The observed values here at SEC are initially the preliminary values which are replaced with the final values as they become available. We refer folks to the NGDC site for final values. We advise our customers about this on the top of our Recent Solar Indices at http://www.sec.noaa.gov/ftpdir/weekly/RecentIndices.txt. Official data archive is more in their charter vs. our real-time/near real-time operational responsibilities. That being said, the older values (four months ago and earlier) should match in both locations. We appreciate a heads-up on any discrepancies. The prediction issue is more confusing. There are several methods to predict sunspots, many of them available on the web. Certain people like one method over another; consequently, it is impossible to agree on a "one for all" method. The sunspot prediction here in the Space Environment Center is officially sanctioned by the International Space Environment Service (ISES). The ISES, with representatives from several different countries, is a permanent service of the Federations of Astronomical and Geophysical Data Analysis Services. It would be considered the "official" forecast. But some will argue that it is not the best and opt for a different method. This ISES Cycle 23 forecast was the outcome of an international meeting held in Boulder in September, 1996. An international panel of 12 scientists met to consider a number of predictions (including the McNish-Lincoln method) of the profile and amplitude of Cycle 23. Precursor techniques which use cycle behavior in the declining phase of the previous cycle as a predictor of the next cycle were a big consideration. The predicted Cycle 23 minimum and maximum were established and graphed by a curve fit which smoothes between the most recent observed values and the remaining forecast values. There have been a few revisions, mostly because the cycle maximum prediction of 160 was considerably off. But the prediction for a March 2000 maximum date was very good so the overall curve did not change much. We'll be working with the ISES community again sometime in the next 10 months for another update. The National Geophysical Data Center (NGDC) product that you reference below uses a more pure McNish-Lincoln statistical prediction technique that keys on the date of solar minimum. This method is quite popular, but by the authors own admission, it is a better near-term solar cycle predictor (1 year). Hope this helps. Bill Murtagh