LAURA TO BRING WINDY WEATHER TO SOUTH FLORIDA MONDAY WHILE MARCO IS INCREASING THREAT TO GULF COAST

Tropical Storm Laura finally organized a bit as the broad center of circulation tracked near the southern coast of Puerto Rico today. Wind gusts near hurricane strength and very heavy rain have been reported on the island. The tall mountains in the Dominican Republic are just ahead on Laura’s track, which will likely disrupt the circulation and may weaken the winds once again. The open question is what emerges over Cuba on Sunday.

Even though the center of Laura is likely to pass by to the south of Florida on Monday, gusty winds will extend well north of the system. As a result, a Tropical Storm Watch, indicating the possibility of sustained winds over 40 mph and gusts over 50 mph, has been issued for the Florida Keys.

In the western Caribbean, Marco has significantly strengthened. It’s forecast to become Hurricane Marco as it crosses the Gulf ahead of Laura. Both systems are threats to the Texas, Louisiana, Mississippi, and possibly the Alabama coastlines. The forecast landfall points are still moving around.

The afternoon computer forecast models show both systems making landfall as strong storms, possibly hurricanes. A daunting situation.

It is possible, but not likely, that Laura and Marco could interact in the Gulf. Their timing appears to be offset by a couple of days, however, with Marco arriving in the northern Gulf Monday but Laura not arriving until Wednesday.

In any case, they would not merge if they came close, assuming they both had well-developed circulations. They would deflect each other, and the stronger storm in this kind of interaction normally weakens or dissipates the weaker system.

TROPICAL STORM LAURA

Laura will continue to spread heavy rain and strong gusty winds over Puerto Rico, especially on the south side of the island, as it pulls away to the west. Mudslides and flooding are the big threats, although some areas will get strong winds as well.

Since Laura is just about to cross the Dominican Republic coast, it’s not expected to intensify much more right away. The current track shows Laura’s circulation center moving near or over the 10,000-foot mountains in the middle of the country. These mountains have shredded stronger storms than Laura in the past. It’s not clear what type of system will emerge near the eastern end of Cuba tomorrow.

There’s a chance that Laura’s circulation might skirt around the mountains or eke by over the water with only partial damage, and we have to be aware of that possibility. If a viable circulation gets deflected out over the ocean, Laura could come back quickly into a stronger storm.

In any case, a band over strong winds will extend well north of the circulation center as the air is squeezed between a strong Atlantic high-pressure system and Laura’s low pressure. It’s this band of windy air that is expected in South Florida on Monday.

As the circulation gets disrupted over the mountains, the band of strong winds may spread out, extending farther from the center. The important point is, don’t focus on the center of the storm. The strong winds will occur well north of the middle of the cone.

The atmospheric environment over South Florida and the Bahamas appears conducive for a even stronger storm to develop than forecast, but only if the circulation is not significantly dismembered over the Caribbean mountains and the center tracks over the water. This scenario doesn’t appear likely, but is not impossible. We’ll know tomorrow when the center reaches the vicinity of eastern Cuba.

On Monday, whatever shape Laura is in, the center is forecast to track well south of South Florida and the Keys. The strong and gusty winds with the system are expected to extend well north of the system 100 to 150 miles at that time, however, so areas in the Southern and Central Bahamas as well as the Keys and South Florida can still expect high winds and gusty squalls, especially in areas exposed to winds off the ocean.

High rises, marine interests, and high-profile vehicles and housing need special attention. Balconies should be clear and boats secure. Follow any local orders, especially in the Keys.

The winds will likely be higher in the Keys and Miami-Dade County than in Broward and Palm Beach Counties, but some strong winds are expected over all of South Florida.

If Laura wobbles to the north and tracks over the ocean north of Cuba, there would be time for a stronger system in the vicinity of South Florida on Monday. Everybody needs to stay aware and be informed.

Once Tropical Storm Laura reaches the Gulf of Mexico late Monday, the storm is expected to organize and strengthen. The current thinking is that it will track toward the Texas, Louisiana, or Mississippi coast. Although Alabama is not completely out of the woods. The computer forecast models have been moving around with their prediction for what part of the coast will be most affected, and the afternoon models show a stronger storm, with the potential of a hard hurricane hit about Wednesday.

This would be on top of whatever Marco does on Monday or Tuesday.

TROPICAL STORM MARCO

Marco quickly intensified earlier today. The nose of the high-pressure area that is pushing Laura west is pushing Marco to the north, with the core of the small circulation passing between Mexico’s Yucatan peninsula and western Cuba.

Marco is expected to charge north as a strengthening hurricane. In a couple of days, the atmospheric environment doesn’t look as supportive, so the National Hurricane Center is forecasting the intensity to at least level off. Still, a dangerous storm is forecast to make landfall on Monday.

Hurricane and Storm Surge Watches have been issued for the Louisiana and Mississippi coasts, including Metropolitan New Orleans.

Needless to say, everybody along those coastlines should have the hurricane plans in place and be on high alert. They may well be impacted by two significant storms in two days.