The first storm of the Atlantic hurricane season may enter the Gulf of Mexico as soon as next week, disrupting BP’s efforts to clean up the worst oil spill in U.S. history.

Thunderstorms in the Caribbean may strengthen into a tropical storm this week before heading into the Gulf between Mexico and Cuba, said Jim Rouiller, a senior energy meteorologist at Planalytics Inc. in Berwyn, Pa.

“The first named tropical storm of the 2010 season appears more likely to form over the northwestern Caribbean late this week and will go on to represent a formidable threat to the Gulf along with heightening concerns about the oil slick,” Rouiller said in an e-mail Monday.

Forecasters are predicting this year’s Atlantic hurricane season, which runs until Nov. 30, may be among the most active on record and may hamper BP’s efforts to plug the leaking well. AccuWeather Inc. forecast at least three storms will move through the region affected by the spill.

Atlantic weather systems receive a name when they reach tropical storm status with sustained winds of 39 miles per hour, while hurricanes have a minimum wind speed of 74 miles per hour.

A record 28 Atlantic storms formed in 2005, according to the National Hurricane Center. They included Katrina, whose 170 mile-an-hour winds toppled production platforms and set oil rigs adrift before slamming into New Orleans.

AccuWeather Monday boosted its forecast for the 2010 Atlantic hurricane season to 18 to 21 named storms, up from 16 to 18, and said at least three will move through the region affected by the oil spill. There have been five seasons with 18 or more storms in 160 years of record-keeping, AccuWeather said in an e-mailed statement.

The National Oceanographic and Atmospheric Administration forecast 14 to 23 named storms for this season. Above-normal sea temperatures west of Africa and a decline in the Pacific cooling phenomenon known as El Niño, which helps impede Atlantic hurricane development, are contributing to the storm activity, forecasters say.

Three storms, two of them hurricane-level, may pass through the oil spill area, while three more may come close enough to affect cleanup operations and other rig activity, AccuWeather chief hurricane forecaster Joe Bastardi said.

The Gulf is home to about 27 percent of the U.S.’s oil and 15 percent of its natural gas production, the Energy Department says. It also has seven of the 10 busiest U.S. ports, according to the Army Corps of Engineers.

Authorities have closed 36 percent of federal waters in the Gulf to fishing following the oil spill, equivalent to 86,985 square miles.

The April explosion and sinking of the Deepwater Horizon drilling rig, leased by BP from Transocean, killed 11 workers and has caused as much as 60,000 barrels of oil a day to leak into the Gulf. BP has been using chemical dispersants to break down the fuel and is attempting to collect oil from the damaged well.

The company is also drilling two relief shafts to seal the well that may be completed in August.

Scientists don’t agree on the effect of storms on oil spills. While hampering capping operations, the extra mixing and wave action from a storm may break down the oil in a more effective and less harmful way than chemical dispersants, Norm Duke, a senior research fellow at University of Queensland’s Marine Botany Group in Australia, said in an e-mail last month.

The benefits of a storm breaking up the oil naturally would likely be outweighed by spreading it further and preventing work to stop the leak, according to Darren Kindleysides, director of the Australian Marine Conservation Society.