Tropical Storm Alberto (2006)

Tropical Storm Alberto was the first tropical storm of the 2006 Atlantic hurricane season. Forming on June 10 in the northwestern Caribbean, the storm moved generally to the north, reaching a maximum intensity of before weakening and moving ashore in the Big Bend area of Florida on June 13. Alberto then moved through eastern Georgia, North Carolina, and Virginia as a tropical depression before becoming extratropical on June 14.

Across the Western Caribbean, the storm produced heavy rainfall, causing some minor damage. In Florida, a moderate storm tide caused coastal damage and flooding, while Alberto's outer rainbands produced several tornadoes. The storm was indirectly responsible for two drownings off the coast of Tampa Bay. In North Carolina, heavy rainfall caused locally severe flooding, and one child drowned in a flooded storm drain near Raleigh. The remnants of Alberto produced strong winds and left four people missing in Atlantic Canada. Overall, damage was minor along Alberto's path.

Meteorological history

In early June 2006, an area of convection persisted across Central America and the western Caribbean in association with a broad, nearly stationary trough of low pressure. Thunderstorms increased and became more concentrated on June 8 after a tropical wave moved into the western Caribbean, and an upper-level low to its west increased outflow over the system. The disturbance moved slowly north-northwestward, and development was initially inhibited by marginally favorable upper-level winds and land interaction. The system gradually organized, and by June 10 a circulation formed with sufficiently organized convection for the National Hurricane Center to classify it Tropical Depression One. At this point the storm was located about south of the western tip of Cuba.

The depression tracked to the northwest through the Yucatán Channel into an area of increased wind shear, which left the center exposed and elongated. Despite its poor structure, the system maintained strong winds in its eastern semicircle. The depression intensified into Tropical Storm Alberto early on June 11 about southwest of the Dry Tortugas, based on Hurricane Hunters' reports of flight level winds of in a few convective bands. Upon becoming a tropical storm, the low-level circulation had become better defined, though forecasts predicted the wind shear would increase, preventing significant strengthening of the storm. One forecaster at the National Hurricane Center remarked the system resembled a subtropical cyclone. However, deep convection developed and built westward against the wind shear as the overall organization improved. At the same time Alberto turned northeastward under the influence of an approaching trough. On June 12, the circulation abruptly reformed under the area of deepest convection, which coincided with the storm's passage over the loop current; consequentially, Alberto quickly strengthened to reach peak winds of about west-northwest of Tampa, Florida.

Though it was projected to track over cooler waters and stay in an area of increased shear, forecasters at the National Hurricane Center predicted Alberto would attain hurricane status and make landfall at that intensity. The storm maintained peak intensity for about 18 hours, and while accelerating northeastward, Alberto's convection diminished as the cloud pattern became elongated. On June 13, dry air became entrained in the circulation, leaving the center exposed from the convection and the wind field greatly broadened. A partial eyewall developed in the western semicircle of the center; however, winds were well below hurricane force. Alberto continued to weaken, and made landfall at about on June 13 with winds in Taylor County, Florida, about southeast of Tallahassee.

The storm maintained a well-organized structure and banding features over land, while continuing to produce winds of tropical storm force as it moved into Georgia. Early on June 14, the storm weakened to tropical depression status while located near the city of Millen, Georgia. Alberto began to lose tropical characteristics soon thereafter, and about six hours after weakening to a tropical depression it transitioned into an extratropical cyclone. Late on June 14 it accelerated northeastward to emerge into the Atlantic Ocean, and on June 15, it entered the area of responsibility of the Canadian Hurricane Centre. While over open waters, Alberto's remnants began to re-intensify; later that day, the extratropical remnant low attained winds of and a pressure of 969 mbar while a short distance south of Nova Scotia. At this time, the low presented a well-defined comma structure. After passing near Sable Island, the remnants of Alberto crossed the Avalon Peninsula of Newfoundland on June 16. The extratropical storm turned to the east-northeast and later to the east as it continued its rapid forward motion, and on June 19 the remnants of Alberto merged with an approaching cold front near the British Isles.

Preparations

By June 12, the Cuban government had evacuated over 25,000 people in the western portion of the country due to the threat of flooding. The National Hurricane Center recommended tropical storm warnings for the Isle of Youth and the Pinar del Río Province early on June 10, but they were not issued by the Cuban government.

In northwestern Florida, officials issued a mandatory evacuation order a day before the storm moved ashore for about 21,000 citizens in Levy County, Citrus County, and Taylor County. Several schools were closed as well, and converted into shelters. In all, about 350 coastal residents took refuge in emergency shelters. Prior to the arrival of the storm, Florida governor Jeb Bush declared a state of emergency for the state. A tropical storm watch was first issued for portions of the Florida Panhandle about 43 hours prior to landfall. As Alberto was predicted to continue intensifying, the National Hurricane Center issued a hurricane warning from Longboat Key to the mouth of the Ochlockonee River approximately 25 hours before landfall. A tropical storm warning extended southward to Englewood and westward to Indian Pass. A tropical storm warning was also issued from Flagler Beach, Florida to the mouth of the Santee River in South Carolina. As the storm moved inland, local National Weather Service offices issued flood watches for portions of North Carolina, Virginia, and the Delmarva Peninsula. Additionally, flood and flash flood warnings were issued for some portions of the country from South Carolina through Virginia.

While Alberto was becoming extratropical over land, the Canadian Hurricane Centre issued gale warnings for offshore waters of Nova Scotia, and later for Newfoundland. In addition, the Atlantic Storm Prediction Center issued inland wind warnings for coastal regions of Nova Scotia. Due to the prediction for precipitation, the Atlantic Storm Prediction Center posted rainfall warnings for all Atlantic coastal regions of Nova Scotia.

Impact

Caribbean

In its early stages of development, the tropical depression which later became Alberto produced heavy rainfall across the western Caribbean. A station on Grand Cayman reported of rain in one 24-hour period. In Cuba, rainfall amounted to in Pinar del Río province, where one station recorded in one hour. On the Isle of Youth, precipitation accrued to in Sumidero. Air and marine travel was disrupted between the Cuban mainland and the Isle of Youth. In Havana Province rainfall totaled at Playa Baracoa. Much of the precipitation fell over a fairly short period of time, and was beneficial, as the area had been suffering from severe drought conditions. In Pinar del Río province, the precipitation flooded of crop land. The storm damaged about 50 houses across the country, about half of which in Havana

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