NC STATE UNIVERSITY

Matthew D. ParkerNorth Carolina State Univ.

Raleigh, NC

CSTAR workshop: High-shear, low-CAPE (“HSLC”)

tornadoes/sig. severe introduction

16 November 2012

individual report influence - 160 km radius

Mean Tornado Environment: ML CAPE & 0-6 km Shear

2004-2005: 3277 tornado reports | 344 tornado days

Max MLCAPE Over Plains

Lower MLCAPE and Stronger Shear

courtesy: Steve Weiss

ML CAPE (J/kg, color fill), 0-6 km Shear (kt, blue barbs) (year=2004-2005, month=ALL)

ML CAPE ≥ 2000 J kg -1 | 0-6 km Shear ≥ 35 kt | ML CIN ≥ - 100 J kg -1

Integrated 2003 - 2006 “environment hours” High CAPE; Strong Shear; Moderate CIN

Integrated 2003 - 2006 “environment hours” High CAPE; High Shear; Moderate CIN

Max 240 hr or 60 hr/yr

courtesy: Steve Weiss

ML CAPE ≤ 1000 J kg -1 | 0-6 km Shear ≥ 35 kt | 0-1 km Shear ≥ 20 kt ML LCL ≤ 1000 m | ML CIN ≥ - 100 J kg -1

Integrated 2003 - 2006 “environment hours” Low CAPE; High Shear; Low LCL; Mod. CIN

Max 480 hr or 120 hr/yr

courtesy: Steve Weiss

High CAPE | Strong Shear Low CAPE | Strong Shear

• 26% of F2+ tornadoes

• local axis 30-60 hr/year

• 22% of F2+ tornadoes

• widespread 80-120 hr/year

48% of all F2+ tornadoes

courtesy: Steve Weiss

Basic parameters:

• Monthly conference calls for planning, O2R/R2O, etc.

• By consensus, HSLC is considered to be: 0-6 km shear > 35 kts and SBCAPE <

500 J.kg

• By consensus, landfalling TC cases are omitted

• Initial “training dataset” of regional cases identified by NWS collaborators Baseline for radar and parameter studies Best events singled out for detailed NWS case

studies

• Additional data from SPC to supplement our work Mesoanalysis data for detailed case studies

(delivered online for use in Google Earth) Relational database for all reports (not just the

collaborator-identified cases)

Specific aims (end products):

• Quantification of significant differences in ingredients for events vs. nulls; a new composite parameter idealized for HSLC (Sherburn lead)

• Statistical assessment of radar signatures (convective mode, trackable mesovortices, other signatures like broken-S) associated with events vs. nulls (Davis lead)

• Stats for groupings of interest: day vs. night, summer vs. winter, near vs. far from radar, S.E. U.S. vs. other regions, etc. (both projects)

• A population of thorough case studies (events and nulls) whose environments and radar signatures will be compared to (and motivate) the longitudinal environmental and radar statistics (Moore, Lane, Coleman team leaders)