 In late April 2002 , an area of convection , or thunderstorms , persisted to the west @-@ southwest of Diego Garcia in the south @-@ central Indian Ocean , associated with a trough near the equator . The system had a broad circulation , and initially moved slowly to the east @-@ southeast . It developed due to an increase in the Madden – Julian oscillation ( MJO ) , which moved eastward across the Indian Ocean . The same system spawned a disturbance in the northern Indian Ocean that later struck Oman as a tropical cyclone . Such simultaneous systems in opposite hemispheres occasionally occur in the spring or autumn ; in May 2002 , the powerful MJO pulse produced two such sets of storms , later producing a set in the eastern Indian Ocean that became a deep depression that struck Myanmar and Tropical Storm Errol to the southwest of Indonesia . On April 30 , Météo @-@ France ( MFR ) classified the system as a zone of disturbed weather . It slowly organized , prompting the Joint Typhoon Warning Center ( JTWC ) to issue a tropical cyclone formation alert late on May 2 , around the time that MFR classified it as Tropical Disturbance 14 . The thunderstorms became more concentrated around an increasingly well @-@ defined center , and with minimal wind shear , the system strengthened into Tropical Depression 14 on May 3 . That day , the JTWC initiated advisories on Tropical Cyclone 23S . 
