* copy this directory to your home directory.
(cd ..; tar -cvf $HOME/ports.tar ports; cd $HOME; tar -xvf ports.tar; rm ports.tar)

* sudo vi /opt/local/etc/macports/sources.conf, add the line
file:///Users/<myusername>/ports
  just *before* the line
rsync://rsync.macports.org/release/ports [default]

* cd /Users/<myusername>/ports; sudo portindex

* sudo port install py27-netcdf4
This will install netcdf4-python from svn HEAD. To periodically upgrade, just do
   - sudo port uninstall py-netcdf4
   - sudo port install py-netcdf4 (this will re-download and rebuild)