Disturbance Becomes Depression in Eastern Atlantic as Expected

After coming off the African coast on Saturday, and growing under the warmth of the summer sun and over the warm waters of the Eastern Atlantic, the tropical disturbance, Invest 90L, became the seventh tropical depression of the season as expected late Monday afternoon. The question is how strong will TD #7 become and whether or not it will be a threat to the islands and the United States.

As of the 5:00 PM EDT advisory on Monday afternoon from the National Hurricane Center, Tropical Depression Seven is located about 360 miles to the West-Southwest of the Southernmost Cabo Verde Islands just off the West African coast. Based upon satellite imagery, maximum sustained winds in TD #7 are estimated to be at 35 miles per hour with gusts up to 45 mph.

Minimum central pressure in the center of circulation for Tropical Depression Seven, is estimated at 1006 millibars, or 29.71 inches of Hg. Strengthening is expected to continue over the next 48 hours, and TD #7 could be upgraded to a tropical storm as early as later on Monday night. The depression is moving to the West at 18 miles per hour. The tropical system is currently no threat to land, and there are no watches and warnings in effect.

Looking at the forecast discussion on the depression from the NHC, the intensity is expected to gradually ramp up over the next 72 hours. By this time tomorrow, the depression is expected to be a fairly strong tropical storm with 60 mph winds. Within 48 hours, the system is forecast to become the season’s third hurricane. Three days from now, the depression is expected to peak with 90 mph winds.

Tropical Depression Seven is in a very healthy environment. Upper level winds are light to moderate out of the east. Sea surface temperatures are also conducive for development. The only factor that could hinder development is dust and dry air that is lurking to the west of the system, and according to the NHC’s discussion, is wrapping into the western flank of the system.

The forecast track has Tropical Depression Seven moving to the West-Northwest over the next 36 to 48 hours. This general motion is anticipated because the depression is currently moving underneath a ridge of high pressure in the Eastern Atlantic. However, beyond that point, the system is expected to take a turn to the north as it finds a weakness in that subtropical ridge.