SPC analysis Derecho Composite Parameter
Notes:
In summary, many favorable factors for a significant squall line with damaging winds across northern Pennsylvania and southern New York appeared to be present for this case. Positive factors included very large CAPE immediately downstream from that area, dry air, and strong winds and wind shear. The derecho composite parameter (DCP) is a function of all of these parameters. Specifically, parameters in the DCP are Downdraft CAPE, most unstable CAPE, 0-6 km shear and 0-6 km mean wind. The plot on the right indicate that values of greater than 2 indicate a favorable environment for a derecho. In this case, values ranged from 5 to 10 across central New York and eastern Pennsylvania.Click on image to toggle between images.
Slide 16