Developing Tropical Storm Katia is likely to become major Hurricane Katia -- with potential, albeit slim chance of eventually striking the U.S. as Hurricane Irene did last week.

While Vermont still battles flood waters and millions along the U.S. East Coast pick up after Hurricane Irene, Tropical Storm Katia has formed and is slowly strengthening as it moves across the Atlantic. The storm is expected to soon reach hurricane strength, possibly escalating to major storm category.

Early forecast models show Hurricane Katia is not expected to hit the U.S., while perhaps striking in the Caribbean, but some experts say it's far too early to know. Ruling out a strike on the U.S. from Hurricane Katia at this point would be a mistake, according to Weather Underground found Dr. Jeff Masters.

The long-term fate of Katia is unknown, Masters, a hurricane expert, wrote on his blog.

He said in daily commentary that uncertainty is prominent in the storm's forecast. Models do not suggest that Florida is in the picture, but anything could happen from among many possible scenarios.

The storm had maximum sustained winds late Tuesday morning near 45 miles per hour, and the U.S. National Hurricane Center in Miami said gradual strengthening is forecast. Katia is expected to be near hurricane strength by late Wednesday or early Thursday, as the second official hurricane of the 2011 Atlantic season.

Forecasts show Katia could become a major hurricane by the weekend.

It's still well out to sea. A lot of things can happen ... We don't show it affecting any land areas for five days. Beyond that is merely speculation, NHC senior hurricane specialist Richard Pasch told Reuters. 

On Tuesday, Katia was centered about 630 miles west-southwest of the southernmost Cape Verde Islands, moving west-northwest at 18 miles per hour. Another hurricane specialist said Katia could impact the Caribbean, but it's too early to tell if the storm will become the second to hit the U.S. this season after Hurricane Irene.

Katia's storm name replaces Katrina in the rotating storm roster because of the catastrophic damage from the 2005 storm which ravaged the U.S. Gulf Coast, causing catastrophic flooding in New Orleans and virtually destroying the Mississippi coastline.