Louisiana may get hit by a hurricane this weekend. New Orleans is already flooded.

A storm is brewing in the Gulf of Mexico, and the National Hurricane Center expects it to become a hurricane by Friday or Saturday, with potentially dangerous impacts along the coasts of Mississippi, Texas, Louisiana, and the city of New Orleans.

The storm could bring as much as 20 inches of rain to the region, which isn’t good, considering that the region is already inundated with rain. The city of New Orleans flooded this week from heavy storms, with many streets covered with a dangerous amount of water. The Mississippi River is expected to rise to 19 or 20 feet by the weekend, which is near the height of the city’s levees.

On Thursday, the storm in the Gulf intensified into tropical storm, named Barry. By Saturday, it may have maximum winds at 75 miles per hour, making it a category 1 storm on the Saffir-Simpson wind scale.

The wind speed is just one of the dangerous components of the storm. (In general, coastal flooding tends to be the deadliest aspect of a hurricane.)

In this hurricane, storm surge — the seawater pushed onshore by the hurricane’s winds — may top 3 to 6 feet, flooding low-lying areas (of which Louisiana has plenty). On Thursday, the National Hurricane Center issued a Storm Surge Warming, which “means there is a danger of life-threatening inundation from rising water moving inland from the coastline in the indicated locations during the next 36 hours.”

This storm is also expected to generate a dangerous amount of rain — more than a foot of it in some areas — which can contribute to inland flooding along the banks of rivers.

Local officials are not expected to issue evacuation orders for residents of New Orleans or other areas in the path of the storm. For now, residents are being told to “shelter in place.”

It’s still early and forecasts can change. But here’s the forecast as of Thursday morning from the National Hurricane Center.

And here’s the forecast for rainfall.

Finally, here are the key messages the National Weather Service wants the public to know:

1. Barry is expected to bring storm surge, rainfall, and wind hazards to the central Gulf Coast during the next several days.

2. There is a danger of life-threatening storm surge inundation along the coast of southern and southeastern Louisiana where a Storm Surge Warning has been issued. The highest storm surge inundation is expected between the Mouth of the Atchafalaya River and Shell Beach. Residents in these areas should listen to any advice given by local officials.

3. A Tropical Storm Warning and Hurricane Watch are in effect for much of the Louisiana coast and additional watches and warnings could be required later today. Residents in these areas should ensure they have their hurricane plan in place.

4. The slow movement of this system will result in a long duration of heavy rainfall threat along the central Gulf Coast and inland through the Mississippi Valley through the weekend and potentially into early next week. Flash flooding and inland flooding will become increasingly likely, some of which may be significant, especially along and east of the track of the system.