A real-time regional forecasting system for the Eastern Indian Ocean (EIO),called the Experimental Platform of Marine Environment Forecasting for EIO (EPMEF_EIO),is introduced in this paper.EPMEF_EIO consists of a regional atmosphere model and a regional storm surge model,and performs a real-time run four times a day.Output from the Global Forecast System (GFS) from the National Centers for Environmental Prediction (NCEP) is used as the initial and boundary conditions of two nested domains of the atmosphere model,which can exert a constraint on the development of small-and meso-scale atmospheric perturbations through dynamical downscaling.Then the system outputs the 3 day forecast of 72 km,24 km,8 km for Indian Ocean-EIO-Sri Lanka.The forecasted winds at 10 m height from the atmosphere model are used to drive the storm surge model,obtaining the 1/12°-1/36° results for EIO-Sri Lanka.By comparing observation data from the Sri Lanka Station Meteorological Tower of the South China Sea Institute of Oceanology,Chinese Academy of Sciences,TC best track data,and data from the Colombo tide gauge station,it is found that the daily variations of the model forecasted temperature and relative humidity are smaller than the observations;the overall root mean square error (RMSE) of the air temperature is 1.26℃,and the coefficient is 0.8;the overall RMSE of relative humidity is 7.0,and the correlation coefficient is 0.7.The model forecasted wind speed is mostly larger than the observation,with an overall RMSE of 2.3 m/s and a correlation coefficient of 0.65.The forecasted wind direction of the model can grasp the main trend of variation,with an overall RMSE of between 20°-32° and a correlation coefficient of about 0.65.The average error of model track forecast is 110.5 km,166.4 km,and 181.0 km at 24 hour,48 hour,and 72 hour,respectively.In addition,the overall RMSE of the model water level forecast is 0.035 m,accounting for about 5% of the maximum amplitude,and the correlation coefficient with the observation reaches 0.996.This shows that the model has the ability to simultaneously forecast tidal and storm surge processes.EPMEF_EIO,established primarily for research purposes with the potential to be implemented into operations,provides valuable information to the operational forecasters of local marine/meteorological agencies or international TC forecast centers.