# Computation of absolute precipitation forecast from precipitation anomaly forecast in NOAA CFSv2

I am currently trying to use absolute precipitation forecasts for medium term range (3wk-2mth). As no models of NOAA have absolute precipitation on this timerange, my idea was to compute those forecasts by adding the forecasted anomaly to the long term average. However, I was not able to find the long term average.

1. Is this approach right?
2. Where can I find a grib or DODS resource with the long term averages?