Hurricane Ernesto was the costliest tropical cyclone of the 2006 Atlantic hurricane season. The sixth tropical storm and first hurricane of the season, Ernesto developed from a tropical wave on August 24 in the eastern Caribbean Sea. Ernesto first affected the northern Caribbean, reaching minimal hurricane status near Haiti before weakening and moving across eastern Cuba as a tropical storm. Despite initial predictions for it to track through the eastern Gulf of Mexico as a major hurricane, Ernesto moved across eastern Florida as a weak tropical storm. After turning to the northeast, it re-intensified and made landfall on August 31 on the North Carolina coast just below hurricane status. Late the next day, Ernesto became extratropical after entering southern Virginia. The remnants spread moisture across the northeastern United States before dissipating over eastern Canada on September 4.
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. Damage in Virginia was estimated at over $118 million (2006 USD), prompting the declaration of a federal disaster area. Total damage in the United States was estimated at $500 million (2006 USD).
Meteorological history
On August 18, a tropical wave moved off the coast of Africa. It tracked westward, and its convection began organizing and concentrating on August 22. 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. As it approached the Lesser Antilles, a surface low developed, and with the confirmation of a closed low-level circulation from the Hurricane Hunters, it is estimated the system developed into Tropical Depression Five on August 24 about north-northwest of Grenada.
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. Despite the shear, convection intensified near the center as banding features improved, and on August 24, the depression intensified into Tropical Storm Ernesto. Convection deepened and expanded, though wind shear displaced the low-level center to the west of the convection. By August 26, the structure had become much better-defined, and within five days Ernesto was forecast to be located about south of the Gulf Coast of the United States as a powerful hurricane. The center reformed under the deepest convection after wind shear decreased, and at the same time outflow increased in all quadrants. Turning northwestward, a small eye formed, and early on August 27 Ernesto attained hurricane status about south-southwest of the border between Haiti and the Dominican Republic.
Upon becoming a hurricane, Ernesto was believed to be undergoing rapid intensification. 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. The center became broad and ill-defined, though it was forecast to re-intensify to hurricane status before striking Cuba. 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 . Hindered by increased wind shear from an upper-level low over the Bahamas, the storm weakened further before striking just west of Guantánamo Bay in Cuba as a minimal tropical storm. With very warm water temperatures and a favorable upper-level environment, one forecast remarked the possibility of Ernesto strengthening greatly over the Straits of Florida and eastern Gulf of Mexico to hit western Florida as a major hurricane. Ernesto remained over land as a minimal tropical storm for about 18 hours before reaching the Straits of Florida. Convection gradually increased over the warm waters, though Ernesto failed to strengthen significantly due to its disrupted inner core. An eastward-moving high pressure system over the southeastern United States allowed a continued northwest movement, and at 0300 UTC on August 30 the storm struck Plantation Key in the upper Florida Keys with winds of . Two hours later, Ernesto made landfall on the Florida mainland in southwestern Miami-Dade County.
Moving through a weakness in the subtropical ridge, the storm turned to the north through the state. Operationally, the National Hurricane Center downgraded Ernesto to tropical depression status while over the state, though post-analysis indicated the system maintained tropical storm status. Ernesto retained a well-organized cloud pattern over land, and after emerging over the Atlantic Ocean near Cape Canaveral, convection again increased and began wrapping into the circulation. Upon reaching the Atlantic Ocean, Ernesto accelerated north-northeastward ahead of an approaching deep layer trough. The convection increased as the storm strengthened over warm waters, and late on August 31 Ernesto attained an intensity of while located about south-southwest of Wilmington, North Carolina. Shortly prior to moving ashore, an eye began to develop, and early on September 1 the storm made landfall on Oak Island, North Carolina very near the threshold between tropical storm and hurricane status. The National Hurricane Center remarked the possibility that Ernesto could have been a hurricane at landfall, due to the possibility that the strongest maximum wind was not sampled.
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. It re-intensified to a gale over the Mid-Atlantic states, only to weaken to an extratropical depression near Pennsylvania. With a large high pressure area to its east, the remnants turned to the north-northwest, reaching southern Ontario on September 3. After turning northeastward, the extratropical remnants of Ernesto were absorbed into a larger storm over Quebec on September 4.
