There is generally not a dominant weather feature that is steering the storm, so model forecasts can vary widely between each other and from run to run.
Looping hurricanes have happened before, including Hurricane Jeanne, which in 2004 appeared to be heading out to the open Atlantic only to turn around and strike the Florida coast.
While all eyes are focused on Hurricane Irma, Hurricane Jose is also looming to the west and could still threaten the United States later this week. It is forecast to weaken to Category 1 strength in a few days, with winds between 75 and 90 miles per hour.
The big question is: Is Jose something for the United States to worry about?
The hurricane center's forecast shows Jose reintensifying into a hurricane by early Thursday and turning more to the west, a track that could bring it within a few hundred miles of the Bahamas by the weekend.
Caicos before Irma
- GFS, the American forecast model, and the ECMWF, the European one - keep Jose over the ocean.
"If you hear a rumor, especially on social media, regarding what Jose may or may not do", it said in its morning discussion, check a reliable source, such as Mount Holly or the hurricane center.
The National Hurricane Center recognizes this uncertainty in its Tuesday morning forecasts for Jose, saying "after (three days), the confidence in the forecast decreases as the guidance diverges significantly".
"Within the next 72 hours we would get a better picture of Jose in terms of posing any immediate threat to the country at this time". The loop back toward the coast comes after Jose is expected to travel southwest - essentially backwards - and then move closer to shore.
The full hurricane season lasts until November 30, although the peak season generally stretches from about mid-August to mid-October.