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.
About Allegheny Power: Serving about 29,000 square miles and about 1.4 million customers in parts of Maryland, Ohio, Pennsylvania, Virginia and West Virginia. (see website)