In the Caribbean, a storm is brewing that could wash out Memorial Day

Memorial Day is a holiday that draws people outside. It was created to honor those who have died while serving in the nation's armed forces and also marks the unofficial start of summer.

This year, though, the family cookouts, beach excursions and roads trips that often accompany the long weekend might get rained out.

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The Caribbean Sea storm that the National Hurricane Center has been tracking is expected to march north and arrive in the Gulf of Mexico, and near Florida, by the weekend.

Forecasters say it will more than likely develop into a tropical system and could become the first named storm of the Atlantic hurricane season, which doesn't technically start until June 1.

Regardless of whether or not the it becomes a tropical system — it would be named Alberto — the storm is expected to bring up to three to six inches of rain to the Tampa Bay region. All that water, combined with this month's rains, could cause rivers to breach their banks and flood low-lying areas.

"It's mostly looking like a heavy rain event," National Weather Service meteorologist John McMichael said. "The main impact will be heavy rains that could exacerbate rivers and areas prone to flooding. The ground is already saturated, so more rain will only cause more problems."

710 PM: New Special Tropical Weather Outlook issued- There is a high chance (70%) of a subtropical or tropical depression forming in the central or eastern Gulf of Mexico this weekend. Heavy rain is the main threat for now. Full details:https://t.co/m9946DoYYi pic.twitter.com/Di3pggLuZl— NHC Atlantic Ops (@NHC_Atlantic) May 23, 2018

710 PM: New Special Tropical Weather Outlook issued- There is a high chance (70%) of a subtropical or tropical depression forming in the central or eastern Gulf of Mexico this weekend. Heavy rain is the main threat for now. Full details:https://t.co/m9946DoYYi pic.twitter.com/Di3pggLuZl

@NHC_Atlantic now giving the disturbance near the Yucatan a 70% chance of tropical development in the next few days. Still looks to mostly be a heavy rain maker for Florida. #flwx pic.twitter.com/MD44igbZVL— NWS Tampa Bay (@NWSTampaBay) May 24, 2018

@NHC_Atlantic now giving the disturbance near the Yucatan a 70% chance of tropical development in the next few days. Still looks to mostly be a heavy rain maker for Florida. #flwx pic.twitter.com/MD44igbZVL

Hurricane center forecasters on Thursday said the storm, currently called Invest 90L, had a 70 percent chance of developing into a tropical system within the next 48 hours, and a 90 percent chance within five days.

What does that mean for travel plans over the three-day weekend? AAA had estimated that 2.2 million Floridians would hit the road and travel at least 50 miles this weekend — despite nationwide gas prices of $2.87 a gallon, the highest Memorial Day price since 2014.

But while gas prices don't appear to be keeping people off the road this weekend, AAA spokesman Mark Jenkins said, the weather just might.

"I think there's a really good chance that it could put a damper on some people's travel plans," Jenkins said. "Especially those who were planning on going to the beach, maybe those who were going to theme parks."

However, he said, those with non-refundable travel plans might try to tough it out despite the poor weather. For many, he said, the decision to travel or stay home might be made at the last-minute, depending on what the weather is like outside.

And while visitors from outside the state might be discouraged by the impending weather, the storm could encourage some Floridians to travel north and get out of the state.

But in general, Jenkins said, people do their best to stick to their plans rain or shine: "This being the kickoff to the summer travel season, people will want to travel if they can."

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The weather could have other implications beyond affecting traffic and vacation plans. Four rivers in the Tampa Bay area reached flood warning levels last week, McMichael said, including the Alafia and Little Manatee rivers. He said it was very likely those rivers will be at risk of flooding again.

When Hurricane Irma inundated the region last year, residents who live along the Alafia river found themselves flooded out of their homes. This week the water reached knee-high along some streets, which is why residents have been anxiously tracking rainfall totals.

One thing forecasters aren't worried about right now is high winds being generated by the storm, McMichael said, which could make conditions much worse. Of course, that could change if the tropical system strengthens significantly.

"Obviously if it develops strong wind conditions, we would need to watch its path," McMichael said. "But currently, our predictions say that Tampa Bay is in for a very damp and rainy holiday weekend."

Contact Josh Solomon at (813) 909-4613 or jsolomon@tampabay.com. Follow @ByJoshSolomon.

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