However , that was not for too long as vigorous convection persisted over the well defined LLCC with tightly curved banding wrapped in , Sonca continued to strengthen gradually and the JTWC reported winds of at least near the center .
However , that was not for too long as vigorous convection persisted over the well defined LLCC with tightly curved banding wrapped in , Sonca continued to strengthen gradually and the JTWC reported winds of at-least 50 kn near the center .