Target Period Issue Date

Forecast made for
located in or near

Tercile Probabilities

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Precipitation Biweekly Probability Forecast

Calibrated Subseasonal tercile category biweekly-precipitation forecasts from the Subseasonal eXperiment (SubX)

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. 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 1999-2014 training period of the calibration of the forecast.

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 SubX 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.

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:

Dataset Documentation

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 precipitation: Global 1˚ NOAA UNIFIED precipitation data set, historical and real-time available here.

Instructions

Helpdesk

Contact help@iri.columbia.edu with any technical questions or problems with this Map Room.