Skillful sub-seasonal (monthly) to seasonal (the water year) precipitation forecasting would support many facets of water management, providing lead time for preparing for extreme events and allowing for more efficient operation of water infrastructure. Current forecast practices and scientific capabilities for making skillful forecasts beyond the weather time domain,
however, are limited.
Through a series of prior annual workshops on climate variability, climate extremes, and drought held by the Council and the California Department of Water Resources (CDWR), some possible opportunities for improving forecasting skill at a regional scale have been identified. The purpose of this May 2015 workshop was to develop a Western vision for improving monthly and seasonal precipitation forecasting, loosely modeled after the Council’s vision for an observing network for Western extreme precipitation. The analyses performed to understand patterns responsible for heavy precipitation events at a regional scale – such as atmospheric river storms or the Southwest monsoon — also point out pathways to explore for improving forecasting of these events.
The timing is ripe for efforts to improve monthly and seasonal forecasting. Drought in the West has called attention to the need for better information to support preparedness and response, and NOAA’s report on the California drought provides a focal point for followup actions. The National Weather Service (NWS) is reviewing approaches for developing experimental week three and week four outlooks. The National Research Council has convened a committee to develop a U.S. research agenda to advance subseasonal to seasonal forecasting.