New Area to Watch for Next Week in the Atlantic

A disturbance expected to emerge off Africa could slowly develop but poses no immediate threat to land

As we’ve been previewing in newsletters this week, a tropical wave – a ripple in the atmospheric winds at around 10,000 feet that resembles an ocean wave – is set to roll off Africa in the next few days and could gradually develop next week over the open Atlantic.

On Wednesday afternoon, the National Hurricane Center added this formation zone to its 7-day outlook and is maintaining low development chances into early next week.

Forecast models are largely bullish on its development prospects, with the newcomer AI-based models more enthusiastic about development next week than their physics-based counterparts.

Forecast low-pressure tracks through next Saturday, September 20, 2025, from the traditional European model ensemble system (top) and the European model’s latest AI-based ensemble forecast system (bottom). The AI-based ensembles are more bullish on development odds next week than their physics-based counterparts. Credit: Weathermodels.com

Forecast low-pressure tracks through next Saturday, September 20, 2025, from Google’s AI-based DeepMind hurricane model. The model is bullish on development odds over the central Atlantic next week. Credit: Weathernerds.org

For now at least, the system poses no immediate threat to land, but until it’s fully formed, expect wide bookends on its future track next week. It’s nothing for us back stateside to worry about at this time.

Atlantic shedding its hostile shell

For much of August, the Atlantic was in a mostly conducive configuration for tropical development. Storm-busting wind shear across the bellwether Caribbean was scraping near-record lows, which in August is typically one of our most reliable predictors for overall hurricane season activity (lower wind shear in the western tropical Atlantic in August has a very strong relationship with busier hurricane seasons).

Zonal wind shear for the western tropical Atlantic so far this year (black line) compared to past hyperactive hurricane seasons (blue line), above-average hurricane seasons (orange line), average hurricane seasons (gray line), and below-average hurricane seasons (green line). Generally, lower wind shear in the Caribbean suggests higher hurricane season activity. From early August to early September, zonal wind shear in this bellwether region was the 2^nd lowest on record. Credit: Dr. Phil Klotzbach/Colorado State University

Relationship between zonal wind shear over the western tropical Atlantic in August and overall hurricane season activity, as measured by the Accumulated Cyclone Energy or ACE. When shear in the Caribbean is low in August, ACE, or hurricane activity, is typically high. The closer r (known as the Pearson correlation coefficient) is to 1 or -1, the stronger the relationship is between the two. An r-value of -0.7, as shown here, indicates a very strong (negative) relationship. Credit: Dr. Phil Klotzbach/Colorado State University

But since late August, wind shear has ramped up, especially just east of the U.S. into the western Atlantic, courtesy of a persistent jet stream dip that’s been plaguing South Florida with round after round of flooding rains.

Other than in early June, we’ve seen more flood alerts issued for South Florida over the past week than in any other week this year. And unlike in most Septembers, none of the flood alerts were associated with a tropical system.

Number of flood advisories issued per calendar day in 2025 by the National Weather Service in Miami. Since last Wednesday, NWS Miami has issued more flood advisories than any other week this year besides the first week of June. Credit: Iowa Environmental Mesonet (IEM)

Unfortunately for us but fortunately for the tropics, we get another week or so of this pronounced jet stream dip that’ll keep us stormy but also ward off would-be storms. By the third week of September, however, this changes, and the jet stream lifts north, opening the door to much reduced wind shear over the tropical Atlantic.

Forecast wind shear departures from average for the third week of September (September 21-26, 2025) from the European model ensemble system indicates reduced wind shear from the Caribbean into the tropical development belt across the Atlantic.

While this is happening, the much stronger-than-average Atlantic subtropical high pressure (AKA the Bermuda/Azores High) that’s been sweeping dry air from northern latitudes into the tropics will begin to weaken, helping to re-juice the tropical Atlantic.

Forecast normalized mean sea level pressure anomalies for the third week of September (September 21-26, 2025) from the European model ensemble system showing a weakened Azores/Bermuda high. Credit: TropicalTidbits.com

The upshot is increasingly conducive conditions ahead to round out September, so don’t expect the back part of the month to be as forgiving as these unusually quiet first few weeks.