There is another similar thread going tonight where people are posting advice to those worried a out flooding. The thread is called something like 'help I'm scared my house is going to flood' lots of people have said some very sensible things, for what it's worth my two pennies worth is as follows....
I would start to move anything of monetary or sentimental value upstairs tonight, it's a pita but it would be one less thing to do in a hurry. Also find something large and heavy (logs are ideal) and move them inside to use to prop up large pieces of furniture on. We flooded over a metre the first time but the last couple of times something like this would have been a life saver! It may also sound obvious but organise child or pet care 'just in case' for tomorrow (again its one less thing to worry about.)
Also have bottles of water a bag packed in case you have to get out quickly and make sure all documents are somewhere safe.
It is also worthwhile checking your insurance policies, e.g. Who would pay for temp accommodation if you had to move out for a while etc.
One of the low points we had was trying to find somewhere else to live. Holiday houses are best as they are fully equipped (we lost all kitchen equipment, sofas, washing machines etc) we lost Internet access due to our flooding so trying to find somewhere was awful. Maybe having a list to hand compiled before would help?