Hurricane Cosme was a minimal hurricane that threatened

Hawaii Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only stat ...

in mid-July 2007. The sixth

tropical cyclone 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 and squalls. Depend ...

, third named storm and first hurricane of the

2007 Pacific hurricane season The 2007 Pacific hurricane season was a below-average Pacific hurricane season, featuring one major hurricane. The season officially started on May 15 in the eastern Pacific and on June 1 in the central Pacific, and ended on November 30 ...

, Cosme originated from a tropical wave that emerged off the coast of Africa on June 27 and tracked westward before emerging in the eastern Pacific. A system along the wave organized, and it was classified as a tropical depression on July 14, a tropical storm on July 15, and a hurricane on July 16. Cosme reached peak intensity as a Category 1 hurricane on the Saffir-Simpson Hurricane Scale, but quickly weakened due to cooler waters. Steadily decreasing in strength, the storm was downgraded to a tropical depression before passing to the south of the

Hawaiian Islands The Hawaiian Islands ( haw, Nā Mokupuni o Hawai‘i) are an archipelago of eight major islands, several atolls, and numerous smaller islets in the North Pacific Ocean, extending some from the island of Hawaii in the south to northernmost Kur ...

. The depression crossed into the Central Pacific and degenerated into a

remnant low A post-tropical cyclone is a former tropical cyclone that no longer possesses enough tropical qualities to be considered a tropical cyclone. The word may refer to a former tropical cyclone undergoing extratropical transition or a tropical cyclone ...

by July 23. Because Cosme stayed far from land, effects were mostly minor. Swells up to and up to of rainfall were reported, in addition to wind gusts of 40 mph (65 km/h). No fatalities or injuries were reported, and only minimal damage occurred.

Meteorological history

The origins of Cosme can be traced back to 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 left the coast of

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

on June 27, 2007. Due to a lack of associated

convection Convection is single or multiphase fluid flow that occurs spontaneously due to the combined effects of material property heterogeneity and body forces on a fluid, most commonly density and gravity (see buoyancy). When the cause of the convec ...

, the wave was difficult to track across the

Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...

and

Caribbean Sea The Caribbean Sea ( es, Mar Caribe; french: Mer des Caraïbes; ht, Lanmè Karayib; jam, Kiaribiyan Sii; nl, Caraïbische Zee; pap, Laman Karibe) is a sea of the Atlantic Ocean in the tropics of the Western Hemisphere. It is bounded by Mexico ...

. 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 Prime Meridian and the 140th meridian west poleward to the 3 ...

(NHC) estimated that the wave emerged into the

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...

on July 8. Because the system was embedded within the

Intertropical Convergence Zone The Intertropical Convergence Zone (ITCZ ), known by sailors as the doldrums or the calms because of its monotonous windless weather, is the area where the northeast and the southeast trade winds converge. It encircles Earth near the thermal e ...

(ITCZ), development was initially slow. However, when it separated from the ITCZ on July 13, the disturbance increased in convective organization, and was classified as Tropical Depression Six-E about midway between

Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...

and

. It tracked westward at due to steering currents of a tropical easterly flow. Although

wind shear Wind shear (or 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 or horizontal ...

was generally light, ocean temperatures were only marginal for tropical cyclone intensification. Forecasters experienced difficulty in locating the exact center of circulation. By July 14, convection had steadily decreased, although the storm's movement was initially uncertain due to its location within a broad low pressure area. Early on July 15 the depression's appearance on

satellite imagery Satellite images (also Earth observation imagery, spaceborne photography, or simply satellite photo) are images of Earth collected by imaging satellites operated by governments and businesses around the world. Satellite imaging companies sell ima ...

improved, and at 1800 UTC the NHC upgraded the depression to tropical storm status, and gave it the name "Cosme". Shortly after attaining tropical storm status, the previously-broad circulation consolidated as banding features developed. The inner core gradually condensed and tightened, as indicated by a
AMSR-E
overpass. On July 16 an

eye Eyes are organs of the visual system. They provide living organisms with vision, the ability to receive and process visual detail, as well as enabling several photo response functions that are independent of vision. Eyes detect light and conv ...

began to form and Cosme intensified to attain winds of . Tracking northwest towards a weakness in the mid-level

ridge A ridge or a mountain ridge is a geographical feature consisting of a chain of mountains or hills that form a continuous elevated crest for an extended distance. The sides of the ridge slope away from the narrow top on either side. The line ...

