The record day for Atlantic tropical storm activity comes during a record-setting year for named storms. Beta is the 23rd named storm of 2020, the most on record through Sept. 18. It formed 34 days before the 23rd name storm, Beta, in 2005, the year that holds the record for the most named storms in an entire season. There are still six weeks left in the official 2020 hurricane season.
Beta is forecast to weave a serpentine path through the Gulf of Mexico, its exact track highly uncertain. While the core of its winds may or may not cross land, significant rainfall and possible flooding are forecast for the Texas coast.
“There is an increasing risk of heavy rainfall and flooding along the northwest Gulf Coast Sunday through at least the middle of next week as Beta is forecast to move slowly toward and along or offshore of the coast through that time,” the National Hurricane Center wrote. It also cautioned that storm surge, tropical storm and/or hurricane watches are likely to be issued Friday night or Saturday for the western Gulf Coast.
Some places along the Texas coastline could see a foot of rainfall by the end of the week. And areas of southwest Louisiana, still recovering from Hurricane Laura’s assault three weeks ago, could also see substantial rainfall.
A morning satellite pass over what formerly had been called Tropical Depression 22 revealed a tight, organized circulation, but a lack of tropical storm-force winds. That meant the system was getting its act together but wasn’t strong enough to receive a name or tropical storm designation yet.
But that same instrument, known as a scatterometer, returned data suggestive of some 40 mph winds north of the center late in the afternoon, and Beta was born. A scatterometer is a device that emits pulses of propagating radiation, and then estimates winds based on the characteristics of the signal that is bounced back from ocean waves.
Currently, Tropical Storm Beta is around 250 miles southeast of the mouth of the Rio Grande, or the United States-Mexico border. Over the next few days, Beta will gradually strengthen as it meanders north, potentially becoming a hurricane offshore by late in the weekend.
Eventually, high pressure and an approaching cold front to the north will suppress Beta’s northward progress, forcing the storm to jog westward toward the Texas Gulf Coast. Heavy rain could arrive along the immediate shoreline by late Sunday into Monday, and slowly work its way northeastward.
Right now, it’s looking like many places near the beaches could see either side of a foot of rainfall, but that high-stakes precipitation forecast is just beginning to come into focus. Beta’s rainfall will probably walk a steep west-to-east gradient, meaning subtle track shifts of a little farther inland or offshore would have significant implications for exactly how much rain falls and where.
In addition, there is also a chance that a Predecessor Rain Event, or PRE, develops over portions of East Texas and Louisiana well ahead of Beta. That means moisture drawn north from the system could unleash heavy downpours in areas away from the storm’s center.
In this case, the nearing cold front could help focus moisture enough that heavy rainfall could occur and bring flooding inland, but confidence in whether and where such heavy rain could unfold is very low.
Jason Samenow contributed to this report.