The Atlantic hurricane season, which has had its slowest start since 2014, may soon experience activity with a developing system over the subtropical Atlantic, although its potential is limited. The system, known as Invest 90L, has displayed characteristics typical of a tropical depression, such as a well-defined circulation and warmer air at its center. However, it lacks sustained deep thunderstorm activity, leading to only light to moderate rainfall.
As of Monday morning, satellite images reveal that thunderstorms are still struggling to consolidate around the circulation. The latest estimates from Sunday indicated surface winds of 30 to 35 mph, just below the threshold for tropical storm status. The National Hurricane Center currently assesses a 70% chance of the system evolving into a short-lived tropical depression or storm today before conditions become unfavorable for further development.
Historically, systems like 90L can arise unexpectedly in the subtropical regions, but they typically have less time to strengthen compared to those that form in the warmer waters of the Main Development Region. The environment in the tropical Atlantic is expected to remain largely inactive through the end of June, with this week’s conditions likely continuing into early July.
In keeping with the previous year’s trends, when a potent system like Hurricane Beryl formed at this time, the current forecast suggests a quiet period ahead for the Atlantic. Despite the challenges to development, the activity of Invest 90L offers a reminder that the hurricane season can still produce surprises, encouraging vigilance as we move deeper into the season.