Western Kentucky University
Variations and Trends in Heavy and Extreme Precipitation in Kentucky between 1949-2022
Grade Level at Time of Presentation
Senior
Major
Meteorology and Environmental, Sustainability, and Geographic Studies
Institution 23-24
Western Kentucky University
KY House District #
20
KY Senate District #
32
Faculty Advisor/ Mentor
Dr. Zachary Suriano
Department
Department of Earth, Environmental, and Atmospheric Sciences
Abstract
Precipitation plays a crucial role in the Earth’s water cycle, providing freshwater supplies for consumption, industrial, and agricultural needs. However, the occurrence of extreme precipitation, such as the Kentucky events in July 2022 and 2023, has the potential to cause dangerous flash flooding, which can lead to significant loss of life and property. Previous studies have investigated the trends in precipitation across the U.S., including in Kentucky where findings indicate the presence of a small number of isolated regions with temporal trends in annual precipitation. Despite these previous efforts, many questions remain on how precipitation event frequency and intensity variation has changed across the Commonwealth at monthly time scales. The objective of this study is to determine the climatology of precipitation distribution across Kentucky since 1950 and specifically investigate the spatial and temporal variabilities and the trends in event frequency and intensity. Here we find heavy and extreme precipitation events over the south-central and western parts of the state are 2-3 times more frequent relative to northern and eastern regions. Within the calendar year, heavy and extreme events exhibited a spatial shift in regional frequency, moving from a typical zone of higher frequency from November-May in the west, to peak relative frequency in mid-summer in the east. Over time, we find a significant decrease in annual precipitation event frequency and total magnitude of over 0.5 days/year and 1.0 inch/decade, respectively, across central Kentucky. Monthly precipitation totals decreased by approximately 0.5 inch/decade over the south-central region in January and increased in the bluegrass region in April and in the northwestern half of state in October by as much as 0.8 inch/decade. Evaluating the variations in precipitation events is a critical first step in understanding why these events occur and how they may or may not change in the future.
Variations and Trends in Heavy and Extreme Precipitation in Kentucky between 1949-2022
Precipitation plays a crucial role in the Earth’s water cycle, providing freshwater supplies for consumption, industrial, and agricultural needs. However, the occurrence of extreme precipitation, such as the Kentucky events in July 2022 and 2023, has the potential to cause dangerous flash flooding, which can lead to significant loss of life and property. Previous studies have investigated the trends in precipitation across the U.S., including in Kentucky where findings indicate the presence of a small number of isolated regions with temporal trends in annual precipitation. Despite these previous efforts, many questions remain on how precipitation event frequency and intensity variation has changed across the Commonwealth at monthly time scales. The objective of this study is to determine the climatology of precipitation distribution across Kentucky since 1950 and specifically investigate the spatial and temporal variabilities and the trends in event frequency and intensity. Here we find heavy and extreme precipitation events over the south-central and western parts of the state are 2-3 times more frequent relative to northern and eastern regions. Within the calendar year, heavy and extreme events exhibited a spatial shift in regional frequency, moving from a typical zone of higher frequency from November-May in the west, to peak relative frequency in mid-summer in the east. Over time, we find a significant decrease in annual precipitation event frequency and total magnitude of over 0.5 days/year and 1.0 inch/decade, respectively, across central Kentucky. Monthly precipitation totals decreased by approximately 0.5 inch/decade over the south-central region in January and increased in the bluegrass region in April and in the northwestern half of state in October by as much as 0.8 inch/decade. Evaluating the variations in precipitation events is a critical first step in understanding why these events occur and how they may or may not change in the future.