Hurricane Vince (2005) - Meteorological History

Meteorological History

On October 5, an operationally unnamed subtropical storm which had gone unnoticed by the NHC was absorbed by a temperate frontal low, which was moving to the southeast over the Azores. The low pressure system gained a more concentrated circulation and lost its frontal structure after absorbing the subtropical storm. The developing system became a subtropical storm itself early on October 8, 580 miles (930 km) southeast of Lajes in the Azores. However, the NHC decided not to name the system Vince at the time, because the water temperature was too low for normal development for a tropical cyclone. The storm gradually gained the tropical characteristics of symmetry and a warm inner core and became a tropical storm the next day. Its transformation to a tropical system occurred over water cooler than 24 °C (75 °F), much colder than the 26.5 °C (80 °F) usually required for tropical development.

Soon after it became a tropical storm on October 9 near Madeira, with a ragged eye already present, the NHC officially named it Tropical Storm Vince and began to issue advisories. At the time there was some uncertainty as to whether Vince was tropical or subtropical but, in his post-season analysis, forecaster James L. Franklin of the NHC conceded that Vince had formed as a subtropical storm and had evolved into a tropical storm before it was named. The storm's ragged eye quickly solidified and contracted into a "bona fide" eye with a diameter of 15 mi (25 km). This increase in organization was accompanied by strengthening, and Vince reached its peak strength as a hurricane with 75 mph (120 km/h) winds later that day. The NHC forecaster decided that "if it looks like a hurricane, it probably is, despite its environment and unusual location".

Hurricane Vince's impressive organization was very short lived as westerly wind shear began to erode the eye within hours. In response, the storm weakened to a tropical storm shortly thereafter. A broad low-level trough approached the storm from the northwest, pulling the convection northward as the storm's low-level center accelerated eastward. On October 10, two brief bursts of convection surprised forecasters, but with the sea surface temperature as low as 22 °C (72 °F), the flares were not sustained. Vince continued to weaken as it approached the Iberian Peninsula and became a tropical depression on October 11, shortly before it made landfall near Huelva, Spain. The fast-moving tropical depression quickly dissipated over land. Its remnants moved across southern Spain, dumping rain on the drought-ridden region, and moved into the Mediterranean Sea south of Alicante in the early hours of October 12.