Isaac remained a Category 1 hurricane for almost 24 hours, at which time the storm began to accelerate east-northeastward. Early on October 1, the National Hurricane Center noted that minimal deep convection persisted near the center and much of it was displaced to the north. Mid-level dry air and low-level cold air began entering the western quadrant of the storm, which caused it to begin its extratropical transition. By 0600 UTC on October 1, Isaac weakened to a tropical storm. The National Hurricane Center noted that further weakening would be slow, due to the large wind field associated with the storm. At 1500 UTC on October 1, the National Hurricane Center issued its final advisory on the storm; Isaac fully transitioned into an extratropical cyclone about three hours later, while located about halfway between Newfoundland and the Azores. The extratropical remnants rapidly tracked east-northeastward and affected the British Isles on October 3 and October 4, eventually merging with another extratropical low while north of Scotland early on October 4. Late on September 22 and early on September 23, the National Hurricane Center noted that due to several computer forecast models indicating a westward track, impact in the Lesser Antilles was possible, though unlikely. However, Isaac continued its west-northwestward path and passed more than northeast of the Lesser Antilles. While Isaac made its closest approach to Bermuda on September 29, it produced high waves offshore the island. Although Isaac had stayed away from the eastern coast of the United States, swells from the storm caused a boat with four passengers to overturn on September 30. One of the passengers died from drowning. The state of North Carolina issued a heavy surf warning on October 1, as swells from Isaac were predicted. Along the Grand Strand in South Carolina, rough surf and minor coastal flooding was reported. As an extratropical system, Isaac produced winds near gale-force on the British Isles during the day of October 3. After Isaac passed the British Isles, a bird called the blue-winged warbler was seen in Europe for the first time.