The National Hurricane Center has upgraded Tropical Storm Otto to Hurricane status and it may do something no other hurricane on record has ever done: strike Costa Rica.
While tropical cyclones and their remnants have impacted Central America before, no hurricane has ever struck Costa Rica since records were maintained in 1851. It is also the latest hurricane to form in the Atlantic basin since Epsilon in 2005. Otto is the latest calendar year hurricane in the western Caribbean since Martha in 1969 (by a day) and the second latest on record since 1851. Satellite images indicate that Otto is continuing to strengthen.
The overall satellite pattern has become more symmetric, with a large mass of intense convection near the center. With Dvorak intensity estimates ranging from 65 to 77 kt, the wind speed was set to 65kt by the National Hurricane Center which makes Otto the seventh hurricane of the season. Environmental conditions appear favorable for continued strengthening, with warm water and weak-to-moderate southeasterly shear during the next couple of days. Most of the guidance models show Otto making landfall as a category 1 hurricane on Thursday and so does the official forecast. Stronger shear, as well as land interaction over central America, will probably prevent Otto from restrengthening over the eastern Pacific.
Satellite fixes suggest that Otto has been drifting westward during the day. A mid-level ridge is still forecast to build over the northwestern Caribbean Sea by tomorrow, which should cause Otto to move slowly to the west or west-northwest. As the ridge builds, the forward speed should increase, especially as the cyclone moves across the eastern Pacific and gradually loses latitude in that basin. The most notable change is that the guidance has come into better agreement on the track, although there are still some significant speed differences. Overall, the guidance envelope has shifted a bit to the north and is faster, and the official forecast follows that trend.
According to the National Hurricane Center, a Hurricane Warning will likely be required tonight or early tomorrow for portions of Costa Rica and Nicaragua.
Visit our Tropical Weather Page here for further information about this system and a review of all tropical cyclones that were near US waters for the 2016 season: https://weatherboy.com/hurricanes-tropical-weather/