During the second week of September, a trough of low pressure formed over the eastern Gulf of Mexico. It produced some showers, but otherwise did not show signs of development. Fortunately for the disturbance, it moved extraordinarily slowly, drfiting generally westward for five days until it was off the coast of Texas. Meanwhile, Tropical Depression Nineteen moved into the Gulf and strengthened into Hurricane Sally, which made conditions near the trough unfavorable for cyclonogenesis. As before, though, it wasn't going anywhere. It next dipped south toward the Bay of Campeche, and was vigorous enough to produce heavy rain near the coastline of southern Texas and Mexico as it went. Around the 15th, a surface low-pressure center formed and gradually deepened. It moved little, but thunderstorm activity became concentrated, culminating in the formation of Tropical Depression Twenty-Two during the evening of September 17.
A trough over the United States tugged the depression slowly toward the northeast or north-northeast over the next day toward the central Gulf of Mexico. Convection increased some, but the center was a bit elongated. Nevertheless, measurements indicated the presence of tropical storm force winds on the 18th, so the depression strengthened into Tropical Storm Beta. Oddly, two additional storms had been named in the time between Tropical Depression Twenty-Two formed and when it strengthened to a tropical storm; these two took the names Wilfred and Alpha, leaving Beta for our depression. Beta was the 23rd named storm of 2020, only the second time this occurred after 2005's Alpha, which was named on October 22 of that year (note that 2005 had an unnamed subtropical cyclone identified after the season's conclusion, explaining why Alpha was the 23rd storm).
Beta strengthened some that evening and its minimum pressure dropped a fair bit. It was still being affected by shear from the steering trough, which exposed the center of circulation overnight. The displaced moisture brought steady rain to southern Lousiana for a day or so. On the 19th, the trough lifted out to the northeast and Beta missed its escape route. Instead, it turned westward and slowed to a crawl as a new ridge built in to the north. Wind shear decreased some too, allowing convection to recover the center that afternoon. The storm had a new threat to deal with: a dry continental airmass approaching from the west. It did a decent job combating this and maintained a central dense overcast. On the 20th, Beta reformed a bit farther west and picked up some speed in that general direction, maintaining its intensity as a moderately strong tropical storm.
By September 21, the system neared the central Texas coastline. Steering currents were collapsing again and Beta slowed down, bringing an extended period of frequent rainfall to some parts of southeast Texas. The storm weakened a bit too due to land interaction. It officially made landfall that night and weakened to a tropical depression during the morning of September 22. Dry continental air eliminated nearly all deep convection, but Beta still was a wet storm at the surface: the Houston area received over a foot of rain from the storm. There wasn't much to steer the cyclone, but it started moving east-northeast over land that afternoon, tracing a weak upper-level trough. The cyclone was far enough from the coast that weakening continued, and it degenerated into a remnant low late on September 22. This low brought moderate rainfall across the south, Ohio valley, and ultimately mid-Atlantic as it moved northeastward for the next several days before dissipating.
Beta was a well-organized tropical storm in the satellite image above, taken on September 20.
The storm took a slow, meandering track through the Gulf of Mexico before making landfall in Texas.
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