Weather Forecast Accuracy Gets Boost with New Computer Model

Washington – Civilian and military weather forecasters have adopted for day-to-day use an advanced forecasting model that more accurately predicts several kinds of extreme weather.

The new computer model was created through a partnership that includes the U.S. National Oceanic and Atmospheric Administration (NOAA), the U.S. National Center for Atmospheric Research (NCAR) and more than 150 other organizations and universities in the United States and around the world.

According to an August 25 NCAR press release, the high-resolution weather research and forecasting (WRF) model is the first to serve as the backbone of the nation's public weather forecasts and a tool for cutting-edge weather research.

Because the model fulfills both functions, it is easier for research findings to be translated into improved operational models, leading to better forecasts.

NOAA's National Weather Service adopted the WRF as the main model for its one-to-three-day U.S. forecasts and as a key part of the National Weather Service ensemble modeling system for short-range forecasts.

By late 2007, the WRF will shape forecasts that serve more than a third of the world's population. The national weather agencies of Taiwan, South Korea, China and India are adopting the model.

The U.S. Air Force Weather Agency also has used WRF for several areas of operations around the world.

"The Weather Research and Forecasting model development project is the first time researchers and operational scientists have come together to collaborate on a weather modeling project of this magnitude," said Louis Uccellini, director of NOAA's National Centers for Environmental Prediction.

Tests over the last year at NOAA and the Air Force Weather Agency have shown that the new model offers many benefits over older models, including:

• Cutting by more than half errors in nighttime temperature and humidity across the eastern United States;

• Depicting flight-level winds in the subtropics in a stronger and more realistic manner, leading to improved turbulence guidance for aircraft;

• Outperforming the previous model in more than 70 percent of the situations that the Air Force Weather Agency studied; and

• Incorporating data from satellites, radars and a wide range of other tools with greater ease than earlier models.

NCAR is experimenting with an advanced research version of WRF, with very fine resolution and innovative techniques, to demonstrate potential for improving the accuracy of hurricane track, intensity and rainfall forecasts.

Scientists from NOAA, the Naval Research Laboratory, the University of Rhode Island and Florida State University are developing a special hurricane-oriented version of WRF, called HWRF, to support NOAA hurricane forecasting.

The high-resolution HWRF will track waves and other features of the ocean and atmosphere, including the heat and moisture exchanged between them. Data from satellites, aircraft, and other observing tools will enhance the HWRF depiction of hurricane cores and the ocean below them.

WRF also can depict intense squall lines, supercell thunderstorms and other types of severe weather.

No model can pinpoint hours ahead of time where a thunderstorm will form, but WRF is better than many models in predicting what kinds of storms could form and how they might evolve.

About 4,000 people in 77 countries are registered WRF users. Many users suggest improvements that are tested for usefulness at a facility based at NCAR and supported by NOAA.

The full text of the press release is available on the NCAR Web site.