Big weather events become news events, and there is a transition period. Monday afternoon, during the approach of hurricane Sandy I watched one of the New York stations for about an hour and a half and then another station for an hour. This was mid-afternoon as the storm surge was beginning and any number of reporters were being soaked and blown about. Interestingly, I only saw a meteorologist one time on only one of the stations.
The point, as made before, is that as the news event grows, and station assets are moved into place, there is likely still a weather event going on and viewers east (in this odd case, west) of the live trucks still need to have you tell them what they can expect next.