While water vapor loops do help visualize where the highs and lows and wind patterns are, it is often what you can't see that has the greatest effect. First, the high pressure areas often have complex shapes that are invisible in the WV loops mostly because High Pressure areas are often dry and contain little moisture making them 'invisible'. Secondly, WV loops are based upon data on the amount of water in the upper atmosphere unlike the visible and IR images which tend to be visualizations of reflected energy from much lower levels of the atmosphere. As hurricanes are affected more by mid-levels of the atmosphere, the WV loops often do not predict the real movers of hurricane weather. It is just one more good tool for use in forecasting, but by itself, it doesn't tell the whole story.