Tehuantepecer

Last updated August 13, 2023

Tehuantepecer, or Tehuano wind, is a violent mountain-gap wind that travels through the Chivela Pass in southern Mexico, across the Isthmus of Tehuantepec. It is most common between October and February, with a summer minimum in July. It originates from eastern Mexico and the Bay of Campeche as a post-frontal northerly wind, accelerated southward by cold air damming, that crosses the isthmus and blows through the gap between the Mexican and Guatemalan mountains. The term dates back to at least 1929.^[1] This wind can reach gale, storm, even hurricane force. The leading edge of its outflow (or cold front) may form rope cloud over the Gulf of Tehuantepec. These winds can be observed on satellite pictures such as scatterometer wind measurements, they influence waves which then propagate as swell and are sometimes observed 1,600 km (1,000 mi) away (such as in the Galapagos Islands). These strong winds bring cooler sub-surface waters to the surface of the tropical eastern Pacific Ocean and may last from a few hours to 6 days.

Climatology

The synoptic condition is associated with the formation of high-pressure systems in Sierra Madre in the wake of an advancing cold front. Tehuantepecers primarily occur during the cold season months for the region in the wake of cold fronts, between October and February, with a summer minimum in July caused by the westward extension of the Azores-Bermuda high pressure system. Wind magnitude is greater during El Niño years than during La Niña years, due to the more frequent cold frontal incursions during El Niño winters.^[2] Tehuantepec winds reach 20 knots (40 km/h) to 45 knots (80 km/h), and on rare occasions 100 knots (190 km/h). The wind's direction is from the north to north-northeast.^[3] It leads to a localized acceleration of the trade winds in the region, and can enhance thunderstorm activity when it interacts with the Intertropical Convergence Zone.^[4] The effects can last from a few hours to six days.^[5]

As seen by weather satellites

This TRMM weather satellite shows the wind impact of a Tehuantepecer from December 16, 2000, at 1315 UTC. Tehuan1216001315Z.jpg — This TRMM weather satellite shows the wind impact of a Tehuantepecer from December 16, 2000, at 1315 UTC.

Its leading edge shows up as a rope cloud within the visible and infrared channels of weather satellite images, and since it lies at the leading edge of a density (temperature and dew point) discontinuity, its leading edge by definition it is a cold front, though it has also been described as a squall line, with embedded rain squalls sometimes seen.^[5] Within polar orbiting imagery, a corridor of strong low-level winds show up this feature within scatterometer data retrievals, with its leading edge at the south to southwest edge of the wind surge.

Ocean impact

Tehuantepecers can be felt up to 160 kilometres (100 mi) out to sea in the tropical eastern Pacific Ocean.^[3] Sustained winds at sea have been recorded as high as 49.9 m/s (97.0 kn), with gusts as high as 60.2 m/s (117.0 kn), with a wind event in February 1974 which sandblasted the ship which took the observation.^[6] These winds cause waves which then propagate as swell and are sometimes observed 1,600 kilometres (1,000 mi) away (e.g., in the Galapagos Islands). Its effects can appear similar to a tropical cyclone, though the sky is usually clear. The surface wind can also change local ocean currents during an event.^[5] These strong winds upwell sub-surface waters, cooling the tropical eastern Pacific Ocean by as much as 14 °F (9 °C),^[7] and may last 4–7 days.

Related Research Articles

The 1940 Pacific hurricane season ran through the summer and fall of 1940. Before the satellite age started in the 1960s, data on east Pacific hurricanes was extremely unreliable. Most east Pacific storms were of no threat to land. During this season, there is a former typhoon that crossed into central north Pacific.

The 1938 Pacific hurricane season ran through the summer and fall of 1938. Before the satellite age started in the 1960s, data on east Pacific hurricanes was extremely unreliable. Most east Pacific storms were of no threat to land. However, 1938 saw an unusually active season, with numerous tropical cyclones forming in January and a hurricane struck Northern California in February, killing five people. On August 18, Cyclone Mokapu caused record August rainfall, and a record low pressure when it struck Hawaiian Islands. It brought down power lines and damages into a plantation.

The 1936 Pacific hurricane season ran through the summer and fall of 1936. Before the satellite age started in the 1960s, data on east Pacific hurricanes was extremely unreliable. Most east Pacific storms were of no threat to land. There are numerous damaging tropical cyclones during the season, and half of tropical cyclones during the season became hurricanes.

