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Comment Forecasting practices (Score 5, Informative) 235

Most forecasting is done by meteorologists viewing the predicted conditions based on a numerical model that normally gets run every 12 hours. The model's forecast is usually pretty good out to 72 hours or so. What happens is that an experienced weather-guesser (ex-Navy, here) will look at the model's output (which lags realtime to some degree) and compare the prediction to the actual conditions for the timeframe in question. If the correlation is high, he/she will put more faith into the model's longer term predictions. If the model isn't tracking reality very well, the forecaster will rely on experience rather than the numerical prediction for the longer-range forecast.

Sounder data from the available weather satellites is used to seed the modelling software as close to its run time as possible, to set up starting conditions for the observable areas. If that data is lacking, the previous model run data closest to the time of the new run is used. (GIGO applies...)

The realtime data can also come from radiosondes, official observations stations, buoys, or what have you. Losing a bird doesn't mean the forecasting infrastructure will fall apart; it just means that imagery will come from a different source (= different angle, with attendant distortion), and some loss of realtime input for the model run.

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