Boundary layer features influencing convection inititiation on 12 June 2002 during IHOP_2002

The International H₂O Project (IHOP_2002) was designed to sample the three-dimensional time-varying moisture field to better understand convective processes. Numerous research and operational water vapor measuring systems and retrievals were operated in the U.S. Southern Great Plains from 13 May to 25 June 2002. This was done in combination with more traditional observations of wind and temperature. Convection initiation (CI) missions were designed to maximize observational overlap from multiple instruments to better understand the processes leading to the development of deep, moist convection. This particular study examines the impact of different boundary-layer features upon a convection initiation event on 12 June 2002. The storms intensified and produced damaging winds and hail. The various clear-air, pre-convective features include i) a dryline, ii) a warm front, iii) their intersection, iv) a mesolow, v) internal gravity waves and vi) horizontal convective rolls.

Many unique instruments were positioned to sample the pre-convective environment on 12 June 2002. The Leandre II water vapor DIAL, ELDORA airborne Doppler radar and P-3 in situ measurements provide information on the moisture and vertical velocity distribution within the boundary layer. Radiosondes and dropsondes provide profiling information throughout the atmosphere. Although other ground-based sensors (i.e., S-Pol radar, mobile radars and mobile mesonets) were farther west than the CI area, they are useful for illustrating the high-resolution boundary-layer kinematics and thermodynamics.

The combination of these high-temporal and -spatial resolution measurements provide a detailed account of interactions between the various boundaries, mesolow, waves and rolls and their impact upon convective development. The objective is to improve our understanding regarding the scales of boundary layer features that are important in influencing the timing and location of new convection.