Data - Monthly Rainfall of a region for the past 20 years.
Objective - To Forecast for the next 2 years.
In the collected data, 10 out of 13 values for January are 0s and the other three are (1.9, 0.9, 0.2). When done forecasting for the next 2 years, The values obtained for January are negative (i.e. -1.66, -0.49). Since I am dealing with Rainfall data is there a way to get the forecasting values for January to be 0 or positive.