Exploring the Occurrence of Tropical Storms and Hurricanes After the Official End of the Atlantic Hurricane Season
The Atlantic hurricane season, which officially ends on November 30, is a well-known six-month period characterized by tropical storms and hurricanes. However, history has shown that tropical development can occur beyond this timeframe. In this article, we delve into the phenomenon of late-season storms and hurricanes, examining their frequency, characteristics, and impact. While these occurrences are relatively rare, they serve as a reminder that the Atlantic Basin can still produce powerful weather systems even after the official end of the hurricane season.
Late-Season Storms: An Analysis of December Formations
Unveiling the Occurrence and Characteristics of December-Forming Storms
While the June through November hurricane season encompasses the majority of Atlantic storms and hurricanes, it is important to note that the start and end dates are arbitrary. Analyzing NOAA’s historical hurricane tracks database, we find that since the late 19th century, 13 storms first became tropical or subtropical in December. Notably, these storms were distinct from those that formed in November and persisted into December. The most recent occurrence was in December 2013 when a brief subtropical storm developed in the eastern Atlantic Ocean south of the Azores.
Late-Season Hurricanes: The Rarity of December Intensification
Examining the Infrequent Strengthening of December-Forming Storms into Hurricanes
Out of the 13 December-forming storms, only four eventually intensified into hurricanes, with none surpassing Category 1 strength. The most recent instance was in December 1984 when Hurricane Lili formed northeast of the Leeward Islands. While the majority of December storms remained far from land in the central Atlantic Ocean, some, such as Odette in 2003 and Olga in 2007, triggered deadly flooding and mudslides in Hispaniola.
Beyond the Atlantic: January and February Anomalies
Uncovering the Occurrence of Tropical Storms in January and February
The unusual occurrence of late-season storms extends beyond December. In mid-January 2023, a subtropical storm formed off the Northeast Seaboard, eventually making landfall in Nova Scotia, Canada. In 2016, Hurricane Alex became the second Atlantic hurricane to form in January, packing peak winds of 85 mph. Two other January storms formed in 1951 and 1978, generally north or northeast of the Leeward Islands and Puerto Rico. Additionally, a tropical storm made landfall in South Florida in February 1952, causing damage due to high winds and heavy rain.
The Science Behind Late-Season Development
Understanding the Factors that Contribute to the Formation of Late-Season Storms
Late-season storms often originate from non-tropical sources, such as upper-level lows and cold fronts. When an upper-low becomes stationary over warmer-than-normal waters for an extended period, thunderstorms can develop and transform a cold-core system into a subtropical or tropical storm. This scenario typically occurs when a blocking pattern prevents the system from moving.
Conclusion:
While the official Atlantic hurricane season captures the majority of storm activity, the occurrence of late-season storms and hurricanes serves as a reminder that nature does not always adhere to arbitrary dates. The rarity of these events highlights the exceptional nature of late-season tropical development. As we reflect on the 2022 hurricane season, it is crucial to remain vigilant and prepared for the potential of late-season storms, emphasizing the need for continued monitoring and forecasting beyond November 30.
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