A hurricane becomes a Category 1 once it achieves windspeeds of 74mph. Hurricane Lee's winds are now blowing at 75mph.
The storm is currently 1,130 miles off the coast of the northern-most Leeward Islands, according to the National Hurricane Centre.
Hurricane Lee is expected to undergo rapid intensification — in which its wind speeds increase by at least 35mph in less than 24 hours — over the coming days, according to CNN.
Forecasters believe the storm will become a Category 4 with sustained wind speeds of up to 150mph by Friday night.
“To get to Category 4 or 5 intensity the environment has to be nearly perfect, which it looks like is the forecast for Lee,” David Zierden, Florida's state climatologist, told the outlet.
The storm's 150mph forecast is only 7mph shy of it reaching a Category 5 hurricane.
The last Category 5 in the Atlantic was Hurricane Ian in 2022.
Hurricanes have increased in intensity in general due to the climate crisis contributing to warmer waters, and this year especially due to El Nino effects.
It's unclear at this time if Hurricane Lee will threaten the US mainland, though even if it doesn't reach the coast it will still produce dangerous surf and rip current conditions.
The storm's current path will threaten the eastern Caribbean — including Puerto Rico, Hispaniola, and the Leeward Islands — as it travels north.
The storm is spinning up just as the climatological peak of hurricane season — 10 September — draws near.