Tropical Depression 13 has now upgraded to Tropical Storm Lee and is threatening to bring heavy rainfall to the New Orleans areas over the Labor Day weekend, as bands of thunderstorms pass over in the next couple of days.

The latest report from the U.S. National Hurricane Center puts Lee at just 200 miles southeast of Cameron, La., and 210 miles southwest of the mouth of the Mississippi River. Lee is now packing maximum sustained winds of 40 mph and is moving northwest at 2 mph.

Tropical cyclones become tropical storms when their winds exceed 39 miles per hour. They turn into hurricanes when their winds reach more than 74 miles per hour.

Louisiana Gov. Bobby Jindal declared a state of emergency on Thursday, citing that the storm could drench the state with up to 15 inches of rain over the weekend.

Jindal warned that heavy rains, substantial winds and tidal surges from the Gulf of Mexico could create flash flooding in parts of New Orleans.

Get ready for the wind, get ready for the rain, it's coming and it's going to be here for a while, Jindal said at a briefing in Baton Rouge.

Mississippi Gov. Haley Barbour has also declared an emergency for seven coastal counties, as reported by The Baltimore Sun.

Some offshore oil companies and gas operators in the Gulf of Mexico have already moved out of the area at the first notification that a storm was brewing.

By the numbers

The Bureau of Ocean Energy Management, Regulation and Enforcement (BOEMRE) on Friday said personnel have been evacuated from a total of 169 production platforms, which is equivalent to 27 percent of the 617 manned platforms in the Gulf of Mexico.

Production platforms are structures located offshore from which oil and natural gas are produced. Unlike drilling rigs, which typically move from location to location, production facilities remain in the same location throughout a project's duration.

BOEMRE said operator reports showed that it is estimated that approximately 47.6 percent of the current oil production in the Gulf of Mexico has been shut-in. It is also estimated that approximately 33 percent of the natural gas production in the Gulf of Mexico has seen similar fate. That's about 666,000 barrels of oil.

Lesson learned from Katrina

Officials have declared emergencies because of the possibility for flooding is a grave reminder of what happened in 2005 when they were hit by Hurricane Katrina.

Katrina destroyed 80 percent of the city with flood waters and killed more than 1,500 people. The damage it caused took more than $80 billion from the government's coffers.

There may be some minor flooding for short periods of time, Jerry Sneed, deputy mayor of public safety, told CNN, adding that the city's system of levees and locks should hold up under the strain.