 The storm revolved around an upper-level low over the eastern United States, and also to the southwest of a ridge over Atlantic Canada that the NHC described as "highly anomalous"; this caused Sandy to turn to the north and northwest.Maintaining an eye and deep convection, the hurricane intensified, reaching a secondary peak of 100 mph (160 km/h) by 1200 UTC on October 29; at this time, the cyclone was moving over a small area of the Gulf Stream with waters in excess of .Around that time, Sandy had a wind field of over 1,150 mi (1,850 km) in diameter.