The OWLeS (Ontario Winter Lake-effect Systems) campaign, winter 2013-14

The NSF-funded OWLeS project will examine the formation mechanisms, cloud microphysics, boundary layer processes and dynamics of lake-effect systems (LeS) using new observational tools capable of detailing characteristics not documented in previous LeS field experiments. OWLeS is a collaborative effort, involving several universities in the proximity of the Great Lakes (SUNY-Oswego, Hobart and William Smith Colleges, University of Illinois in Urbana – Champaign, Penn State University, Millersville University, as well as the National Center for Atmospheric Research, the Center for Severe Weather Research, the University of Utah, the University of Alabama in Huntsville, and the University of Wyoming. The OWLeS project focuses on Lake Ontario because of its geometry and size, frequency of LeS, nearby orography, and location usually downwind of the other Great Lakes.

Both short-fetch LeS (those oriented at large angles to the long axis of the lake) and long-fetch LeS (those more aligned with the lake's long axis) will be targeted in OWLeS, to be conducted in December 2013 and January 2014. Facilities include the University of Wyoming King Air with cloud radar and cloud lidar (WCL) systems, three Doppler on Wheels (DOW) radar systems, and an array of PI-supported mobile and stationary flux, surface, and sounding systems. The overarching objectives of the OWLeS project are to: a) describe the upwind surface and atmospheric factors determining the three-dimensional structure of short-fetch LeS convective bands that develop over a relatively-warm, open water surface; b) understand the development of, and interactions between, internal planetary boundary layers (PBL) and residual layers resulting from advection over multiple mesoscale water bodies and intervening land surfaces; c) examine how organized, initially convective LeS structures in short-fetch conditions persist far downstream over land, long after leaving the buoyancy source (i.e., the ice-free water); d) examine how surface fluxes, lake-scale circulations, cloud microphysics and radiative processes affect the formation and structure of long-fetch LeS; e) understand dynamical and microphysical processes controlling the fine-scale kinematic structures and lightning characteristics of intense long-fetch LeS; f) provide in situ validation of operational (S-band) and research (X-band) dual-polarization hydrometeor type classification and lake-effect snowfall QPE; and g) understand the influence of downwind topography on LeS generated over Lake Ontario.

It is anticipated that research based on observations taken during OWLeS will add understanding benefitting fields of mesoscale and boundary layer meteorology, cloud microphysics, mountain meteorology, as well as forecasting of these intense storm systems.