 Tropical Storm Ivan gradually became better organized as wind shear decreased , and its outflow expanded in all quadrants . Satellite imagery late on September 3 depicted a well @-@ defined curved band wrapping around much of the circulation . The next day , the deep convection temporarily became ill @-@ defined , before reorganizing and developing an eye feature . Convection strengthened further as the feature transitioned into an eye , and Ivan became a hurricane at around 0600 UTC on September 5 . After reaching hurricane status , Ivan began to rapidly intensify with continued favorable conditions , and in an 18 ‑ hour period the pressure dropped 39 mbar ( 1 @.@ 15 inHg ) as the winds increased by 60 mph ( 95 km / h ) ; early on September 6 Ivan attained an initial peak intensity of 135 mph ( 215 km / h ) while located about 825 miles ( 1330 km ) east of the island of Tobago in the southern Lesser Antilles . 
