Once maximum winds reach 74 miles per hour, it's considered a hurricane. Tuesday, Otto intensified into a hurricane near Nicaragua and Costa Rica, just north of Panama. "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 was centered about 225 miles (360 kilometers) east of Limon, Costa Rica.
The storm, with maximum sustained wind speeds of 75mph (121km/h), is now moving in from the Atlantic Ocean and could be the first hurricane to be recorded in Costa Rica since records began in 1851.
A hurricane watch is in effect from the Costa Rica-Panama border to south of Bluefields.
That means deadly flooding and mudslides are likely, forecasters said. The country of Panama, which has also never been directly struck by a tropical system is under a tropical storm watch.
Its rains "will likely result in life-threatening flash floods and mud slides", while "life-threatening surf and rip current conditions" will be experienced along the coasts of Panama, Costa Rica and Nicaragua, the United States center warned.
The hurricane center expected Otto to turn more to the west today and increase its speed.
This portion of Central America is unaccustomed to hurricane landfalls.
The last to do so was Tropical Storm Olga in December 2007.
Up to 1.4 million people in Haiti still require aid as a result of Hurricane Matthew, according to Reuters.
Wind shear is expected to be weak to moderate, but sufficient to keep a lid on further significant intensification before landfall.
The Latest on tropical weather in the Caribbean (all times local): 7 p.m. Late-season Hurricane Otto is crawling westward toward Central America's Caribbean coast with little change in strength.