MIAMI, United States (AP) — Tropical Storm Omar formed off the US East Coast yesterday as Tropical Storm Nana approached the coast of Central America, the US National Hurricane Center reported.

Forecasters predict Nana will strengthen to a hurricane by the time it makes landfall tomorrow and said people in Honduras, Guatemala, Belize, and Mexico’s Yucatan Peninsula should closely monitor the storm’s progress. Strong winds, a dangerous storm surge and very heavy rainfall causing flash flooding are likely.

An Air Force Reserve Hurricane Hunter aircraft crew flew into Nana as it took shape south of Jamaica, recording maximum sustained winds of 50 mph (85 kmh) with higher gusts. Nana was moving west at 18 mph (30 km/h) on a path that could damage Central America today and Thursday.

The National Hurricane Center later said the entire coast of Belize had been placed under a tropical storm warning and a hurricane watch.

Nana and Omar are the earliest 14th and 15th named storms on record, beating the 2005 arrivals of Nate on September 6 and Ophelia on September 7, according to Colorado State University professor Phil Klotzbach.

The National Hurricane Center expects Tropical Storm Omar to be short-lived. The storm had maximum sustained winds of 40 mph (65 km/h) yesterday evening, with little change expected overnight. Omar was 225 miles (365 kilometres) east of Cape Hatteras, North Carolina, and moving east-north-east at 15 mph (24km/h). Forecasters predicted it will weaken tonight.