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Cat 2 Otto Slams Nicaragua, Costa Rica; Strongest Late-Season Hurricane on Record

By: Jeff Masters and Bob Henson 6:12 PM GMT on November 24, 2016

Small but potent Hurricane Otto plowed into the Caribbean coast around 1 PM EST Thursday less than 20 miles north of the border between Nicaragua and Costa Rica, making history in the process. As Otto approached the Central American coast, the storm’s eye was clearly visible on satellite--a compelling sight any time of year, but especially on the same day that people in the United States were celebrating Thanksgiving and putting thoughts of hurricane season out of their minds. With top sustained winds of 110 mph at the top of the Category 2 range as of 1 PM Thursday, Otto was in a three-way tie as the strongest Atlantic hurricane ever recorded this late in the year (see Figure 3 below). Otto is also the latest hurricane to make landfall anywhere in the Atlantic basin in records going back to 1851. A Category 1 storm passed about 30 miles north of the Turks and Caicos Islands on November 28, 1887. In addition, Otto now holds the mark for the southernmost hurricane landfall on record for Central America. No hurricane or tropical storm has ever been recorded in Costa Rica, but it is possible Otto's center will pass over parts of northwestern Costa Rica while Otto is still a tropical storm or hurricane (see below).

Otto’s small size allowed it to vault to top-end Category 2 strength from Wednesday night to Thursday morning after it had weakened to tropical storm strength earlier on Wednesday. As Otto approached the coastline, its hurricane-force winds only extended out to 15 miles from its center and tropical-storm-force winds extended out to 70 miles. Because the more powerful winds are on the right-hand side of a Northern Hemisphere hurricane, this meant Nicaragua would bear the brunt of Otto’s winds, although parts of far northeast Costa Rica were experiencing much rougher conditions than they are accustomed to.

Figure 1. Enhanced infrared image of Hurricane Otto as it approached the coast of southern Nicaragua and northern Costa Rica at 1515Z (10:15 am EST) Thursday, November 24, 2016. Image credit: NOAA/NESDIS.

Figure 2. Two children are embraced by their father in Bluefields, Nicaragua, as Hurricane Otto approached on November 23, 2016. Image credit: INTI OCON/AFP/Getty Images.

Otto’s impact on people and structures was minimized by its landfall location, as the storm was moving across the sparsely populated area encompassed by the Indio Maiz Biological Reserve and the Punta Gorda Natural Reserve. There may be significant damage to the reserves themselves, though. The small town of San Juan de Nicaragua (formerly Greytown, population about 1300) may have experienced hurricane conditions as Otto’s eye passed just to the north of it. Later on Thursday, winds up to tropical-storm force may affect the more populated region around Nicaragua’s capital, Managua. There are no weather stations in Weather Underground’s PWS network within 50 miles of Otto’s landfall location, and the last Hurricane Hunter foray into Otto’s inner core was just after 11Z Thursday (6:00 am EST), so we will have to depend mainly on satellite estimates for Otto’s intensity at landfall.

Rainfall will be a significant threat with Otto from Thursday into Friday. Localized torrents of up to 15” - 20” are possible along Otto’s track across southern Nicaragua and northern Costa Rica. The outer fringes of Otto’s circulation may produce rains of 5” or more along higher elevations along the Caribbean coast of Honduras and the Pacific coast of western Panama and southern Costa Rica.

Figure 3. Tracks of all Atlantic tropical storms and hurricanes recorded between 1851 - 2016 on November 24 or later. A total of 50 storms have been observed this late in year; only three of these reached Category 2 strength prior to Otto. Otto is tied for strongest Atlantic hurricane ever observed this late in the year, along with a 1934 storm that had 110 mph winds at 7 am EST November 24, and an 1853 hurricane that also had 110 mph winds at 7 am EST November 24. Image credit: NOAA.

Otto may become the first storm to keep its name from Atlantic to Pacific
A ridge of high pressure to Otto’s north will keep the storm rolling westward on Thursday afternoon and evening across southern Nicaragua and northern Costa Rica, which are far less mountainous than other parts of Central America. In fact, part of Otto’s northern circulation could pass over Lake Nicaragua, one of the top-ten biggest freshwater lakes in the Americas. With land influence at a relative minimum, Otto is projected by NHC to be a tropical storm when it enters the Pacific early Friday. If Otto does maintain its identity as a named storm, as expected, it will keep the name Otto in the Pacific. Should Otto dissipate but its remnants manage to redevelop in the Pacific, the new storm would take the name Virgil from the Eastern Pacific list.

