How can I move all directories below a certain size?

I want to move all directories in the current directory that are below a certain size Here, I've managed to do a selection:

for dir in *
do
    if [[ $(du -s "$dir" | awk '{print $1}') -le 50000 ]]
    then
      ls -l "$dir"
    fi
done

I now figured I should use dirname to get the directory, but somehow it complains no matter what I do;) Do we have a neat way to do this?;)