A Disturbance in the Atlantic Is Being Watched for Tropical Development as it Tracks Westward

weather.com meteorologists
Published: September 15, 2019

A tropical disturbance in the central Atlantic Ocean bears watching for possible development into a tropical depression in the week ahead.

The area of disturbed weather is located midway between the Cabo Verde Islands and the Lesser Antilles. Gradual development of this system is possible and a tropical depression may form later this week as it tracks west-northwest across the tropical Atlantic.

The National Hurricane Center has given this system a high chance of development within the next 5 days, and the odds have been increased in the latest outlooks.


Potential Development Areas

It's too early to determine if this system – whether a tropical depression, tropical storm or still an unorganized disturbance – will eventually bring any significant impacts to any Caribbean land areas this week. Any impacts to the Lesser Antilles would more likely be in the Leeward rather than the Windward Islands.

Beyond that, it's also far too soon to determine if this system will eventually become a threat to the mainland United States.

Elsewhere in the Atlantic Basin, we're also monitoring Humberto off the Southeast coast, which may threaten Bermuda as a hurricane.

(MORE: Humberto Forecast

There is also a large area of showers and thunderstorms in the Gulf of Mexico that is being monitored for possible tropical development. This disturbance has only a low chance of development before moving onto the Texas coast late Monday or Tuesday.

(MORE: What We're Watching the Gulf of Mexico

Active Atlantic Ahead?

There are signs the background environment over the Atlantic Basin may be waking up again after Hurricane Dorian's rampage.

Dr. Michael Ventrice, a meteorological scientist at The Weather Company, an IBM Business, noted on Twitter that the overall weather pattern in mid- to late September will likely be favorable for an uptick in tropical activity in the Atlantic Basin.

One contributor to this is a large-scale atmospheric disturbance called a Kelvin wave, a wave that propagates eastward along the equator and is often a precursor to tropical cyclone birth by a day or two. The next Kelvin wave is predicted to pass through the tropical Atlantic Ocean between Sept. 15 and 25, Ventrice said.

This Kelvin wave may also coincide with the enhanced phase of the Madden-Julian Oscillation (MJO), according to Ventrice. The MJO is another large-scale tropical disturbance that moves eastward around the Earth every 30 to 60 days, with phases that enhance and suppress thunderstorms occurring on opposite sides of the planet.

This wave of activity by itself does not create thunderstorms, tropical waves or hurricanes. It does, however, make the atmosphere more hospitable for these features.

(MORE: The MJO's Role in Hurricane Season Forecasting

We're now in the peak of hurricane season, so every disturbance in the tropics must be monitored closely for development.

As Neal Dorst of NOAA's Hurricane Research Division points out, September is a peak month not only in the Atlantic Basin, but is also part of a broad peak of activity in the Eastern Pacific and Western Pacific basins of the Northern Hemisphere.


The Weather Company’s primary journalistic mission is to report on breaking weather news, the environment and the importance of science to our lives. This story does not necessarily represent the position of our parent company, IBM.