A methodology for adjusting error estimates during disaggregation of seasonal forecasts

The NOAA Climate Prediction Center is producing a monthly suite of climate forecasts, including three-month outlooks for temperature, precipitation, and degree days for an entire year in advance. These outlooks have potential value in support of risk-based decision making in agriculture and natural resource management. Unfortunately, the forecasts are generated for equal-area regions that represent one or more climate divisions, each about (380 km)2. Given our knowledge of significant climatological variations at smaller scales (sub-divisional), it seems reasonable to disaggregate the outlooks accordingly. As part of this effort, we are developing a methodology to track concurrent changes in the error (uncertainty) of the forecast. This paper will describe our initial methodology.