I am looking for a daily forecast of sea level pressure and/or geopotential height at 500 hPa (over Europe and North Atlantic at least). I need medium-term forecasts, that is from t0 to 30 (or 45 days) from an initialization. This initialization would be done for each day. I found many sources on the web, but it was for real-time forecasts and I need retrospective data (ideally from 1980s, and not only maps). Any precise URL to find such data in CFSv2 and/or ECMWF model (or any other model) will be useful.
The resource I can think of that is closest to what you need is GEFS reforecast project: http://www.esrl.noaa.gov/psd/forecasts/reforecast2/
Although I believe that the forecasts are not as long as what you would like.
Try with http://nomad3.ncep.noaa.gov/ncep_data/index.html
you can get grib(or png) files with a lot of fields
cheers
daily CFSv2 is available at NCDC
we are serving the monthly at
http://iridl.ldeo.columbia.edu/SOURCES/.NOAA/.NCEP/.EMC/.CFSv2/
including an on-going copy of the rotating archive -- we are also gathering some of the daily but have not yet put it out as a public dataset.