Western states water managers could get subseasonal to seasonal (S2S) forecasts to plan for less predictable winter precipitation. They could get forecasts of up to six weeks or two years, respectively. In contrast, conventional weather forecasts presently offer a lead time of two weeks. Refer to the chart, below.
Forecast skill or detail is expected to be coarse with longer-range forecasts. However, water managers will have the ability to foresee either a dry or wet winter.
They will still need to rely on short-term weather forecasts to predict storm events and measurable impacts.
Implementing S2S precipitation forecasting will require improvements to weather and climate models as well as access super-computers to test the models.
The National Oceanic and Atmospheric Administration (NOAA) report, Subseasonal and Seasonal Forecasting Innovation: Plans for the Twenty-first Century is being presented to the U.S. Congress to substantiate a $15 million annual investment to develop the S2S forecasting concept into a water management tool.
Western states advocates see the scientific methodology as an equally high priority as hurricane forecasting to the East Coast.
Proponents describe S2S as a macro water management tool, where as Forecast Informed Reservoir Operations (FIRO) is a micro tool to generate schedules for efficient reservoir storage.