Tropical Storm Carlotta formed as the result of a breakdown in the Intertropical Convergence Zone to the south of Mexico. A tropical wave that traversed Central America around June 11 may have contributed to the storm's formation as well.[1] On June 12, the Miami-based National Hurricane Center (NHC) reported that a broad area of low pressure had formed several hundred miles south of southeastern Mexico.[2] The NHC continued to monitor the disturbance over the next two days as it drifted northward.[3] Initially, strong upper-level winds prevented development,[2] but the system increased in organization unexpectedly on June 14.[4] Following further structural improvements, the NHC upgraded the system to tropical depression status at 18:00 UTC while it was located about 140 mi (220 km) south of Acapulco.[1] Around that time, the NHC forecast that a mid-level ridge over Mexico would weaken the following day, and would leave the depression in an area of light steering currents.[5] Despite being located in a favorable environment with low to moderate wind shear and sea surface temperatures exceeding 86 °F (30 °C),[6] the depression experienced minimal change in intensity over the next 18 hours. After the system's center reformed farther north, the NHC amended its intensity forecast to indicate reduced strengthening, citing the fact that the system would spend less time over water.[7] Around 18:00 UTC on June 15, the system strengthened into a tropical storm, after which it was assigned the name Carlotta.