Investigating the Impact of Fine-Scale Gulf Stream SST Gradients on the Development of Bomb Cyclones in the Community Earth System Model 2

Atmospheric bomb cyclones that form off the United States east coast are high impact, complex weather systems. Many ingredients must come together to produce a storm of this magnitude. In recent years, high-resolution studies have indicated that one such critical ingredient is fine-scale Gulf Stream sea-surface temperature (SST) variability. However, studies still lack consensus on which particular aspect of the variability is most critical (e.g. absolute SST vs. the SST gradient, pre-conditioning vs. direct influence). Through novel high-resolution simulations in Community Earth System Model 2 (CESM2), this study attempts to isolate the influence of the fine-scale SST gradient specifically, motivated by the impact fine-scale heat flux gradients are expected to have on lower-level frontogenesis and subsequent cyclone development. Through targeted fine-scale SST gradient perturbations, the results illustrate how preexisting SST gradients can impact the frequency and intensity of bomb cyclones and may offer useful information regarding seasonal forecasting of these systems.