With warm water temperatures, the system strengthened and began to develop tropical characteristics. Subsequent to the development of banding features, convection contracted and deepened over the increasingly well-defined center, and is estimated it became a tropical storm by early on September 2, while located about 685 miles (1,100 km) north of the Hawaiian island of Kauai. The storm quickly developed a central dense overcast, and by 00:00 UTC on September 3 Dvorak classifications began on the cyclone. With water temperatures of over 82 °F (28 °C), it strengthened rapidly as an approaching cold front caused it to accelerate to the northeast. An eye became apparent on satellite imagery, and the storm intensified into a hurricane at 18:00 UTC on September 3, while located about 1,170 miles (1,885 km) south of Aniakchak National Monument and Preserve in Alaska. Upon becoming a hurricane, the cyclone was small, measuring about 85 miles (140 km) in diameter.