Mountain jet

The North Pacific east of about 120°W is strongly influenced by winds blowing through gaps in the Central American cordillera.

In the winter, cold high-pressure weather systems move southward from North America over the Gulf of Mexico.

The arrival of these cold surges, and their associated anticyclonic circulation, strengthens the trade winds at low latitudes, and this effect can last for several days.

The winds blow at speeds of 80 km/h or more down the hillsides from Chivela Pass and over the waters of the Gulf of Tehuantepec, sometimes extending more than 500 miles (800 km) into the Pacific Ocean.

The surface waters under the Gulf of Tehuantepec wind jet can cool by as much as 10 °C in a day.