Tropical Depression Sixteen

Tropical Depression Sixteen has formed in the southwest Caribbean Sea and may become a rare Thanksgiving hurricane before dousing parts of Central America with flooding rainfall in the coming days.The center of Tropical Depression Sixteen was located about 300 miles east of the Nicaraguan Caribbean coast.Tropical Depression Sixteen will move very little the next several days. Late this week, high pressure will build to its north, and the clockwise steering flow around that high will send this system westward towards the coast of Nicaragua or Costa Rica. Currently, wind shear is keeping somewhat of a lid on intensification.

However, later this week, wind shear is expected to relax, and the tropical cyclone is expected to become a rare, late-season hurricane before making landfall in Nicaragua or Costa Rica.It will be a concern for Central America, however, including Nicaragua, Costa Rica and Panama. This region will be at risk for heavy rain capable of causing flooding and mudslides. Some locations may pick up over 10 inches of rain from this system.

In addition, areas of heavy rain well to the north of the circulation may trigger flooding in parts of Honduras and Belize. Any wind and storm surge impact will depend on the strength of the system as it moves inland, which remains uncertain at this time.

The future "Otto" is expected to weaken rapidly soon after making landfall, as the circulation is ripped apart by the higher terrain of Nicaragua and Costa Rica.

How Unusual is a Named Storm This Late in the Hurricane Season?

As waters cool farther north and east, and upper-level winds strengthen, the area where tropical cyclones can form shrinks.

In November, tropical cyclones typically form where the waters are warmest. Thus, one cluster of storms forming in November is in the western Caribbean Sea.

A second broad area of formation is in a broad swath of the western and central Atlantic Ocean, sometimes spinning off from an old frontal boundary, sometimes transitioning from a cold-core low to a subtropical or tropical cyclone.According to NOAA's best track database, prior to January 2016's strange Hurricane Alex, only 18 storms of at least tropical storm strength had formed on or after November 21 dating to 1950.

The last to do so prior to Alex and the current system was Tropical Storm Olga in December 2007.

If the current system becomes a hurricane, that would be even more rare on a couple of fronts.

Only nine tropical cyclones became hurricanes in the Atlantic Basin after November 21 from 1950 through 2015. The last to do so was Epsilon in December 2005. 

Only one of those nine hurricanes occurred in the southwest Caribbean Sea, Hurricane Martha in 1969.

Systems that do develop across the Caribbean Sea can gain some organization, as the area has supported such late-season hurricanes as Kate in 1985 and Michelle in 2001. The former became the latest landfalling hurricane in Florida’s history on Nov. 21.

Since 1851, Florida has been impacted by eight tropical storms and hurricanes in November. The only other states with more than one November impact were also in the Southeast: Alabama, Georgia and North Carolina.

Typically, November tropical systems follow upper-level flow and cold fronts northeastward into the Atlantic Ocean. 

 In the period of record from 1851 to 2014, no tropical storm or hurricane has impacted the western Gulf Coast from Texas to Mississippi.

In 2015, Hurricane Kate was an early-November oddity, forming from a tropical wave that first soaked the Lesser Antilles, then becoming the farthest north hurricane so late in the season on record north of Bermuda. 

By the way, Atlantic Basin tropical storms even form in December, and January, on rare occasions. 

 https://www.wunderground.com/news/tropical-depression-sixteen-tropical-storm-otto