An Investigation of Convective Initiation within Dryline Zones

Drylines mark a transition zone between hot dry air and warm moist air, and are a common topic of interest due to their role in convective initiation. Analyses at a high spatiotemporal resolution (400 m, 5 min) produced from the ARPS Data Analysis System (ADAS) and the three-dimensional variational assimilation system (3DVAR) result in a unique, detailed perspective of dryline zone features.

Three cases from 2010 are presented including data collected during April 7th, May 10th, and May 19th. In each case, a leading edge theta-e boundary east of the primary dryline moisture gradient acts as a focal point for convective initiation rather than the primary dryline itself. This leading edge is collocated with a vertical low level relative humidity wedge from the west found in cross section analyses. These findings produced in the analyses coincide with observations from WSR-88D radar reflectivity fine lines. These results and possible physical explanations for these phenomena are reviewed.