Nadine turned northward on September 14 as it tracked along the periphery of a subtropical ridge.[12] Shortly thereafter, a Tropical Rainfall Measuring Mission (TRMM) pass indicated that core convection began re-organizing. However, because wind shear displaced the mid-level circulation to the north of the low-level circulation, Nadine was not upgraded to a hurricane.[13] Because Nadine would approach colder sea surface temperatures, significant strengthening was considered unlikely.[13] Due to an increase in satellite intensity estimates and re-organization, Nadine was upgraded to a hurricane at 1800 UTC on September 14. Six hours later, Nadine reached an initial peak intensity with winds of 80 mph (130 km/h).[1] Satellite imagery indicated that a ragged eye feature was attempting to develop late on September 15.[14]