What is the < WW > in the non geo-tagged storm report tweets?
The two sets of WWs are used to help a computer separate out the location sent in a storm report tweet, from the vital storm report. This location is then plotted on a map to help NWS forecasters determine the location of a storm report. The important part of the storm report tweet is the location, and that is in between the to sets of WW. Without the WWs your location will not be plotted on a map and thus not be useful to the NWS forecasters.