Rapid Update Cycle (RUC) Model

The Rapid Update Cycle (RUC) model is run at NCEP. This regional model focuses on short-term (up to 12 hour) forecasts and small-scale (mesoscale) weather features. Forecasts are prepared every three hours for the contiguous United States. The model uses 25 vertical layers (using the theta coordinate system, as compared to the sigma system for the NGM model and the eta system for the ETA model). Horizontal resolution on this model is 40 km.

On a variety of Web-based data pages, you might run across data for "RUC/MAPS", or sometimes just MAPS. MAPS is the development version of the RUC, run in real time at the Forecast Systems Laboratory (FSL). RUC is the operational version, run at NCEP. MAPS is an experimental version of the RUC. Only the RUC runs in the fully operational sense at NCEP. Both MAPS and RUC are high-frequency data assimilation and mesoscale numerical weather prediction systems.

RUC models generate a significant amount of data, as shown in the table below (Source: RUC2 documentation from the Forecast Systems Laboratory, a branch of NOAA. Click on the check mark to see the current graphic. Click on your "Back" button to get back to this reading.)

	All  times	Anal-  ysis	Fcst projection times (h)
			03	06	09	12
All fields
Sfc temp/wind
Sfc dewpt/wind
Surface RH/temp/wind
Surface wind
Precipitation/sfc temp
Precip type
Snow accum/sfc temp
12-h Precip accum
12-h Snow accum
Snow water depth
MAPS mean sea-level press
3-h sfc press change
CAPE/CIN
Helicity/storm motion
Conv cloud top
Precipitable water
Soil moisture
Tropopause pressure
500mb height/vorticity
850mb RH/temp/wind
700mb vertical velocity/height
250mb wind
Sfc visibility
Sfc wind gust speed
Boundary layer height
Cloud base
Stable cloud top

Another good site for RUC information (including animations) is NOAA's RUC data resource page.