The third hurricane of the Atlantic season, Hurricane Humberto, built rapidly into a major storm at the weekend, attaining Category 5 status as it accelerated into a northwesterly turn from the Caribbean, on track to pass west of the island tomorrow night.

A tropical storm watch went into effect last night, and the Emergency Measures Organisation is to meet today, as the newly formed Tropical Storm Imelda was also deemed a potential threat.

The Bermuda Weather Service predicted that the weather would deteriorate today, with southeasterly swells, hazardous seas and rip currents building as Humberto passes west tomorrow, and into Wednesday, dropping to Category 2 strength.

Humberto’s influence was expected to help drag Imelda eastward on a course towards the island. The storm, forecast to become a Category 1 hurricane, showed potential to approach Bermuda late this week.

A spokeswoman for the Ministry of National Security said yesterday that Imelda was “bringing severe wind and rain across central Bahamas and may influence local conditions in the coming week”.

Michael Weeks, the Minister of National Security, said the Government and EMO were “fully engaged, and guided by the Bermuda Weather Service”.

Mr Weeks warned residents not to grow complacent, noting that there had been “some near misses this season regarding severe storms”.

He added: “Hurricane Humberto is a dangerous storm, and with another system developing to our south, every household in Bermuda should take the necessary steps to be prepared.

“Review your emergency plans, secure your property and stay tuned to official updates.”

Further advisories will be issued after the EMO meeting.

As of 9am this morning, Humberto was 364 miles south-southwest of Bermuda, and was predicted to make its closest point of approach at 9pm tomorrow, passing 219 miles to the northwest.

However, meteorologists emphasise that any predictions are subject to change.

The BWS said winds out of the south tomorrow would grow strong, with gale-force gusts becoming storm-force by the evening and overnight, particularly in elevated and exposed areas.

A small-craft warning was in effect yesterday. Much as was seen recently with the near passage of Hurricane Gabrielle, a Category 3 storm, the South Shore can once again expect heavy seas.

Powerful gusts are expected to persist into Wednesday.

The BWS noted today that Humberto and Imelda were both considered potential threats to Bermuda and said that “after some brief reprieve after Humberto clears the area by Wednesday evening, conditions begin to rapidly deteriorate once more late Wednesday night”.

It added in its long-term forecast for Thursday and Friday: “The long range period sees Hurricane Imelda lingering early on before gradually exiting to the northeast.”

David Burt, the Premier, will remain in close contact with Cabinet during a trip to Europe this week.

Mr Burt said: “While no direct threat to the island is currently anticipated from Hurricane Humberto, storm tracks are unpredictable and, given the size of the storm, vigilance is warranted.”

He advised residents to heed warnings from the EMO on both storms.

Belco, the island’s electricity provider, said that its crisis management team was bracing for the storm, with reserves strategically placed in the western and eastern ends of the island and crew assignments on hand for a rapid response.

The company reminded residents to keep trees on their property clear of power lines, and to call 295-5111 or e-mail treetrimming@belco.bm three weeks in advance to schedule a power shutdown to cut foliage back safely.

Shelly Leman, Belco’s managing director, said the island had been “fortunate to have escaped any impacts from Hurricane Gabrielle” — but cautioned residents not to let their guard down.

She added: “I urge residents to prepare now for potential storm conditions and encourage all residents and businesses in Bermuda to review their own hurricane safety plans as well as tips and advice on the Belco website and social-media channels to keep their family and property safe should we be impacted by major Hurricane Humberto.”