The Oklahoma–Kansas Mesoscale Convective System of 10–11 June 1985: Precipitation Structure and Single-Doppler Radar Analysis

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  • 1 Department of Atmospheric Sciences, Oregon State University, Corvallis, Oregon
  • | 2 Department of Atmospheric Sciences, University of Washington, Seattle, Washington
  • | 3 National Center for Atmospheric Research, Boulder, Colorado
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Abstract

The 10–11 June mesoscale convective system observed in Kansas during PRE-STORM is studied using a variety of observations including conventional radar, satellite, and single-Doppler radar. This storm, at maturity, consisted of a strong line of convection trailed by a broad region of stratiform rain. The PRE-STORM Doppler radar observations show that the general airflow pattern is similar to that seen in previously analyzed cases; however, since the Doppler observations were quite extensive in time and space, they permit several details of the airflow to be revealed for the first time.

A rear inflow jet, front-to-rear flow aloft, and a mesoscale updraft and downdraft were all present. The mesoscale downdraft commenced at the top of the slanted rear inflow jet. Sublimation and evaporation of hydrometeors in this flow apparently generated the necessary cooling to drive the mesoscale downdraft circulation. The intensity and slope of the rear inflow jet varied with location in the storm, which apparently led to differences in both the intensity and depth of the mesoscale downdraft. The intrusion of this inflow jet into the rear of storm occurred at quite high levels and was probably responsible for disruption of the continuous oval cloud shield as viewed by satellite.

The front-to-rear flow situated above the rear inflow jet contained mesoscale upward motion. Vertical velocities obtained by the EVAD (Extended Velocity–Azimuth Display) method reveal a strong mesoscale updraft, with speeds approaching 50 cm s−1. Vertically pointing observations indicated that convective-scale updrafts and downdrafts were present within 20 km of the convective line. Convective-scale features were not observed in the remaining portion of the trailing stratiform region.

Abstract

The 10–11 June mesoscale convective system observed in Kansas during PRE-STORM is studied using a variety of observations including conventional radar, satellite, and single-Doppler radar. This storm, at maturity, consisted of a strong line of convection trailed by a broad region of stratiform rain. The PRE-STORM Doppler radar observations show that the general airflow pattern is similar to that seen in previously analyzed cases; however, since the Doppler observations were quite extensive in time and space, they permit several details of the airflow to be revealed for the first time.

A rear inflow jet, front-to-rear flow aloft, and a mesoscale updraft and downdraft were all present. The mesoscale downdraft commenced at the top of the slanted rear inflow jet. Sublimation and evaporation of hydrometeors in this flow apparently generated the necessary cooling to drive the mesoscale downdraft circulation. The intensity and slope of the rear inflow jet varied with location in the storm, which apparently led to differences in both the intensity and depth of the mesoscale downdraft. The intrusion of this inflow jet into the rear of storm occurred at quite high levels and was probably responsible for disruption of the continuous oval cloud shield as viewed by satellite.

The front-to-rear flow situated above the rear inflow jet contained mesoscale upward motion. Vertical velocities obtained by the EVAD (Extended Velocity–Azimuth Display) method reveal a strong mesoscale updraft, with speeds approaching 50 cm s−1. Vertically pointing observations indicated that convective-scale updrafts and downdrafts were present within 20 km of the convective line. Convective-scale features were not observed in the remaining portion of the trailing stratiform region.

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