As the calendar reaches mid-August, the environment over the tropical Atlantic Ocean typically becomes more favorable for tropical cyclone formation.  The Sea Surface Temperature warms and vertical wind shear decreases.  Despite the ongoing El Nino in the tropical Pacific Ocean, we are seeing the typical pattern develop in the Atlantic for this time of year.  A low level circulation within an area of thunderstorms over the eastern Atlantic Ocean became better organized on Tuesday and the National Hurricane Center classified the system as Tropical Depression Four (TD4).  At 11:00 a.m. EDT on Tuesday the enter of Tropical Depression Four was located at latitude 10.6°N and longitude 36.5°W which put it about 1665 miles (2765 km) east of the Windward Islands.  TD4 was moving toward the west at 13 m.p.h. (20 km/h).  The maximum sustained wind speed was 35 m.p.. (55 km/h) and there were wind gusts to 45 m.p.h. (75 km/h).  The minimum surface pressure was 1009 mb.

TD4 is currently in an environment that is favorable for intensification.  The upper level winds are light and the thunderstorms are generating upper level divergence in all directions.  It is currently over water where the Sea Surface Temperature is near 28°C.  As long as TD4 moves westward, it will stay over warmer water and intensification will be likely.  If TD4 were to move more toward the northwest, then it would move over slightly cooler water and less intensification would occur.  Since TD4 is forecast to move west, it is expected to become Tropical Storm Danny, and it could be a hurricane later this week.

A subtropical ridge north of TD4 is steering it toward the west and that steering motion is expected to continue for the next 24 to 48 hours.  Later this week an upper level trough passing north of the ridge is expected to weaken the ridge, which could cause TD4 to move northwesterly for a day or so.  After the upper level trough moves off to the east, the subtropical ridge is forecast to steer TD4 back more toward the west.  On its anticipated track TD4 is expected to be east of the Windward Islands this weekend.