Carlotta, the third named storm of the 2018 Pacific hurricane season, formed as the result of a breakdown in the Intertropical Convergence Zone.

Early on June 17, Carlotta reached peak intensity with maximum sustained winds of 65 mph (100 km/h) and a minimum central pressure of 997 mbar (29.44 inHg) while located only 30 mi (50 km) south-southeast of Acapulco.

The system then began to interact with land and experience wind shear, which resulted in the storm weakening to tropical depression status later in the day.

[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.

[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.

[10] Over the next twelve hours, Carlotta experienced little change in organization before peaking at 00:00 UTC on June 17, with maximum sustained winds of 65 mph (100 km/h) and a minimum central pressure of 997 mbar (29.44 inHg) while located only 30 mi (50 km) south-southeast of Acapulco.

[11] As the system started tracking towards the northwest, Carlotta began to weaken because of increasing interaction with land and northerly wind shear.

[14] The system's remnants dissipated around 06:00 UTC while located offshore of the Mexican coast between Manzanillo and Zihuatanejo, having never made landfall as a tropical cyclone.

[18] On June 17 at 03:00 UTC, the warning was extended westward from Acapulco to Tecpan de Galeana and cancelled to the east of Punta Maldonado.

[21] Tropical Storm Carlotta caused flooding in southern Mexico, with the states of Aguascalientes, Guerrero, Michoacán, Oaxaca, and Puebla, being affected, as well as the Yucatán Peninsula.

In the Yucatán Peninsula, Carlotta, a tropical wave, and another low-pressure system dropped 70–400 mm (3–20 in) of rain, causing severe flooding.

In the Costa Chica region, the storm damaged several palapas on a beach and the fishing equipment of at least 80 families, preventing them from working.