The impact of cold-air damming on precipitation during the South Carolina 2015 flood

Analyses of observed precipitation accumulations, reanalysis datasets, and high-resolution numerical simulations characterize the impact terrain, specifically through cold-air damming (CAD), has upon the intensity, placement, and evolution of rainfall during the 2015 October 1-5 South Carolina flood associated with non-landfalling Hurricane Joaquin. Improving understanding of the role of this indirect form of orographic precipitation enhancement in extreme precipitation events could aid in weather prediction and risk assessment of possible damage to aging water management infrastructure, such as the likely cascading dam failures that occurred during this event. Examination of ASOS data determined that the CAD event, identified by the strongest temperature gradient, peaked on 3 October 2015 where the temperature difference between the coast and eastern side of the mountains exceeded 15ºC. Differences between reanalysis and operational forecast solutions of the strength of temperature gradients and wind flow coincide with marked variations in the timing and intensity of the resulting precipitation. WRF-ARW is used to model the event with terrain modification experiments to quantify the impact that the Appalachian Mountains have on the CAD and atmospheric stability and the subsequent precipitation characteristics. These experiments indicate that modifying the terrain alters the CAD’s stability and maintenance spatially and temporally, which although caused alterations in the placement of localized maximums, but did not alter the event’s extremity. Precipitation formation within the main plume is most enhanced along the area of increased confluence along the leading edge of the CAD, which then falls over the state of South Carolina. This enhancement along the leading edge is most influenced by the CAD’s evolution.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Atmospheric Sciences

Grantor

University of Illinois Urbana-Champaign

Year dc:date

2025

Author dc:creator

• Sepulveda, Jackie M.

Contributors dc:contributor

• Hence, Deanna
• Nesbitt, Stephen W
• Dominguez, Francina

• Extreme Rainfall
• Cold-air Damming
• Meteorology
• Infrastructure
• Weather
• Flood

Statement dc:rights

• Copyright 2025 Jackie Sepulveda

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/129946

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F129946