This paper demonstrates an approach to develop a prediction based model for forecasting Boro rice areas in the haor region of Bangladesh. Forecasting the rice areas can contribute in creating a centralized monitoring system for planning effi-cient storage and proper utilization methods. This leads to the development of proposing a new vegetation index (VI). The approach considers a new vegetation index combining NDVI (Normalized Difference Vegetation Index), EVI2 (Enhanced Vegetation Index 2) and OSAVI (Optimized Soil-Adjusted Vegetation Index) for latest version MODIS (version-6) data. The method will forecast total Boro rice areas at the beginning of the Boro season (Dec-Jan) which is more than 3 months earlier from harvesting time without using any ground truth data. 3 Dimensional plotting method and k-Nearest Neighbor classifier have been used on only sowing period (Dec-Jan) data to predict Boro rice pixels. Our new VI has achieved an accuracy of 72%, recall 0.7020, precision 0.4183 and F1 score 0.5175.