Watching Two Areas In Atlantic Basin

T​ropical development is possible late this week in the western Caribbean Sea, a rarity for November during a strong El Niño, and could bring flooding rain to Hispaniola, including Haiti. In addition, an area off the Southeast Coast has a low chance of tropical development.

W​hat we’re watching: A cluster of showers and thunderstorms is percolating from north of Panama into the western Caribbean Sea east of Honduras and Nicaragua. Computer forecast models over the past several days have consistently hinted that an area of low pressure could form later this week in that general location east of central America and south of Jamaica.

A second area is also being monitored: A​n area of low pressure is expected to develop near South Florida in the next day or so. Development into a tropical cyclone is unlikely as it moves northeastward near the Bahamas and off the East Coast into this weekend. However, it will produce gusty winds and heavy rain.

W​hat could happen in the Caribbean: If hostile shearing winds remain low enough, and if thunderstorms can continue to coalesce near an area of low pressure over water that is still very warm, a tropical depression or storm could form sometime late this week in that area of the southwest Caribbean Sea. If it becomes a storm, it would be named “Vince”.

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W​here it could head: The system is expected to be pulled northeastward toward Jamaica, eastern Cuba and Hispaniola by Friday or Saturday, then into the southwest Atlantic Ocean by Sunday, where it is expected to transition to a non-tropical low. This will not be a threat to the mainland U.S.

W​hat are the potential impacts: Regardless of whether this becomes a depression, storm, or remains a nameless area of low pressure, the potential for heavy rainfall appears to be the most serious threat from Jamaica and eastern Cuba to Haiti and the Dominican Republic late this week into the weekend.

T​his rain will be heaviest over hilly and mountainous terrain and will probably fall along and to the east of the system’s path, with lighter rainfall totals on the system’s western flank. Dangerous flash flooding and landslides are possible, particularly in Haiti.

Rip currents are possible later this week along south-facing shorelines of Jamaica, eastern Cuba, Haiti and the Dominican Republic. If this system becomes Tropical Storm Vince, some stronger wind gusts could add to the threat of downed trees in rain-soaked ground, and power outages.

W​hy this would be so unusual: As we’ve discussed before, November is still hurricane season, and typically generates a storm every 1 to 2 years. The western Caribbean Sea is one place that typically happens.

I​n records dating to 1950, only three systems have previously become depressions or storms in November during a strong El Niño in the Atlantic Basin. As you can see in the track map below, none of those systems did so in the Caribbean Sea.

S​o, this could be a first for the tropical Atlantic in at least 73 years.

Check back with us at weather.com for updates to this forecast in the days ahead.

M​ORE ON WEATHER.COM

-​ How The 2023 Atlantic Hurricane Season Measures Up

-​ A Typical November During A Stronger El Niño In The Tropics

-​ 6 Changes A Stronger El Niño Could Bring This Winter

-​ How El Niño Got Its Name

Jonathan Erdman is a senior meteorologist at weather.com and has been covering national and international weather since 1996. His lifelong love of meteorology began with a close encounter with a tornado as a child in Wisconsin. He studied physics at the University of Wisconsin-Madison, then completed his Master’s degree working with dual-polarization radar and lightning data at Colorado State University. Extreme and bizarre weather are his favorite topics. Reach out to him on X (formerly Twitter), Threads and Facebook.

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.