Tropical Storm Iota is brewing in the Caribbean Sea, threatening a second tropical strike for Nicaragua and Honduras after they were ransacked by Category 4 Hurricane Eta.

The National Hurricane Centre in Miami said Iota could bring dangerous winds, storm surge and as much as 30in of rain to the two Central American countries, approaching their coasts as early as Monday.

The storm is more than 300 miles south-south-east of Kingston, Jamaica, with maximum sustained winds of 40mph, and moving to the west-south-west at 5mph.

Iota could wreak more havoc in a region where people are still grappling with the aftermath of Eta.

That system hit Nicaragua last week as a Category 4 hurricane, killing at least 120 people as torrential rains brought flash floods and landslides to parts of Central America and Mexico.

Then it meandered across Cuba, the Florida Keys and around the Gulf of Mexico before slogging ashore again near Cedar Key, Florida, and dashing across Florida and the Carolinas.

The Tampa Bay area was buffeted with gusty winds and rain, and there was one US death linked to Eta, a man who was electrocuted in his flooded garage as he was laying sandbags.

Iota is already a record-setting system, being the 30th named storm of an extraordinarily busy Atlantic hurricane season. Such activity has focused attention on climate change, which scientists say is causing wetter, stronger and more destructive storms.

Eta was the 28th named storm of this year’s hurricane season, tying the 2005 record for named storms. Theta, the 29th, is weakening over the far eastern Atlantic Ocean.