Simplify the following text for a Grade 11 native English-speaking person.
Original: The convection gradually consolidated over the system , and by late on the 1st Chris reached winds of 60 mph ( 95 km\/h ) while passing 50 miles ( 80 km ) north of the northern Leeward Islands .
Simplified: The convection slowly covered the entire system , and by late on the 1st Chris reached winds of 60 mph ( 95 km\/h ) while passing 50 miles ( 80 km ) north of the northern Leeward Islands .