Atlantic Disturbance Developing, Forecast Trends Encouraging for the Caribbean and Florida

Soon-to-be Lee expected to become a powerful hurricane by later this week as it nears the northernmost Caribbean islands this weekend

The disturbance moving through the east-central Atlantic – dubbed Invest 95L – continues to organize and is expected to become Tropical Depression Thirteen or Tropical Storm Lee by later today. Though the system is poised to strengthen into a powerful hurricane this week, models have trended away from the northeastern Caribbean islands for this weekend and for now forecast an escape route before it reaches Florida. Bermuda will also need to monitor the progress of future Lee closely for next week.

Full steam ahead for future Lee

Morning satellite shows storminess still organizing, but increasingly focused near the center of the developing circulation of 95L. The system is traveling along a tropical convergence zone known as the monsoon trough. While this strip of broad storminess and background spin can boost short-term development, it can also stifle growth once a system forms. As the disturbance breaks free of the monsoon trough tomorrow and Thursday, a period of robust strengthening should commence, and soon-to-be Lee is expected to be a hurricane before the workweek is out.

Forecast models for now trending away from the Caribbean and Florida

The system will be traveling west-northwest this week under high pressure steering to the north. Models have trended northward since yesterday, giving more cushion for a potential brush with the northeastern Caribbean islands this weekend.

Odds of 95L or future Lee passing within about 100 miles of a given location based on overnight runs of our most reliable global forecast models. Model runs have trended northward with the system, suggesting a center farther away from the northernmost Caribbean islands this weekend. Those in the islands should continue to follow the forecast trends this week. Credit: Tomer Burg/University of Oklahoma

Even if the islands are spared direct impacts from the expected hurricane, trailing rain bands and destructive surf well away from the center could pose problems from the Lesser Antilles westward to Puerto Rico and the U.S. Virgin Islands into early next week.

Long-range models are advertising a pronounced jet stream dip off the southeast U.S. next week which would help to turn the system northward before reaching the Bahamas or Florida.

While the trends are encouraging, this is still a week away, and the error bars with a forecast this far out are high, so we’ll need to follow the trends in the days ahead. At least for now the trends are leaning away from Florida.

Those in Bermuda or with interests there will need to carefully monitor the forecasts for any potential threat next week.

More storms ahead

Behind Invest 95L, another strong tropical wave – designated Invest 96L this morning – is rolling off Africa today and tomorrow. 96L will lift quickly northward toward the Cabo Verde Islands over the next few days and forecast models show that general northwest motion continuing into the weekend. The environment looks to favor another named storm over the eastern Atlantic and possible hurricane into next week. Once past the Cabo Verde Islands, the system is expected to remain over the open Atlantic.

Franklin’s curious curtain call

The remnants of once-powerful Hurricane Franklin are located north of the Azores in the northeastern Atlantic. The non-tropical low pressure will be diving south toward Portugal where water temperatures are running well above average. Forecast models suggest a low chance that Franklin regenerates into a rare tropical or subtropical storm between the Azores and Portugal by this weekend.