The North American Regional Climate Change Assessment Program (NARCCAP) represents the next step in investigating the behavior of weather phenomena in current and future climate. Specifically, variations in mid-latitude cyclone tracks attributable to a warming climate have potential socio-economic consequences via the redistribution of precipitation on regional spatial scales. This manuscript assesses the impacts of a warming climate on cyclone tracks in the NARCCAP model suite. Specifically, cyclones are generated from eight 33-year simulations for the twentieth Century (1968–2000) and eight 33-year simulations for the A2 greenhouse scenario (2068–2100). To provide comparison, cyclone tracks are also generated from the Climate Forecast System Reanalysis (CFSR) and ERA Interim (ERA_INT) reanalysis datasets from 1979 to 2016. The results support that the NARCCAP model suite is capable of producing a reasonable cyclone frequency and intensity climatology when compared with the reanalysis datasets. Comparison of the ensemble twentieth Century cyclone (20C) tracks with the ensemble A2 cyclone tracks demonstrate a zonally-oriented poleward shift in cyclone track frequency in response to a warming climate. Intensity differences were regionally oriented, with cyclones being more intense in the A2 relative to the twentieth Century scenarios west of the Appalachians, suggesting cyclones acquire greater latent heat from warmer western Atlantic/Gulf of Mexico moisture sources in A2. A sector analysis revealed a higher total frequency of cyclones in both reanalysis datasets relative to either NARCCAP scenario. For intense cyclones, the NARCCAP model simulations produced more frequent cyclones in the Great Lakes and East Coast sectors. In contrast, reanalysis produced a higher frequency of weak cyclones for all sectors except Atlantic Canada. In addition, NARCCAP simulations were found to be capable of reproducing the broadness of intensity distributions in the reanalysis datasets, likely due to the fine spatial gridding in the NARCCAP models. Sector analysis for frequency and intensity affirmed the ensemble results, with individual model simulations showed a reduction in frequency for all sectors except the Canadian Maritimes for A2 relative to 20C. For intensity, cyclones were once again overall more intense for the upper Midwest/Great Lakes sector for A2 relative to 20C. The results of this research demonstrates the ability for regional climate models to be used to assess changes in synoptic-scale phenomena in a warming climate. Future work will focus on assessing cyclone structure including changes in moisture transport, precipitation, and the low-level jet.

北美区域气候变化评估计划（NARCCAP）代表了调查当前和未来气候中天气现象行为的下一步。具体而言，由于气候变暖，中纬度气旋路径的变化会通过在区域空间尺度上重新分配降水而产生潜在的社会经济后果。该手稿评估了NARCCAP模型套件中气候变暖对气旋路径的影响。具体来说，气旋是根据20世纪（1968-2000）的八个33年模拟和A2温室情景（2068-2100）的八个33年模拟生成的。为了进行比较，还从1979年至2016年的气候预测系统重新分析（CFSR）和ERA临时（ERA_INT）重新分析数据集中生成了气旋轨道。结果证明，与重新分析数据集相比，NARCCAP模型套件能够产生合理的气旋频率和强度气候。通过对20世纪整体气旋（20C）轨道与A2整体气旋轨道的比较，可以看出随着气候变暖，气旋轨道频率向纬向偏移。强度差异是区域性的，相对于阿巴拉契亚以西的20世纪情景，A2的气旋强度更大，这表明气旋从A2的西大西洋/墨西哥湾较热的湿气源获得了更大的潜热。部门分析显示，相对于任一NARCCAP方案，两个重新分析数据集中的气旋总频率更高。对于强旋风，NARCCAP模型模拟在大湖区和东海岸地区产生了更频繁的气旋。相反，除了加拿大大西洋沿岸地区外，所有区域的再分析产生较高频率的弱旋风。此外，发现NARCCAP模拟能够在重新分析数据集中再现强度分布的广度，这可能是由于NARCCAP模型中的精细空间网格化所致。频率和强度的行业分析证实了整体结果，单独的模型仿真显示，除加拿大海事部门A2相对于20C以外，所有行业的频率均下降。就强度而言，相对于20C，中西部/大湖区上部的A2气旋总体上更加强烈。这项研究的结果表明，在气候变暖的情况下，可以使用区域气候模型评估天气尺度现象的变化。未来的工作将集中在评估旋风分离器的结构上，包括水分传输，降水和低空急流的变化。