Monitoring for Development Near Florida by this Weekend

Forecast models show a tropical system approaching Florida and the southeast U.S. this weekend, but keep it weak for now

We continue to follow a large tropical wave moving toward the easternmost Caribbean islands with little fanfare. The disturbance – a ripple in the atmospheric winds about 10,000 feet up resembling an ocean wave – is mostly dry and absent any significant weather for now but is expected to fire off rounds of storminess beginning tomorrow, which could allow it to develop as it approaches the Bahamas and Florida on Friday into the weekend.

The National Hurricane Center is indicating a tropical depression may form by late week as the system is nearing the Bahamas.

While squally weather with gusty winds and occasional downpours may accompany the system’s passage through the northeastern Caribbean tomorrow and Thursday, a significant tropical threat isn’t expected in these areas.

Possible development near the Bahamas by Friday

It’s not until the system is nearing the Bahamas on Friday that development becomes a little more likely.

Even so, forecast models continue to show modest southerly wind shear nearby from an upper-level high positioned east of the system. This should serve as a speed bump to quick development despite the very warm waters east of Florida.

An area of high pressure aloft, situated just east of the developing system by late Friday, could impart modest wind shear across the system, slowing development. Forecast from the European model. Credit: TropicalTidbits.com

This is reflected in our computer models, which largely depict a strong tropical wave, tropical depression, or perhaps low-end tropical storm (Debby) into the weekend.

The positioning of the upper-level high is critical as to how much development happens by this weekend. A more westward-oriented high pressure situated near or over the developing system would allow for further organization, though it’s worth noting at this stage none of our guidance shows the threat of a strong system.

Will it affect Florida?

By Friday a dip in the jet stream digging into the central U.S. will help to bend the system northward around the western periphery of the subtropical high-pressure steering.

The question is not whether it bends but where it bends. The good news for Florida is a stronger, more organized system would feel the tug of the higher jet stream winds sooner and favor a turn farther east. A weaker system would probably head farther west, perhaps affecting the peninsula or even sliding into the eastern Gulf this weekend.

Forecast low pressure tracks from the European model ensemble system. Each track shows a different scenario based on different starting conditions, giving us a flavor of possibilities. Weaker scenarios track farther west and closer to Florida, with stronger scenarios turning north sooner and tracking farther east of Florida. Credit: Weathernerds.org

Until we have a consolidated system with a defined center, we won’t have a better picture of how close it’ll get to Florida. The disturbance is quite large, and where within the broader system a smaller circulation takes shape will determine how much it impacts our weather.

The bottom line this week

We expect a tropical depression or low-end tropical storm could form by the end of the work week as it nears the Bahamas. A weaker system would tend to favor a more westward trajectory near or over Florida, while a stronger, more organized system would tend to bend northward farther east. A lot will depend on where the center of the large and still-disorganized disturbance ultimately forms, which we won’t know for at least another few days.

Given the time of year and development timeline closer to land, interests from the Bahamas to the southeastern U.S. – including folks in Florida, southeast Georgia, and the Carolinas – should monitor the progress of this system this week.