Some weather models are better than others

Weather models are indispensable for meteorologists

pgeweather@pge.comMarch 30, 2013 

Many people don’t realize it, but weather models are almost indispensable in giving guidance to meteorologist.  In other words, it’s one of the main tools in a forecaster’s tool box use to help predict the weather. 

What are these models? They’re collections of mathematical formulas, usually run on very powerful computers, which produce forecasts for a specific location over time.   These models collect as much weather information as possible around the world. Think of the analogy of a butterfly flapping its wings in the southern hemisphere that eventually leads to a large storm in the northern hemisphere.

This vast amount of data is then fed to computers. These computers perform billions of calculations to mimic the motion of weather patterns in the Earth’s chaotic atmosphere. This type of forecasting is possible because movements of the atmosphere follow natural laws, which can be expressed in mathematical equations.

British mathematician Lewis Fry Richardson first proposed numerical weather prediction in 1922. He wasn’t very successful because without modern computers, it would literally take him nearly three months of performing calculations to produce a weather forecast that only predicted the weather 24 hours in the future. But his work laid the foundation for the first real success by the U.S. Joint Numerical Weather Prediction Unit in 1955. Since then the U.S. has pioneered the groundbreaking science of computer weather modeling.

However, according to some meteorologists, the European Center for Medium-Range Weather Forecasts (ECMWF) model has proven more accurate than the National Oceanographic and Atmospheric Administration (NOAA) Global Forecasting System (GFS) model. The European model predicted that Hurricane Sandy would swing toward the East Coast two days before the NOAA’s model predicted it.

Unlike the GFS model predictions which are free to the public and available on many websites, the European Model charges for much of its products. If you would like to explore the output of the European Model, the Weather Underground has an application on their website called wundermap. It can be viewed at www.wunderground.com/wundermap/

Weather models can range from the simplistic, like an Excel spreadsheet, to the incredibly complex that run only at supercomputing sites. One of the simplistic models I use for predicting the height and period of ocean waves along the Pecho Coast is the PG&E MATLAB wave model. This model takes wave data from the offshore buoys, which can be thousands of miles away and produces a prediction of resultant wave height at the Diablo Canyon Power Plant waverider buoy.

Some of the most complex weather models in the world are run just north of us in Monterey at the Fleet Numerical Meteorology and Oceanography Center by the U.S. Navy. To keep sailors out of harm’s way, they produce some of the world's best maritime weather forecasts.

Their computers are ranked in the top 10 percent of all supercomputer sites worldwide. Their models process millions of data points from weather balloons, marine buoys, ship and surface observations, aircraft, satellites and other oceanographic resources. One of the models they produce is called The Coupled Ocean/Atmosphere Mesoscale Prediction System (COAMPS). To be crystal clear, I served 24 years in the Navy and I tend to be biased towards this group of patriots.  Never-the-less, after forecasting for decades along our coastline, it's become my favorite. This model predicts wind and rain about 48 hours in the future.  Visit their Web site at www.nrlmry.navy.mil/coamps-web/web/home.

Did you know? PG&E delivers some of the nation’s cleanest power. Nearly 60 percent of the electricity the company provides to customers comes from sources that are renewable and/or emit no greenhouse gases.

John Lindsey’s column is special to The Tribune. He is a media relations representative for PG&E and a longtime local meteorologist. If you have a question, send him an email at pgeweather@pge.com.

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