Tropical Storm Laura has strengthened in the Caribbean and is poised to accelerate into a hurricane, while Tropical Storm Marco has weakened sooner than expected, sparing the US Gulf Coast from two simultaneous hurricanes that had been forecast.

The dual storms have taken offline nearly 10 per cent of the United States’ crude oil production, as energy companies shuttered operations to ride out the weather.

The changed forecast from the National Hurricane Center bought a little more time for residents along Louisiana’s coast to prepare for the one-two punch.

Marco could still bring dangerous winds and rain on Monday evening, with Laura forecast to make landfall on the US Gulf Coast on Wednesday night.

Laura traced the southern coast of Cuba on Monday morning but the brunt of the storm was offshore, helping the Caribbean nation avoid serious damage after Laura killed at least 10 people in Haiti and the Dominican Republic.

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The storm downed trees in Cuba, ripped away flimsy roofs and caused minor flooding on Sunday evening. In Jamaica, there were reports of landslides and flooded roads.

Laura was heading toward the Gulf of Mexico at 31km/h, according to the NHC.

By Tuesday, it was expected to have reached hurricane strength. By Wednesday night, stronger still, it was expected to hit the US Gulf Coast as a category two or three hurricane.

Despite Marco’s weakening, with the NHC predicting it would slow to a tropical depression by Monday night, that storm still threatened to soak the Louisiana coast.

This year’s hurricane season has been complicated by the coronavirus pandemic, forcing many people to weigh the risks of leaving their homes and potentially exposing themselves to the virus.