[3][4] On August 15 the system underwent more robust intensification, and a subsequent mission by the hurricane hunters found flight-level winds of 90 kn (100 mph; 170 km/h).

[nb 1] Reanalysis by the National Oceanic and Atmospheric Administration (NOAA) in 2012 determined that the cyclone, which was of limited extent at the time, passed between Guadeloupe and Dominica with winds of 65–70 mph (100–110 km/h);[6] contemporary observers then considered the storm an open wave, a "slight disturbance", as neither island reported winds higher than 35 mph (56 km/h), though the center of circulation was deemed to be quite small.

[7][8] On August 16, Tropical Storm Charlie, continuing to deepen, attained maximum sustained winds of 75 mph (120 km/h) by 06:00 UTC, becoming equivalent to a Category 1 hurricane on the current Saffir–Simpson scale.

Maintaining its north-of-due-west heading, the hurricane moved rapidly west-northwestward over the eastern Caribbean, while located about 180 miles (290 km) south-southwest of San Juan.

[9] The city of Kingston reported peak winds of 110 mph (180 km/h) as the center passed 8 mi (13 km) to the south, and the minimum central pressure in the eye was tentatively estimated to have been near 958 mb (28.3 inHg).

[2][7] The small hurricane weakened rapidly once inland, and some time after 06:00 UTC left Jamaica with winds of 85 mph (140 km/h), but quickly re-intensified over water.

[7] By 18:00 UTC on August 19, the cyclone regained major-hurricane intensity, and six hours later peaked with winds of 130 mph (215 km/h), equivalent to a low-end Category 4 hurricane.

[7] At 19:00 UTC, Charlie made landfall near Ciudad Madero, just north of Tampico, at the same intensity, equivalent to a low-end Category 3 hurricane.

[2] The city of Tampico entered the southern portion of the storm's eye, registering a minimum barometric pressure of 28.81 inHg (976 mb) and peak winds of 110 mph (180 km/h).

[11] On August 17, the Weather Bureau noted that the hurricane would affect Jamaica, though it was not expected to strengthen significantly; the agency also reported that the probabilities were equal for the cyclone to pass north or south of the island.

[14] The hurricane was also expected to re-strengthen prior to its second landfall in Mexico, though the Weather Bureau also noted that there was a chance for the storm to affect Texas.

[14] Although the possibility never materialized, the agency expected rain bands and rough seas to affect southern Texas, and small watercraft were urged to remain in ports until the hurricane moved inland.

[15] On August 21, the cyclone was expected to move ashore between Nautla and Tuxpan,[15] though it eventually made landfall further north near Tampico.

[15] In the Harlingen Valley region of southern Texas, precautionary measures were taken and Red Cross divisions organized a meeting at the local city hall.

[16] In Tampico, oil industries erected barriers to protect fields, and authorities planned to evacuate residents from the surrounding low-lying areas.

[17] The cyclone was compact when it moved through the Lesser Antilles, and the strongest winds on land in the eastern Caribbean islands did not reach gale force.

[7] In Jamaica, the hurricane produced heavy rainfall that peaked at 17 inches (430 mm) in Kingston,[18][7] which caused numerous landslides across eastern sections of the island.