The CCSR/IRI probabilistic seasonal climate forecast of precipitation and near-surface temperature is based on a super-ensemble of re-calibrated forecasts from the Subseasonal Consortium (SubC) (Pegion et al., 2019) NOAA NCEP CFSv2, NCEP GEFSv12, and NOAA/ESRL FIM HYCOM. New SubC forecasts are issued weekly on Fridays. https://journals.ametsoc.org/view/journals/bams/100/10/bams-d-18-0270.1.xml
The default map shows the latest forecast for weeks 2-3 ahead (i.e. the 14-day Saturday-Friday target period, 9 to 22 days after the forecast is issued), as probability of the dominant tercile category. Previous forecasts can be viewed through the control bar menu. The weeks 3-4 forecast (i.e. the 14-day target period, 16 to 29 days after the forecast is issued) is also available.
Selecting the Weekly tab, the default map shows the latest forecast for week 1 ahead (i.e. the 7-day Saturday-Friday target period, 2-8 days after the forecast is issued), as probability of the dominant tercile category. Previous forecasts can be viewed through the control bar menu. The week 2, week 3, and week 4 forecasts (i.e. the 7-day target periods, 9-15, 16-22, and 23-29 days after the forecast is issued) is also available.
The probabilistic forecasts are obtained from the statistical calibration of each model, initialized on Wednesdays) from the SubC database which are combined with equal weight to form multi-model ensemble precipitation tercile probabilities forecasts. Individual model forecasts are calibrated separately for each point, start and lead using Extended Logistic Regressions (ELR; Vigaud et al, 2017) based on the historical performance of each model, and thus provide reliable intra-seasonal climate information in regards to a wide range of climate risk of concerns to the decision making communities and for which subseasonal forecasts are particularly well suited.
NASA GPCP V1DD V1p3 precipitation dataset available here used for the calibration. For precipitation, the NOAA NCEP CPC gridded Daily Global Surface Air Temperature Data Set is used (land points only).