Tropical Storm Harvey has strengthened while moving north through the Gulf of Mexico, forecasters said Thursday morning (Aug. 24). The storm's maximum sustained winds have increased to 60 mph and Harvey is expected to strengthen into a hurricane by Friday.

Harvey is on track to approach the southern Texas coast on Friday (latest track), and potentially bring heavy rain to New Orleans and Louisiana starting over the weekend.

Hurricane Harvey: 5-day tracking map The most current map of storm's projected path

As of 7 a.m., Harvey was 380 miles southeast of Port O'Connor, Texas, and about 335 miles southeast of Port Mansfield, Texas. It's moving northwest at 10 mph and forecasters expect it to speed up before stalling over Texas.

Harvey is expected to drop 10 to 15 inches of rain with isolated maximum amounts of 25 inches over the Texas coast through next Wednesday. Rainfall from Harvey may cause life-threatening flooding, forecasters warned.

As of Thursday morning, the National Weather Service was estimating that New Orleans could see about 4 to 6 inches of rain through Thursday from the storm.

Forecasters say, however, that the "rainfall swath" of Harvey is uncertain, and small changes in the storm's position could bring a lot more or less rain.

Because the storm is expected to stall over Texas, the National Weather Service says Southeast Louisiana may not see the heaviest rain from the system until next Tuesday or Wednesday. Still, other storms could produce heavy rain.

"Do not let your guard down," the weather service's forecast says. "Locally heavy rainfall will be possible each and every day starting Saturday and possibly lasting through Wednesday."

Harvey is expected to drop 10 to 15 inches of rain with isolated maximum amounts of 25 inches over the Texas coast through next Wednesday. (Image via National Hurricane Center)

Tropical-storm-force winds extend outward up to 115 miles from the center.

Watches and warnings

The following watches and warnings have been issued for Tropical Storm Harvey:

A storm surge warning is in effect for Port Mansfield to San Luis Pass.

A storm surge watch is in effect for:

south of Port Mansfield to the mouth of the Rio Grande

north of San Luis Pass to High Island

A hurricane warning is in effect for Port Mansfield to Matagorda.

A tropical storm warning is in effect for:

north of Matagorda to High Island

south of Port Mansfield to the mouth of the Rio Grande

A hurricane watch is in effect for south of Port Mansfield to the mouth of the Rio Grande.

A tropical storm watch is effect for south of the mouth of the Rio Grande, Texas, to Boca de Catan, Mexico.

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Reporter Beau Evans contributed to this story.

Carlie Kollath Wells is a morning reporter at NOLA.com | The Times-Picayune. Have an early-bird tip? Send it to her: cwells@nola.com or Twitter @carlie_kollath.