A tropical storm that weakens from a hurricane or tropical cyclone level and then regains strength to the level of a tropical storm is known as a zombie storm. Paulette first evolved in the Central Atlantic Ocean on September 6, 2020 as Tropical Depression Seventeen before strengthening to a tropical storm on September 7.
Paulette became a hurricane on September 12, passing over Bermuda before weakening into a post-tropical on September16th in the North Atlantic Ocean.
By September 14, Paulette was a category 2 hurricane and was part of five tropical cyclones that had formed in the Atlantic Basin. This was the first time since September of 1971 that this many tropical storms were active in the Atlantic at the same time.
NASA’s Terra satellite measured an increase in the strength of Paulette as it evolved back into a tropical storm on September 22.
NASA’s Integrated Multi-satellitE Retrievals for GPM or IMERG was able to measure rainfall amounts on September 22 for Paulette. On 3:30 a.m. EDT (0730 UTC) that day, IMERG calculated that Paulette was generating 5 mm (0.20 inches) of rain per hour at its center.
Paulette devolved back into a post-tropical storm (which NASA defines as “a generic term for a former tropical cyclone that no longer possesses sufficient tropical characteristics to be considered a tropical cyclone.”) later that day.
By September 23, NASA reported that Paulette was expected to become a “remnant low” later in the day.
The National Weather Service highlighted the unusual term “zombie tropical storms” in a tweet reporting the emergence of this storm.
Tropical storms tend to weaken as they move over cooler waters or land. With climate change, warming ocean waters are creating conditions where storms can restrengthen.
Paulette – Atlantic Ocean. (2020, September 23). NASA Blogs. https://blogs.nasa.gov/hurricanes/2020/09/23/paulette-atlantic-ocean-9/