ESRL Global Systems Division

New ESRL Weather Forecast Computer Model Goes On Line at NWS/NCEP on May 1

Starting Tuesday, May 1, NOAA began using a sophisticated new weather forecast computer model to improve predictions of quickly developing severe weather events including thunderstorms, winter storms, and aviation hazards such as clear air turbulence. The Rapid Refresh (RAP) now provides NOAA's most frequently updated weather forecast, replacing an older model that served a similar function. The RAP also extends the geographical coverage of NOAA's weather situational awareness information to all of North America, not just the contiguous U.S., as was the case for the older model.

The RAP, developed by NOAA's Earth System Research Laboratory (ESRL) in Boulder, Colorado and NOAA's National Centers for Environmental Prediction (NCEP) in Camp Springs, Maryland, updates every hour with a new forecast extending out 18 hours for North America. Such forecasts are especially important in aviation, where fast-developing weather conditions can affect safety and efficiency, but they are equally important for severe weather and energy-related forecasting. "When accurate and timely weather modeling is needed most, the new RAP delivers," said Louis Uccellini, Ph.D., director of NCEP, a part of NOAA's National Weather Service (NWS).

"The United States is the only country in the world that updates computer model forecasts every hour using the latest observations from an extensive network of ground- and satellite-based sensors, radars and aircraft," said Dr. Stan Benjamin, lead developer of the new model and a research meteorologist at ESRL's Global Systems Division.

The new model was tested extensively, running experimentally for 22 months at NCEP, and will replace the older rapidly updated model, Rapid Update Cycle (RUC). In comparisons with the older model, the RAP has proved more skillful. "Overall, RAP provides equal or better forecasts than its predecessor for all variables, from winds to precipitation," Benjamin said.

Many people from several institutions made noteworthy contributions to the development of the RAP model. These include ESRL, Cooperative Institute for Research in the Atmosphere, Cooperative Institute for Research in Environmental Sciences, and National Center for Atmospheric Research.

NOAA's mission is to understand and predict changes in the Earth's environment, from the depths of the ocean to the surface of the sun, and to conserve and manage our coastal and marine resources. The new RAP will dramatically improve NOAA's ability to predict atmospheric changes that could lead to severe storms and aviation hazards.

Contact information
Name: Stan Benjamin
Tel: 303-497-6387