High Quality Content by WIKIPEDIA articles! Prognostic charts are maps which display what the weather is expected to be like at a future time; in other words, a forecast map. Within the United States, manual prognostic charts generated by the National Centers for Environmental Prediction have special symbols which require interpretation. Those generated by atmospheric models as output from numerical weather prediction can have a variety of information on them, such as temperature, wind, precipitation, automated weather fronts, or derived atmospheric fields such as vorticity, stability indices, or frontogenesis. Errors with prognostic charts can be determined either via absolute error, or by considering persistence and absolute error combined.