. Cleo was one of the longest-lived storms of the season...
in 1964
1964 Atlantic hurricane season
The 1964 Atlantic hurricane season officially began on June 15, 1964, and lasted until November 15, 1964. These dates conventionally delimit the period of each year when most tropical cyclones form in the Atlantic basin...
. Cleo was one of only four Category 5 hurricanes whose names were not retired (six if counting Dog and Easy which were named using the phonetic alphabet).
Cleo became a Category 5 hurricane at 49.8 W, farther east than any other storm.