, the cyclone continued to intensify and was upgraded to Hurricane Cosme late on July 16, about east of

Hilo Hilo () is a census-designated place (CDP) and the largest settlement in Hawaii County, Hawaii, Hawaii County, Hawaii, United States, which encompasses the Hawaii (island), Island of Hawaii. The population was 44,186 according to the 2020 United ...

. The hurricane reached peak intensity with winds of 75 mph (120 km/h), although due to cooler waters it quickly weakened to a tropical storm, as the eye became ragged and cloud-filled. By July 17, the cloud pattern had deteriorated, and its winds decreased to 45 mph (75 km/h). The center subsequently became exposed, with just a few thunderstorms confined to the southwest portion of the storm as it began to accelerate to the west. As easterly vertical wind shear increased, convection temporarily reformed in a concentrated area southwest of the center. As Cosme reached steadily cooler water temperatures, it was downgraded to a tropical depression late on July 18 about southeast of Hilo, Hawaii; at around the same time, the storm entered the forecast responsibility of the

Central Pacific Hurricane Center 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 Pacifi ...

. Tracking westward at , maximum sustained winds were with localized higher gusts. Gradually weakening, Tropical Depression Cosme passed south of the

on July 20 with a minimum central pressure of 1010

mbar The bar is a metric unit of pressure, but not part of the International System of Units (SI). It is defined as exactly equal to 100,000 Pa (100 kPa), or slightly less than the current average atmospheric pressure on Earth at sea leve ...

. On July 22, the depression came within of

Johnston Island Johnston Atoll is an unincorporated territory of the United States, currently administered by the United States Fish and Wildlife Service (USFWS). Johnston Atoll is a National Wildlife Refuge and part of the Pacific Remote Islands Marine Nation ...

, and later that day, it degenerated into a remnant low.

Preparations and impact

Initially, Cosme was predicted to make landfall on

as a tropical storm. In anticipation of the storm, the National Weather Service issued a flash flood watch for the island of Hawaii on July 20. Also, small craft advisories were in effect for

Maui The island of Maui (; Hawaiian: ) is the second-largest of the islands of the state of Hawaii at 727.2 square miles (1,883 km2) and is the 17th largest island in the United States. Maui is the largest of Maui County's four islands, which ...

and Hawaii; wind advisories were issued for summits in those regions. High surf advisories were also put into effect for coastal areas. The Hawaii County Civil Defense prepared for the storm by planning for increases in emergency response personnel and opening of evacuation centers. County crews worked to clean out drains and culverts to prevent flooding. Because the depression stayed far from land, the effects were mostly minor and little damage was reported. A strong

trade wind The trade winds or easterlies are the permanent east-to-west prevailing winds that flow in the Earth's equatorial region. The trade winds blow mainly from the northeast in the Northern Hemisphere and from the southeast in the Southern Hemisph ...

swell north of Cosme generated waves up to high. Rain bands produced up to of rainfall, causing small stream and drainage ditch flooding, as well as ponding on roadways in portions of Hilo, Puna, and Kau. The rainfall helped to relieve a persistent drought which had existed for several months. Wind gusts reached 40 mph (65 km/h) in southern portions of Hawaii, causing no known damage.

References

{{DEFAULTSORT:Cosme 2007 Pacific hurricane season Category 1 Pacific hurricanes Hurricanes in Hawaii 2007 in Hawaii

Cosme Cosme, Cosmè, or Cosmé may refer to: * Cosme (name), including a list of people with the given name or surname * Cosme District, Churcampa province, Peru * Tropical Storm Cosme (disambiguation), various storms See also * San Cosme (disambig ...

de:Pazifische Hurrikansaison 2007#Hurrikan Cosme nl:Orkaanseizoen van de Grote Oceaan 2007#Orkaan Cosme