This satellite image of Lee shows strengthening early on Saturday morning. Drenching rain was already pouring down over southern Louisiana.

Tropical Storm Lee will cause major flooding along the Gulf Coast this weekend, including in New Orleans.

Tropical Storm Lee formed in the Gulf of Mexico on Friday afternoon. Since then, Lee has been moving very slowly northward while strengthening over the warm waters of the Gulf.

“Lee’s winds could strengthen further as the storm churns over very warm waters today,” according to AccuWeather.com Meteorologist Matt Alto.

The latest stats on Lee can be found at the AccuWeather.com Hurricane Center.

“However, rain is going to be the biggest impact of Lee with as much as 20 inches of rain being unleashed over the course of the Labor Day weekend. This is due to the very slow movement of the tropical storm,” according to Alto.

AccuWeather.com’s Expert Senior Meteorologist Alex Sosnowski recently drew a comparison to the slow-moving Tropical Storm Allison that dumped more than 40 inches of rain in Alvin, Texas, the greatest 24-hour rainfall ever recorded in the U.S.

More than half a foot of rain has already been unleashed by Lee over some communities of southern Louisiana.

“New Orleans is in the bulls-eye of the flooding rain,” said Alto. The New Orleans levees will be tested by the excessive rainfall.

Alto also cautions that “enough rain will pour down that winds could cause significant damage in some communities. Trees and power lines will topple over easily as the ground becomes water-logged.”

A 26-foot sail boat broke lose from its mooring and went over the sea wall near Christian Pass Harbor from Lee’s winds and rough seas early on Saturday morning.

Thunderstorms producing gusty winds have already, and will continue to down trees and cut power in some cities and towns along the Gulf Coast through the weekend.

Thousands of customers were without power early on Saturday morning in the southern parishes of Louisiana due to gusty winds from the lashing of the outer bands of Lee.

Waterspouts and tornadoes will also be a threat from southeastern Louisiana to the Florida Panhandle near and to the east of the center of Lee this weekend.

The tornado threat will be especially high as Lee moves onshore late on Saturday night or early on Sunday morning.