Forecast Models Undecided on Fate of Atlantic Disturbance

Guidance waffles on when and where our next named storm may form and where it could head

The tropical wave that rolled off Africa Sunday – a system we’ve been following since last Thursday and discussed in detail in yesterday’s newsletter – continues to move harmlessly through the deep tropical Atlantic with only scattered, disorganized storminess.

While forecast models still call for gradual development by late week into the weekend, they’ve been jumpy, with some modeling systems fluctuating wildly from run-to-run on exactly where and how much development may come. The jumpiness of models indicates high uncertainty with this one, and we’ll need to stay patient until the system is better defined and the models have a better handle on its future.

Interests in the eastern Caribbean and Lesser Antilles should continue to check back periodically on the forecast, especially as we approach the weekend. Any threat to the islands, if at all, wouldn’t come until the middle to latter part of next week so we have some time to feel this out.

Hurdles ahead

At least for the short term, the system will be battling strong upper-level winds and dry air in the vicinity which should stave off development.

The environment should improve deeper into next week, but the Atlantic will be undergoing a period of transition into the more conducive side of the MJO, and models suggest some hurdles to pronounced development may remain.

The American GFS is still in the quick-turn-north camp, though less so than it advertised on Monday.

The European model has trended in the direction of the GFS, with its ensemble scenarios farther north and east of the islands next week.

Forecast low-pressure tracks from the American GFS model ensemble system (top), the European model ensemble system (middle), and Google DeepMind’s latest cyclone ensemble system (bottom) through next Thursday, September 11, 2025. The European model has trended north toward the American GFS since Monday while the machine learning-based Google DeepMind favors a weaker and farther west/south path toward the islands for mid to late next week. Credit: Weathernerds.org

Meanwhile the newest AI models, including Google’s DeepMind experimental hurricane model, are farthest south and west, but keep it weaker as it approaches the Lesser Antilles for the middle to latter part of next week.

The bottom line is it’s too early in the game to say with confidence whether it’ll bend quickly northward next week or take a more gradual bend farther west, putting the islands in play.

One positive thing for the mainland U.S. for the foreseeable future is a very amplified weather pattern and persistent jet stream dip in the east. This would overall support a turn east of the U.S. for storm systems moving in from the east.

Forecast 500 mb geopotential height standardized anomalies for 10 days out (Saturday, September 13, 2025) from the European model ensemble system. The deep blue shading off the southeastern U.S. indicates a pronounced jet stream dip which would favor a turn east of the U.S. for any storm system approaching from the east. Although this forecast is still 10 days out, the strong signal for an amplified pattern and jet stream dip in the east is a positive signal for this one turning before it gets across the Atlantic. Credit: TropicalTidbits.com

That’s still 10-plus days out, but at the moment the pattern is in our favor with this one.