Hurricane Season Is Not Over Yet: Invest 90L May Develop in the Atlantic Ocean This Week

Jonathan Erdman
Published: November 19, 2019

A disturbance east of the Lesser Antilles may become the latest Atlantic tropical or subtropical storm, a reminder the 2019 Atlantic hurricane season isn't over yet.

The area of low pressure, known as Invest 90L, is over 200 miles northeast of the northern Leeward Islands, drifting northwestward. An "invest" is a naming convention used by meteorologists to identify disturbances that may develop.

Satellite imagery shows that a surface circulation is attempting to form near where this system is producing persistent shower and thunderstorm activity. If a well-defined circulation forms, then this system could be classified as a depression or storm by the National Hurricane Center (NHC).

For now, the NHC has given Invest 90L a high chance of development into a depression or storm. Fortunately, it's no threat to land.


Potential NHC Development

Even if it does develop, it's expected to curl north of the Leeward Islands, including Puerto Rico and the Virgin Islands.

It's also expected to curl soon enough to remain east of Bermuda. Jet stream winds and an approaching cold front will eventually catch up to it and sweep it into the North Atlantic Ocean.

If it becomes either a tropical or subtropical storm, it would earn the name Sebastien.

It's Not Too Late

With Thanksgiving next week, it may sound weird to be discussing tropical development this late in the season, especially given the record cold and snow this fall in parts of the nation.

(MORE: Seven Crazy Things We've Seen This Hurricane Season

But this isn't unusual, and it's happened a number of times this century.

Roughly 3% of an average Atlantic hurricane season's activity occurs after Nov. 18, according to Dr. Phil Klotzbach, tropical scientist at Colorado State University.

Since 1950, 24 tropical or subtropical storms have developed in the Atlantic Basin from Nov. 19 through New Year's Eve, according to NOAA's best track database. That's an average of one such late-developing storm roughly every three years.

The map of those storms shows a common corridor through the central Atlantic Ocean north of Puerto Rico and the Leeward Islands, similar to the location of Invest 90L.

Tracks of all Atlantic storms since 1950 that formed from Nov. 19 through Dec. 31.

Eight of those post-Nov. 18 storms formed this century. The most recent was Olga in mid-December 2007.

The record-smashing 2005 hurricane season's three final named storms – Delta, Epsilon and Zeta – each formed after Nov. 18. Tropical storms Odette and Peter ended the 2003 season in early December.

Not every storm this late in the season stays out to sea.

On Thanksgiving Day 2016, Hurricane Otto made landfall near the Nicaragua-Costa Rica border at Category 3 intensity. Otto was the latest-in-season Atlantic Basin hurricane landfall on record and the first known hurricane to track over Costa Rica.

In 1985, Hurricane Kate became the latest-in-season U.S. hurricane landfall on record. It plowed ashore at Mexico Beach, Florida, on Nov. 21.

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.


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.