Additional tropical disturbances bear watching in the Atlantic, coinciding with the historic peak of hurricane season. One system, located southwest of the Cabo Verde Islands off the coast of Africa, will probably earn a name by the weekend as it gradually organizes and shifts westward, while another storm could form off the East Coast and sneakily slip out to sea.
Due to Nicholas, flash flood watches stretched from Southeast Louisiana to the Florida Panhandle Wednesday. The National Weather Service declared a level 3 out of 4 “moderate risk” of flash flooding and excessive rainfall, noting that the greatest totals, possibly approaching the double digits, could fall in some of the same waterlogged areas hit hard by Hurricane Ida just over two weeks ago.
As Nicholas trudged ashore Monday into Tuesday, up to 14 inches of rain was reported in Galveston, Tex., with widespread totals between 6 and 10 inches close to the coast. Houston proper saw a bit more than half a foot, but amounts climbed quickly south and east of the city.
Areas near the coastline also gusted over hurricane force, including a gust to 94.5 mph on Matagorda Bay. Port O’Connor gusted to 75 mph, with a gust to 81 mph clocked at Magnolia Beach to the northwest.
Slightly lesser rainfall amounts have been reported in Louisiana since Tuesday, but many locations in the central and southern part of the state have seen at least four inches. Here are some select reports through 11 a.m. Wednesday:
- Bunkie (about midway between Alexandria and Lafayette): 10.58 inches
- Near Baton Rouge: 5.29 inches
- New Orleans: 4.34 inches
- Lafayette: 4.13 inches
Nicholas now and the forecast through Friday
Nicholas was a tropical depression late Wednesday morning, meaning its winds had died down below the 39 mph tropical storm threshold. It was centered 30 miles east of Lake Charles, La., though all of its rainfall was located in bands far east of the center.
A slug of heavy rain was soaking southeast Louisiana, the southern third of Mississippi and coastal Alabama. Flash flood warnings were in effect just north of New Orleans and around Gulfport and Mobile. Rainfall rates may approach three inches per hour in the heaviest bands, but most of the rain was pushing east out of New Orleans.
“These bands could produce locally in excess of 6 inches through this afternoon,” wrote the Weather Prediction Center. “Should any of these bands train perfectly across an urban area, significant flash flooding would be possible.”
The Big Easy picked up 4.73 inches of rain on Aug. 29 associated with Hurricane Ida, though areas to the southeast near the storm’s point of landfall probably saw triple that. Doppler radar estimated widespread totals of 10 to 15 inches in the same areas that are getting wet again Wednesday.
“There is the potential for excessive rainfall in some locations where slow-moving thunderstorms move repeatedly over the same areas,” warned the Weather Service.
On satellite imagery, Nicholas no longer resembled a tropical cyclone, but rather was beginning to feel the effects of dry air intruding from the west. That was causing the leading edge of heavy rainfall to bow outward, tracing an arc as it shifted east-northeast.
Weather models indicate the heaviest rain will become more fragmented as it rolls across the Deep South and eventually toward the Southeast, its moisture largely blending in with traditional September showers and thunderstorms by the time Friday rolls around.
The Weather Service cautions that a few locations near the immediate coastline of Mississippi, Alabama and extreme northwest Florida could see as much as 6 to 10 inches of additional rainfall, but amounts should be less in the vast majority of locales.
Other systems to watch
Meteorologists have also been tracking a number of other systems across the Atlantic as the tropics once again spark to life, including one north of the Leeward Islands and Bahama chain that could develop in the coming days. The Hurricane Center estimates a 70 percent likelihood of it acquiring tropical characteristics and becoming a tropical depression or storm in the days ahead. The name “Odette” is up next on the list.
That system would probably parallel the East Coast but, aside from rough surf and rip currents along Atlantic beaches, spare the Lower 48 any direct impacts, passing between the Eastern Seaboard and Bermuda.
A potentially more interesting system, dubbed Invest 95L, recently ejected off the west coast of Africa near Senegal, and is passing south of the Cabo Verde Islands. It does appear primed for development, but has been lacking sustained deep convection, or shower and thunderstorm activity. It will probably gel into a tropical depression by the weekend.
Thereafter, its path will take it west through the Atlantic’s Main Development Region, or MDR. That’s the ocean basin’s equivalent of “hurricane alley,” and, in September, houses extremely warm waters that usually prove conducive to strengthening. Considerable uncertainty remains, particularly since the system has yet to develop, but all signs point to this being one to watch.
Jason Samenow contributed to this report.