sentences:  Shortly thereafter, a large, yet weak low-level circulation formed within the system.The system drifted erratically for several days as it slowly organized; the system underwent several cycles of developing and losing convection.On April 11, the system maintained a persistent area of well-organized deep convection, and subsequent to an increase in upper-level outflow, the Joint Typhoon Warning Center (JTWC) classified the system as Tropical Depression 02W at 1800 UTC on April 11.