ESRL/PSD Reforecast Products
The ESRL/PSD "Reforecast" project has produced a dataset of historical weather forecasts generated with a fixed numerical model,
a 1998 version of NCEP's Global Forecasting System (GFS, formerly known as MRF).
Forecasts for each day since 1979 have been made with this GFS version, comprised of a 15-member ensemble forecasts run out to 15 days.
Real-time forecasts are ongoing.
Among the advantages associated with this long reforecast dataset is that model forecast errors can be diagnosed from the past forecasts and corrected,
thereby dramatically increasing the forecast skill. Statistically corrected forecasts from this older version of the GFS have been shown to
outperform forecasts from newer versions of the GFS that do not include any statistical post-processing.
Also, the long reforecast dataset has lead to improved probabilistic forecasts of rare extreme events.
(a) 24 hour observed precipitation amounts for 9 January 1995; (b) Average 1-day precipitation forecasts; (c) Today's forecast calibrated with old reforecasts and precipitation analyses. (Click image to enlarge.)