Weather Regime Diagnostic Tools for Sub-Monthly Ensemble Forecasts

This project will develop a set of tools to diagnose and downscale sub-seasonal to seasonal (S2S) forecasts from CFSv2 and other S2S models over North America in the week 3-4 range, based on the methodology of large-scale recurrent, persistent weather regimes (WRs) also known as large-scale meteorological patterns (LSMPs). The new tools will provide CPC forecasters with low-dimensional insight into the high-dimensional S2S forecast ensemble evolution in real time, leading to improved week 3-4 forecasts. The WRs will also provide perfect-prognosis downscaling tools for daily precipitation and temperature characteristics and hazards at week 3-4 leads, providing additional guidance to the CPC operational forecasters.