Rapid Update Cycle
Encyclopedia
The rapid update cycle is an atmospheric prediction system that consists primarily of a numerical forecast model
and an analysis system to initialize the model.
The RUC was designed to provide accurate short-range (0- to 12-hr, later expanded to 18-hr in 2010) numerical forecast guidance for weather-sensitive users, such as those in the aviation community. Significant weather forecasting
problems that occur in the 0- to 12-hr range include severe weather in all seasons (for example, tornado
es, thunderstorms, snow, and ice storms) and hazards to aviation (for example, clear air turbulence
, icing, and downburst
s).
The RUC runs at the highest frequency of any forecast model at the National Centers for Environmental Prediction
(NCEP), assimilating recent observations to provide very high frequency updates of current conditions and short-range forecasts. This update frequency is still only once an hour (the standard interval for ASOS
observation reporting), and with current computational limitations and the time required to assimilate all of the data, there is approximately an hour delay in producing the forecasts. Because of this, it is common practice to use a one-hour forecast from the RUC as a current analysis, as the one-hour forecast comes out only a few minutes before the time it is forecasting for. There is also little possibility for error in a one-hour forecast, meaning that the RUC's one-hour forecast will not usually vary greatly from the actual state of the atmosphere at that particular point in time.
The RUC is scheduled to be replaced by the rapid refresh (RR) model, based on the WRF
, though the date for the transition has been pushed back several times and it is uncertain when, or if, the transition will ever actually take place.
Mathematical model
A mathematical model is a description of a system using mathematical concepts and language. The process of developing a mathematical model is termed mathematical modeling. Mathematical models are used not only in the natural sciences and engineering disciplines A mathematical model is a...
and an analysis system to initialize the model.
The RUC was designed to provide accurate short-range (0- to 12-hr, later expanded to 18-hr in 2010) numerical forecast guidance for weather-sensitive users, such as those in the aviation community. Significant weather forecasting
Weather forecasting
Weather forecasting is the application of science and technology to predict the state of the atmosphere for a given location. Human beings have attempted to predict the weather informally for millennia, and formally since the nineteenth century...
problems that occur in the 0- to 12-hr range include severe weather in all seasons (for example, tornado
Tornado
A tornado is a violent, dangerous, rotating column of air that is in contact with both the surface of the earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. They are often referred to as a twister or a cyclone, although the word cyclone is used in meteorology in a wider...
es, thunderstorms, snow, and ice storms) and hazards to aviation (for example, clear air turbulence
Clear Air Turbulence
Clear Air Turbulence is an album by British jazz-rock fusion band Ian Gillan Band, released in 1977 with cover by Chris Foss. The album was reissued in 1989 by Virgin Records on CD.- Track listing :...
, icing, and downburst
Downburst
A downburst is created by an area of significantly rain-cooled air that, after reaching ground level, spreads out in all directions producing strong winds. Unlike winds in a tornado, winds in a downburst are directed outwards from the point where it hits land or water...
s).
The RUC runs at the highest frequency of any forecast model at the National Centers for Environmental Prediction
National Centers for Environmental Prediction
The United States National Centers for Environmental Prediction delivers national and global weather, water, climate and space weather guidance, forecasts, warnings and analyses to its Partners and External User Communities...
(NCEP), assimilating recent observations to provide very high frequency updates of current conditions and short-range forecasts. This update frequency is still only once an hour (the standard interval for ASOS
Automated airport weather station
Automated airport weather stations are automated sensor suites which are designed to serve aviation and meteorological observing needs for safe and efficient aviation operations and weather forecasting...
observation reporting), and with current computational limitations and the time required to assimilate all of the data, there is approximately an hour delay in producing the forecasts. Because of this, it is common practice to use a one-hour forecast from the RUC as a current analysis, as the one-hour forecast comes out only a few minutes before the time it is forecasting for. There is also little possibility for error in a one-hour forecast, meaning that the RUC's one-hour forecast will not usually vary greatly from the actual state of the atmosphere at that particular point in time.
The RUC is scheduled to be replaced by the rapid refresh (RR) model, based on the WRF
Weather Research and Forecasting model
The Weather Research and Forecasting model, , is a specific computer program with a dual use for forecasting and research. It was created through a partnership that includes the National Oceanic and Atmospheric Administration , the National Center for Atmospheric Research , and more than 150 other...
, though the date for the transition has been pushed back several times and it is uncertain when, or if, the transition will ever actually take place.
External links
- NCEP RUC Homepage – Includes forecast output images and descriptions of the diagnostic variables available from the model output.