The History of Numerical Weather Prediction Part lll

A more recent addition to the numerical weather prediction suite of products is “ensemble modeling.” With ensemble modeling, many forecasts are run with slightly varying initial conditions from different models and an average, or “ensemble mean,” of the different forecasts is created. This ensemble mean can extend forecast skill to the two-week range because it averages over the many possible initial states, to essentially “smooth” the chaotic nature of the atmosphere. In addition, this technique provides information about the level of uncertainty for different conditions because of the large ensemble of forecasts available.
All of the development during the 1960s – 1990s meant computer resources were stretched to the limit. As soon as new computer resources became available, they were fully utilized with higher-resolution models with improved representation of physical processes, using more and more sophisticated and complex modeling techniques and an increasingly larger number of observations from around the globe, especially from satellites. Advances in predictive skill could be shown to be directly proportional to advances in computing and modeling.
However, the computer-based forecast is not the only reason for the improvements in forecasting accuracy the world enjoys today. The interpretation of the model forecasts by human forecasters has been shown to provide a consistent amount of additional forecast improvement throughout the evolution of numerical weather prediction. Our ability to interpret the many “moods” of the atmosphere has not yet been matched by equations and computer chips.

In the present day, operational numerical weather prediction centers around the globe run a myriad of models. These models, some of which were developed and are run by NOAA’s National Weather Service, produce a wide variety of products and services. In the United States, over 210 million observations, the vast majority obtained from satellites, are processed and used each day as input into global and regional models producing forecasts for atmospheric and oceanic parameters, hurricanes, severe weather, aviation weather, fire weather, volcanic ash, air quality, and dispersion. The current operational computers run with a sustained computational speed of 14 trillion calculations per second. More than 14.8 million model fields are generated every day, six million of which are derived from the global ensemble runs.
In 2005, the first dynamic climate forecast system was implemented, making forecasts out to one year. Models that predict space weather on an operational basis are not far off. Demands for more and more detailed weather information increase on a regular basi
The future holds more areas for progress in environmental modeling. An Earth systems modeling approach offers a way to couple models from oceanic, land, cryospheric (ice), and atmospheric disciplines in order to transfer information among model components. The suite of forecast products will expand beyond weather, water, and climate services to include ecosystems and incorporate the needs of more customers, such as the transportation, health, and energy communities.
Numerical weather prediction has advanced significantly since the idea was formed by Bjerknes and tested by Richardson. The six weeks of tedious computations endured by Richardson can now be done in the blink of an eye. The past century’s efforts have resulted in a level of accuracy for weather prediction that saves countless lives and property each year. Numerical weather prediction can indeed be considered one of the most significant achievements of the 20th century.

We are now in Florida and will start our cruise tomorrow. This weeks post it part lll of The History of Numerical Weather. Friday was a very nice day down here with lots of sun and mild (to us) temperatures in the low 60’s Got to a car wash and washed off most of the salt that had been on the car. Looking ahead it now looks wet and mild for the foreseeable future in Michigan that does not mean it will not snow but the chances are there will be more rain than snow in the next 3 to 4 weeks or more, Is winter over?? Who knows maybe it will be a bookend or was it front loaded with nothing much coming Anyway I will post more in late January. There is a post ready to go for next weekend..

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