Air Motion Characteristics in the Anvil of a Severe Thunderstorm during CCOPE

Abstract

An analysis of aircraft-measured data obtained in the lower portion of a High Plains thunderstorm anvil is presented. A ?wind shadow? is still evident 5 to 7 core diameters downstream of the storm core. The wind fluctuations are predominantly horizontal on large scales and isotropic on small scales. Little evidence for gravity waves is found in this convectively neutral region of the anvil. Small-scale turbulence is encountered sporadically along cross-anvil penetrations. Weak zones of smooth cloud-edge downdraft are found along the lateral boundaries. The power spectra of the wind components is shallower than the ?5/3 value predicted for an inertial subrange turbulent cascade at the smallest scales resolved (<2 km). Lightning is encountered/triggered by the aircraft twice in different relatively turbulent regions far from the storm core where the temperature is ?35°C and small graupel is present.