Probabilistic Forecasts, Based on NCEP GEFS Reforecasts, Version2
These NOAA PSL GEFS Reforecast Version 2 webpages will no longer be available after November 30, 2020. See the note below on access to the new version.
Note: As of 23 September 2020, the Global Ensemble Forecast System has been upgraded to a much improved version 12, and this page for the older model version is now obsolete. We have also, regrettably, discontinued production of many value-added experimental forecast products, including post-processed probabilistic forecast guidance, Extreme Forecast Indices, and GEFS-based teleconnection indices, due to lack of funding.
A near-realtime (4-day archive) of new GEFSv12 forecasts can be obtained from the NCEP NOMADS site: https://nomads.ncep.noaa.gov/, using the links for the GFS Ensemble 0.25 Degree data set. A historical archive of older GEFSv12 forecast data may be accessed from the NCEI NOMADS site: https://www.ncdc.noaa.gov/data-access/model-data/model-datasets/global-ensemble-forecast-system-gefs. For questions, please contact email@example.com.
GEFSv12 reforecasts spanning 2000-2019 are available via Amazon Web Services for free download, at https://noaa-gefs-retrospective.s3.amazonaws.com/index.html. One can set up scripts to loop over days and member and download sequences of global fields. If you have questions or comments about the reforecast data set or the associated products, please contact: firstname.lastname@example.org.
This page presents experimental probabilistic forecasts, produced with the non-homogeneous Gaussian regression technique of Gneiting et al. (Monthly Weather Review, 2005). Two predictors are used for each variable: that variable's forecast ensemble mean and spread (e.g., T850 forecast ensemble mean and spread for the T850 predictand). Forecasts are available for 2m temperature, 850mb temperature and 500mb height at several forecast leads, ranging from 2-3 days to 8-14 days.
We follow the NOAA Climate Prediction Center definitions of forecast day. Their definition of day 1 is that it includes the 6-hourly data from forecast hours 30, 36, 42 and 48. The 6-10 day forecast is thus defined as forecast hours 150-264; the 8-14 day forecast is forecast hours 198-360. For example, for the forecast initialized 00Z January 1, day 1 includes forecast data between 06Z January 2 - 00Z January 3. Day 2 includes forecast data between 06Z January 3 - 00Z January 4, etc.
These forecasts will usually (but not always) be updated by 16 UTC each day. They likely will not be available as consistently as operational products from the National Weather Service. Also please note that this is an experimental forecast product, and is not an official forecast of NOAA or its National Weather Service.
We welcome feedback on this product. Email comments to: email@example.com .
This is a Research and Development Application