A Comparison of Arctic and Atlantic Basin Cyclone Track and Intensity Forecast Uncertainty

Abstract Summer Arctic cyclones (ACs) are long-lived, synoptic-scale features associated with strong winds and precipitation that can lead to reductions in sea ice. Consequently, a better understanding of the upper-tropospheric low-level thermodynamic features that limit the predictability of these storms may lead to better sea ice predictions. Here, the position and intensity variability of an August 2013 AC are assessed using ensemble-based sensitivity and compared to a midlatitude cyclone. Results suggest that the position and intensity variability of these storms are largely associated with both upstream and downstream uncertainty of mesoscale features embedded within the larger-scale potential vorticity features associated with cyclogenesis. Further, the intensity variability of the AC is also associated with uncertainty to a thermal boundary near the cyclone, whereas the Atlantic basin cyclone’s intensity variability is sensitive to low-level temperature and moisture along the polar front preceding the cyclone. Significance Statement Arctic cyclones (ACs) are long-lived, large-scale storms that are a common occurrence during the summer. These storms can have large implications on sea ice concentration and extent. Therefore, it is important to understand how the uncertainty and dynamics of features at the top of the troposphere and near the surface impact the predictability of the storm position and intensity. The same methodology is applied to a midlatitude cyclone for comparison, as midlatitude predictability has been studied in depth. Results suggest that both the position and strength of these storms are dependent on the shape of the upper-level feature. Further, the strength of the AC is also dependent on the magnitude of a frontal boundary along the coast, whereas the strength of the midlatitude cyclone depends on the thermal boundary along the upper-level front merging with the surface cyclone.