A Comparison between Recorded Rainfall and NexRad-Estimated Rainfall

The difference between radar rainfall rate and observed rainfall rate during widespread mesoscale precipitation events was investigated during the time period 21 June to 10 August 2019 in and around the Mt. Joy, Pennsylvania area. Radar rainfall rate data was obtained from the National Oceanic and Atmospheric Administration (NOAA) National Centers for Environmental Information archive from the product “Interactive Map Tool”. The observed rainfall was collected by a 16-member array of rain gauges placed in an approximate grid around Mt. Joy, Pennsylvania. The gauges are plastic liter bottles with the bottom cut off, hung upside down, and attached to a piece of metal rebar with a test-tube vice. In addition, a subproject on rain gauge wetting was preformed to determine systematic error in rainfall amounts when measuring rain totals in the field. Primarily, the research is conducted to understand the variability of rain fall as measured by an array of gauges and to compare that to the rainfall rates derived from radar in lee of the Appalachian Mountains. This presentation will discuss the methodology and results from this research effort, noting the differences across the grid and the differences between the measured rainfall rates from the gauges and the derived rates from the radar.