Display problems with U2711 monitor

Hi,

I have a U2711 ultra sharp monitor that has recently been having problems.  Occasionally the left half of the screen gets lots of tiny horizontal lines. They flicker for about 10 seconds then go away. It happens every few minutes, especially when I first turn the monitor on.  I live in Hawaii so I thought it might be the humidity?  Any ideas about the cause or ways to troubleshoot or fix this?  

Thanks!