CHARACTERISTICS OF DRYLINE PASSAGE DURING COPS-91

The characteristics of dryline passage are documented through an analy sis of data from an instrumented surface mesonetwork in the Texas panh andle, and western and central Oklahoma during the Cooperative Oklahom a Profiler Studies field program. Some eastward-moving drylines at the surface during the day were characterized by monotonic drops in dewpo int after dryline passage; others were marked by a series of rapid dro ps punctuated by periods of no change after dryline passage, which sug gests that the dryline often progresses in discrete steps, rather than continuously. The dryline during the daytime was not always collocate d with a pressure trough, although the strongest dryline observed was. Analyses of surface pressure traces indicated that westward-moving dr ylines during the evening did not display behavior characteristic of s trong, intense density currents, as had been found in other studies. E vidence is presented, in one case, of 90-min oscillations in water vap or and wind behind the dryline, which may have been associated with th e downward transport of momentum associated with gravity waves aloft.