Upper panel of the plot shows population-weighted high and low temperature for each day (note: day-1 has high temperature only). Lower panel shows the forecast electricity demand for the service area of the company, in percentage of the normal demand expected under normal weather conditions during this 7-day period.
as observed at Chapel Hill, Williams Airport
About Piedmont EMC (NC): Serving 29,000 members in parts of Alamance, Caswell, Durham, Granville, Orange and Person counties in north central North Carolina. (see website)