The US National Hurricane Center says this year's Atlantic hurricane season has broken the record for the number of named storms.
Subtropical storm Theta in the north-east Atlantic is the 29th, breaking the previous record of 28 set in 2005.
Theta is moving north-eastwards towards southern Europe.
Forecasters say another system is forming in the Caribbean which could be named in coming days.
Meteorologists say several factors are behind the increasing number of tropical storms.
The most influential are very warm sea surface temperatures, low wind shear and the La Nina effect.