I doubt very seriously Matthew would drop below 900 mb. Katrina’s lowest was 902mb out in the Gulf and Camille made landfall at 906 mb.
That’s not to say this is not a very dangerous storm. And those refusing to evacuate would do well to remember the phone calls to 911and radio and news stations in South Mississippi where people were in their attics begging for someone to come get them. They played those calls on national news. One of them was a girl I went to nursing school with who lived in Ocean Springs and refused to evacuate. Her and her husband were SURE they were far enough inland. The sheriff’s dept even marked their door and told them they were doing it so they would know where to start looking for bodies after the storm, I think partially because they were trying to scare them into evacuating and because they also knew it was a serious possibility they would drown.
Her, her husband and children managed to survive by floating out of their attic to someone else’s. They left Mississippi all together after that.
If your told to evacuate, do it.
I remember sitting in a lifeguard tower at a Cape Canaveral beach in 2005 watching Ophelia just sort of drift up the coast. It was no Katrina or Matthew but it was massive and the eye was probably 70 miles from shore at the time.