Ernesto first affected the northern Caribbean, reaching minimal hurricane status near Haiti before weakening and moving across eastern Cuba as a tropical storm.

The deaths of at least eleven people were attributed to Ernesto, which dumped heavy rains throughout its path, especially in the Mid-Atlantic region of the United States.

While moving across the Caribbean, it affected several countries, and initially Ernesto posed a threat to the Gulf Coast of the United States around the one-year anniversary of Hurricane Katrina.

[2] The next day, convection increased along the wave axis, and Dvorak classifications from the Tropical Analysis and Forecast Branch of the National Hurricane Center began at 1200 UTC on August 23.

[3] Located to the south of a ridge across the southwestern Atlantic Ocean, the depression tracked west-northwestward through an area of dry air and westerly wind shear.

[5] By August 26, the structure had become much better-defined, and within five days Ernesto was forecast to be located about 275 mi (443 km) south of the Gulf Coast of the United States as a powerful hurricane.

Turning northwestward, a small eye formed,[7] and early on August 27 Ernesto attained hurricane status about 95 mi (200 km) south-southwest of the border between Haiti and the Dominican Republic.

[7] However, the small inner core deteriorated as the circulation interacted with the mountainous terrain of southwest Haiti, and it quickly weakened back to tropical storm status.

[8] It continued to weaken due to land interaction, and early on August 28 Ernesto passed just offshore of the southwestern tip of Haiti with winds of 45 mph (70 km/h).

Convection gradually increased over the warm waters, though Ernesto failed to strengthen significantly due to its disrupted inner core.

[1] Ernesto retained a well-organized cloud pattern over land,[10] and after emerging over the Atlantic Ocean near Cape Canaveral,[1] convection again increased and began wrapping into the circulation.

The convection increased as the storm strengthened over warm waters, and late on August 31 Ernesto attained an intensity of 70 mph (110 km/h) while located about 170 mi (270 km) south-southwest of Wilmington, North Carolina.

[1] After landfall the storm rapidly weakened, and about eight hours after moving ashore, Ernesto deteriorated to tropical depression status.

Interacting with a pre-existing frontal zone that extended eastward through Virginia, Ernesto quickly lost its tropical characteristics, and late on September 1 it transitioned into an extratropical cyclone.

[1] Several low-lying citizens in Gonaïves were evacuated after local meteorologists anticipated up to 20 inches (510 mm) of rain in some mountainous areas.

Cattle were moved to higher ground, tourists were evacuated from hotels in the southeastern province of Granma, and baseball games scheduled for the evening of August 27 in Havana were played earlier in the day.

[17] On August 26, about four days prior to Ernesto striking the state, the government of Florida activated its Emergency Operations Center, while the National Guard was placed on standby, following a "warning order" to its commanders.

[19] Officials issued a mandatory evacuation order for all visitors and non-residents in the Florida Keys about three days before the storm passed through the area.

[23] There were initial fears that Ernesto would make landfall days after Hurricane Katrina's one-year anniversary, and that the levees in New Orleans might not be able to withstand a strong storm surge.

[25] On August 29, a hurricane watch was issued from the mouth of the Altamaha River in Georgia to Cape Fear, North Carolina.

North Carolina Governor Mike Easley activated 200 National Guard troops and had other emergency teams on standby.

[39] In the Florida Keys, Ernesto produced tropical storm force wind gusts and light rainfall, causing minor flooding.

Ernesto dropped heavy rainfall across southwest Florida, with a state maximum of 8.72 inches (221 mm) recorded at South Golden Gate.

In South Carolina, the storm brought over 7 inches (180 mm) of precipitation to North Myrtle Beach, which caused ponding on roadways.

[43] The rainfall caused freshwater flooding in low-lying areas, as well as along major and minor roadways; the floodwaters left a 12 mi (19 km) portion of Interstate 40 closed in Duplin County.

[50] In Washington, D.C., the storm produced wind gusts of up to 45 mph (72 km/h) which, in combination with heavy rainfall, resulted in a few downed tree branches and power lines.

In Delaware, the winds left 151,000 people without power, and the adverse conditions canceled several Labor Day Weekend events.

[48] In southern New Jersey, 80 mph (130 km/h) winds left over 200,000 buildings without power, while high waves flooded or closed several roads and bridges.

A man was trying to rescue his golden retriever from a drainage steam, while he was sucked into an outflow pipe, and was found dead after being pulled out of a manhole.

The declaration allocated federal funding to assist in paying for debris removal and the rebuilding of public infrastructure damaged by Ernesto's flooding, including roads, parks, and government buildings.