First, It is nearly useless for the command prompt to pop up during  the running time of subprocess.Popen with shell=False.
Second, the popping up command prompt would interrupt users and do bad to user experience of GUI applications.
Third, I found QProcess within Qt won't pop up the command prompt  in using.

It would be convenient to add an argument to suppress the command prompt from popping up when using subprocess.Popen with shell=False on Windows, many users are missing the feature and these are many similar feature request questions like the following 
http://stackoverflow.com/questions/7006238/how-do-i-hide-the-console-when-i-use-os-system-or-subprocess-call
http://stackoverflow.com/questions/1765078/how-to-avoid-console-window-with-pyw-file-containing-os-system-call/12964900#12964900
http://stackoverflow.com/questions/1016384/cross-platform-subprocess-with-hidden-window