While at major hurricane status, Ivan kept very strong convection in its core with a well-defined eye. Operationally, the probability for further rapid strengthening was considered nearly nine times the average of a normal hurricane. Accordingly, Ivan was forecasted to pass near Barbados with winds of about 150 mph (240 km/h). Shortly after becoming a Category 4 hurricane, the outer convection of the hurricane became ragged. Hurricane Hunters found a Saharan Air Layer in the northern portion of the eye, leaving the eyewall eroded which caused a marked decrease in winds; by late on September 6 Ivan weakened to winds of 105 mph (165 km/h). The inner eyewall died out as a 23 mile (37 km) outer eyewall became took over, and at the same time, the overall organization of the hurricane improved. Ivan then re-gained major hurricane status as it approached the Lesser Antilles, and at 2130 UTC on September 7 the cyclone passed 7 miles (11 km) south-southwest of the southern tip of Grenada, its closest approach to the island. At the time, the hurricane maintained an eye diameter of 12 miles (19 km), with the northern portion of the eyewall producing strong winds on the island.