A vigorous upper-level low developed west of Alberto on August 7 and August 8. This caused an increase in vertical shear, weakening the hurricane down to a tropical storm on August 9. The low also caused the storm to turn to the northwest. However, on August 10, Alberto became better organised and was upgraded to hurricane status again. It then moved in a gradual curve towards the north and northeast through a break in a subtropical ridge between August 11 and August 12. Alberto made its closest approach to Bermuda on August 11, passing about 345 mi (555 km) east of the island. The strong storm became a Category 3 major hurricane on August 12 and reached its second and highest peak intensity of 125 mph (205 km/h), and a 60 mi (95 km) wide eye was observed. Alberto was an unusual storm in that it reached its peak intensity at a high latitude, north of 35˚N, after it had re-curved. The hurricane began to weaken due to increasing upper-level westerlies on August 13 and August 14, while moving east-northeastward. Alberto was downgraded to a tropical storm on August 14.