The system encountered high wind shear south of Jamaica but subsequently reached its peak intensity as a Category 2 hurricane as it made landfall on the Yucatán Peninsula.

Ernesto briefly emerged in the Bay of Campeche as a strong tropical storm before dissipating over the mountainous terrain of Mexico.

At the time, the depression was located about 810 mi (1305 km) east of the Lesser Antilles, moving west-northwestward due to an anticyclone to its north.

[4] In the 12 hours after its formation, the system's convection became disorganized due to westerly wind shear and dry air, and the NHC remarked the potential for degeneration into a tropical wave.

[6] After becoming a tropical storm, Ernesto initially had difficulty maintaining convection near the center, and its rapid westward movement prevented significant organization.

[10] Although the satellite appearance was well-organized, a Hurricane Hunters flight on August 4 observed a disorganized structure,[11] and early the next day the circulation became exposed to the northwest of the convection;[12] the weakening was possibly due to dry air and some mid-level shear, despite otherwise favorable conditions.

[14] Early on August 6, convection redeveloped over the center after Ernesto slowed its westward movement,[15] and decreasing wind shear allowed for restrengthening.

[28] At 1200 UTC on August 4, the government of Jamaica issued an island-wide tropical storm watch, which was upgraded to a warning only three hours later.

Before Ernesto passed south of Jamaica, the government of Honduras issued a tropical storm watch from its border with Nicaragua to Punta Castilla at 0900 UTC on August 5.

Additionally, a tropical storm warning became in effect from Punta Sal to the border with Nicaragua, including the Bay Islands Department.

[1] In Nicaragua, the civil defense authorities of the North Caribbean Coast Autonomous Region evacuated about 1,500 fishermen in the Miskito Cays, transporting them back to their respective communities.

[31] Rainfall generated by the storm in Petén Department caused minor flood damage to 14 homes in Ixobel, 6 residences in El Rastro, and 24 dwellings in Poptún.

[1] Authorities in the Mexican state of Quintana Roo were moving more than 1,300 tourists from resorts in Mahuahal and other spots to Chetumal, a bayside city that was expected to see less rain and wind than the coast.

Almost all of the country's crude oil exports are shipped to refineries on the Gulf Coast of the United States from the three ports.

Also in the state of Veracruz, a teenage girl died after her car got dragged in a current, and a 62-year-old man was killed by a lightning strike.

[40] In the United States, authorities in the Florida Panhandle and Alabama warned swimmers of potentially dangerous rip currents that will affect the coast for a few days.