Flash floods are capable of occurring everywhere in the United States. These events are extremely destructive and are responsible for the most deaths every year of any weather-related phenomena. Flash floods occur most often when a large amount of precipitation falls in a short amount of time. When the ground is not able to absorb this precipitation it flows into streams and waterways. If the water overflows the banks of a waterway, flooding begins. In order to get a better understanding of the conditions that cause flash flooding, it is useful to study weather situations that cause heavy precipitation events.
This investigation examines the circumstances responsible for flooding in south central Kentucky on 1 March 1997. This heavy rain event received significant synoptic-scale forcing from a cold front advancing into the area from the Mississippi River Valley. Additionally, the Appalachian Mountains over eastern Kentucky stalled this system and altered the windflow, leading to enhanced moisture convergence over the state. Further, significant convective activity occurred due to the high degree of instability and synoptic-scale forcing. The end result was as much as 30 cm of rainfall in some locations.
PC-GRIDDS, was used to analyze the initialization data for the ETA-model to investigate this scenario. PC-GRIDDS allows for model output to be analyzed at a variety of atmospheric levels. A valuable aspect of this software is that it enables one to analyze not only conventional meteorological variables (e.g., sealevel pressure, moisture content, or winds), but more complex calculations (e.g., lifted index, moisture convergence, or absolute vorticity). Through the use of this software package, forecasters can determine conditions that contribute to heavy precipitation, thereby leading to improved warnings of flash flood events