Hurricane Epsilon was the twenty-seventh named storm, and the fifteenth hurricane of the 2005 Atlantic hurricane season, forming from an extratropical area of low-pressure in the central Atlantic Ocean on November 29. Epsilon was one of the strongest hurricanes recored for so late in the year, and was also the longest-lasting December hurricane, beating the previous record held by Hurricane Lili of the 1984 Atlantic hurricane season. Despite an extremely hostile environment for development, Epsilon became a hurricane on December 2, holding onto hurricane status for several more days, frustrating forecasters at the National Hurricane Center. Epsilon dissipated on December 8.

Epsilon caused no reported deaths and no damage, since it remained at sea throughout its lifetime.

Epsilon on December 4
Formation November 29, 2005
Dissipation December 8, 2005
Highest winds 85 mph
Lowest pressure 981 mbar
Deaths None reported
Damages None
Areas affected No land areas

Meteorological History

Epsilon developed out of a non-tropical low-pressure area in the central Atlantic Ocean on November 29 that had gradually acquired tropical characteristics in the wake of earlier Tropical Storm Delta. At the time, the depression was well east of Bermuda, and never would get close to land at all. Epsilon gradually strengthened into a strong tropical storm, but weakened slightly on December 1. At this point, the official forecasts from the National Hurricane Center predicted that Epsilon would weaken further in its highly sheared environment, as well as an environment with SSTs well below the threshold for tropical cyclogenesis. They also predicted Epsilon to become an extratropical cyclone again. Unexpectedly, on December 2, Epsilon strengthened again, becoming a hurricane over waters cooler than 21-24°C (70-75°F) as well as continuing strong wind shear, conditions that would normally be very unconducive to development of a tropical cyclone.

Despite this strengthening, the official forecasts continued to predict weakening and eventual dissipation of Epsilon, but Epsilon defied all predictions of weakening, and maintained hurricane strength for several days out in the open waters of the Atlantic Ocean. At one point on December 4, it was thought that Epsilon weakened back to a tropical storm, but post-season analysis revealed that Epsilon did not weaken at all, and stayed at hurricane strength. Hours later, Epsilon strengthened to its peak of 85 mph winds. Epsilon frustrated forecasters at the National Hurricane Center, defying all their predictions. Epsilon maintained hurricane status for 5 days after gaining it, with most of the six-hour forecasts within that 5-day period calling for it to weaken below hurricane strength. Dr. Lixion Avila said that Epsilon developed a structure similar to that of an annular hurricane, which allowed it to maintain its strength despite hostile environmental conditions.

On December 7, a strong upper-level low from the northwest disrupted Epsilon's organization. The continuing high wind shear and cooler waters finally weakened it to a tropical storm that day. Epsilon quickly weakened further into a tropical depression on December 8, and dissipated shortly thereafter.


No land areas were impacted from Epsilon, and no ships came into contact with tropical-storm force winds. Epsilon caused no damage or deaths.

Naming and Records

When Tropical Storm Epsilon formed on November 29, it was the first time ever that twenty-seven tropical or subtropical storms had formed in the Atlantic basin in one season. Epsilon was also only the 6th ever recored hurricane in December in the Atlantic basin, and Epsilon spent more time as a hurricane during December than any other storm in the Atlantic basin, with the previous record being held by Hurricane Lili of 1984.

See Also

2005 Atlantic hurricane season