Tropical Depression Thirtyone formed over the Caribbean Sea on Friday morning. At 10:00 a.m. EST on Friday the center of Tropical Depression Thirtyone was located at latitude 14.2°N and longitude 74.3°W which put it about 310 miles (500 km) south-southeast of Kingtson, Jamaica. The depression was moving toward the west-southwest at 7 m.p.h. (11 km/h). The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there were wind gusts to 45 m.p.h. (75 km/h). The minimum surface pressure was 1007 mb.

The circulation around an area of low pressure over the Caribbean Sea exhibited much better organization on visible satellite imagery on Friday morning and the National Hurricane Center designated the system as Tropical Depression Thirtyone. A band of thunderstorms wrapped about three quarters of the way around the center of circulation on the southern, eastern and northern sides of the center. Other bands of showers and thunderstorms were revolving around the center of the depression. Storms near the center generated upper level divergence which pumped mass away to the north and east of the depression.

Tropical Depression Thirtyone will move through an environment favorable for intensification during the weekend. The depression will move over water where the Sea Surface Temperature is near 29°C. An upper level trough over the western Caribbean Sea will produce southwesterly winds which blow toward the top of the depression during the next 12 hours. Those winds will cause vertical wind shear, but the shear may not be strong enough to prevent Tropical Depression Thirtyone from strengthening into a tropical storm. The upper level trough will move westward away from the depression and the wind shear will decrease during the weekend. Tropical Depression Thirtyone is likely to strengthen into a tropical storm during the next 12 hours. It could rapidly intensify into a hurricane on Saturday and it could strengthen to a major hurricane by Sunday.

Tropical Depression Thirtyone will move south of a high pressure system over the western Atlantic Ocean. The high will steer the depression toward the west during the next several days. On its anticipated track it could approach the coast of Nicaragua on Sunday. It will likely be a hurricane at that time and it could be a major hurricane. Nicaragua and Honduras are still trying to cope with floods and other damage caused by Hurricane Eta a few days ago. Another hurricane could have catastrophic consequences for that region.

Elsewhere over the Atlantic Ocean, Tropical Storm Theta Passed south of the Azores and Tropical Storm Eta completed a transition to an extratropical cyclone. At 10:00 a.m. EST on Friday the center of Tropical Storm Theta was located at latitude 31.7°N and longitude 23.8°W which put it about 470 miles (760 km) south-southeast of the Azores. Theta was moving toward the east at 12 m.p.h. (19 km/h). The maximum sustained wind speed was 60 m.p.h. (95 km/h) and there were wind gusts to 75 m.p.h. (120 km/h). The minimum surface pressure was 993 mb.