 On September 30 , a well @-@ developed tropical wave moved off the eastern coast of Africa and entered the Atlantic Ocean . Deep convection formed around a prominent mid @-@ level circulation as it moved towards the west . However , the convection diminished on October 2 before entering the Caribbean Sea a week later . Upon entering the Caribbean Sea , shower and thunderstorm activity redeveloped around the low . Continued development followed and the low was designated as Tropical Depression Fifteen at 0600 UTC on October 13 while located about 190 miles ( 305 kilometres ) south of the southeastern tip of the Dominican Republic . The previous steady westward motion that the system took across the Atlantic halted as it entered an area of weak steering currents and significant motion was not expected for another day or two . As the structure of the storm improved , it was upgraded to a tropical storm and the National Hurricane Center ( NHC ) gave it the name Omar . 
