Mesoscale Convective Vortices (MCVs) Observed During the Bow-Echo and MCV Experiment (BAMEX) 2003

1. Mesoscale Convective Vortices (MCVs) Observed During the Bow-Echo and MCV Experiment (BAMEX) 2003 Stanley B. Trier and Christopher A. Davis NCAR, Boulder, Colorado USA Related Papers: Part I: Kinematic and Thermodynamic Structure (Davis and Trier 2007, Mon. Wea. Rev.) Part II: Influences on Secondary Deep Convection (Trier and Davis 2007, Mon. Wea. Rev.)

2. Raymond and Jiang (JAS 1990) Conceptual Model of Isentropic Lifting within a Steady Balanced Vortex (e.g., MCV)

3. Contents: 1) Brief Overview of Methodology 2) Mesoscale Vertical Motions within the MCV Environment (a) Kinematic (b) Steady, Isentropic 3) MCV Influences on Secondary Convection (a) Thermodynamic Influences (b) Vertical Shear Influences 4) Conclusions

4. Analysis Method • Dropsonde, profiler and MGLASS data • composited to common reference time • (constant MCV motion assumed) • Kinematic (full) w calculated from upward • integrated divergence along triangles • Steady, isentropic w also calculated using • triangles (requires thermodynamic data) • Restrictions on minimum angle, triangle area • Overlapping triangles used to assess • “confidence” (s) • 25-km analysis grid

5. Average Kinematic wProfiles by Sector (Downshear, Upshear)

6. IOP 5 Omega Vertical Velocity (mb/s) 800-hPa Kinematic w / 600-hPa Relative Winds 800-hPa Isentropic w / 600-hPa Relative Winds Localized CAPE, Moderate Vortex, Strong Shear (Strong Vortex Tilt)

7. IOP 5 Omega Vertical Velocity (mb/s) 750-hPa Kinematic w / 600-hPa Relative Winds 750-hPa Isentropic w / 600-hPa Relative Winds Widespread CAPE, Weak Vortex, Moderate Shear

8. IOP 1 Omega Vertical Velocity (mb/s) 800-hPa Kinematic w / 600-hPa Relative Winds 800-hPa Isentropic w / 800-hPa Relative Winds No CAPE, Moderate Vortex, Strong Shear

9. IOP 4 Omega Vertical Velocity (mb/s) 800-hPa Kinematic w / 600-hPa Relative Winds 800-hPa Isentropic w / 800-hPa Relative Winds No CAPE, Moderate Vortex, Strong Shear (Large-scale Influence)

10. IOP 8 Omega Vertical Velocity (mb/s) 800-hPa Kinematic w / 600-hPa Relative Winds 800-hPa Isentropic w / 600-hPa Relative Winds Widespread CAPE (E-SE), Strong Vortex, Weak Shear

11. PBL Equivalent Potential Temperature (High, Low), Ground Relative Winds, and 600-mb MCV Center (x) IOP 5 IOP8 IOP 15

12. Variability of Thermodynamic Vertical Profiles Across MCV in Secondary Convection Cases Weak vortex in moderate vertical shear Moderate vortex in strong vertical shear IOP 5 IOP 15

13. Average Surface to 3.5-km AGL Vertical Shear in Different MCV Sectors Downshear (Solid) and Upshear (Hollow) Sectors Sectors to the Right (Solid) and Left (Hollow) of Downshear

14. Conclusions • Heaviest precipitation downshear, upshear typically precipitation free Significant secondary convection in 3 of 5 cases

15. Conclusions • Heaviest precipitation downshear, upshear typically precipitation free Significant secondary convection in 3 of 5 cases • Vertical motion influenced by environmental vertical shear and MCV strength DU/VT >= 1 (IOPs 5 and 15) Mesoscale vertical motion dipole DU/VT < 1 (IOP 8) Far more complicated vertical motion pattern

16. Conclusions • Heaviest precipitation downshear, upshear typically precipitation free Significant secondary convection in 3 of 5 cases • Vertical motion influenced by environmental vertical shear and MCV strength DU/VT >= 1 (IOPs 5 and 15) Mesoscale vertical motion dipole DU/VT < 1 (IOP 8) Far more complicated vertical motion pattern • Large variations in thermodynamic vertical structure across the MCVs MCV-induced vertical motions and horizontal advection influence conditional instability Downshear destabilization Upshear stabilization

17. Conclusions • Heaviest precipitation downshear, upshear typically precipitation free Significant secondary convection in 3 of 5 cases • Vertical motion influenced by environmental vertical shear and MCV strength DU/VT >= 1 (IOPs 5 and 15) Mesoscale vertical motion dipole DU/VT < 1 (IOP 8) Far more complicated vertical motion pattern • Large variations in thermodynamic vertical structure across the MCVs MCV-induced vertical motions and horizontal advection influence conditional instability Downshear destabilization Upshear stabilization • MCVs can significantly modify vertical shear Shear typically enhanced over that of environment (most dramatic SE of MCV center)

18. Conclusions • Heaviest precipitation downshear, upshear typically precipitation free Significant secondary convection in 3 of 5 cases • Vertical motion influenced by environmental vertical shear and MCV strength DU/VT >= 1 (IOPs 5 and 15) Mesoscale vertical motion dipole DU/VT < 1 (IOP 8) Far more complicated vertical motion pattern • Large variations in thermodynamic vertical structure across the MCVs MCV-induced vertical motions and horizontal advection influence conditional instability Downshear destabilization Upshear stabilization • MCVs can significantly modify vertical shear Shear typically enhanced over that of environment (most dramatic SE of MCV center) • Limitations of this analysis Unable to follow evolution (inferences consistent with previous modeling studies) Only daytime MCV cases sampled (secondary convection results may lack generality)

19. Average q’Profiles by Sector (Downshear, Upshear)