 On October 27 , an area of convection with a broad circulation persisted southeast of Guam , and slowly consolidated due to moderate wind shear and westerly outflow . That day , the Japan Meteorological Agency ( JMA ) classified the system as a tropical depression about 380 km ( 235 mi ) to the southeast of Hagåtña , Guam . At 2100 UTC on October 28 , the Philippine Atmospheric , Geophysical and Astronomical Services Administration ( PAGASA ) began issuing advisories on the depression , giving it the local name <unk> . The next day , the JMA upgraded the depression to Tropical Storm <unk> ( 1329 ) , and the Joint Typhoon Warning Center ( JTWC ) also classified it as Tropical Depression <unk> . By that time , the storm was moving steadily westward due to the subtropical ridge to the north . With the warm waters of the Philippine Sea , lessening wind shear , and improving outflow , <unk> gradually strengthened , and the JTWC also upgraded <unk> to tropical storm status on October 30 after an eye feature developed . 
