I noticed for the genPredictors function, some of the inputs to the short term forecasting model is prevDaySameHourLoad and prev24HrAveLoad. It seems that the prev24HrAveLoad uses the current day load and averages it on a 24 hour basis and the prevDaySameHourLoad uses the load from the previous day. I m not sure how these 2 inputs can be used to predict the next day load forecast for the ANN model. For example if today is Sunday and I want to predict the load for tomorrow (Monday) and I m running the load forecast application today at 1 PM, I can't use prevDaySameHourLoad as an input because Sunday is the previous day for the forecasted day Monday and I wouldn't have the 24 hour historical data for Sunday as I m running the program at 1PM on Sunday, so data from 1 PM up to midnight is unknown. Second the prev24HrAveLoad input depends on the actual load data for that day, which for this example would be the load data that I m forecasting for the next day (Monday). I m not sure how these 2 inputs can be used to predict the day ahead load if it requires historical data that you might not have yet.