A package of changes to the RUC will be implemented at NCEP within the next few weeks, perhaps by the end of March and if not, then during April.

These changes are described in a web page at http://ruc.fsl.noaa.gov/ppt_pres/RUC-Mar04change-1.htm.

The changes are to improve precipitation, cloud, and surface forecasts. The model changes include a change to vertical advection of moisture, definition of coastline land-use, and two smaller microphysics-related changes. This change improves the amount and areal coverage of precipitation, and also includes the evolution of soil moisture.

The analysis change is to use PBL depth in aid the assimilation of METAR data. This change is helpful especially for more accurate surface dewpoint and CAPE forecasts. An example of how forecasts for the 10 November 2002 tornado outbreak were improved from this change is included in the web page.

These changes are already being used in the dev and dev2 RUC runs from FSL available from the RUC web page.

Stan Benjamin