Tuesday, November 22, 2016

Hurricane Warning Issued Ahead of Category 1 Otto; Forecast to Make Very Rare Thanksgiving Hurricane Landfall In Central America

November 22,2016
Otto strengthened into the seventh hurricane of 2016 Atlantic hurricane season late Tuesday afternoon in the southwest Caribbean Sea, and is forecast to be an extremely rare late November hurricane landfall, posing a danger of flooding and mudslides in parts of Central America.
This makes Otto the latest hurricane formation on record in the Caribbean Sea, surpassing Hurricane Martha in 1969, according to the National Hurricane Center (NHC).
(MORE: Hurricane Central)
A hurricane warning was issued Tuesday evening from Limon, Costa Rica, to Bluefields, Nicaragua.
A hurricane watch is in effect for the coast of Nicaragua north of Bluefields to Sandy Bay Sirpi, and for the coast of Costa Rica south of Limon to the Costa Rica/Panama border. This means that hurricane conditions are possible here within 48 hours.
In addition, a tropical storm warning is in effect in Panama from Nargana to Colon, and in Nicaragua north of Bluefields to Sandy Bay Sirpi, where tropical storm conditions are expected overnight and into Wednesday. A tropical storm warning was also issued late Tuesday afternoon for San Andres Island, a Colombian island in the Caribbean Sea located about 125 miles east of the Nicaragua coast. Tropical storm conditions are also expected into Wednesday there.
A tropical storm watch is also in effect from west of Colon, Panama, to the Costa Rica/Panama border. This means that tropical storm conditions are possible here within 48 hours.
(LATEST NEWS: Hurricane Otto Impacts Central America)
Hurricane Otto has begun to move ever so slowly west-northwestward, and is located about 285 miles east-southeast of Bluefields, Nicaragua, as of Tuesday night.

Current Storm Status
Otto is expected to gain a faster motion toward the west-northwest or west on Wednesday, as clockwise steering flow around high pressure building to its north will send this system westward toward the coast of Nicaragua or Costa Rica.

Projected Path
Tropical storm-force winds currently extend out to about 60 miles from the center of circulation, making Otto a relatively small tropical cyclone. Hurricane-force winds only extend outward 10 miles from the center.
Wind shear is expected to be weak to moderate over the next few days, and small tropical cyclones can also intensify quickly, particularly given heat content in the southwest Caribbean Sea is well above average for this time of year.
Given all this, Otto will continue to intensify, making landfall as a rare late-season hurricane in Nicaragua or Costa Rica on Thanksgiving Day.
Heavy rain, flash flooding and mudslides will be major concerns for Central America, including Nicaragua, Costa Rica and Panama. Some locations may pick up over 15 inches of rain from Otto.
In addition, areas of heavy rain well to the north of the circulation may trigger flooding in parts of Honduras and Belize.

Forecast Rainfall
Any wind and storm surge impact will depend on the strength of the system as it moves inland, which remains somewhat uncertain at this time.
Otto is expected to weaken soon after making landfall, as the circulation is hampered by the higher terrain of Nicaragua and Costa Rica. However, there is some potential for the circulation to survive in some form once it emerges into the eastern Pacific Ocean. Atlantic tropical cyclones crossing into the eastern Pacific Basin have happened numerous times in the past

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

November Atlantic Basin tropical cyclones aren't all that unusual.
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.
Tropical cyclone origin points for November.
According to NOAA's best track database, only 18 storms of at least tropical storm strength had formed on or after November 21 dating to 1950.
The last to do so was Tropical Storm Olga in December 2007. In fact, it's now been over 10 months between the season's first named storm, the aforementioned Alex, and Otto.
If Otto 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.
Furthermore, in NOAA's entire best track database dating to 1842, there have been only three November or later Nicaragua hurricane landfalls, none of which were anywhere near as late as Otto could be.
  • Hurricane Ida: November 5, 2009
  • Unnamed Hurricane: November 1, 1890 (best track has 00 UTC landfall)
  • Unnamed Hurricane: November 4, 1887
It only gets more bizarre if a Costa Rica landfall occurs.
NOAA has only one tropical storm landfall, in any month, either from the eastern Pacific or Caribbean Sea side in their 174-year database, a December 1887 tropical storm.
There is no record of a landfalling hurricane in Costa Rica, according to the NOAA best tracks database. Otto could be a historical first, there.

More November Perspective

According to NOAA's best track database, there have been 36 Atlantic tropical cyclones of at least tropical storm strength in November from 1950 through 2015. Twenty of those became hurricanes.
Just eight years ago, Hurricane Paloma reached Category-4 intensity, the second-strongest November hurricane of record, damaging or destroying nearly every building on Cayman Brac, according to the National Hurricane Center's final report. "Paloma" was retired from the Atlantic hurricane name list following this event.
(MORE: Retired Atlantic Hurricane Names)
In the period of record from 1851 to 2014, no tropical storm or hurricane has impacted the western Gulf Coast from Texas to Mississippi.
November tropical storm and hurricane impacts in the United States
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 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.
Check back with us at weather.com for the latest on this tropical cyclone.

MORE: Hurricane Otto, November 2016

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