The first named storm of the 2024 Atlantic hurricane season, Alberto, formed in the southern Gulf of Mexico late Wednesday morning as it slowly progressed toward the coast of northeast Mexico into the evening. The developing storm was pushing ashore both heavy rains and, in some coastal communities, a significant ocean surge.
The storm is expected to make landfall in northeastern Mexico on Thursday morning while its effects will be felt as far north as coastal Louisiana.
It’s the United States’ first taste of tropical trouble, but experts are calling for a long, busy season with many more threats on the way.
The storm’s most significant impact so far has been its surge, or storm-driven rise in ocean waters above normally dry land at the coast. Social media video showed water inundating coastal communities, including Surfside Beach to the south of Galveston, flowing over roads and underneath elevated homes while overwhelming storm drains.
This is why you shouldn’t always focus on the landfall. Incredible storm surge in #Texas HUNDREDS of miles from the center of the storm spinning off the coast of Mexico. #PTC1 #Txwx #stormsurge #Alberto #Hurricaneseason @bclemms pic.twitter.com/9WW8owSalw
— Jonathan Petramala (@jpetramala) June 19, 2024
The surge on Wednesday morning in Galveston Bay reached 4 feet, producing its 7th highest water level on record.
Bands of heavy rain were also pushing inland with flood watches blanketing South Texas and the Rio Grande Valley, and stretching along the coastline to Cameron Parish, La.
A tropical storm warning covers coastal counties from just south of Galveston to the U.S.-Mexico border, and incudes Rockport, Corpus Christi and Brownsville. Tropical storm-force winds with 50-mph gusts are probable along the shoreline.
Through early evening on Wednesday, 1 to 4 inches of rain had fallen along much of the Texas coast from Galveston southward. A few areas near Rockport had received even a bit more than that. Wind gusts in this zone had reached 30 to 45 mph.
As of 5 p.m. Central time, Alberto had maximum sustained winds of 40 mph and was moving to the west-southwest at 9 mph. The Hurricane Center said Alberto is a large tropical storm with tropical-storm-force winds extending up to 415 miles north of the center.
How much rain?
Scattered downpours were pivoting ashore in South Texas throughout Wednesday and should continue through midnight or so. They probably won’t make it much north of San Antonio or Victoria.
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Storm totals could reach 4 to 8 inches, with localized totals over 10 inches possible. Downpours will taper to intermittent showers by early Thursday.
A near record-moist air mass will be in place, allowing for intense rainfall rates. A weather balloon launched Wednesday morning from Brownsville recorded 2.78 inches of moisture present from the bottom to the top of the atmosphere. That’s just shy of the 2.93-inch record set on July 17, 1996.
Some of the storm’s most serious flooding is probable in northeast Mexico and Central America.
“Life-threatening flooding and mudslides are likely in and near areas of higher terrain across the Mexican states of Coahuila, Nuevo Leon, and Tamaulipas, including the cities of Monterrey and Ciudad Victoria,” the Hurricane Center wrote.
However, some of the rainfall in Mexico will be quite beneficial, as the area has been enduring serious drought.
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Rains from a large, swirling area of showers and thunderstorms across the southwest Gulf of Mexico and Central America, known as the Central American Gyre, have produced disastrous flooding in parts Guatemala and El Salvador, causing at least 14 fatalities, according to the Associated Press. This same gyre spawned Alberto and could give rise to another storm in the Gulf of Mexico next week.
Wind and surge
6/19 4 AM CDT: Moderate coastal flooding from Potential Tropical Cyclone #One is likely along much of the Texas coast today and continuing through midweek. Please check https://t.co/0BMJEzOlHs for updates. pic.twitter.com/VrmJk1a0Ca
— NHC Storm Surge (@NHC_Surge) June 19, 2024
It’s still looking like 40- to 50-mph gusts will be possible along the immediate coastline from Houston-Galveston southward, with lesser but still blustery winds expected inland.
The onshore flow will push water against the coast, leading to a surge of up to 2 to 4 feet in the most prone areas and 1 to 3 feet elsewhere. Because of the system’s sprawling circulation, the surge was forecast to affect areas hundreds of miles from its center, as far away as the western coast of Louisiana.
Tornado risk
When tropical cyclones and disturbances hit land, sporadic tornadoes sometimes occur ahead, and to the right, of the center. Since South Texas will be in the “front right quadrant” of the system, a subtle change of low-level winds with height, known as wind shear, could support an isolated tornado risk.
The National Weather Service Storm Prediction Center has advertised a Level 1 out of 5 Marginal risk for severe weather.
Jason Samenow contributed to this report.
