 On June 12 , a tropical disturbance developed off the west coast of Costa Rica , moved westward and entered the eastern Pacific after crossing Panama . The system became better organized as it tracked to the west @-@ northwest as a westerly Kelvin wave provided favorable conditions for development . Convection increased around a developing low pressure area , and the National Hurricane Center ( NHC ) estimated a 50 % chance of tropical cyclogenesis by late on June 12 . After further organization , the NHC initiated advisories on Tropical Depression Three @-@ E at 0300 UTC on June 14 , while the system was located about 515 mi ( 830 km ) south @-@ southeast of Puerto Ángel , Oaxaca . At the time , the depression was located in an area of low wind shear and warm sea surface temperature conditions that were considered favorable for intensification . In addition , it had a small circulation , which increased the possibility for rapid deepening . The system moved northwestward after forming due to an extended ridge to the northeast . About six hours after forming , the depression intensified into Tropical Storm Carlotta , after rainbands increased around the center . 
