This weather glitch occurs after you have selected a choice between riding with Panam in the Van or meeting her at the wraith camp. The moment you make the choice, a very strange weather effect is triggered that turns everything bright white and then into a hazy gray fog that obscures your view of seeing far off into the distance (Like Nintendo 64 fog). This will occur regardless of what time of day it is and I have yet to find any way of keeping it from happening. This type of weather actually visually impairs the quest since the sand storm seen far off into the distance is no longer visible but the characters will still comment on it. This weather sticks around permenantely no matter where I go.