Another half-foot or more of rainfall was possible for some, with totals in some spots likely to close in on 20 inches. As Beta continues to drift northeast through Wednesday, “[f]lash, urban, and minor river flooding is likely” the National Hurricane warned.
Much of Texas’s Harris County, which includes Houston, was under flash-flood warnings Tuesday morning because of the torrential rain and rising river levels. Parts of State Highway 288 were underwater south of Houston and closed in both directions.
Slow-moving Beta isn’t going anywhere soon, the waterlogged atmospheric eddy unloading copious Gulf moisture in a swath from the Middle Texas Coastline to the mid-South.
The National Weather Service’s Weather Prediction Center issued a rare high risk of excessive and flash-flooding rainfall for the Houston metro area, while a moderate risk extends into extreme southwest Louisiana, which was devastated by Hurricane Laura less than a month ago.
Beta made landfall at 11 p.m. Monday near the southern end of Texas’s Matagorda Peninsula with maximum sustained winds of 45 mph. It put 2020 into a tie with 1916 for most landfall tropical storms and hurricanes in a single season. Six of these storms have come ashore from the Gulf of Mexico.
When it formed Friday, Beta became only the second storm in 15 years to be named after a Greek letter, the first spot claimed by Subtropical Storm Alpha, which breezed through a narrow strip of Portugal in the past week. All future storms for the remainder of this season will be assigned names from the Greek alphabet, since a record number of systems have formed exhausting the 2020 list of conventional hurricane names.
Tropical Depression Beta now
On Tuesday morning, Beta had weakened to a depression and was centered 15 miles east-northeast of Victoria, Tex., although it wasn’t raining there. In fact, dry air had hollowed out Beta and eroded its rainfall from the south and west. The bulk of the heavy rains were ongoing to the north and east.
The depression was drifting northwest at just 2 mph, barely walking pace, and will stall before very slowly inching northeast. The heaviest rain was found in its narrow feeder bands spiraling inward from Galveston Bay northeast to the Bolivar Peninsula, with a much broader slug of moderate to at times heavy rain from Victoria northward to College Station.
A foot of rain had already been measured early Tuesday in Brazoria County, while 10 inches had fallen near Galveston. In Harris County, which includes Houston, 11.36 inches was reported near the town of Bellaire. Houston Hobby airport was up to 8.40 inches.
Weather models suggest a very slow expansion and progression of those heavy rain bands northeast, the deluges not likely to abandon the greater Houston area until overnight Tuesday. From there, the heavy rain will spread over the Golden Triangle region of Southeast Texas and southwest Louisiana, including Beaumont, Port Arthur, and Orange. Rainfall rates could top two to three inches per hour.
The atmosphere preceding Beta was so moist that heavy rains were breaking out along a cold front ahead of it in Oklahoma, southwest Arkansas and Louisiana.
Rain will move out of Texas entirely by lunchtime Wednesday, the heaviest by then over western Louisiana with secondary showers in southern Arkansas and across much of Mississippi. The gradually-weakening core of Beta’s precipitation will continue northeast through Mississippi and northwest Alabama before likely drenching Nashville and Middle Tennessee with several inches of rain Thursday night.
Beta had also brought storm-surge flooding along the shores of the Gulf of Mexico, an increase in water levels that was still bringing high water to the coastline early Tuesday.
On Monday, a 3.6-foot surge was observed in Rollover Pass, Tex., on the east side of Galveston Bay, while Corpus Christi was subject to a 2.3-foot surge. Water levels also increased along the Louisiana border as Beta’s decaying wind field shifted northeast. Significant coastal flooding was reported in Cameron, La. ahead of Beta on Monday.
With Beta downgraded to a tropical depression, the Hurricane Center discontinued storm surge warnings Tuesday morning. They had been in effect in effect from Sargent, Tex., about 70 miles south of Houston, to the Louisiana state border.
Other storms to watch
Meanwhile, Beta has company in the Atlantic. Hurricane Teddy was taking on a nor’easter-like structure as it underwent extratropical transition Tuesday morning, while sweeping north toward the Canadian Maritimes. Its western cloud shield was bringing a milky overcast to portions of Rhode Island, coastal Massachusetts, and the New Hampshire Seacoast and Maine, as well as a slight increase in water levels in Maine.
Tropical Storm Warnings are in effect in Nova Scotia, where Environment Canada cautions that “[because] trees are still in full leaf … winds could cause limbs to break with some tree falls, likely leading to many power outages.”
Gusts there will likely top 60 mph. Up to four inches of rain are also probable, including in Halifax proper.
While remaining north of the East Coast, Teddy’s large swells are forecast to “cause life-threatening surf and rip current conditions,” according to the Hurricane Center.
Adding one more thing to the pile was a zombie tropical storm roaming the eastern Atlantic. Paulette, which had degenerated into a remnant swirl and lost its name, reformed into a 60 mph tropical storm Monday night. Since it developed out of the same cohesive central vortex, it kept its previous name.
Paulette will harmlessly pass between the Azores and the Cabo Verde Islands before once again dissipating in the days ahead.