Original estimates indicated that Katrina had made this landfall as a Category 4 hurricane, with winds; however, as indicated above, the storm weakened just before landfall to Category 3 intensity. The reasons for this weakening are not completely understood; while the eye-wall replacement cycle played a part, slightly increasing shear, dropping sea-surface temperatures, dry air on the western semicircle of the storm, and interaction with the continental landmass also may have played a role in weakening the cyclone. This follows the trend of previous strong cyclones in the Gulf of Mexico: most cyclones with minimum central pressures of or less have weakened over the 12 hours before making landfall in the Gulf Coast of the United States.