Residents in Cuba and southern states in the United States are making preparations for severe weather.

Alberto – the first named storm of the 2018 hurricane season – has formed in the Caribbean and is churning towards the US Gulf Coast.

Currently, the storm is located just to the northwest of Cuba and classed as “subtropical”. This means that it is transforming from a “regular” weather system into a tropical one which gets its energy from the warm waters of the ocean.

At the moment its growth is being hindered by strong winds in the upper atmosphere, but as the storm tracks northwards these winds are expected to ease, allowing the storm to complete its transition into a fully tropical system.

This would mean the storm would become more compact around its centre, with the strongest winds and rain located here.

It would also become more symmetrical. At the moment almost all of the showers are on the east of Alberto’s centre, with the heaviest rains falling across Cuba and Florida.

Despite its predicted strengthening, Alberto is not expected to become a hurricane. The winds are predicted to be no more than 100 kilometres per hour on landfall, but flooding is likely to be a major issue.

The US-based National Hurricane Centre is warning that Alberto could produce up to 600 millimetres of rain in western Cuba. This is more rain than Havana expects in the first six months of the year, and is likely to produce life-threatening flash floods and mudslides.

Although Alberto is not expected to make landfall on the US Gulf Coast until 00:00 GMT on Tuesday, heavy rains are expected to start across the region today and continue for several days.

Over 350mm of rain is possible along the coast, which in the long term will be beneficial, given the dry conditions which have prevailed in recent weeks. However, such a large amount of rain in a short period of time is likely to result in significant flooding.

Alberto has formed before the official start of the hurricane season, which starts on June 1. Historically this is fairly unusual, but this is the fourth year in a row that this has happened and is believed to be due to climate change.