Analysis of Dry Spell Patterns on Peaks of the Southern Appalachians and their Associated Weather Conditions

Drought in the Appalachian Mountains can pose risks of wildfires, threaten the rich ecosystems, and strain cities’ water resources. By defining a dry spell as an intermediate state between normal and drought conditions, relationships between periods of dryness, succeeding drought, and associated weather conditions can be explored for better prediction and mitigation of drought and their associated risks. The Coweeta and Pigeon River Basin rain gauge networks, located in western North Carolina, provide hourly rainfall data spanning from 2009-2023 which were used to make a local climatology of dry periods. These rainfall data were coupled with 0 - 100 cm soil moisture data from NASA’s Land Data Assimilation Dataset to verify that these periods depleted environmental moisture, a crucial parameter for the Appalachian’s bionetwork. Dry events with lengths in the top 5th percentile were classified as dry spells while dry periods with lengths in the 1st percentile were classified as droughts. Both dry spells and droughts were associated with high 500 mb geopotential height anomalies over the central and southeastern United States. The Coweeta River Basin exhibited overall drier conditions than the Pigeon River basin, likely due to its smaller size and topographic interference of approaching northwesterly weather systems. These results support future research on the occurrence of defined dry spells and their relationship to drought, wildfire, and economical risks in this region.