Tropical Storm Beta was spreading heavy rains over coastal Texas and Louisiana on Monday as it trekked slowly west-northwestward at less than 7 mph toward an expected landfall in Texas on Monday night. Though Beta was not predicted to intensify, its slow movement will make it capable of bringing widespread torrential rains of 5 – 10 inches and damaging flooding to the coast.

At 2 p.m. EDT Monday, September 21, Beta was 45 miles southeast of Port O’Connor, Texas, heading west-northwest at 7 mph with maximum sustained winds of 45 mph and a central pressure of 999 mb. Heavy rains from Beta were affecting much of the Texas and Louisiana coasts, with the heaviest rains of 4 – 8 inches having fallen over coastal Louisiana near the mouth of the Mississippi River. Rainfall amounts along the Texas coast were generally 1 – 3 inches.

The live storm surge tracker at Trabus Technologies showed Beta was bringing storm surge heights of two to four feet along much of the Texas and Louisiana coast. The maximum storm surge heights observed as of 2 p.m. EDT Monday were:

3.9 feet: Shell Beach, Louisiana (east-southeast of New Orleans);
3.5 feet: San Luis Pass, Texas (south of Houston);
3.5 feet: Matagorda Bay, Texas (southwest of Houston); and
3.1 feet: Rollover Pass, Texas (east of Houston).

On Monday morning, a TCOON observing site at Port O’Connor, Texas, measured a wind gust of 40 mph in Beta, and a NOAA buoy located just east of Galveston, Texas, reported a sustained wind of 39 mph, gusting to 43 mph.

Beta was feeding off of very warm ocean waters in the western Gulf of Mexico that were 29 – 30 Celsius (84 – 86°F), about 0.6 Celsius (1°F) above average. Typically, such warm waters would provide Beta with an unusually high amount of moisture for producing heavy rains. However, satellite images showed Beta was fighting moderately high wind shear and dry air at upper levels, and this was keeping heavy thunderstorm activity limited.

Forecast for Beta

Conditions for further development are expected to be marginal through landfall, with moderately high wind shear of 15 – 20 knots and dry air continuing to hinder Beta.

The model consensus is that Beta will make landfall in Texas on Monday night and penetrate inland no more than 50 miles by Tuesday, as the ridge of high-pressure steering Beta weakens and puts the storm in an area of weak steering currents. A weak trough of low pressure to the north then is expected to take over steering Beta, inducing a slow east-northeast to northeast motion, roughly parallel to the coast.

Beta’s track during this period likely will be just inland. However, if Beta’s track takes it back over water near the upper Texas coast, it might rejuvenate slightly and dump heavier rains than currently predicted over coastal Texas and Louisiana. Given its very slow motion and the very warm Gulf waters feeding it, Beta could end up being a prodigious rainmaker, and flooding due to its heavy rains will be the chief damaging impact of the storm. Fortunately, the type of widespread biblical rainfall seen in this region with Hurricane Harvey is not expected.

Category 1 Teddy brushing Bermuda; Nova Scotia and Newfoundland landfalls expected on Wednesday

At 2 p.m. EDT Monday, Hurricane Teddy had weakened to a category 1 storm with top sustained winds of 90 mph and a central pressure of 960 mb. Teddy was headed north-northeast at 18 mph as a large hurricane, with tropical storm-force winds extending out up to 230 miles from the center.

Teddy’s gigantic wind field had created waves 12 feet high spanning an area of ocean 1,070 miles across, with waves 35 feet high near the center. The hurricane was generating big swells and dangerous surf conditions and riptides along much of the southeastern U.S. East Coast, with waves of 10 – 15 feet common in the offshore waters. Waves up to 20 feet high were battering Bermuda, along with heavy rain squalls and winds gusting to tropical storm-force.

Forecast for Teddy

As Teddy interacts with the trough of low pressure steering it to the north, the hurricane will absorb energy from the trough, and likely intensify by Tuesday night into a category 2 hurricane with 105 mph winds, despite an expected increase in wind shear. Teddy’s wind field will expand, and is predicted to extend out up to 450 miles from the center by Tuesday evening. Teddy’s wave field will expand and amplify in response, with NOAA’s WaveWatch 3 model predicting that Teddy on Tuesday will create waves over 50 feet high across an area over 100 miles in diameter. Dangerous surf conditions will intensify along the mid-Atlantic, New England, and Atlantic Canada coasts through Wednesday.

Also see: Unusually warm sea temperatures fueled Harvey’s devastating rains

Once Teddy encounters the cooler waters north of the Gulf Stream, at the latitude of New Jersey, steady weakening should occur, but Teddy will maintain a very large wind field as it transitions to an extratropical storm. Teddy is likely to pass near or over northeastern Nova Scotia on Wednesday morning, with a second landfall later on Wednesday expected in Newfoundland. Landfall in Nova Scotia likely will be as a strong extratropical storm with winds of 60 – 75 mph, with heavy rain and widespread gale-force winds likely the main threat.

Bob Henson contributed to this post.

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Posted on September 21, 2020 (2:52pm, EDT)