As Hurricane Florence missed the Eastern Shore, many are wondering why the Governor, and eventually the President declared the State of Emergency and ordered a mandatory evacuation?
As unpredictable as storms are, how reliable and accurate is the official forecasts produced by the National Hurricane Center, which earlier in the week produced the possibility of Florence causing chaos in southern Virginia?
The official NHC forecast features a forecast track surrounded by a “cone of uncertainty.” That should tell you all you need to know. Or not know.
But what about computer models?
Forecast models are computer simulations of the atmosphere. Meteorologists record measurements about the atmosphere as it currently is and use that to simulate what could happen in the future according to the laws of physics. But they are all flawed because of imprecise input and limited computer resources.
Models are run on some of the planet’s more powerful computers, and they still require hours to complete.
The European model is produced by the European Centre for Medium-range Weather Forecasts. It is one of several models run by various organizations around the globe that meteorologists consider reliable and useful in forecasting tropical cyclones.
In recent years the ECMWF model has earned a reputation for being more advanced than other models. It is often the best performing model.
Every year, the NHC compares its official forecasts with what actually happened. They also compare the accuracy of models with reality.