Tropical Storm Laura and a separate tropical depression brewing near Honduras may make landfall as hurricanes in an area stretching from Texas to the Florida Panhandle, the National Hurricane Centre says.
It would be the first time two cyclones have entered the US Gulf of Mexico since 1959 - and meteorologists say two storms have converged in the Gulf simultaneously on only a very small number of occasions.
And while a Category 3 hurricane and moderate tropical storm hit the US Gulf of Mexico together in 1933, there are no records of two hurricanes occurring in the ocean basin at the same time.
However, meteorologists say there is still considerable uncertainty around how the systems may develop and move in coming days, particularly as they cross land.
He said it was unlikely they would combine, but added: "More than likely one will become stronger, and inflict more vertical wind shear causing the other to weaken.
"But if they stay of equal strength, then they will probably prevent each other from getting really strong."
David Streit, of Commodity Weather Group, said that sometimes when storms interact, they can orbit each other and the speed of one cyclone can accelerate the other.
This is part of something known as the "Fujiwhara effect".
Tropical Storm Laura is currently east of the Antilles and was upgraded from a depression on Friday, with sustained winds of 45 miles per hour.
It is forecast to make landfall as a hurricane on Wednesday in an area spanning Louisiana to the Florida panhandle.
Tropical Depression 14 - which would be named Marco if it strengthens - is on course to make landfall on Tuesday near the Texas and Louisiana border.
https://news.sky.com/story/two-hurricanes-forecast-to-hit-us-gulf-at-same-time-in-unprecedented-weather-event-12054135