Hurricane Lee forecast to become a Category 5; forecast for US ...

Hurricane Lee strengthened into a Category 2 hurricane Thursday morning and will only further intensify into a Category 5 storm, days before a precarious and uncertain northward track that much of the US East Coast will have to watch closely.

The Category 2 storm was packing maximum sustained winds of 105 mph as of early Thursday, located about 870 miles east of the northern Leeward Islands, according to the National Hurricane Center.

Even more rapid intensification is expected because the forecast track takes the hurricane across some of the warmest waters in the Atlantic Ocean and through relatively calm upper-level winds. Lee is now forecast to reach 160 mph Category 5-strength Friday night as it approaches the eastern Caribbeanand is still expected to be a dangerous hurricane over the southwestern Atlantic early next week.

There is increasing confidence that the center of Lee will pass to the north of the northern Leeward Islands, the Virgin Islands and Puerto Rico this weekend and into early next week, but tropical storm conditions, life-threatening surf and rip currents could occur on some of these islands over the weekend.

There is little confidence in what happens along the East Coast of the US next week, after Lee passes the islands. Dangerous surf and rip currents will threaten the Eastern Seaboard, but it’s too soon to know whether this system will reach the US mainland.

Computer model trends for Lee have shown the hurricane taking a turn to the north early next week. But exactly when that turn occurs and how far west Lee has managed to churn at that time will play a huge role in how close it may get to the US.

CNN’s Robert Shackelford, Monica Garrett and Nouran Salahieh contributed to this report.