UPDATED 6pm: Otto became the latest hurricane formation on record in the Caribbean Sea, surpassing the previous record-holder Martha in 1969.
The Category 1 storm packs maximum sustained winds of 75 mph.
Nicaragua and Costa Rica have issued a hurricane watch, while the weather service of Panama has issued a tropical storm warning.
On the forecast track, Otto should approach the coasts of Nicaragua and Costa Rica on Thursday.
Otto is the seventh — and likely last — hurricane of the season.
ORIGINAL: Tropical Storm Otto is gaining strength in the southern Caribbean, and is forecast to become a rare November hurricane by Wednesday, according to a Tuesday morning advisory by the National Hurricane Center.
Maximum sustained winds have increased to near 70 mph.
The storm — currently located 625 miles south of Grand Cayman and 225 miles southeast of San Andres, Colombia — is stationary, and little motion is expected until tonight, followed by a turn toward the west Wednesday night. On the projected track, Otto will make landfall as a hurricane in either Nicaragua or Costa Rica.
The last tropical storm to form in November was Melissa in 2013. The last hurricane to form in November was 2009’s Ida.
A Tropical Storm Watch is in effect for San Andres, Colombia.
The National Hurricane Center says interests in Nicaragua, Costa Rica, and Providencia Island should monitor the progress of Otto.
“Outer rain bands from Otto are expected to produce rainfall accumulations of 3 to 6 inches over San Andres and Providencia islands, and portions of central and western Panama and southeastern Costa Rica through Wednesday, with isolated totals upwards of 10 to 15 inches across northeastern Costa Rica and the higher terrain of Nicaragua,” said the NHC’s advisory. “These rains could result in life-threatening flash floods and mud slides. Additional heavy rainfall may move into portions of Costa Rica Wednesday night into Thursday as the system approaches the coast.”