Prvi zadetek na Googlu(epsgram):
http://www.ecmwf.int/products/forecasts ... grams.html
Total precipitation in the 10-day EPSgram is accumulated precipitation (sum of convective and large-scale) over six-hour periods (00-06 UTC, 06-12 UTC, etc); accumulated over 24-hour periods (00-24 UTC) in the 15-day extended EPSgram. Probabilities for intervals longer than the 6- and 24-hour time intervals cannot be deduced from the EPSgram (except in dry weather, when all members repeatedly forecast no rain). Be aware that periods of probabilities >0% in every interval can give a visual impression of uninterrupted rain. Conversely, if one looks only at the median, one can sometimes get the false impression that protracted dry spells are likely. Because of its higher resolution, the deterministic model run is generally more able to generate more realistic precipitation amounts than the EPS and Control runs.
The y-axis range is chosen separately for each meteogram, so that at least 90% of the predicted values are covered; consequently, the y-axis range commonly varies in steps from one location to the next and, for the same location, from one forecast to the next. When the top of the distribution is beyond the scale maximum in the 10-day EPSgram, the largest 6-hourly totals are shown at the top as red numbers.