Subseasonal tercile categories temperature forecasts with pattern-based calibration from the Subseasonal eXperiment (SubX)
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. New forecasts are issued weekly on Fridays.
When navigating to a forecast of which Target Period is in the past, a smaller side map shows a verification of the forecast as the observed tercile values according to the training period of the calibration of the forecast. Before May 1, 2021, the climatological period is 1999-2014; After May 1, 2021, the climatological period is 1999-2016.
Clicking on the forecast map will show, for the clicked grid box, the probabilities for the 3 forecasts categories (Below-, Near- and Above- Normal).
The probabilistic forecasts shown here are obtained from the statistical calibration of three models (NCEP CFSv2, NCEP GEFS, and NOAA/ESRL FIM HYCOM, each run on Wednesdays) from the SubC database which are combined with equal weight to form multi-model ensemble temperature tercile probabilities forecasts. Individual model forecasts are calibrated separately for each point, start and lead using Extended Logistic Regression using Laplacian eigenfuctions for spatial pattern correction (L-ELR; Vigaud et al, 2017). The calibration is 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.
Subseasonal-to-seasonal forecasting techniques are still under development. This Maproom shows the type of experimental forecast information currently being created at these time scales in real time.
References:
Forecast: Global 1˚ Multi-Model Ensemble forecasts probabilities by category and dominant terciles probabilities available here obtained from the statistical calibration of three models (NCEP CFSv2, NCEP GEFS, and NOAA/ESRL FIM HYCOM) from Subseasonal Experiment (SubX).
Historical Temperature: NOAA NCEP CPC gridded Daily Global Surface Air Temperature Data Set at 0.5 degree from 1979-present. here.
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