Hurricane Paula (2016)

Hurricane Paula was the strongest Atlantic December hurricane on record. Its formation was spurred from record-warm waters on December 9, and would persist until December 14.

Meteorological History
On December 2, the GFS model first identified an area of low pressure acquiring subtropical characteristics in the central Atlantic. The 2016 hurricane season was thought to have finished slightly above average with 15 named storms, 6 hurricanes, and 3 major hurricanes. However, the NHC began to monitor the Atlantic basin for off-season development. A small area of clouds and rain showers developed south of the Azores, in a similar location to where Hurricane Alex had formed 11 months earlier.

On December 5, the extratropical low had developed a closed circulation, and began to produce winds in excess of 60 mph as it meandered southwestward. Due to this, the NHC gave the system a medium (40% chance) of development during the next 5 days. The system slowly moved southward, to an area just north of the Lesser Antilles. Frontal features with the system dissipated on December 8 as it began to acquire subtropical characteristics.



At 21:00 UTC on December 9, the NHC initiated advisories on the system, named Subtropical Storm Paula. Initial forecasts showed the system peaking as an upper-end tropical or subtropical storm. The storm was first classified with winds of 60 mph and a minimum pressure of 991 mbar. However, on December 10, Paula began to become increasingly tropical; in the process, it slightly weakened to 50 mph. As a result, Paula was re-classified as a subtropical cyclone at 15:00 UTC on December 10. Subsequently, the NHC initiated a Tropical Storm Warning for the Bahamas as the system passed to the north of the islands. Entering an area with record-warm waters of 81 F, Paula began to intensify. An eye began forming, and the NHC noted that intensification into a hurricane was unlikely, but not out of the question. At 15:00 UTC on December 11, Paula unexpectedly intensified into a category 1 hurricane with winds of 80 mph. Very low wind shear, likely a result of La Nina, and record-warm waters allowed the system to develop into a moderate hurricane at a time of year when tropical cyclone formation is very rare in the Atlantic. It was a very rare occurrence of hurricanes occurring both before and after the official season (with Alex back in January).

Rapid intensification continued on December 11, with Paula continuing to improve its organization on satellite imagery. The eye became more well-defined, and the cloud tops significantly cooled.

At 00:00 UTC on December 12, Paula unexpectedly intensified into a category 2 hurricane. Paula would retain this intensity for the next 12 hours, making it the first known December Category 2 Atlantic hurricane on record. Later that afternoon, Paula began to weaken. Paula was downgraded to a category 1 hurricane at 12:00 UTC on December 12. By 18:00 UTC on December 13, Paula was downgraded to a tropical storm.

At 00:00 UTC on December 14, the NHC discontinued advisories on Paula, as it officially transitioned back into an extratropical cyclone. The extratropical remnants of Paula would make landfall in Great Britain, causing one fatality.