Hurricane Alberto (2000)

Hurricane Alberto was a Cape Verde-type hurricane that formed over the Atlantic Ocean on August 3, 2000 and became extratropical on August 23. Alberto was the first named storm, the first hurricane, and the first major hurricane of the 2000 Atlantic hurricane season.

Hurricane Alberto was notable for its long existence, lasting for 19.75 days, making it the longest-lived Atlantic storm in 2000. Alberto was also notable for the unusually large loop it completed in the open Atlantic that spanned approximately 5 degrees latitude and 8 degrees longitude. Also, Alberto was able to attain hurricane status on three separate occasions. The tropical wave that eventually became Alberto affected the west African mainland near Senegal, and the extratropical remnants passed close to Iceland and Jan Mayen. However, there were no reports of damages or casualties as a result of Hurricane Alberto.

Meteorological history

A well-formed tropical wave was identified over central Africa based on satellite imagery on 30 July. The wave moved steadily westward and moved off the African coast on 3 August. Once over the open Atlantic Ocean, the wave quickly developed and became Tropical Depression Three later that day. The depression moved to the west-northwest and was upgraded to Tropical Storm Alberto early on August 4. Alberto continued to strengthen, but moved to cooler waters late on August 5 and weakened briefly. However, the storm strengthened again early on 6 August, and it was upgraded to hurricane status, as an eye developed in its centre. The upgrade was accompanied with a brief westward turn. However, Alberto continued to move to the west-northwest later that day, reaching its first peak intensity of 90 mph (150 km/h) on 7 August.

A vigorous upper-level low developed west of Alberto on August 7 and 8. This caused an increase in vertical shear, weakening the hurricane down to a tropical storm on 9 August. The low also caused the storm to turn to the northwest. However, on 10 August, Alberto became better organised and was upgraded to hurricane status again. It then moved in a gradual curve towards the north and northeast through a break in a subtropical ridge between 11 August and 12 August. Alberto made its closest approach to Bermuda on the 11th, passing about 345 mi (555 km) east of the island. The strong storm became a Category 3 major hurricane on 12 August and reached its second and highest peak intensity of 125 mph (205 km/h), and a 60 mi (95 km) wide eye was observed. Alberto was an unusual storm in that it reached its peak intensity at a high latitude, north of 35˚N, after it had recurved. The hurricane began to weaken due to increasing upper-level westerlies on 13 August and 14 August, while moving east-northeastward. Alberto was downgraded to a tropical storm on 14 August.

As early as 10 August, computer models anticipated the hurricane to accelerate to the northeast and become extratropical within three days, but this did not materialise. A westerly trough that had been influencing Alberto’s motion outran the storm, and a strong ridge developed to the north and west, causing the storm to turn abruptly to the south on 15 August, and to complete a large loop over the open Atlantic. Alberto turned to the southwest on 16 August and to the west on 17 August. The storm then took a sharp turn toward the northwest as a large, slow-moving mid-level trough was carving out over the eastern United States. Alberto began to strengthen, and reached hurricane status for the third time on 18 August. The hurricane continued to turn to the north on 19 August and to the northeast on 20 August and 21 August. During this time, Alberto reached a third peak intensity of 105 mph (165 km/h) on 20 August, and a 70 mi (110 km) wide eye was observed. Operationally, Alberto reached a peak intensity of 110 mph (175 km/h), but after reanalysis, it was reduced to 105 mph (165 km/h).

Hurricane Alberto began to weaken on 22 August as it accelerated into higher latitudes. It was downgraded to a tropical storm early on 23 August. Initially, it was forecast to become extratropical on 22 August, but a little burst of colder cloud tops enabled Alberto to remain tropical for a longer time, persisting into 23 August, while it moved into a very high latitude at 53˚N. The weakening storm finally became extratropical late on 23 August, while accelerating to the north-northeast, passing near Iceland on 24 August. Winds dropped below gale-force, as the centre turned to the east-northeast on 25 August. Alberto dissipated about 85 mi (140 km) east of Jan Mayen later that day.

Preparations and impact

Very minimal impact occurred as a result from Hurricane Alberto. In Dakar, Senegal, 25 mm (1 in) of rain was received as the pre-Alberto tropical wave passed over the city. A discussion was issued on August 9 prompting residents in Bermuda to monitor the progress of the storm until it safely passed. Also, from August 12 to August 14, public advisories were issued advising people from Azores to monitor the progress of Hurricane Alberto. This stopped when Alberto began to slow its motion and began to turn to the south, away from the Azores. Some swells were reported along the east coast of the United States a few days after the storm's recurvature. No reports were available on the impact of Alberto on Iceland, but it was estimated that winds of at least tropical storm force were experienced there. Otherwise, there were no known reports of damage or casualties as a result of Hurricane Alberto.

Records and naming

Hurricane Alberto completed the largest loop ever observed over the Atlantic Ocean, spanning approximately 5 degrees latitude by 8 degrees longitude. The storm is the seventh longest-lived storm in the Atlantic Ocean (lasting 19.75 days), and is also the second longest-lived Atlantic storm during August (the longest lived is the 1899 Hurricane San Ciriaco). Alberto was able to retain tropical characteristics at an unusually high latitude, up to 53˚N. The last storm to do so was Hurricane Frances in 1980.

This storm marked the fourth occasion the name "Alberto" had been used to name a tropical cyclone in the Atlantic. Due to the lack of any effects from Hurricane Alberto, the name was not retired by the World Meteorological Organization and the name was reused for Tropical Storm Alberto in the 2006 Atlantic hurricane season. The name was not retired after 2006, and the next time it will be used is the 2012 season.

See also

• List of tropical cyclones

References

External links

• National Hurricane Center's archive on Hurricane Alberto
• National Hurricane Center's Tropical Cyclone Report on Hurricane Alberto
• Track of Alberto from Unisys