A storm system hovering over the northern Gulf of Mexico that had already dropped more than eight inches of rain on New Orleans gained strength on Thursday to become Tropical Storm Barry.
The flash flooding that plagued some neighborhoods in New Orleans on Wednesday served as a warning to residents along the Gulf Coast of what was to come as the slow-moving storm made its way toward an expected landfall on Saturday, possibly as a hurricane: rain, and a lot of it.
Where is it going to hit?
New Orleans is at the eastern edge of the forecast models for the storm’s path, which show that its center could make landfall almost anywhere along the Louisiana coast. The model from the National Hurricane Center also shows the potential for major flooding as far inland as Baton Rouge and southwestern portions of Mississippi.
In the video below, the center’s specialists explain what the forecast “cone” is and its limitations.
“The cone represents the probable track of just the center of the storm,” one of the specialists, John Cangialosi, says. “The center of the storm stays within the cone for roughly two out of every three forecasts.”
The specialists added that hazards associated with a storm usually extend beyond the edge of the cone, and the cone should not be relied on as an indicator of whether to evacuate or not.
So, how much rain is going to fall?
About 10 to 15 inches of rain is predicted to fall starting late Thursday night through Sunday. “The rain is going to be there because it’s a very slow-moving storm,” said Freddie Zeigler, a lead forecaster in the New Orleans/Baton Rouge office of the National Weather Service. “Some of the areas that do not usually flood can flood.”
Will the levees hold?
The Mississippi River, already swollen by spring rains, is expected to crest at New Orleans this weekend at close to 20 feet. The city’s levees along the river are between 20 and 25 feet high, according to Ricky Boyett, the spokesman for the Army Corps of Engineers in the New Orleans District.
“We’ll be getting to the top of some of our lower levees if the forecast holds,” he said, cautioning that it was still too early to lock in a prediction.
Mr. Boyett said the Corps was trying to identify any low areas and reinforce them. “We’re not concerned with integrity” of the levees, he said, only with how high the water rises.
But what about the winds? Or storm surge?
The wind picked up to tropical storm speeds of at least 39 miles per hour on Thursday morning. The storm could become a hurricane by late Friday, meaning its winds would have reached at least 74 m.p.h.
National Hurricane Center forecasters also predicted storm surges of three to six feet along the coastal areas. By comparison, the storm surge from Hurricane Katrina in 2005 was at least 25 feet along the Gulf Coast.
Mr. Zeigler said that the Weather Service and the National Hurricane Center in Miami were updating their forecast every couple of hours, and urged residents in Louisiana, Mississippi and Texas to keep checking, as the storm’s path may change.
