Complex sentence: Continuing to track west-northwest beneath a large subtropical ridge, Kim began to clear out an eye on the evening of July 23; subsequently, Kim, as forecast by the JTWC, entered a period of rapid deepening.
Split into simpler sentences: Continuing to track west-northwest beneath a large subtropical ridge, Kim began to clear out an eye on the evening of July 23. Subsequently, Kim, as forecast by the JTWC, entered a period of rapid deepening.