Skip to main content
U.S. flag

An official website of the United States government

Dot Gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.


The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

From The Radar-enhanced RUC To The WRF-BASED Rapid Refresh


The Rapid Update Cycle (RUC, Benjamin et al. 2004a,b), covering 2/3 of North America, continues to be the only 1-h (hourly updating) assimilation and mesoscale forecast cycle in the world running as part of an operational numerical prediction center (US National Centers for Environmental Prediction - NCEP). RUC prediction grids are used heavily as mesoscale guidance for short-range forecasts, especially for aviation, severe-weather, and situational awareness forecast users. In this report, we summarize both significant changes planned for a RUC upgrade at NCEP later in 2007 and testing and development toward the 2009-planned implementation of the Rapid Refresh (RR), an hourly update analysis/forecast cycle succeeding the RUC. The RR differs from the RUC in using a version of the Weather Research and Forecast (WRF) model and a version of the Gridpoint Statistical Interpolation (GSI) analysis (used at NCEP), both including RUC-unique enhancements, over an extended North American domain. These modifications and subsequent testing for both RUC changes and RR development are described in this paper.

Article / Publication Data
Available Metadata
Fiscal Year
Published On
June 01, 2007

This publication was presented at the following:

22nd Weather Analysis and Forecasting Conference
American Meteorological Society
Conference presentation


Not available


Authors who have authored or contributed to this publication.

  • Tracy L. Smith - Not Positioned Gsl
    Cooperative Institute for Research in the Atmosphere, Colorado State University
    NOAA/Global Systems Laboratory