A broad area of low pressure resulted from the consolidation of the two waves on August 1, when it was situated about 750 mi (1,210 km) west-southwest of the Cape Verde Islands.

Over the course of the next 24 hours, shower and thunderstorm activity became increasingly consolidated with the low, but the system lacked a well-defined circulation to be considered a tropical cyclone at the time.

Thunderstorm activity became increasingly well defined, and it is estimated that the depression became Tropical Storm Colin at 0600 UTC on August 3 while centered 840 mi (1,350 km) east of the Lesser Antilles.

[1] As the remnants passed north of the northern Leeward Islands, a reconnaissance aircraft investigated the system on August 4, but no closed circulation was found.

A combination of microwave and satellite imagery during the morning hours of August 5 revealed the reformation of a closed low, and Colin's remnants regained tropical storm status at this time while located 280 mi (450 km) north-northeast of San Juan, Puerto Rico.

[1] Despite relatively unfavorable vertical wind shear impacting Colin, deep thunderstorm activity developed atop its center of circulation.

Data from a reconnaissance aircraft during the afternoon hours of August 5 revealed that the system reached a peak intensity with winds of 60 mph (97 km/h) and a minimum barometric pressure of 1,005 mbar (29.7 inHg).

Further weakening occurred over the next few hours as the cyclone's center of circulation became elongated, and Colin once again degenerated into a trough of low pressure at 1200 UTC while located approximately 100 mi (160 km) southwest of Bermuda.

[4] These values were later decreased after Colin weakened on August 6, with only a minimal storm surge forecast and rainfall roughly 1 in (25 mm) less than previously stated.