The output from your vncmgr command includes a line in this format. (Each x is a number.)
ssh -l username -L xxxx:localhost4:xxxx casperxx.ucar.edu "bash .vnctunnel-default"
Follow these steps to copy and paste the necessary information from that command into the PuTTY interface for Windows.
bash .vnctunnel-default
Starting SSH tunnel to the VNC server... Now load VNC on your local computer and connect to: localhost:xxxx VNC will ask for a one-time password. Use the following: xxxxxxxx This terminal session will hang until the tunnel is killed. To kill the tunnel, simply type C-c/Control-C. Make sure you close VNC before you kill the tunnel!