Ensemble trajectories and moisture quantification for the Hurricane Joaquin (2015) event
Chasity Henson, University of Missouri, Columbia, MO
Patrick Market, University of Missouri
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Abstract
Hurricane Joaquin (2015), an extratropical cyclone, and a frontal boundary contributed to heavy precipitation over South Carolina in October 2015. A deformation zone between the cyclones led to the development of a moisture plume perpendicular to the coastal front, which enhanced the precipitation intensity over a confined region of South Carolina. The source of moisture and the moisture transport characteristics were examined using the Air Resources Laboratory (ARL) Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model to determine if the moisture plume could be classified as an atmospheric river, as defined by Zhu and Newell (1998). Further, simulations of the event were compared using HYSPLIT and moisture budgets, to analyze and quantify the moisture. The Weather Research and Forecasting (WRF) – Advanced Research WRF (ARW) model was used to create a control simulation, a simulation with Hurricane Joaquin’s vortex and moisture removed, and a simulation with the removal of terrain to manipulate the strength and location of the coastal front. Precipitation totals from the simulations suggest that Hurricane Joaquin and its associated moisture contributed only 30% of the total rainfall received by South Carolina in 2015, with the coastal front having a major influence on the location and intensity of precipitation. Results show a moisture plume still present without Hurricane Joaquin, but the strength, duration, and position of the moisture transport was affected when the hurricane was removed. Using HYSPLIT and moisture budgets allows for the analysis of the dynamics generating the precipitation. The precipitation with this event was largely due to the location and intensity of the extratropical cyclone and stationary front.