Under favorable conditions , Felix began Process_start to rapidly deepen Cause_change_of_strength while curving Motion_directional northwestward .

Shortly thereafter , Keith began Process_start to rapidly deepen Cause_change_of_strength , and peaked Cause_change_of_position_on_a_scale as a Category 4 hurricane Catastrophe less than 24 hours later .

although a large , sprawling Expansion system , near-record high sea surface temperatures enabled Preventing_or_letting rusty to quickly deepen Cause_change_of_strength .

Around that time , the storm turned Becoming back to the west-northwest and continued to deepen Cause_change_of_strength .

For almost a century thereafter , conservatives and liberals fought Hostile_encounter to reverse or to deepen the social and political changes Change unleashed by those rebellions Change_of_leadership .

Thereafter , it curved Motion_directional northwestward and continued to deepen Cause_change_of_strength .

After passing Motion_directional near Guam , Irma continued to deepen Cause_change_of_strength , and was estimated to have attained Getting typhoon intensity early on November 21 .