Forecasters prepared southeast Louisiana residents for a powerful cold front expected to push into the region early Saturday, posing a risk of heavy rain, hail, tornadoes and damaging straight-line winds.
As the front was sweeping across Oklahoma, Texas, Arkansas and northwest Louisiana on Friday, powerful supercell storms were spotted within and ahead of the front's advancing squall line, prompting tornado watches reaching into the ArkLaTex region.
In southeast Louisiana, weather forecasters said, straight line wind gusts Louisiana could surpass 75 mph early Saturday and spawn tornadoes that rate as EF-2 twisters or greater on the Enhanced Fujita scale.
Both sets of wind conditions could bring down trees and power lines and damage even well-built structures.
"It's a very dynamic system, and some of those tornadoes, if they do develop, could be on the stronger side," said Fred Zeigler, a meteorologist with the National Weather Service office in Slidell, said.
EF-2 tornadoes pack winds of 111 mph to 135 mph.
Southeast Louisiana and a northern sliver of the state along the Mississippi River faced an enhanced risk of severe thunderstorms Saturday, meaning at least a 10% chance existed of a tornado appearing within 25 miles of any location within that area.
The Lafayette area was expected to have the low pressure front pass through between 4 and 8 a.m. Saturday, the Baton Rouge area between 5 and 9 a.m. Saturday and the Covington, New Orleans and Houma areas between 8 a.m. and noon, forecasters said.
The front will have passed through all but perhaps the far eastern tip of southeast Louisiana, along the edges of St. Bernard and Plaquemines parishes, by noon Saturday, Zeigler said.
"It's going to be moving at a pretty good rate across the state," he said.
The Weather Service's Storm Prediction Center says that tornadoes and other heavy winds could arise not only from the squall line of storms along the advancing front but also from a handful of powerful "supercell" storms ahead of the front.
Rain is expected to be about 1 to 3 inches, while hail greater than 1 inch in diameter is also expected.
Once the front passes through, conditions are expected get cooler and drier on Saturday and Sunday.