VERTICAL CLOUD STRUCTURE IN A MIDLATITUDE CYCLONE FROM A 94-GHZ RADAR

The vertical structure of clouds associated with a developing midlatit ude cyclone was studied using a 94-GHz cloud radar accompanied by a ho st of other surface-based instruments and rawinsondes. A thickening ci rrostratus deck was observed as the storm approached. As the storm dre w near, low-level moisture advection increased, and a drizzle-producin g stratus deck quickly developed. A rather lengthy period of light to occasionally moderate rain accompanied the passage of the storm. When the storm pulled away to the northeast and the rain ended, the charact er of the stratus deck changed markedly, with no drizzle production ev ident. Other cloud features observed included generating cells and the ir resultant fallstreaks and an ''eye'' that apparently accompanied th e passage of a negatively tilted upper-level trough, as evidenced by m easurements from a 50-MHz wind profiler located near the cloud radar. Rawinsonde measurements showed that the cloud radar also traced the de scent of the melting layer. Satellite observations indicated that atte nuation often limited the ability of the radar to detect cloud top whe n precipitation was occurring. As a result, the radar-reported cloud t ops were 2-5 km lower than those indicated from the satellite cloud-to p temperatures during the heaviest precipitation. During very light pr ecipitation and precipitation-free periods, the satellite brightness t emperatures yielded slight underestimates of cloud-top height. In spit e of the attenuation, the cloud radar revealed many detailed structure s of the clouds of a fairly typical midlatitude cyclone and captured t he entire 3-day event.