Little has changed in the tropics on September 9 from the situation reported here in the September 8 post other than diminishing prospects for 94L’s developing into named storm Teddy. So  this posting will briefly update yesterday’s report, and we’ll continue to eye activities in the tropics in this extraordinary hurricane season going forward.

Paulette a threat to Bermuda

In the central Atlantic, Tropical Storm Paulette, featuring 60 mph winds at 11 a.m. EDT Wednesday, was headed west-northwest at nine mph towards Bermuda, which was in the National Hurricane Center’s five-day cone of uncertainty. Paulette was struggling with high wind shear of 20 – 30 knots from an upper-level trough of low pressure to its west. Wind shear is expected to increase through Friday, potentially causing Paulette to begin weakening. The shear is predicted to relax back to 20 – 25 knots on Sunday and Monday, which may allow Paulette to intensify into a category 1 hurricane as it approaches Bermuda.

None of the 0Z or 6Z Wednesday runs of the European and GFS models, and none of their 72 ensemble members, showed Paulette making landfall along the U.S. East Coast next week, and Bermuda currently appears to be the only land area facing a possible Paulette landfall.

Rene not a threat to land

In the eastern Atlantic, Tropical Storm Rene, a minimal tropical storm with 40 mph winds at 11 a.m. EDT Wednesday, was headed west-northwest at 13 mph into the central Atlantic, far from any land areas. With adequately warm waters near 26.5 degrees Celsius (80°F), moderate wind shear, and a moist atmosphere, conditions appear favorable for Rene to intensify into a hurricane by Friday. Rene is expected to turn to the northwest by Saturday and begin weakening, and it is unlikely to affect any land areas.

Southeastern U.S. states need to keep an eye on 94L

An area of low pressure located about 350 miles southeast of the North Carolina coast on Wednesday afternoon was headed northwest at about 10 – 12 mph. Satellite images showed that 94L had begun to produce a small area of heavy thunderstorms near the center of its weak surface circulation. Conditions for development through Thursday night appeared favorable, with the 12Z Wednesday run of the SHIPS model predicting a moderate 5 to 15 knots of wind shear, ocean temperatures near 29 degrees Celsius (84°F), and a moist atmosphere with a mid-level relative humidity of 65 – 70%. However, 94L’s weak circulation and some dry air aloft will inhibit development, and the system has very little model support pointing to its becoming a named storm. On its current track, 94L will be near the Carolina coast by Thursday evening, leaving little time for significant strengthening to occur. An Air Force hurricane hunter aircraft flight, scheduled to investigate 94L on Wednesday afternoon, was cancelled given the lack of development of the storm. The flight has been rescheduled for Thursday morning. In an 8 a.m. EDT Wednesday Tropical Weather Outlook, NHC gave 94L two-day and five-day odds of development of 30%.

The future Sally: a tropical wave emerging from Africa on Thursday?

The top models for forecasting tropical cyclone genesis continue to give strong support for development to a new tropical wave predicted to emerge from the coast of Africa on Thursday.

This wave is predicted to move mostly westward at low latitude at about 15 mph next week. Given its lower-latitude position compared to Paulette and Rene, this new tropical wave may be a long-range concern for the Caribbean and North America. Five of the 51 ensemble members from the 0Z Wednesday, September 9, run of the European ensemble forecast showed that this new system would be a hurricane in the Caribbean late next week.

However, the future track of the system may well depend upon the position and strength of Paulette and Rene, and on the structure of the wave once it emerges from Africa – variables very difficult to accurately predict. In an 8 a.m. EDT Wednesday Tropical Weather Outlook, NHC gave the new wave two-day and five-day odds of development of 40% and 80%, respectively.

The next two names on the Atlantic list of storms are Sally and Teddy.

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Posted on: September 9, 2020 (1:40pm EDT).