Tropical Storm Dorian, the first tropical cyclone to form in the deep Atlantic tropics this season, is gradually becoming better organized as it approaches the Lesser Antilles. In the western Atlantic, Invest 98L is still likely to develop, but it is less likely to become an intense storm than initially predicted.

Dorian getting better organized over the tropical Atlantic

Tropical Storm Dorian, the first tropical cyclone to form in the deep Atlantic tropics this season, is gradually becoming better organized as it approaches the Lesser Antilles. In the western Atlantic, Invest 98L is still likely to develop, but it is less likely to become an intense storm than initially predicted.

As of 5:00 p.m. EDT Sunday, Tropical Storm Dorian was centered near 11.5°N 54.2°W, and was moving westward at about 14 mph. Maximum sustained winds were 45 knots (50 mph), with an estimated minimum pressure of 1003 mb. Dorian has strengthened today, with convection becoming better organized near the center. Microwave imagery confirms the strengthening trend, with a convective band wrapping about 3/4 around the center. Dorian is a small tropical cyclone, so the exact intensity of the cyclone is uncertain. A low-level recon mission will investigate Dorian tomorrow, which should give us a better idea of Dorian’s actual intensity. Two reliable global models continue to show Dorian remaining very weak, with the GFS and ECMWF models actually opening Dorian up into a tropical wave over the eastern Caribbean. However, the UKMET and HWRF models are more aggressive and show a more north track. The SHIPS statistical guidance also remains aggressive with Dorian, strengthening it into a hurricane in about 48 hours. Although the National Hurricane Center currently predicts Dorian will be a hurricane over the eastern Caribbean Sea, it is also a distinct possibility Dorian is a weak tropical storm or even an open wave at this time. What happens with Dorian during the next 24 hours is crucial for its future.

A Tropical Storm Warning is currently in effect for Barbados, St. Lucia, and St. Vincent and the Grenadines. A Tropical Storm Watch is currently in effect for Martinique and Grenada (as well as its dependencies). Interests in the Lesser Antilles should prepare for tropical storm conditions on Monday night into Tuesday morning. Afterward, Dorian or its remnants are likely to impact Hispaniola on Thursday. Interests in eastern Hispaniola should also monitor the progress of Dorian.

98L still likely to develop over the western subtropical Atlantic

Invest 98L over the western Atlantic is still likely to develop into a tropical cyclone, though model support has decreased for it to become a strong cyclone. The National Hurricane Center (NHC) gives 98L a 70 percent chance of development within 48 hours, and an 80 percent chance within five days. The next name on the Atlantic naming list is Erin. 98L should move northeastward away from the United States East Coast, but it could affect Atlantic Canada late this week.