Hurricane Ivo was a minimal hurricane that threatened the coast of Mexico during mid-September 2007. The 12th tropical cyclone, ninth named storm and fourth hurricane of the 2007 Pacific hurricane season, Ivo originated from a tropical wave that left the coast of Africa on September 1 and traversed the Atlantic, crossing into the Pacific Ocean on September 15. The wave subsequently spawned a low pressure system that developed into Tropical Depression 12-E by September 18. After being upgraded to a tropical storm the next day, the cyclone intensified to attain peak winds of on September 21, a Category 1 hurricane on the Saffir-Simpson Hurricane Scale. Uncertainty in the storm's track prompted a tropical storm watch to be issued along portions of the coast of Baja California, although the storm never affected land as an active tropical cyclone.

Meteorological history

A tropical wave associated with little or no convection moved off the east coast of Africa on September 1, 2007 and entered the Atlantic Ocean. The wave traversed the Atlantic, crossing Central America on September 15 where the disturbance began to show signs of organization. The next day, a broad area of low pressure developed within the wave. Continuing to organize, the low became a tropical depression at 0600 UTC on September 16, about south-southwest of Manzanillo, Mexico.

Initially, the exact location of the center of circulation was somewhat uncertain, which led to difficulty in predicting the direction of movement. Located on the southern side of a mid-level ridge extending westward from northern Mexico, the depression was in an environment of light northwesterly wind shear. Subsequently convective bands began to form near the center. Later that day, overall satellite presentation improved, and the cloud pattern became symmetric with excellent outflow. Tracking west-northwestward as a result of the mid-level ridge, the cyclone intensified, and was upgraded to Tropical Storm Ivo early on September 19. Ivo developed a ragged eye, and at 0000 UTC on September 20 it was upgraded to a hurricane as the cyclone began to turn northward. With an area of deep convection near the center, the hurricane reached peak intensity of at 1800 UTC. At the time well-defined yet displaced eyewall features were evident. Early on September 21, an eye appeared on satellite imagery, but quickly degenerated. At around the same time, the overall structure of the hurricane became ragged, and the storm slowed in forward movement. Westerly flow associated with a large upper-level low pressure system began to undercut the outflow of Ivo, and it weakened to tropical storm status late on September 21.

The convective pattern rapidly deteriorated with the warming of cloud tops, likely due to southeasterly wind shear. After several hours with limited thunderstorm activity, a burst of convection generated to the north of the center, early on September 22. At 0000 UTC on September 23 the storm was downgraded to a tropical depression to the west-southwest of the southern tip of Baja California. Convective activity quickly diminished, and the remnants of Ivo had dissipated entirely later that day, never approaching land as an active tropical cyclone.

Preparations and impact

Initially, some forecasts predicted the storm would strike the Baja California Peninsula as a tropical storm. On September 22, uncertainty in predicting Ivo's track and intensity prompted the Mexican Government to issues a tropical storm watch from Sante Fe to Cabo San Lucas. At 0900 UTC the next day, the advisory was discontinued, as the storm had weakened substantially before approaching land. In Cabo San Lucas authorities advised residents to stock up on water and food in preparation for potential evacuations. On September 23, before the imminent arrival of Ivo the south coast of Baja California, the director of Civil Protection in the state reported that just over 100 shelters would be cleared for use in the municipalities of Los Cabos, La Paz and Comondú, respectively. The General Coordination of Civil Protection advised shrimp fishing parties to pay close attention to the storm.

No significant effects were reported on land, as the storm dissipated before approaching the coast. However, the remnants spread rainbands over the southern tip of Baja California. Due to lack of any significant effects from Hurricane Ivo, the name Ivo was not retired and is included on the list of names for the 2013 Pacific hurricane season.

See also

• List of Pacific hurricanes
• Timeline of the 2007 Pacific hurricane season

References