Complex sentence: The remnant low of Cosme continued westwards for the next couple of days before degenerating into a surface trough on July 1, which was absorbed by an upper level cyclone the following day.
Split into simpler sentences: The remnant low of Cosme continued westwards for the next couple of days before opening up into a surface trough on July 1. The trough was absorbed by an upper level cyclone the following day.