Tropical Storm Ivan slowly became more organized as wind shear decreased, and its outflow expanded in all quadrants. Satellite imagery late on September 3 showed a well-defined curved band wrapping around much of the circulation. The next day, the deep convection temporarily became disorganzied, 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 reached its first peak intensity of 135 mph (215 km/h) while about 825 miles (1330 km) east of the island of Tobago in the southern Lesser Antilles.