Comparing Richardson Number to CAPE for Soundings at Locations Impacted by the June 29, 2012 Derecho Before and After

The June 29, 2012 derecho was a large storm complex that impacted a portion of the United States including parts of the Midwest and Mid-Atlantic regions. A key component to the duration and intensity of a storm system of this magnitude is Convective Available Potential Energy (CAPE). Knowing exactly how much CAPE is in the atmosphere before a derecho comes through can be indicative of how the system will evolve in the hours to come. As much as CAPE is important for being a signal of how unstable the atmosphere is, the Richardson Number within the boundary layer can also be used to see how unstable the atmosphere may be. Studying the comparison of both the recorded CAPE values, as well as calculating the Richardson Number using other given atmospheric variables from before and after the passage of the derecho was conducted in order to see if there was any similarity during the June 29, 2012 derecho. The desired outcome of this study was to see that the negative Richardson Number, indicative of unstable conditions, was calculated compared to the CAPE values that were recorded from soundings at six different locations all impacted by the derecho. Using the nearest sounding from before and after were used at all six locations. The soundings provided the necessary information needed to calculate the Richardson Number within the boundary layer and provided the CAPE values. The purpose of this study was to look at a specific weather event that impacted a large area across the United States and try to come up with an answer as to whether the CAPE and Richardson Number within the boundary layer had any comparisons. The June 29, 2012 derecho was a historic storm and by utilizing how vast this system was, data was used to compare two values expressive of how unstable the air was before and after the derecho’s passage.