Tropical Storm Rafael is coming soon. It poses an uncertain threat to the U.S. Gulf Coast

CNN
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A rare November tropical threat could hit the United States over the weekend, amid an unusual and relentless hurricane season that shows no signs of easing.

Tropical Depression Eighteen formed in the Caribbean Sea on Monday morning and is expected to strengthen and become Tropical Storm Rafael on Monday afternoon. It will then strengthen into a hurricane by midweek as it moves over the northwest Caribbean Sea.

Rafael is expected to devastate Cuba as a hurricane and then emerge in the Gulf of Mexico. From there, the storm's final direction and intensity in the Gulf and possibly along the U.S. Gulf Coast will be difficult to determine precisely because the system has only just formed and is still several days away from reaching the area.

“It is still too early to determine what impacts, if any, may occur,” the National Hurricane Center said. Everyone from the U.S. Gulf Coast and northeastern coast of Mexico needs to closely monitor updates.

Early forecasts from the hurricane center show the center of the system will reach the U.S. Gulf Coast somewhere from the Florida-Alabama border to Louisiana later this weekend. But that area could shift dramatically in the coming days as the system passes through the Caribbean.

The drastic differences between two major forecast models regarding the direction of the storm once it enters the Gulf of Mexico highlights the forecast uncertainty. One shows Rafael making landfall in western Cuba and then migrating generally northwest before making landfall somewhere between Louisiana and the Florida Panhandle. The hurricane center's forecast is more similar to this scenario.

But another model shows that Rafael has the potential to make an abrupt left turn once he enters the open Gulf. From there it trends generally west and could break up completely or instead make landfall in northeastern Mexico or the western Gulf Coast.

Any shifts will have a significant impact on the storm's flood threat in Florida and other parts of the Southeast. The storm will increase rainfall in these areas before it potentially arrives there. This means any areas that receive rain from the storm later this week or over the weekend will be at increased risk of flooding.

Five hurricanes hit the Gulf Coast this year, but this storm is unlikely to be as severe as Hurricanes Helene and Milton because its strength could be affected by Cuba's terrain and hostile, storm-busting winds over the Gulf.

Tropical activity typically wanes in November, but an occasional storm occurs during this month. However, according to hurricane expert Michael Lowry, landfall in the US is exceptionally rare, with 98% of named storms making landfall in the US before November. The Atlantic hurricane season ends on November 30th.

While the threat the system poses to the US is still uncertain, the threats in the Caribbean earlier this week are much clearer.

Hurricane and tropical storm warnings are already in effect early Monday for Cuba, Jamaica and the Cayman Islands. More warnings are likely to be issued in the coming days as confidence grows in the system's ultimate strength and speed.

The bulk of the system's storms occurred over the Caribbean Sea early Monday, but heavy rain had already begun in parts of Hispaniola and Jamaica.

The system could bring torrential rain and flash flooding to more parts of the western Caribbean over the next few days. These heavy rains could also lead to mudslides, particularly in the mountainous terrain of Jamaica and southern Cuba.

Rainfall totals of 3 to 6 inches are expected for Cuba, the Cayman Islands and Haiti. Parts of Jamaica could see double-digit rainfall.

The system could also deliver strong winds, especially if it reaches hurricane strength late Tuesday or early Wednesday. Dangerous storm surges could also flood parts of the Cayman Islands and western Cuba.

CNN meteorologist Robert Shackelford contributed to this report.