THE FRONT-RANGE BLIZZARD-OF-1990 .2. MELTING EFFECTS IN A CONVECTIVE BAND

A north-south-oriented line of convection, associated with a melting-i nduced mesoscale front, formed south of the Mile High Radar (MHR) duri ng the early hours of the Front Range blizzard of 6-7 March 1990. The kinematic Structure of the mesoscale front, that is, precipitation ban d, was examined by analyzing single-Doppler radar data from MHR with t wo analysis techniques. The results from the analyses were augmented a nd compared with observations from three surface stations within the W inter Icing and Storms Project (WISP) area. Because of the extraction of the latent heat of fusion from the atmosphere as ice particles melt ed, the temperature dropped rapidly as the rainband passed This result ed in a large poor of stable, 0 degrees C air behind the mesoscale fro nt. As the melting continued, this pool expanded toward the east where it was not blocked by terrain. It expanded into a convectively unstab le air mass with strong southeasterly winds. A band-parallel low-level jet developed east of the band and remained essentially stationary, w hile the band propagated beneath and to the east of the jet, at which point the band dissipated. The shallow pool of stable air continued to move slowly to the east.