Target Date Issue Date Lead Time

Forecast made for
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Probability of Exceedance

Probability Distribution

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Precipitation Flexible Biweekly Forecast

This subseasonal forecasting system consists of probabilistic precipitation forecasts based on the full estimate of the probability distribution.

Probabilistic subseasonal forecasts from multi-model ensembles through the use of statistical recalibration, based on the historical performance of those models, provide reliable information to a wide range of climate risk and decision making communities, as well as the forecast community. The flexibility of the full probability distributions allows delivery of interactive maps and point-wise distributions that become relevant to user-determined needs.

The default map shows globally the biweekly precipitation forecast probability (colors between 0 and 1) of exceeding the 50th percentile of the distribution from historical 1995-2014 climatology. The quantitative value (in mm/week) of that percentile is indicated by the contours. What makes the forecast flexible is that underlying the default map is the full probability distribution for the forecast and climatology. Therefore, the user can specify the historical percentile or a quantitative value (here precipitation in mm/week) for probability of exceedance or non-exceedance. The climatological reference on which the forecast probability of (non-)exceeding is computed can be tailored by defining its starting and ending years.

Clicking on a point on the map will show the local culmulative distribution and probability distribution fucntions of the forecast (green) together with the climatological distribution (black dotted).

Dataset Documentation

Distribution parameters: The ELR parameters of the climatological observed reference and the forecast for each model are available here.

More Information

TBD

Instructions

Helpdesk

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