The rapid update cycle (RUC) was an atmospheric prediction system that consisted 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, tornadoes, thunderstorms, snow, and ice storms) and hazards to aviation (for example, clear air turbulence, icing, and downbursts).
The RUC ran 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 was common practice to use a one-hour forecast from the RUC as a current analysis, as the one-hour forecast would come 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 would not usually vary greatly from the actual state of the atmosphere at that particular point in time.
The RUC was decommissioned on May 1, 2012; it was replaced by the Rapid Refresh (RR or RAP) model, based on the WRF. Like the RUC, the Rapid Refresh model also runs hourly out to 18 hours on a 13-km grid spacing, but also covers a wider area and includes an experimental high-resolution mode that offers 3-km resolution at 15-minute intervals A backup version of the RUC continues to run.
Famous quotes containing the words rapid and/or cycle:
““Five o’clock tea” is a phrase our “rude forefathers,” even of the last generation, would scarcely have understood, so completely is it a thing of to-day; and yet, so rapid is the March of the Mind, it has already risen into a national institution, and rivals, in its universal application to all ranks and ages, and as a specific for “all the ills that flesh is heir to,” the glorious Magna Charta.”
—Lewis Carroll [Charles Lutwidge Dodgson] (1832–1898)
“Oh, life is a glorious cycle of song,
A medley of extemporanea;
And love is a thing that can never go wrong;
And I am Marie of Roumania.”
—Dorothy Parker (1893–1967)