Bertha again began to quickly strengthen on July 9 as a new eye had formed and the system became more symmetrical. The NHC upgraded Bertha to a category two hurricane with winds of 105 mph (170 km/h) and stated that Bertha could strengthen further to a major hurricane again, but instead weakened into an 85 mph (135 km/h) category 1 hurricane. Bertha has become the longest-lived pre-August Atlantic tropical cyclone on record. On July 12, Bertha slowed in movement, and was close to becoming still and by July 13 this slow movement weakened the storm to tropical storm strength. On July 18, Bertha strengthened back to a hurricane as its forward motion increased. As it moved over cooler waters, it weakened a bit to a tropical storm late on July 19. It finally became extratropical on July 20 southwest of Iceland.