Hurricane José has reached Category 3 strength, but the Bermuda Weather Service said it is not a threat to the island “at this time”.

As of 6pm storm’s closest point of approach within the next 72 hours was expected to be 599 nautical miles south at 6pm on Sunday.

However, the BWS warned the system could come closer after that time.

According to the US-based National Hurricane Centre, the storm reached Category 3 strength this afternoon, making it the third major hurricane of the 2017 season.

At 6pm, José was about 1,214 nautical miles southeast of Bermuda and was headed west-northwest at 18mph, boasting maximum sustained winds of 120mph with higher gusts.

A hurricane watch has been issued for the dual-island nation of Antigua and Barbuda, while a tropical storm watch is in effect for Anguilla, Montserrat, Saint Kitts and Nevis, Saba and Sint Eustatius.

The news came as Category 5 Hurricane Irma — one of the strongest hurricanes ever recorded in the Atlantic — caused widespread destruction across the Caribbean, reducing buildings to rubble and leaving at least nine people dead.

Packing winds of 185mph, the storm made landfall in Antigua and Barbuda early yesterday. While Antigua escaped major damage, Prime Minister Gaston Browne said Barbuda had been left “barely habitable”.

Irma also caused major damage in Saint Martin — an island comprised of French territory Saint-Martin and the Dutch section Sint-Maarten — and the nearby French territory Saint-Barthelemy.

Meanwhile, more than half of Puerto Rico’s three million residents were without power and at least one death has been reported in Anguilla, while the British Virgin Islands were also battered by the storm.

The Dominican Republic, Haiti, Turks and Caicos, Cuba and the Bahamas are also in Irma’s path and there is a possibility it will hit Florida over the weekend. Mandatory evacuations of vast areas of coastal South Florida began yesterday.

Irma is expected to weaken over the next few days, but the NHC said the storm could remain Category 5 until sometime tomorrow.

The BWS said the storm is not considered a threat to Bermuda “at this time”, with its closest point of approach within 72 hours having past.

As with Hurricane José, however, the BWS warn that the storm could come closer after the 72 hour window passes.

Hurricane Irma, which is so strong it is even showing up on seismometers for measuring earthquakes, follows in the wake of Hurricane Harvey, which caused catastrophic flooding in Texas since it made landfall as a Category 4 storm on August 25.

James Dodgson, director of the Bermuda Weather Service, said Hurricane Irma is being kept away from the island by a strong Bermuda-Azores ridge of high pressure.

He explained: “This has the associated impact of steering Irma on its current west-northwestward track just north of the Greater Antilles and towards the Florida peninsula.”

While he said José is being steered by the same ridge, a weakness in the ridge is forecast to develop this weekend, potentially allowing the storm to make a northward shift.

Mr Dodgson added: “At this stage it is too early to say if José will continue on that track or will in fact deviate from that track.

“Model consistency and confidence is currently poor in the long-range forecast projections for José.”

And he urged the public to keep a close eye on BWS forecasts at www.weather.bm and tropical update bulletins as the hurricane season continues.

Meteorologists are also watching Hurricane Katia, which formed in the Gulf of Mexico and reached hurricane strength yesterday afternoon.

The National Hurricane Centre said the storm was yesterday moving towards the east-southeast at around 3mph and should gradually turn southeastward during the next 24 hours.

On the forecast track, the centre of Katia is expected to remain offshore of Mexico through Friday morning.

Mr Dodgson said that the Atlantic is now at the height of the hurricane season, with all of the “nascent ingredients” just right for storm development.

He added: “This season has also been forecast to be more active than average due to two main factors — anomalously warm sea surface temperatures as well as reduced wind shear in the main tropical regions where hurricanes form.

“Increased wind shear prevents tropical cyclones from developing and maturing as it literally rips apart the forming system.

“With the latest early August official NOAA Atlantic hurricane season forecast update calling for up to as many as 19 named storms, we still have some way to go, as even with developing Tropical Storm Katia, that only brings the named storm tally to 11 so far.

“The official season continues for almost another three months, until the end of November.”

He said it was not unusual to have multiple major storms active in a short span of time.

Mr Dodgson added that four Category 4 storms were recorded in 2010 between late August and September.