A developing storm in the Gulf of Mexico promises to bring heavy, potentially flooding rain to Florida starting Sunday and lasting into much of next week.

Forecasters still aren't sure yet if the system will become a named tropical storm, or even potentially a low-end hurricane. But regardless of tropical (or subtropical) development, locally heavy rains are forecast to occur over portions of the Florida Peninsula late this weekend into next week, the National Hurricane Center said.

"While the exact track and intensity of the feature unfolding in the gulf have yet to be determined, Florida will bear the brunt this time around," AccuWeather chief on-air meteorologist Bernie Rayno said. "At this time, the intensity will range from a sprawling tropical rainstorm to perhaps a strike from a more compact, full-blown hurricane."

Forecasters are primarily worried about rain at the moment.

Many inches to a foot or more of rain may fall in some locations, with the most rainfall likely to be from Interstate 4 south to the Keys, according to AccuWeather. Some locations could get up to 30 inches of rain.

According to the National Weather Service forecast office in Miami, with these rain-driven threat setups, "it is important to emphasize that a less organized system (in terms of central pressure or max winds) does not necessarily imply lesser impacts," as the more sloppy systems can still have fairly significant impacts.

Hurricane possible, AccuWeather says

"Should development take place in the southwestern gulf and move along a narrow east-northeast path toward the Florida Peninsula, there is the time and potential for the feature to strengthen into a tropical storm and hurricane," AccuWeather's Alex DaSilva said.

The hurricane center is less bullish about the storm, saying only that "a tropical or subtropical depression or storm could form during the early to middle part of next week," the center said in a Friday morning forecast.

Other forecasters also aren't calling for a hurricane: According to University of Miami meteorologist Brian McNoldy, "several models are now showing a weak low-pressure center over south or central Florida on Tuesday into Wednesday, possibly a low-end tropical storm."

If it becomes a named storm, the next name on the list is Milton.

Rain, not wind, the primary threat

According to McNoldy, there's general agreement that the system will begin to drift east toward the Florida peninsula, with rainfall beginning on Sunday and lasting for days. "It could develop into a tropical or subtropical depression or storm by then, but wind will not be the primary hazard from this; it will be rain," he said.

Heavy rainfall is likely for Central and South Florida between Sunday and Tuesday, meteorologist Ryan Truchelut said.

Kirk and Leslie continue to spin in the Atlantic

Out in the Atlantic Ocean, Hurricane Kirk and Tropical Storm Leslie continue to spin far from land. Large swells from Kirk could bring life-threatening surf and rip currents to the East Coast of the U.S. by Sunday, the hurricane center said.

Although predicted to weaken by early next week, Kirk or its remnants is likely to be a long-lived system that may affect much of western Europe in general by the middle of next week, AccuWeather said.

Tropical Storm Leslie is expected to reach hurricane strength by Saturday, but is no threat to any land areas as of Friday morning, the hurricane center said.

(This story has been updated to add new information.)

Contributing: Cheryl McCloud, USA Today Network-Florida