| visualization of uncertainty
in meteorological forecast models
The animation at left is a composite of three forecast models: the NGM, the eta, and the spectral, all products of the National Meterological Center. All of the frames of the animation come from one forecast run, made at the time of the beginning of the animation (7am EST on Feb 2, 1995), for 6, 12, 18, 24, 30, 36, 42, and 48 hours into the future. As you might expect, forecasts are less certain for 36 hours in the future than they are for 6 hours in the future. This graphic shows that uncertainty is the blue-to-red color fills: blue represents areas where the different forecast models agree on the predicted barometric pressure, red represents areas where the models disagree (and thus the forecast is less certain). The blue lines are isobars, lines of equal barometric pressure: they show the average pressure fields predicted by the models. This sequence shows a particularly violent winter storm in February 1995, as it was predicted two days before blizzard-like conditions occurred over central Pennsylvania. Particularly interesting |
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| to note is the high level of agreement among the models on the surface pressure levels over Pennsylvania, New Jersey, and New York, a full two days in advance of the storm. This can be seen at the end of the loop with the blue region over the Middle Atlantic. Indeed, the models were all correct, and this storm was considered one of the best-forecast "nor'easters" in history at the time. | |