Eta had maximum sustained winds of 70 mph (110 kph) late Sunday, the U.S. National Hurricane Center said. It was centered about 215 miles (345 kilometers) east of the Nicaragua-Honduras border and was heading westward at 13 mph (20 kph).
Forecasters expected Eta to become a hurricane during the night and it was predicted to be nearing the Nicaraguan coast early Tuesday.
Forecasters said central and northern Nicaragua into much of Honduras could get 15 to 25 inches (380 to 640 millimeters of rain, with 35 inches (890 millimeters) in isolated areas.
Heavy rains also were likely in eastern Guatemala, southern Belize and Jamaica.
Eta is the 28th named Atlantic storm this season, tying the 2005 record for named storms. However, this is the first time the Greek letter Eta is being used as a storm name because after the 2005 season ended, meteorologists went back and determined there had been a storm that should have gotten a name but didn’t.
Hurricane season still has a month to go, ending Nov. 30. And in 2005, Zeta formed toward the end of December.