BEAUMONT, Texas — National Hurricane Center director Ken Graham warned Saturday not to be fooled by slow-moving Tropical Storm Barry. He says potentially life-threatening rain levels are on the way for Louisiana.  

During a Facebook Live, Graham showed a heavy slough of moisture churning in the Gulf of Mexico. 

RELATED: LIVE UPDATES: Tropical Storm Barry inches to landfall on Louisiana coast

"That is just an amazing amount of moisture," Graham said. "That is off the chart. That's why we've been stressing so much that we need to concentrate on the potential for heavy rain."

Tropical Storm Barry is moving very slow. Gusty winds are being reported across Lafayette, Baton Rouge and New Orleans, but many of those areas remained dry ahead of landfall Saturday. It may not be until late Saturday into Sunday that the heavy rain moves inland. 

"A lot of rain is on the way," Graham warned.

RELATED: Coast Guard rescues 12 trapped in Terrebonne Parish

RELATED: OUTAGES: 33,400 without power in SE Louisiana before Tropical Storm Barry makes landfall

The National Hurricane Center says 83% of fatalities from tropical systems have been from inland rain. 

"Stay off the roads and let's prevent these preventable fatalities," Graham said.

In addition to the heavy rain, south Louisiana, Mississippi and Alabama are bracing for potential tornadoes from Tropical Storm Barry.

RELATED: Sorority helps donate 17,000 meals after Tropical Storm Barry cancels New Orleans convention

RELATED: VERIFY: Is gas surge ahead of Tropical Storm Barry price gouging?