ESRL Global Systems Division

Operational Implementation of the 13-km RUC Model at NCEP

The 13-km version of NOAA's Rapid Update Cycle (RUC13) model became operational at 1200 UTC Tuesday 28 June 2005, at the National Centers for Environmental Prediction (NCEP). This is a major milestone for improving the RUC high-frequency short-range forecasts for NOAA and external users, especially for aviation and severe weather forecasting. The main changes include higher horizontal resolution (from 20km to 13km), improved data assimilation especially for moisture/cloud fields, and improved cloud/precipitation physics. Most notable improvements are in surface and cloud/precipitation forecasts, resulting in part from assimilation of new observation types in the RUC13 (GPS precipitable water (see related story), METAR ceiling/visibility, and mesonet temperature and dewpoint).

The RUC model/assimilation system, developed at NOAA's Forecast Systems Laboratory (FSL), provides high-frequency, hourly analyses of conventional and new data sources over the United States and much of North America. Its hourly short-range numerical forecasts out to 12h duration support aviation, severe storm forecasting, and other mesoscale applications. The RUC is unique within the National Weather Service in that it is the only operational system that provides updated national scale numerical analyses and forecasts more often than every six hours. Techniques for incorporating new types of observations into prediction models aim to provide the best possible estimate of current atmospheric and surface conditions, as well as the best possible short-range forecast.

This major accomplishment was a collaborative effort centered at FSL, NCEP, and NCAR; strengthened by contributions from NWS regions and offices, the FAA, and other NOAA laboratories; and supported through the FAA Aviation Weather Research Program and NOAA base funds. Questions or comments can be addressed to Dr. Stan Benjamin at FSL or, if of general interest, to the RUC Forum.

Contact information
Name: Stan Benjamin
Tel: 303-497-6387