The 1933 Pacific hurricane season ran through the summer and fall of 1933. Before the satellite age started in the 1960s, data on east Pacific hurricanes was extremely unreliable. Most east Pacific storms were of no threat to land.

The 1932 Pacific hurricane season ran through the summer and fall of 1932. Before the satellite age started in the 1960s, data on east Pacific hurricanes was extremely unreliable. Most east Pacific storms were of no threat to land.

The 1930 Pacific hurricane season ran through the summer and fall of 1930. Before the satellite age started in the 1960s, data on east Pacific hurricanes was extremely unreliable. Most east Pacific storms were of no threat to land.

The 1929 Pacific hurricane season ran through the summer and fall of 1929. Before the satellite age started in the 1960s, data on east Pacific hurricanes was extremely unreliable. Most east Pacific storms were of no threat to land.

The 1927 Pacific hurricane season ran through the summer and fall of 1927. Before the satellite age started in the 1960s, data on east Pacific hurricanes was extremely unreliable. Most east Pacific storms were of no threat to land.

The 1928 Pacific hurricane season ran through the summer and fall of 1928. Before the satellite age started in the 1960s, data on east Pacific hurricanes was extremely unreliable. Most east Pacific storms were of no threat to land.

The 1926 Pacific hurricane season ran through the summer and fall of 1926. Before the satellite age started in the 1960s, data on east Pacific hurricanes was extremely unreliable. Most east Pacific storms were of no threat to land.

The 1925 Pacific hurricane season ran through the summer and fall of 1925. Before the satellite age started in the 1960s, data on east Pacific hurricanes was extremely unreliable. Most east Pacific storms were of no threat to land. 1925 season was the first Pacific hurricane season that was covered in detail by Monthly Weather Review, and this season included the most intense November Pacific hurricane on record until beaten by Hurricane Kenneth in 2011.

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 producing anything from cloudiness and mild showers to severe gales, thunderstorms, blizzards, and tornadoes. These types of cyclones are defined as large scale (synoptic) low pressure weather systems that occur in the middle latitudes of the Earth. In contrast with tropical cyclones, extratropical cyclones produce rapid changes in temperature and dew point along broad lines, called weather fronts, about the center of the cyclone.

<span class="mw-page-title-main">Cold-air damming</span>

Cold air damming, or CAD, is a meteorological phenomenon that involves a high-pressure system (anticyclone) accelerating equatorward east of a north-south oriented mountain range due to the formation of a barrier jet behind a cold front associated with the poleward portion of a split upper level trough. Initially, a high-pressure system moves poleward of a north-south mountain range. Once it sloshes over poleward and eastward of the range, the flow around the high banks up against the mountains, forming a barrier jet which funnels cool air down a stretch of land east of the mountains. The higher the mountain chain, the deeper the cold air mass becomes lodged to its east, and the greater impediment it is within the flow pattern and the more resistant it becomes to intrusions of milder air.

The rear-inflow jet is a component of bow echoes in a mesoscale convective system that aids in creating a stronger cold pool and downdraft. The jet forms as a response to a convective circulation having upshear tilt and horizontal pressure gradients. The cold pool that comes from the outflow of a storm forms an area of high pressure at the surface. In response to the surface high and warmer temperatures aloft due to convection, a mid-level mesolow forms behind the leading edge of the storm.

The 1975 Pacific Northwest hurricane was an unusual Pacific tropical cyclone that attained hurricane status farther north than any other Pacific hurricane. It was officially unnamed, with the cargo ship Transcolorado providing vital meteorological data in assessing the storm. The twelfth tropical cyclone of the 1975 Pacific hurricane season, it developed from a cold-core upper-level low merging with the remnants of a tropical cyclone on August 31, well to the northeast of Hawaii. Convection increased as the circulation became better defined, and by early on September 2, it became a tropical storm. Turning to the northeast through an area of warm water temperatures, the storm quickly strengthened, and, after developing an eye, it attained hurricane status late on September 3, while located about 1,200 miles (1,950 km) south of Alaska. After maintaining peak winds for about 18 hours, the storm rapidly weakened, as it interacted with an approaching Cold front. Early on September 5, it lost its identity near the coast of Alaska.

