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Upgrades to Global Forecasting Models

Posted: 5:03 PM, Jun 12, 2019
Updated: 2019-06-12 17:03:19-04

Two of the forecast models that we use everyday – the European and the GFS – both just received substantial upgrades. These improvements will boost the accuracy and efficiency of the global forecasting models. Both models now have more storage and faster processors, which will allow the supercomputers to compute more data to make for a more accurate forecast.

European Centre for Medium-Range Weather Forecasting

What is a forecast computer model anyway? First a set of current condition is ingested into a supercomputer. These values are then plugged into a super long equation for predicting how the atmosphere will change over time. Each model uses it’s own set of current conditions and “forecast equation.” The model is not run for the entire global as a whole. Instead the atmosphere is divided into small cubes that are arranged on a grid. The size of each cube varies model to model, and is referred to as the model’s resolution.  Changes in the wind and air pressure computed within each cube.

The new NOAA supercomputer in Orlando, FL. Courtesy of NOAA.

The Global Forecast System, the GFS or the “American” model, has received the first major upgrade in almost 40 years. The new, faster computer can process eight quadrillion calculations per second. The model’s dynamic core, the key component that computes the wind and air pressure, was also improved. This will boost the day-to-day reliability and speed of the operational numerical weather prediction. Louis Uccellini, the Director the National Weather Service, stated that these improvements will make one to two day forecasts more accurate and increase the level of accuracy of three to seven day forecasts. The “new” GFS has also seen an increase in resolution. The model has been upgraded to nine kilometers and 128 levels over 16 days from 13 kilometers and 64 levels over 10 days.

NOAA

The “new” GFS was run in research mode during last year’s hurricane season. The updated model has brought improvements to weather, water, and climate forecasting. Forecast for extreme events, including severe weather, are more precise several days out. Hurricane forecasts improved and flood information has been expanded.

Added data assimilation for the European model. Courtesy European Centre for Medium-Range Weather Forecasting.

The GFS isn’t the only global forecast model that is getting a tune up. The European, which has been the most accurate weather forecast for a long time, is also implementing upgrades. Upgrades have been made to improve the global mid-range forecast through data assimilation. As mentioned above, before the forecast model can be run the current state of the atmosphere must be ingested. These current conditions are vital for a successful forecast. The ECMWF will now continuously feed recent observations into it’s initial analysis. This will help to reduce forecast error.