Bermuda is making final preparations for an expected brush with Hurricane Humberto, a powerful Category 3 storm that prompted authorities to order the early closing of schools, transportation and government offices.

Govenor John Rankin called up 120 members of the Royal Bermuda Regiment to prepare for possible storm recovery efforts.

National security minister Wayne Caines said schools, government offices and ferries on the British Atlantic island would close at noon and bus service would halt at 4pm.

Officials expect tropical storm-force winds to begin whipping at Bermuda before dawn and warned that hurricane-force gusts could last until early Thursday.

Humberto is predicted to pass just to the north, though a small shift in its path could bring the storm over the island.

In the US, the remnants of Tropical Storm Imelda threatened to drench parts of south-west Texas and south-western Louisiana with up to 18in of rain over the next few days.

It was the first named storm to hit the Houston area since Hurricane Harvey’s much heavier rains flooded more than 150,000 homes around the city and caused an estimated 125 billion dollars in damages in Texas

The US National Hurricane Centre said Humberto’s maximum sustained winds had strengthened to 115mph and it would probably remain a Category 3 hurricane until Thursday although there could be some fluctuations in its winds.

The storm was centred west of Bermuda early on Wednesday and was moving to the east-northeast.

Bermuda is expected to get rainfall of up to 4in, with large swells along the coast.

Meanwhile, Tropical Storm Lorena was moving off Mexico’s Pacific Coast, and forecasters said it could cause heavy rain and flooding in an area of resorts along the shore by Thursday, probably without it reaching hurricane force.

A tropical storm warning was in effect from Zihuatanejo to Cabo Corrientes.

Lorena had top winds of 50mph late on Tuesday.

Tropical Depression Ten also formed far out in the Atlantic on Tuesday and could become a hurricane on Friday as it nears the outermost Caribbean islands, and Tropical Storm Jerry has formed in Atlantic, the season’s 10th named storm.