In what will all but certainly be winters dying breath, a large and powerful coastal storm will develop Tuesday into Wednesday off the southeast states while traversing northeastward to a position southeast of the 40/70 benchmark. In doing so, and owing to a major phase in the mid levels of the atmosphere, the storm will strengthen rapidly and explosively — dropping from around 990mb to somewhere in the 950’s mb. This will make the system the strongest of the season by far, and the strongest in our area since Hurricane Sandy.
The aforementioned phase involves three disturbances which originate from different parts of the mid level flow and jet stream. Pacific and polar energy will merge over the Northeast United States, and a favorable jet structure will allow for rapid strengthening of the low pressure system. More notable for us, however, is how all of this will occur a hair too slow and a tick too far east/northeast — allowing us to dodge what would’ve otherwise been an incredibly high impact storm system.
Although the cutoff in impact will be quite dramatic, with parts of Cape Cod already under a Blizzard Watch, our area still could see some sensible weather effects from the storm passing seaward — even if only from the upper level trough and not directly related to the low pressure itself. Forecast models have been indicating the potential for an area of enhanced lift to cross over the region late Tuesday Night into early Wednesday, possibly proving sufficient to touch off areas of light snow which may bring light accumulations to some areas.
Otherwise, the storm will be incredibly impressive to watch from afar. A cyclone of this nature developing off our coasts is not very common. Although we observe frequent nor’easters, the forecast modeled low pressures in the 950’s and 960’s mb are exceedingly rare — especially for this time of year. The National Weather Service put it well, a few days ago, when they noted that the system’s pressure and breadth was a “once in 10-20 year” event. We’ll surely be capturing and saving some of the satellite imagery Wednesday morning — and counting our lucky stars that Ol man winter’s last breath missed us just barely to the east.