Tropical Storm Zeta has formed in the eastern Atlantic Ocean one a month after the official end of the hurricane season.

Zeta, the 27th named storm this year, formed yesterday about 1,600 kilometres southwest of the Azores, forecasters at the National Hurricane Centre in Miami said.

Zeta is moving in west-northwest at about seven knots with maximum sustained winds of 25 knots, gusting to 35 knots.

The closest point of approach within the first 72 hours will be 1,246 nautical miles east of Bermuda tomorrow afternoon.

Earlier this month, Hurricane Epsilon became the fifth hurricane to form in December in 154 years of record-keeping.