A mid- to upper-level trough slowed the storm almost to a halt early on August 23, before a drift to the north-northwest began. The next National Hurricane Center (NHC) advisory then reported that the eye was becoming more distinct and well-defined. This strengthening trend abated because the storm had churned up the waters over which it was passing, bringing cooler water to the surface as a result of the slow track. Another inhibiting factor may have been related to the same trough that caused the northward turn, though due to a large anticyclone situated over the hurricane, the weakening effects were not substantial. Despite wind shear, the large and powerful circulation resisted weakening for a time. Early on August 25, the shear and the entrainment of drier air into the hurricane took its toll on Bonnie, giving it a ragged appearance on satellite imagery, and the eye briefly became cloud-filled.