Filling up sandbags in Denham Springs. pic.twitter.com/NirxHUrfzH— Brittany Weiss WBRZ (@MsBWeiss) July 10, 2019 ABC News(NEW YORK) — Tropical Storm Barry has formed in the Gulf of Mexico Thursday morning as the dangerous storm nears the coast, threatening to bring heavy rain, flash flooding, storm surge and hurricane conditions.The storm will likely reach hurricane strength on Friday or Saturday before it makes landfall early Saturday along the Gulf Coast.Louisiana’s Plaquemines Parish and Grand Isle are already under mandatory evacuations.“Plaquemines Parish Government has taken all precautions in preparing for Tropical Storm Barry,” Parish President Kirk Lepine said in a statement. “Additional rainfall, high winds, and storm surge are expected.”In Denham Springs, La., residents rushed to fill up sandbags. Heavy rains already inundated New Orleans on Wednesday, flooding streets and homes and leaving drivers stranded. As much as 9 inches of rain fell in the city, with more to come.New Orleans Mayor LaToya Cantrell declared a state of emergency in the city Wednesday afternoon. The city’s recreation summer camps are closed Thursday as a precaution.The main concern with this tropical system is the extreme rainfall that will come to parts of the Gulf Coast beginning Friday and lasting through the weekend.The slow movement of the storm will bring heavy rainfall throughout much of the Gulf Coast and into the Mississippi River Valley.As much as 20 inches of rain is possible in parts of the area, especially in southern Louisiana. Major flash flooding is also possible, as well as a storm surge up to 6 feet along the Louisiana coast, including New Orleans.Current forecasts show the Mississippi River will crest at 20 feet on Saturday. While flood walls and levees along the Mississippi River in New Orleans are designed to withstand this height, they will truly be tested.Some of the heavy rain will also spread into parts of Arkansas and Mississippi this weekend and next week.Tornadoes will also be possible Thursday night and Friday across Louisiana and Mississippi as the storm comes closer to shore.Copyright © 2019, ABC Radio. All rights reserved.Copyright © 2019, ABC Radio. All rights reserved.