Have computer models made it too complicated for anyone to predict the weather anymore? Let me explain how forecasting works. The methods of measuring the atmosphere have changed over the years, and there are more sophisticated methods in some locations but at many stations they are still obtained as they have been for years. At the scattered NWS offices balloons are sent up each day with transmitters that send back their readings of the atmosphere from the earth’s surface to the edge of outer space. These data are fed into the “master” computer at the NMC or National Meteorological Center in DC. The results of this is a computer run which is called a “model.” When I worked they did two runs a day, and the data are so complicated a run would take hours. Now they make many more runs and do it much faster.
From the results of these computer models a serious of charts are sent to the various forecasting offices and TV stations and Airlines and any other entity that can utilize their contents. Originally these charts were actually in the form of paper. Now they are merely sent as readouts on local computers, but they are still “charts.” From these charts the local forecaster then makes predictions for his or her own area. You hear a lot of TV weather people talk about models. “Well, this model says this, but we’ll have the results of the latest model at 11PM.” It is my suspicion that the reason local forecasters use the word “models” so often, is just some CYA way of having something else to blame for a busted forecast.
When I was a forecaster “in the olden days” we had two models that we used. One was called the Primitive Model, which basically was the pure physics of the atmosphere, and the other was the NGM or Nested Grid Model. I haven’t been in a forecast office for 20 years (and I’m not going back!) but apparently now the locals have dozens of models to peruse before they spring their forecast on us. And, therein may lie the problem. Is there just too many data for the forecaster to make a good decision? Or, there may be another reason.
So far this winter our local forecasters have blown two snow/ice predictions. And this is not a minor thing. A busted snow/ice forecast for Atlanta has serious consequences. It results in millions of dollars being wasted, not to mention the inconvenience. It is my belief that our forecasters are relying too much on their “models” while ignoring experience and intuition. Somewhere in my old file folders I have “Johnny Beckman’s Sure Fire Snow Forecaster.” (That is how I facetiously labeled that folder – I do have a sense of humor.) I’m not bragging, but it worked and worked well. Over time, I had intuitively developed a method which I used whenever conditions were deemed favorable for frozen precipitation around the Atlanta area. When I went to work on those occasions, I systematically checked the charts in a sequence that I had found was quite reliable in predicting not only the type of frozen precip that would occur, but also the timing of when it would start and when it would stop. There was no magic involved in this method and the timing might be off somewhat, but it never failed me in the last ten or fifteen years I worked as a forecaster. Perhaps I should dig out that old folder and pass it along to the current crop of predictors because, frankly, they’re not doing a very good job. But, then, I’m an old man, so why should they listen to me? After all, they have all those “models” to rely on.