The Nor'easter That Wasn't: Extratropical Cyclogenesis Without Hurricane Sandy
Starting from 00 UTC 25 October 2012, a 132-hr control run simulates Hurricane Sandy fairly well. The westward and eastward jogs in its track are similar to those observed, but Sandy makes landfall too far north, over Narragansett Bay, too intense, at 933 mb, and too late, at 09 UTC 30 October. An experimental simulation removed the vortex associated with Hurricane Sandy from the 00 UTC 25 October data, but tropical cyclogenesis immediately recommenced anyway. Therefore, additional experiments were performed. First, SSTs near Sandy were lowered such that tropical cyclogenesis was not possible. Second, relative humidity near Sandy was lowered to minimize the impact leftover Sandy moisture would have on any extratropical cyclogenesis along the East Coast.
Preliminary results show that a nor'easter does form even under the most stringent conditions for Sandy removal. The cyclone develops over the North Carolina coast, heads to Montauk Point, and then turns northwest toward Ottawa, Canada. It snows over West Virginia. However, the impacts of this nor'easter, while non-negligible, are simulated to be much less than what was observed with Sandy. This study helps to quantify the degree to which Sandy's impacts on the built environment can be attributed to the tropical cyclone as opposed to those purely attributable to the large-scale extratropical conditions.