Delta’s landfall is expected Friday evening in the coastal region just to the south of the area between Lafayette and Lake Charles, La., where Laura caused heavy damage and cut power in some locations for weeks.
Lake Charles Mayor Nic Hunter urged residents of the southwest Louisiana city to leave. “The latest track for Hurricane Delta does not look good for Lake Charles. You need to evacuate,” he wrote in a Facebook message Thursday.
In a separate video posted to Facebook, Hunter cautioned: “I cannot assure you that Calcasieu Parish [where Lake Charles is located] is going to be a safe place this weekend.”
Social media video showed traffic backed up for miles on Interstate 10 west of Lake Charles, as residents fled town.
Although Delta was a compact storm over the Caribbean, it has grown into a much larger hurricane over the Gulf of Mexico, meaning its impact will be felt over a broad area of the northern Gulf Coast.
A storm surge warning spans High Island to Ocean Springs, Miss. The surge could cause as much as 11 feet of inundation along the coast of west central Louisiana, while elevated seas could affect areas as far west as Galveston Bay in Texas and as far east as Mobile Bay in Alabama.
“Life-threatening storm surge and dangerous hurricane-force winds are likely,” wrote the National Hurricane Center.
Tropical-storm conditions could arrive along the Louisiana coastline by Friday morning.
In Cameron, La., where Laura made landfall, the same evacuation order declared Aug. 27 remains in place. Power is still out in the town and isn’t expected to be restored until January, Weather.com reported.
New Orleans is expected to escape the bulk of Delta’s wind, but a hazardous storm surge of several feet is likely, including at the mouth of the Mississippi River and on Lake Pontchartrain.
At 11 p.m. Thursday, Hurricane Delta was centered 285 miles south of Cameron, La., and was moving north-northwest at 12 mph. It contained 120 mph maximum sustained winds, a 15 mph increase from 11 a.m. as the storm was gradually gaining strength. Hurricane-force winds extended outward up to 40 miles from the center, while tropical-storm-force winds expanded up to 160 miles away.
The Hurricane Center wrote the storm appeared “better organized” late Thursday morning with towering thunderstorms at its core. During the afternoon and evening, a clear eye emerged in the storm center on satellite imagery, a sign of further intensification.
While sea surface temperatures in the Gulf aren’t nearly as warm as the meteorological “rocket fuel” that allowed for its explosive intensification over the Caribbean, the available ocean heat will allow for Delta’s continued strengthening through early Friday morning. The Hurricane Center projects its winds will peak at around 125 mph.
By Friday afternoon and evening, increasing high-altitude winds will begin to disrupt Delta’s structure once it nears the coast. Slightly cooler waters should also favor some weakening but the storm is predicted to come ashore as a high-end Category 2 or low-end Category 3.
Because Delta’s wind field will expand as the storm grows horizontally, its gusts are able to cover more oceanic real estate. That makes the storm more prone to producing a serious storm surge or rise in ocean water above normally dry land that could flood coastal communities.
The National Hurricane Center predicts that, in a worst-case scenario situation where the system makes landfall near the time of high tide, a surge of seven to 11 feet would be possible in Vermilion Bay and points east to near Bayou Lafourche and Port Fourchon.
The Hurricane Center projects a surge of five to eight feet in the area devastated by a surge of up to 17 feet during Hurricane Laura, near and just to the east of Cameron, La. This zone includes the shores of the Rockefeller Wildlife Refuge in rural southwestern Louisiana, along the flood-prone Highway 82. A few communities such as Pecan Island, Grand Chenier and Creole will probably experience flooding.
Calcasieu Lake, on whose northern shores sits Lake Charles, is in line for a two- to four-foot surge, as is part of the neighboring coastline along the Texas-Louisiana border.
To the east of the center, a significant surge is expected at the mouth of the Mississippi River as well. New Orleans could even wind up with a surge of three to five feet, anticipated to affect lakes Pontchartrain, Maurepas and Borgne.
Mobile Bay in Alabama could see a few feet of surge too.
The Acadiana region of Louisiana will be hardest hit by Delta’s strong winds, which could gust upward of 100 mph along the immediate coastline. Gusts topping 90 mph would be possible in Lafayette, a city of more than 125,000, based on current forecasts.
Winds this strong will bring down trees and power lines and result in significant structural damage, particularly to poorly constructed buildings and mobile homes. Thousands of power outages are likely.
The strongest winds will be found in the eyewall, a ring of intense downpours and thunderstorms that surrounds the eye. Ordinarily, winds are most severe to the right of the center, but there is data to support the western side of Delta’s eyewall containing just as much wind.
Subtle shifts in the track could have enormous implications for Lake Charles, which may come very close to or enter the western eyewall. If that happens, gusts to 85 or 90 mph would be possible there. If the eyewall passes to its east, winds would be considerably less but still capable of damage.
Farther inland, winds north of the Interstate 10 corridor and especially north of Highway 190 should be tamer, but still reach tropical storm force. To the east, Baton Rouge could be fringed by tropical storm-force winds, while gusts in New Orleans look to remain below 35 or 40 mph.
Delta’s comparatively swift forward speed means we are unlikely to see the extreme magnitude rainfall that accompanied Hurricane Sally’s Alabama onslaught in mid-September, but double-digit rain totals remain a distinct possibility.
The National Hurricane Center is calling for a widespread swath of 5 to 10 inches of rain in southern and central Louisiana along the spine of Delta’s track, with localized amounts approaching 15 inches.
“Significant flash, urban, small stream and minor to isolated moderate river flooding is likely” from the Louisiana Gulf Coast into lower Mississippi Valley, noted the Hurricane Center.
Rainfall rates in the eyewall could exceed four inches per hour.
A couple of tornadoes also can’t be ruled out, primarily east of Delta’s center. The National Weather Service Storm Prediction Center has called for an “appreciable risk for tornadoes” in the spiral rain bands that sweep ashore in southeast Louisiana and southwest Mississippi. This includes the New Orleans metro area.
Changing winds with height will allow for a few downpours within these squalls to rotate, bringing the potential for quick-hitting, erratic twisters that strike with little warning.
In south central Louisiana, it may be more difficult for the National Weather Service to issue tornado warnings, since the main weather radar used for low-level scanning was obliterated by Hurricane Laura in August.
Delta is set to become the 10th named storm to hit U.S. soil during the 2020 hurricane season, the most recorded in a single year.
Current forecasts also call for Delta’s landfall to occur 10 to 15 miles east of where Laura made landfall. Delta will become the sixth tropical system to directly or indirectly affect Louisiana this year. The state hasn’t been hit by a Category 2 or stronger hurricane during October since Hilda in 1964.
When it formed Monday, Delta became the earliest 25th named storm in the Atlantic on record, by more than a month. Storms in 2020 have been so numerous as to exhaust the National Hurricane Center’s conventional naming list for only the second time on record. Forecasters have turned to Greek letters for names; Delta became the strongest Greek-named storm observed Tuesday.
Between Monday morning and Tuesday afternoon, Delta intensified from a tropical depression to a Category 4 hurricane faster than any other Atlantic storm on record.
Delta’s 75 mph leap in intensity in the 24 hours between Monday morning and Tuesday morning is second-fastest on record for an October hurricane in the Atlantic, trailing only Wilma in 2005. This sort of rapid intensification is expected to become more common and severe in a warming world. Rapid intensification has occurred in six Atlantic storms in 2020.