The Mesoscale and Microscale Structure and Organization of Clouds and Precipitation in Midlatitude Cyclones. VI: Wavelike Rainbands Associated With a Cold-Frontal Zone

Abstract

The cloud and precipitation structure and the airflow associated with wavelike rainbands in a cold-frontal zone have been investigated with Doppler radar, instrumented aircraft, rawinsondes and a network of ground stations. The rainbands were oriented perpendicular to the cold front and embedded within wide cold-frontal rainbands. The wavelike rainbands were 20?40 km long, 3?6 km wide, spaced 9?13 km apart and their tops ranged from 3-5 km in height. The radar reflectivities, convergence/divergence and airflow show regular patterns associated with the rainbands. There is evidence that wavelike rainbands were associated with generating cells aloft. These rainbands may have been initiated by shear instability in the frontal zone, since the resonant mode for such an instability had a similar orientation, movement and spacing to those observed for the rainbands.