Subtropical Storm One was a subtropical cyclone that developed during April of 1992. The storm formed on April 21 about 600 miles southeast of Bermuda. In spite of initial forecasts of the cyclone becoming tropical, it never gained tropical characteristics, and dissipated on April 24 without affecting land. At the time, this was the first April storm on record in the Atlantic. This was later broken by Tropical Storm Ana in 2003.
The cyclone caused no damage and no deaths.
|Formation||April 21, 1992|
|Dissipation||April 24, 1992|
|Highest winds||50 mph|
|Lowest pressure||1002 mbar|
|Part of the||1992 Atlantic hurricane season|
On April 21, a non-frontal low became cut off in the southwestern north Atlantic Ocean and was centered about 600 miles southeast of Bermuda. On this day, satellite imagery revealed a large comma-shaped cloud signature associated with the low. Ship reports indicated that a surface low developed with the system, and it was thus designated Subtropical Storm One at 1200 UTC that day. After forming, the cyclone initially moved northwest at around 10 knots, but its motion gradually slowed over the following two days. At 0600 UTC April 22, a ship report indicated that the cyclone had become a subtropical storm. By 1800 UTC April 23, the cyclone weakened to a tropical depression and became nearly stationary. In addition, strong westerly vertical shear began to impinge upon the cyclone during this time. Early on April 24, the storm turned to the east and dissipated. The remnants could be tracked for another 24 hours before losing their identity.
Initially, the storm threatened Bermuda, with the National Hurricane Center indicating an 18% chance the cyclone would pass within 65 miles of the island; in spite of such predictions, it remained well to the southeast of the island.
The highest winds reported from a ship were 50 mph, from the ship with the call signal C6KD7. In addition to the strong winds, the ship reported a minimum central pressure of 1004.1 mb, along with waves in excess of 64.4 feet; it was based on the ship report that the NHC decided to classify the system.
Records and Naming
When the storm developed on April 21, it became the first time on record in the Atlantic that an April storm developed. However, subtropical cyclones have only been tracked since 1968, and thus, it remains a possibility that there were extratropical cyclones during April prior to that time that were actually subtropical cyclones, but were not designated as such. In addition, this was the first subtropical cyclone not to make the transition into a tropical cyclone since 1984.