The tropical storm, now named Frances, further intensified on August 26 in an environment of low vertical wind shear as its track bent to the west-northwest. Frances rapidly intensified, developing an eye and reaching hurricane strength late that afternoon. An approaching upper-level trough caused Frances to move more northwesterly on August 27. The cyclone reached its primary peak intensity of on August 28. The hurricane turned back to its original westward motion on August 29, as the upper trough moved away the region and the subtropical ridge strengthened to Frances's north.