If you read my Tuesday post on the development of the next nor’easter, you know I wove in a bit of the American Revolutionary War as a bit of an analogy to the developing nor’easter. The question at the time was, When is the data reliable enough to issue a warning on a developing situation? While at the same time, not issuing a warning every time a bunch of men wearing red coats gather for tea. With weather forecasts that effect millions of people, waiting until you see the whites of their eyes just won’t work. Now, 48 hours after my original nor’easter post, the situation has continued to develop yet there are significant changes. These changes can only be considered good news for coastal residents from the Mid-Atlantic to New England.
The good news is that although this storm is still expected to develop into a significant storm, development and nearly all of the effects will be well offshore.
As of today, the area that will become the nor’easter is a cluster of thunderstorms on the North Carolina/South Carolina border. With more time for development, and an eastward push toward the warm Gulf Stream, this cluster was expected to become a pronounced low pressure area and, with more time, a significant low that would turn north while continuing to strengthen — the classic ingredients of the nor’easter. Actually, that part of the forecast hasn’t changed. But there are changes: thanks to upper-level atmospheric features and the high pressure system over the northeastern U.S. and eastern Canada, the low will develop, strengthen and track much farther offshore. Good news indeed for storm-weary Northeasterners.
That said, not all of the storm effects will be confined offshore. Rain and wind are likely, just much less than previously expected. As for snow, we’ll have to wait to see how the snow situation develops — confidence in that situation remains quite low at this time.
What about the computer models that meteorologists put such faith in? Are they to blame when a later forecast differs or even contradicts a previous forecast? Not really. They can only do what they can do. It takes a seasoned and experienced meteorologist to know the pros and cons of each model and exploit them when conditions merit. In this case, the highly-favored ECMWF model was lagging behind the GFS model which, even several days ago, developed the low much farther offshore. Remembering Hurricane Sandy last month and the nor’easter last week, the GFS was not up to the high standards of the ECMWF, yet with the current situation the GFS seems to have the upper hand. Earlier this morning, ImpactWeather’s MarineWatch Manager Joe Basciani commented, “Even if the ECMWF is right 80% of the time, that means it’s wrong 20% of the time.”
This storm is still in its infancy and its full-blown effects are still several days away. However, as the two models come more into agreement — and remain there — confidence in this forecast and the more offshore solution will continue to rise. For now, we’ll continue to closely monitor this situation.
View the ECMWF image from this past Tuesday here.