More than a dozen “crossover” tropical cyclones have been recorded, most of them moving from Atlantic to Pacific rather than vice versa. The most recent was Hermine (2010), which formed as an East Pacific tropical depression before entering the western Gulf and striking the northeast coast of Mexico as a tropical storm. Otto would be the first crossover storm in modern records to keep its name in going from one basin to another, since NHC’s previous practice was to rename such systems. All of Otto’s predecessors in this realm--including Hurricane Cesar-Douglas (1996)--underwent a name change when moving from Atlantic to Pacific or vice versa.

We won’t need to worry about Otto once it enters the East Pacific, as conditions do not favor reintensification and the storm will be moving away from land areas.

Figure 4. Tracking map for Hurricane Otto as of 10 AM EST Thursday, November 24, 2016.

Otto’s ascension to hurricane status gives the Atlantic 15 named storms, 7 hurricanes, and 3 intense hurricanes for the year. The Accumulated Cyclone Energy (ACE) in the Atlantic for 2016 has now reached 133--the Atlantic’s highest ACE value since 2010. The long-term averages for the period 1971 - 2010 in the Atlantic were 12 named storms, 6.5 hurricanes, 2 major hurricanes, and an ACE of 92, so the Atlantic hurricane season of 2016 is above average in all categories. If Otto proceeds into the East Pacific as a named storm, it will be that region’s 22nd tropical storm, which would put 2016 in a tie with 2014 for fifth place for the most number of named storms in the Eastern and Central Pacific.

A rare Thanksgiving Day storm
This is the second Thanksgiving Day in a row that’s kept NHC forecasters busy issuing storm advisories. In 2015, record-warm ocean waters helped Hurricane Sandra off the Pacific coast of Mexico become only the second Thanksgiving Day hurricane in modern records for the Atlantic or Eastern Pacific, and the first major hurricane. Sandra set the record for the latest major hurricane ever observed in the Western Hemisphere, as the storm maintained at least Category 3 strength from 00 UTC November 26 through 00 UTC November 27 (previous record: an unnamed Atlantic hurricane in 1934 that held on to Category 3 status until 00 UTC November 24.) When Sandra peaked as a Category 4 storm with 150 mph winds at 1 am EST (06 UTC) Thanksgiving Day, November 26, it became the latest Category 4 storm ever observed in either the Eastern Pacific (previous record: Hurricane Kenneth on November 22, 2011) or the Atlantic (previous record: ”Wrong Way" Lenny on November 18, 1999.) The only other Thanksgiving Day hurricane ever recorded in the Western Hemisphere was Hurricane Karl of 1980, which spun harmlessly as a minimal Category 1 hurricane far out in the central North Atlantic on Thanksgiving Day that year.

Otto is the first named storm in the Atlantic known to make landfall on Thanksgiving, but several other weaker storms have had NHC forecasters issuing advisories on Thanksgiving Day. This includes 1988’s Tropical Storm Keith, which struck Florida as a tropical storm on Wednesday, November 23, and persisted as a strong tropical storm east of Florida until midday Thanksgiving Day (November 24). In 1998, minimal Tropical Storm Nicole weakened to a depression east of Bermuda early on Thanksgiving Day (November 26), with advisories discontinued at 10 am EST. Nicole did get a new lease on life several days later, becoming a hurricane on November 30 and persisting to become one of just five Atlantic hurricanes on record during the month of December. In the hyperactive Atlantic season of 2005, Tropical Storm Delta roamed the eastern Atlantic on Thanksgiving Day (November 24). And in 2011, a weakening Tropical Storm Keith well out to sea in the eastern Pacific prompted advisories on Thanksgiving Day (November 24). Prior to the establishment of NHC as we know it, an unnamed tropical storm dissipated on Thanksgiving Day 1953 (November 26) well east of Bermuda. Hawaii takes the cake for the worst U.S. hurricane-related impacts during Thanksgiving Week: Hurricane Iwa passed near Kauai on Tuesday, November 23, 1982, during the run-up to the “super” El Niño of 1982-83. Iwa caused one death and inflicted $250 million in damage in Kauai.

We hope all of our U.S. readers have a safe and enjoyable Thanksgiving. We’ll be back with an update on Otto on Friday.

Jeff Masters and Bob Henson


The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.