Forecasters expect a tropical wave to pass south of Cayman over the weekend, bringing several inches of rain, thunder and high winds. Cayman’s first tropical system of the Atlantic hurricane season, which began Wednesday, will likely bring flooding and rough seas for the next couple of days.

Cayman Islands Weather Service chief meteorologist Kerry Powery said the tropical system will likely move north over the Yucatan Peninsula and “will continue to collect moisture over the Caribbean.” The system could develop into a tropical depression once it is in the Gulf of Mexico, he said.

Mr. Powery predicts an inch of rain per day, starting Saturday night through Monday night.

The forecast calls for potential flooding, high winds and high seas. Winds are expected to reach 15 or 20 knots on Saturday and could reach a peak of 20 to 25 knots on Sunday. Winds will likely be a little calmer Monday at 15 to 20 knots.

“Sea conditions will be rough,” he said.

Mr. Powery said the National Weather Service expects to issue small craft advisories for Saturday and Monday, and a small craft warning for Sunday.

He said an upper-level trough had been in control of Cayman’s weather over the past few days, bringing locally heavy storms. As that system moves out, he said, “we should get a reprieve Friday” before the tropical system begins to push in high winds and rain Saturday.

The Atlantic hurricane season began June 1 and runs through the end of October. The second named storm of the year, Bonnie, has been dumping rain along the southeastern United States and began to move off the coast of North Carolina on Thursday, once again strengthening into a tropical depression.

The system moving past Cayman has a 30 percent chance of developing into a tropical depression over the coming week, according to the National Hurricane Center in the U.S., though it will not likely pose any threat to Cayman. If the wave does turn into an organized tropical storm, it would be named Colin and could potentially affect Florida.

Mr. Powery said Cayman’s weather next week is largely dependent on how this system moves once it is in the Gulf of Mexico. But, he said, “showers should decrease.”