Using ensemble numerical simulations with the NASA-Unified Physics Weather Research Forecast (NU-WRF) model and present-day atmospheric initial and boundary conditions, we have investigated possible responses of Sandy-like superstorms under the influence of warmer SST in a double-CO2 climate, as projected by CMIP5 ensemble models. We find that the responses bifurcate into two groups. In the first group, storms are similar to present-day SS from genesis, storm track to extratropical transition, except they propagate faster, and are much stronger, with maximum wind destructive power increased by 50-80%, and heavy rain increased by 30-50%. In the second group, storms have longer exposure time to the Atlantic warm pool, and amplify to super-hurricane strength over the interior of the warm pool, with peak destructive power increased by 100-160%, and heavy rain stronger by 70-180%. However, unlike present-day SS, these second group of storms after exiting the warm pool, re-curve northeastward out to sea, subsequently interact with the developing mid-latitude storm by mutual amplitude modulation, via counter-clockwise rotation around each other. The remnant of tropical storm eventually amplifies into a severe Northeastern coastal storm with landfall over the extreme northeastern regions from Maine to Nova Scotia. The potential societal impacts of these two scenarios will be discussed.