Tropical Storm Bret expands its coverage of thunderstorms to West 

The NHC forecasts the system to pass over the Lesser Antilles as a hurricane on Thursday/Friday, but it should also be noted that there is high uncertainty with this intensity forecast.

Tropical Storm Bret expands its coverage of thunderstorms to West 
Tropical Storm Bret expands its coverage of thunderstorms to West 

Weather: Tropical Storm Bret has quickly expanded its coverage of thunderstorms to the west, where the increasing winds are roughing up seas to lift up some warm sea spray from the 28-degree C waters (3rd pic), when it gets past 50W, there’s a huge area of 29C water which is around 1.6C above normal(4th pic). Normal is the modern average for 1981-2010.

In the outer part of developing systems, the roughing up of seas helps feeder bands form which will help with overall cyclonic rotation.. Also helps beef up the system to block off dry air and warm up a larger area of the atmosphere thus dropping pressure even more. The thing that can stop this is wind shear if it can blow in some dry air, cool of the latent heating process… wind shear is forecast to increase as Bret gets past 50-55W so that’s why NHC has it only reaching 75mph then weakening to 70mph near the islands.

The NHC forecasts the system to pass over the Lesser Antilles as a hurricane on Thursday/Friday, but it should also be noted that there is high uncertainty with this intensity forecast.

Climatologically speaking, Bret is a rather rare tropical cyclone in this part of the Atlantic Ocean for the month of June. June storms usually form close to the United States, and the eastern part of the basin (referred to as the “main development region”) normally doesn’t become favourable for tropical development until August and September. In fact, since the 19th century, only three of 79 June storms have formed east of the Lesser Antilles. 

NHC has adjusted their formation path much more south and wider to reflect the big distances between 2 main possible tracks models are showing(1st pic). More of the main models and many of the ensemble possible tracks, have continued the trend of having 92L move into the Lesser Antilles. It is seems more of them are seeing a stronger high pressure. 

The Lesser Antilles need to take future tropical cyclone 92L more seriously. It is still unclear how soon, these vastly different scenarios will no longer show in forecasts. It is best to just make early preps and do more preps later as there is more certainty of threat.