MIAMI (NewsNation Now) — Forecasters expect the newly-formed Tropical Storm Eta to become a hurricane by Monday, shortly after the system formed in the Caribbean and tied the record for most named storms in a single Atlantic hurricane season.

Eta had maximum sustained winds of 50 mph Sunday afternoon, the U.S. National Hurricane Center said in an advisory. It was centered about 345 miles east of the Nicaragua-Honduras border and was heading westward at 15 mph.

Forecasters expect Eta to become a hurricane by Monday and it was forecast on Tuesday to hit the Nicaraguan coast, where a hurricane warning was posted.

The storm is not expected to affect the U.S.

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 in isolated areas.

Rainfall totals could reach 15 inches in parts of Jamaica, the Cayman Islands and the southern coast of Hispaniola by Thursday evening. Isolated amounts of up to 30 inches (76 centimeters) could fall in portions of Honduras and Nicaragua, forecasters said.

Eta is the 28th named Atlantic storm this season, tying the 2005 record for named storms. This is the first time the Greek letter Eta is being used because after the 2005 season ended, meteorologists went back and determined there was 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 in the end of December.