Mobile Doppler Radar Observations of an Intense Long Lake-Axis Parallel Lake-effect Snowband on 10–12 December 2013 During the Ontario Winter Lake-effect Systems Project

On 10 December 2013, an intense long lake-axis parallel lake-effect precipitation band developed over Lake Ontario in response to an outbreak of cold air over the Great Lakes region. Mobile Doppler and dual-polarimetric radar data were collected on this band in association with the Ontario Winter Lake-effect Systems Project. These data were complimented by soundings and mobile and stationary observations of surface meteorological conditions. The system transitioned between a solid band of precipitation and a broken band consisting of many convective elements several times during its life span. Potential causes for these transitions will be explored, including differential vorticity advection owing to the passage of shortwave troughs, changes in the thermodynamic environment, the propagation of wind shifts through the band, and the presence of mesoscale vortices. There were also several other misoscale vortices that developed; these were most numerous when the band was solid and contained a sharp wind shift early in the observation period. It is likely that horizontal shear instability was the dominant mechanism in the formation of these features. These vortices will also be cataloged by size, strength, and depth.