California precip forecasts have been suspended for the summer dry season --- these forecasts will resume in Oct 2020.

California Medium-Range Precipitation Forecasts, Based on NCEP GEFS Reforecasts and CCPA

Censored, Shifted Gamma Distribution (CSGD) Parametric Method

This page presents high resolution (1/8 degree) experimental precipitation forecasts, based on GEFS (Version 10) Reforecasts and Climatology-Calibrated Precipitation Analysis (CCPA, 2002-2013) datasets. A nonhomogeneous regression model that employs censored, shifted gamma distributions (CSGD) is fitted to these data, and then applied to the real-time ensemble forecasts to turn them into probabilistic forecasts. A detailed description of this technique, including an evaluation of its forecast skill, is given in Scheuerer and Hamill (2015).

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. Precipitation units are mm (25.4 mm = 1 inch).

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Analysis Date (format: yyyymmdd): Latest: Feb 25 2013
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This is a Research and Development Application