Former Subtropical Storm Debby made a transition to a tropical storm on Wednesday. At 11:00 a.m. EDT on Wednesday the center of Tropical Storm Debby was located at latitude 41.2°N and longitude 48.3°W which put it about 1150 miles (1855 km) west-northwest of the Azores. Debby was moving toward the northeast at 12 m.p.h. (19 km/h). The maximum sustained wind speed was 45 m.p.h. (75 km/h) and there were wind gusts to 60 m.p.h. (95 km/h). The minimum surface pressure was 1003 mb.
The structure of former Subtropical Storm Debby changed on Wednesday and it exhibited the characteristics of a tropical storm. More thunderstorms formed around the center of circulation and those thunderstorms rose higher into the atmosphere. Additional bands of showers and thunderstorms developed and revolved around the core of the circulation. Storms near the core began to generate upper level divergence. The strongest winds occurred closer to the center of circulation. The National Hurricane Center designated Debby as a tropical storm based on information from satellites.
Tropical Storm Debby will move into an environment unfavorable for a tropical storm during the next 24 to 48 hours. Debby was over water where the Sea Surface Temperature was near 26°C, but it will soon move over much cooler water. It will start to weaken when it moves over the cooler water. It could take several days for the circulation around Tropical Storm Debby to spin down.
Tropical Storm Debby will be steered toward the northeast as it moves between an upper level trough to the west and an upper level ridge to the east. On its anticipated track Tropical Storm Debby will move between the Azores and Greenland.
Subtropical Storm Debby formed over the North Atlantic Ocean west of the Azores on Tuesday morning. At 11:00 a.m. EDT on Tuesday the center of Subtropical Storm Debby was located at latitude 38.9°N and longitude 48.5°W which put it about 1160 miles (1870 km) west of the Azores. Debby was moving toward the north at 16 m.p.h. (26 km/h). The maximum sustained wind speed was 40 m.p.h. (65 km/h) and there were wind gusts to 50 m.p.h. (80 km/h). The minimum surface pressure was 1008 mb.
A surface low pressure system revolved around the western side of an upper level low over the North Atlantic Ocean during the past few days. More bands of showers and thunderstorms developed around the surface low on Tuesday morning and its circulation become more circular. The National Hurricane Center designated the low pressure system as Subtropical Storm Debby based on satellite imagery. The strongest winds were occurring in a rainband that wrapped around the northern side of the circulation. Bands south of the center of circulation consisted primarily of showers and lower clouds.
Subtropical Storm Debby will move through an environment somewhat favorable for intensification during the next 24 hours. Debby will move over water where the Sea Surface Temperature is between 26°C and 27°C. Subtropical Storm Debby will move between an upper level trough to its west and an upper level ridge to its east. The trough and ridge will produce southeasterly winds which will cause moderate vertical wind shear. Subtropical Storm Debby could strengthen during the next 24 hours. Debby will move over much colder water in about 36 hours and then it will weaken.
The upper level ridge and trough will steer Subtropical Storm Debby in a mainly northerly direction. On its anticipated track Subtropical Storm Debby will remain west of the Azores.