 The origins of Typhoon Etau were from an area of convection that persisted along the west side of a weak circulation near Chuuk State on July 31 . With initially moderate but steadily decreasing wind shear , the system was able to organize as it moved generally westward . On August 2 , the Joint Typhoon Warning Center ( JTWC ) initiated advisories on Tropical Depression 11W . That day , another circulation was developing on the western side of the system , briefly classified by the Taiwan Central Weather Bureau as a tropical depression . The eastern circulation became dominant with pronounced outflow to the south , although it was initially broad and elongated . Later on August 2 , the Japan Meteorological Agency ( JMA ) classified the system as a tropical depression to the northeast of Yap . 
