Interaction of an upper-tropospheric jet with a squall line originating along a cold frontal boundary

Daniel M. Stechman, Robert M. Rauber, Greg M. McFarquhar, Brian F. Jewett, David P. Jorgensen

Research output: Contribution to journalArticle

Abstract

On 8 June 2003, an expansive squall line along a surface cold frontal boundary was sampled during the Bow Echo and Mesoscale Convective Vortex Experiment. The Naval Research Laboratory P-3 aircraft and the National Oceanic and Atmospheric Administration P-3 aircraft simultaneously sampled the leading and trailing edge of this squall line, respectively, with X-band Doppler radars. Data from these two airborne radar systems have been synthesized to produce a pseudo-quad-Doppler analysis of the squall line, yielding a detailed three-dimensional kinematic analysis of its structure. A simulation of the squall line was carried out using the Weather Research and Forecasting Model to complement the pseudo-quad-Doppler analysis. The simulation employed a 3-km, convection-allowing, nested domain centered over the pseudo-quad-Doppler domain, along with a 9-km parent domain to capture the larger synoptic-scale cyclone. The pseudo-quad-Doppler analysis reveals that the convective line was embedded within the upper-tropospheric jet stream, causing local decelerations and deviations in the jet-level flow. The vertical transport of low momentum air from the boundary layer via convective updrafts is shown to significantly decelerate jet-level flow. Pressure perturbations associated with the intrusion of low momentum air into the jet stream-level flow led to deviation of the jet stream flow around the squall line that resulted in counter-rotating ribbons of vertical vorticity parallel to the squall line. Model results indicate that disturbances in the jet stream structure persisted downwind of the squall line for several hours.

Original languageEnglish (US)
Pages (from-to)4197-4219
Number of pages23
JournalMonthly Weather Review
Volume144
Issue number11
DOIs
StatePublished - Jan 1 2016

Keywords

  • Aircraft observations
  • Convective storms
  • Mesoscale systems
  • Radars/Radar observations

ASJC Scopus subject areas

  • Atmospheric Science

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