Tehuantepecer

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. 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.