Preparations
Caribbean About nine hours after Ernesto became a tropical storm, the government of Haiti issued a tropical storm watch from its border with the Dominican Republic to the southwestern tip of the country. As the storm strengthened, the watch was replaced with a tropical storm warning, and about 15 hours prior to its closest approach the warning was replaced with a hurricane warning. Several low-lying citizens in Gonaïves were evacuated after local meteorologists anticipated up to of rain in some mountainous areas. Additionally, authorities advised residents in shanty towns near the ocean to evacuate to emergency shelters.
Jamaican officials issued radio and television advisories for residents in low-lying areas, urging them to be ready and evacuate if necessary. The Jamaican government opened all shelters on the island and placed its armed forces on standby. Long lines for storm supplies were reported at local businesses ahead of the storm as residents rushed to obtain supplies in preparation for Ernesto's onslaught. When a tropical storm warning was put in effect for Jamaica and the central Bahamas, cruise ship companies indicated they were diverting several liners to avoid the storm.
Hurricane warnings were put in effect for six provinces in southeastern Cuba, where significant precipitation ranging up to across the mountainous south was expected as the center of Ernesto tracked slowly across Cuba. Cuban officials evacuated 300,000 people and brought its fishing fleet into harbors. The Cuban state television broadcast extensive warnings about the storm, urging precautions. 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. The threat of the storm caused domestic flights to be canceled.
United States
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. On August 27, the Governor of Florida, Jeb Bush, issued a state of emergency because of the high risk of impact from Ernesto on the state. 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. Mandatory evacuations were later issued for mobile homes and low-lying areas of Monroe, Broward, St. Lucie, and Martin counties; voluntary evacuations were also issued for barrier islands in Miami-Dade and Palm Beach counties. On August 28, forecasters issued a hurricane watch for southern Florida through the Florida Keys. When Ernesto was downgraded to tropical storm status, Governor Jeb Bush urged Florida residents to continue preparations and not wait until it regained hurricane status, as it was forecast to do by the National Hurricane Center. At least 30 shelters were opened, and tolls on four turnpike were lifted. Several schools were closed across southern Florida. The threat of the storm caused NASA to postpone the launch of Space Shuttle Atlantis at Kennedy Space Center to avoid risking damage from the storm.
The storm was initially expected to move into the Gulf of Mexico and affect people recovering from hurricanes Katrina, Rita, and Wilma in the previous year, which caused hundreds of billion in damage and left thousands of houses damaged or destroyed. 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. Officials in New Orleans prepared buses and trains in the event that people needed to evacuate but could not. A possible path over the Gulf of Mexico oil fields, as well as tension with Iran, caused the price of oil to increase, although the prices receded when the threat of the storm receded.
On August 29, a hurricane watch was issued from the mouth of the Altamaha River in Georgia to Cape Fear, North Carolina. The next day, the watch was replaced with a tropical storm warning, which was later extended to Currituck Beach Light in Corolla, North Carolina before the storm moved ashore. In South Carolina, voluntary evacuations occurred in Charleston and Colleton counties.
On August 31 before the storm's arrival, Virginia Governor Tim Kaine declared a state of emergency, putting the Virginia National Guard and state agencies on alert and opening the state's new Emergency Operations Center in suburban Richmond. North Carolina Governor Mike Easley activated 200 National Guard troops and had other emergency teams on standby. Washington D.C. and parts of Maryland and Delaware were put on a Coastal Flood Watch and Flash Flood Watch by the National Weather Service in preparation for Ernesto.
Impact
Caribbean
Shortly before Ernesto developed into a tropical cyclone, the precursor tropical wave produced sustained winds of in Barbados in association with a convective downburst. On the island, the winds downed some trees, and some flooding was reported. Strong winds and rough seas damaged six fishing boats in the southern portion of the island. Squalls in Trinidad left about 12 people injured after winds destroyed several tents. Also on Trinidad, the system produced widespread flooding, which resulted in some crop damage.