The slowly moving system with maximum sustained winds at 70 mph is expected to gain strength over the next 48 hours as it moves erratically in a west-northwestward motion, the National Hurricane Center said in a statement.
When Otto makes landfall Thursday, its biggest threat will be heavy rain and the resulting mudslides. Otto continued to strengthen and the National Hurricane Center expects the storm to reach hurricane strength. If it hits Nicaragua, it would be the latest landfall on record there. The Alajuela communities of Bajos del Toro, San Carlos, Guatuso, Los Chiles, Upala and Río Cuarto de Grecia also faced evacuations, as well as Sarapiquí in the province of Heredia. The stationary storm has maximum sustained winds of 60 miles per hour.
A tropical storm warning was in effect from north of Bluefields to Sandy Bay Sirpi and the Colombian island of San Andres. Otto maintained that strength until November 23 at 7 a.m. EST when it weakened to a tropical storm. That's about 175 miles (280 km) east-northeast of Limon, Costa Rica and 220 miles (350 km) east-southeast of Bluefields, Nicaragua.
The formation of the tropical depression that then became a hurricane was unusual, with just one week to the end of the Atlantic hurricane season, which runs from June 1 to November 30.
The storm caused heavy rains in Panama as it moved roughly parallel to that nation's northern coast. A few months later in May, Tropical Storm Bonnie formed. Otto is a relatively small hurricane right now, with hurricane forces winds only spreading 10 miles from the center and tropical storm force winds 60 miles.