A tropical wave over the Atlantic Ocean west of Africa was being watched for development on Monday afternoon. The tropical wave was designated as Invest 97L on Monday. At 2:00 p.m. EDT on Monday the center of the tropical wave was located at latitude 11.7°N and longitude 22.7°W which put it about 230 miles (350 km) south of the Cabo Verde Islands. The tropical wave was moving toward the west at 19 m.p.h. (30 km/h). The maximum sustained wind speed was 30 m.p.h. (50 km/h) and there were wind gusts to 40 m.p.h. (65 km/h). The minimum surface pressure was 1010 mb.
A tropical wave that moved over the Atlantic Ocean west of Africa during the weekend was being monitored for possible development of a tropical depression on Monday afternoon. The tropical wave exhibited a typical structure. There was no center of circulation evident in the lower levels of the atmosphere. There were linear bands of showers and thunderstorms that were moving with the tropical wave. Thunderstorms near the axis of the wave were generating upper level divergence that pumped mass away from the tropical wave.
The tropical wave will move through an environment favorable for the development of a tropical depression during the next several days. The tropical wave will move over water where the Sea Surface Temperatures are near 27˚C. It will move under the axis of an upper level ridge that extends from the west coast of Africa to the Caribbean Sea. The upper level winds are weak near the axis of the ridge. The tropical wave will move along the southern side of a subtropical pressure system over the Atlantic Ocean. The subtropical high is producing strong easterly winds in the lower level of the atmosphere. The strong low level winds may cause vertical wind shear in the lower levels of the atmosphere, which could inhibit the formation of a tropical depression. The National Hurricane Center is indicating that there is a probability of 40% of the formation of a tropical depression during the next five days.
The subtropical high pressure system will steer the tropical wave quickly toward the west-northwest during the next few days. On its anticipated track the tropical wave could approach the northern Leeward Islands in a few days. It could be a tropical depression or tropical storm by that time.
