The essence of it is that, after the little window of decent weather that was exploited for the invasion, air operations in support of ground troops were impossible for the entire month that followed. We had been depending upon air power to offset the threat of German armor. What saved our bacon is that Hitler and some of his staff bought the ruse of a Calais offensive that never came, bought it so thoroughly that they froze a large Panzer force and other reserves through that whole month of vulnerability and beyond.
Operation Cobra commenced just as the weather relented. As that got rolling, Patton took command of the Third Army. Things changed dramatically. The beachhead became a broad Western Front as the Third Reich unraveled.