MIAMI (AFP) - The 17th storm large enough to earn its own name has formed in the Atlantic Ocean, making Tropical Storm Rina the latest in an already above-average hurricane season, forecasters said on Tuesday (Nov 7).

As of 1500 GMT (11pm Singapore time), Rina posed no threat to land, and was churning in the open Atlantic 1,455km east of Bermuda, the Miami-based National Hurricane Centre said.

With maximum sustained winds of 65kmh, the storm was headed in a north-easterly direction, moving at a speed of 19kmh.

Rina's pace was expected to pick up throughout the day, the NHC said.

This season was expected to be above average, with 11 to 17 named storms anticipated at the outset, a figure forecasters revised upward to 14-19 in August.

In an update posted on Nov 1, the NHC said 2017 so far has been "well above average" in terms of storm activity, compared to the 1981-2010 average.

Normally there are about 12 named storms - of which six become hurricanes - per year in the Atlantic.

With devastating storms like Harvey, Irma and Maria, this has been the busiest Atlantic hurricane season since 2005, when there were 28 named storms, which includes tropical storms and hurricanes.

Current factors that make way for more storms include an ocean that is one to two deg F warmer than average, increasing moisture in the tropical air, a weaker wind shear across the tropical Atlantic and Caribbean, and stronger wind patterns off Africa which more easily whip up storms, according to NHC lead forecaster Gerry Bell.

The season officially runs from June 1 to Nov 30.