In Cigré 2004 was presented the paper SIPREóLICO -HOURLY WIND POWER PREDICTION TOOLS FOR THE PENSILULAR SPANISH SYSTEM the model developed by REE and Carlos III University to forecast wind power production for the following 48 hours to facilitate the system operation and minimize the impact of a high penetration. In that paper in 2004 some improvements were proposed and have already been developed in 2005-2007; the objective of this paper is to describe them from the experience of the operation and the improvements achieved. Meteorological forecasts, using numerical predictions models, of the variables wind speed and direction are of key importance for Sipreólico. In April 2007 Sipreólico is using predictions from Hirlam model H0.16 (resolution 0.16 degrees) supplied by the Spanish National Meteorological Service-models H0.2 and H0.5, with worse resolution, were used until 2006-and also forecast from the European Centre for Medium Term Weather Forecasts (ECMWF) with resolution of 0.5. Some other models are being evaluated at the same time. The combination of wind forecasts from different agencies is done in two steps. In the first step two alternative methods based in different characteristics are used. In the second step the final combination is obtained from the two alternatives of step one. The second step is a combination of the results of first step but using factors between 0 and 1 in relation with the errors of the models. Apart from the combination of different wind forecasts, since 2006 Sipreólico has integrated 2 models that predict the total wind power production of the system; this prediction is based in different techniques and the integration is done in a new combination module. In January 2008 around 92% of the wind power installed in the system is telemetered. The initial development of Sipreólico used hourly mean values of the wind power production to make a forecast each hour, but is not enough for the moments where there are fast variations of the production; it has been modified in order to use mean values of 15 minutes and to be able to calculate 4 times each hour. Since 2006 Sipreólico is calculating using meteorological ensembles so the forecasts are calculated with different probability of occurrence depending of the different meteorological scenarios for the following 48 hours. These results are used to establish the power reserve needed in the system for different horizons. Sipreólico forecasts are calculated for individual wind farms and then aggregated depending on how they are used: nodes, areas, distribution companies, the whole system, etc. REE has developed different applications for congestion analysis in different horizons that use wind power forecasts in the network nodes and let analyze the hourly scenarios automatically. Sipreólico is installed and running since 2005 in REE in the canary system, where the impact of the wind power production in the system makes necessary to have a wind power prediction tool as accurate as possible.