Hurricane watch issued as Tropical Storm Isaias strengthens

A hurricane watch is now in effect along portions of the northern Gulf Coast as Tropical Storm Isaias is forecast to strengthen into a hurricane before reaching the U.S. coast.

As of 10 a.m. CDT Wednesday, Isaias is located about 420 kilometres west-northwest of Progreso, Mexico, and about 870 kilometres south-southwest of the mouth of the Mississippi River.

The storm has maximum sustained winds of 75 km/h, with higher gusts, and is moving east-northeast at 13 km/h. Its minimum central pressure is 1,000 millibars.

The National Hurricane Center expects Isaias to continue moving east-northeast Wednesday before turning toward the northeast and north Thursday and Friday. The storm is forecast to pass north of the Yucatan Peninsula Thursday and approach the northern Gulf Coast Friday.

Rapid strengthening is expected over the next day or two, with Isaias forecast to become a hurricane Thursday.

A hurricane watch is in effect from Bay St. Louis, Mississippi, to Indian Pass, Florida. Tropical storm watches extend from the Jefferson/Plaquemines Parish line in Louisiana to west of Bay St. Louis, and from east of Indian Pass to the Aucilla River in Florida.

A storm surge watch is also in effect from the mouth of the Mississippi River to Yankeetown, Florida.

Storm surge could reach 5 to 7 feet above ground from Ocean Springs, Mississippi, to Indian Pass, Florida, including Mobile Bay. Surge of 3 to 5 feet is possible from the mouth of the Mississippi River to Ocean Springs and from Indian Pass to the Aucilla River.

The system is also expected to bring heavy rainfall. From Friday through the weekend, 75 to 150 millimetres of rain is forecast across portions of the central Gulf Coast, with localized totals up to 250 millimetres possible. Additional rainfall of 25 to 75 millimetres, with localized higher amounts, is possible farther inland across the Southeast.

Flash and urban flooding, along with isolated river flooding, could occur.

Hurricane conditions could begin in the hurricane watch area late Friday, while tropical storm conditions could begin around midday Friday.