 A persistent area of thunderstorm activity southwest of Puerto Vallarta became better organized and strengthened into Tropical Depression Twelve @-@ E on August 16 . Moving northwest , the system developed slowly as it was embedded within the Intertropical Convergence Zone . <unk> shear kept the system from reaching tropical storm strength and caused its ultimate <unk> on August 19 . No damages or fatalities were caused by this depression . 
