Spring Upgrade Package: Precipitation Assimilation

• Simplified / streamlined precipitation assimilation procedures in NAM Data Assimilation System (NDAS). Reasons:

• Original method evolved in step over the years with increasingly more sophisticated microphysics; had become too contrived/cumbersome

• Streamlining makes method more forward-compatible with future modeling systems (WRF or ESMF)

• Streamlining makes precipitation assimilation more robust - some previous EDAS failures linked to attempts to create precipitation not forecast by Eta