<span class="mw-page-title-main">Upper tropospheric cyclonic vortex</span>

An upper tropospheric cyclonic vortex is a vortex, or a circulation with a definable center, that usually moves slowly from east-northeast to west-southwest and is prevalent across Northern Hemisphere's warm season. Its circulations generally do not extend below 6,080 metres (19,950 ft) in altitude, as it is an example of a cold-core low. A weak inverted wave in the easterlies is generally found beneath it, and it may also be associated with broad areas of high-level clouds. Downward development results in an increase of cumulus clouds and the appearance of circulation at ground level. In rare cases, a warm-core cyclone can develop in its associated convective activity, resulting in a tropical cyclone and a weakening and southwest movement of the nearby upper tropospheric cyclonic vortex. Symbiotic relationships can exist between tropical cyclones and the upper level lows in their wake, with the two systems occasionally leading to their mutual strengthening. When they move over land during the warm season, an increase in monsoon rains occurs.

<span class="mw-page-title-main">Cold-core low</span> Cyclone with an associated cold pool of air at high altitude

A cold-core low, also known as an upper level low or cold-core cyclone, is a cyclone aloft which has an associated cold pool of air residing at high altitude within the Earth's troposphere, without a frontal structure. It is a low pressure system that strengthens with height in accordance with the thermal wind relationship. If a weak surface circulation forms in response to such a feature at subtropical latitudes of the eastern north Pacific or north Indian oceans, it is called a subtropical cyclone. Cloud cover and rainfall mainly occurs with these systems during the day.

The Papagayo jet, also referred to as the Papagayo Wind or the Papagayo Wind Jet, are strong intermittent winds that blow approximately 70 km north of the Gulf of Papagayo, after which they are named. The jet winds travel southwest from the Caribbean and the Gulf of Mexico to the Pacific Ocean through a pass in the Cordillera mountains at Lake Nicaragua. The jet follows the same path as the northeast trade winds in this region; however, due to a unique combination of synoptic scale meteorology and orographic phenomena, the jet winds can reach much greater speeds than their trade wind counterparts. That is to say, the winds occur when cold high-pressure systems from the North American continent meet warm moist air over the Caribbean and Gulf of Mexico, generating winds that are then funneled through a mountain pass in the Cordillera. The Papagayo jet is also not unique to this region. There are two other breaks in the Cordillera where this same phenomenon occurs, one at the Chivela Pass in México and another at the Panama Canal, producing the Tehuano (Tehuantepecer) and the Panama jets respectively.

References

↑ Hurd, Willis E. (May 1929). "Northers of the Gulf of Tehuantepec". Monthly Weather Review . American Meteorological Society. 57 (5): 192–194. Bibcode:1929MWRv...57..192H. doi: 10.1175/1520-0493(1929)57<192:notgot>2.0.co;2 .
↑ Romero-Centeno, Rosario; Zavala-Hidalgo, Jorge; Gallegos, Artemio & O'Brien, James J. (August 2003). "Isthmus of Tehuantepec wind climatology and ENSO signal". Journal of Climate. 16 (15): 2628–2639. Bibcode:2003JCli...16.2628R. doi: 10.1175/1520-0442(2003)016<2628:iotwca>2.0.co;2 . S2CID 53654865.
1 2 American Meteorological Society (2012-01-26). "Tehuantepecer". Glossary of Meteorology. Retrieved 2013-05-16.
↑ Fett, Bob (2002-12-09). "World Wind Regimes - Central America Gap Wind Tutorial". United States Naval Research Laboratory Monterey, Marine Meteorology Division. Retrieved 2013-05-16.
1 2 3 Arnerich, Paul A. "Tehuantepecer Winds of the West Coast of Mexico". Mariners Weather Log. National Oceanic and Atmospheric Administration. 15 (2): 63–67.
↑ David M. Schultz; W. Edward Bracken; Lance F. Bosart; Gregory J. Hakim; Mary A. Bedrick; Michael J. Dickinson & Kevin R. Tyle (January 1997). "The 1993 Superstorm Cold Surge: Frontal Structure, Gap Flow, and Tropical Impact". Monthly Weather Review. 125 (1): 6–7. Bibcode:1997MWRv..125....5S. doi: 10.1175/1520-0493(1997)125<0005:TSCSFS>2.0.CO;2 .
↑ Hurd, Willis E. (November 1939). "Tehuantepecer of November 24, 1939". Monthly Weather Review. American Meteorological Society. 67 (11): 432. Bibcode:1939MWRv...67..432H. doi: 10.1175/1520-0493(1939)67<432:ton>2.0.co;2 .