Developmental RUC13 image

Rapid Update Cycle (RUC) model

The primary focus of the Regional Analysis and Prediction (RAP) Branch is research for and development of the Rapid Update Cycle (RUC), which provides high frequency, hourly analyses of conventional and new data sources over the contiguous United States, and short range numerical forecasts in support of aviation and severe storm forecasting and other mesoscale forecast users. A variety of model and assimilation development, verification, and observational data impact activities are carried out under the RUC focus, often with major collaboration with other laboratories. The RUC has a unique role within the NWS in that it is the only operational system that provides updated national scale numerical analyses and forecasts more often than once every 6 hours. It is widely used in NWS Forecast Offices, NWS centers for aviation weather and storm prediction, the FAA, and other facilities. The RAP branch is also working toward a new WRF-based version of the RUC, called the Rapid Refresh (WRF-RR).

Local Analysis and Prediction System (LAPS)

The Local Analysis and Prediction (LAP) Branch responds to the needs of many government agencies and the private sector in the areas of local and mesoscale data analysis, data fusion, data assimilation, quality control, three-dimensional display and visualization, and numerical modeling. Research and development involving the Local Analysis and Prediction System (LAPS) and the implementation of mesoscale forecast models form the primary focus of the branch. The overarching objective is to provide real-time, three-dimensional, local-scale analyses and short-range forecasts (0–24 hours) for domestic and foreign operational weather offices, facilities, and aviation and other field operations.The portable Local Analysis and Prediction System (LAPS) can integrate data from virtually every meteorological observation system into a very high-resolution gridded framework centered on any operational forecast office's domain of responsibility. The quasinonhydrostatic multiscale model has been developed for use on any scale of motion.

Weather Research and Forecasting Model (WRF)

FSL is responsible for leading development of the WRF Rapid Refresh, planned to replace the current RUC in 2007. In collaboration with other organizations, FSL is heavily involved in implementation of the Weather Research and Forecast (WRF) model. This model will be used operationally at the NWS National Centers for Environmental Prediction (NCEP) for the first time next year after many years of development. The WRF model is designed as both an operational model and a research vehicle for the larger modeling community.

Advanced parameterization of small-scale processes

Since 2002, the RUC model has used a new Grell-Devenyi convective parameterization, based on a very simple convective scheme developed by Grell. For the RUC20 implementation, the original scheme was first expanded to include lateral entrainment and detrainment, including detrainment of cloud water and ice to the microphysics scheme discussed in the previous section. In addition, the scheme draws on uncertainties in convective parameterizations by allowing an ensemble of various closure and feedback assumptions (relating to how the explicitly predicted flow controls the parameterized convection, which in turn modifies the environment) to be used every time the parameterization is called. FSL has also developed the RUC-Smirnova land-surface model. Both this scheme and the Grell-Devenyi convective scheme have been added to the WRF model (v2.0) as options. FSL also contributes, with other organizations, on improvements to cloud physics and radiation parameterizations used in both the RUC and WRF models.