“We have a hurricane!” Ken Graham, director of the National Hurricane Center declared Saturday, upgrading Barry from a tropical storm as it slowly plodded along the Gulf Coast of Louisiana.

The large storm is moving at just 6 miles per hour, and is expected to gradually edge closer to the coast, making landfall Saturday afternoon south of Lafayette, about 135 miles west of New Orleans, NOLA.com reported. As it makes its way slowly north, it could dump 20 inches or more of rain across the state.

The structure of the storm is unusual, Graham said, because there is little rain on the northern and western edges of the system, though the winds are heavy in those areas.

The lack of rain won’t be a problem for long, because the other side of the storm is large and wet. “There’s a lot of rainfall still yet to come out of the Gulf of Mexico,” Graham said.

New Orleans may be spared the worst of the storm’s winds, but could receive up to 20 inches of rain. Officials have predicted the Mississippi River’s highest crest, expected to be about 17.1 feet on Monday, will not overwhelm the 20- to 25-foot levees built since 2005’s Hurricane Katrina devastated the city.

The combination of heavy rains, high winds and the storm’s slow slog is nevertheless dangerous. Graham said the storm will travel north through Louisiana, but won’t reach the Arkansas border, about 280 miles away, until Sunday evening.

That tedious progression is reminiscent of the glacial pace of Hurricane Florence in North Carolina and Virginia in September, when days of heavy rain caused massive flooding well away from the coast and at least a half dozen people died.

“Most of the fatalities in the last few years have been from inland flooding,” Graham said, noting that as Barry continues to travel north, Arkansas, Tennessee and even Missouri could see flash flooding.

Tornadoes are also a possibility on the outer edges of the storm, Graham warned.