1. The High-Shear, Low-CAPE SHERB parameter and its evaluation Keith D. Sherburn Department of Marine, Earth, and Atmospheric Sciences North Carolina State University Research to Operations Webinar October 24, 2014

2. Tuesday posters, 3:00-4:15pm (Sessions 5 & 6): –“Synoptic Influence on High Shear, Low CAPE Convective Events”, Jessica R. King and M. D. Parker –“On the usage of composite parameters in High-Shear, Low- CAPE environments”, Keith D. Sherburn and M. D. Parker Wednesday, 4:45pm (Session 12B): –“High-Shear, Low-CAPE environments: What we know and where to go next”, Keith D. Sherburn and M. D. Parker 2 For those attending SLS…

3. High-shear, low-CAPE (HSLC) environments: second “key subclass” of severe weather (Schneider et al. 2006) Over half of significant or violent tornadoes (EF2+) associated with HSLC Relatively high number of missed events and false alarms Few operational or modeling studies 3 Background

4. Typical Features Cool season/overnight Strongly-forced Low LCLs Low-level instability Low-level jet QLCS or mini- supercells Spatially compact Transient rotation Little lightning Credit Mike Strickler, WFO Raleigh Clark (2009)Lane and Moore (2006) Davis and Parker (2014) Sherburn and Parker (2014)

5. Credit Jason Davis

6. Supercell Mesocyclones (9 tor., 13 nontor.) QLCS Mesovortices (17 tor., 12 nontor.) Only vortices within 60 km of the radar Statistically significant differences No statistically significant differences Differences mostly vanish aloft Davis and Parker (2014)

7. Statistically significant differences Davis and Parker (2014)

8. Supercell Reflectivity Signatures Davis and Parker (2014)

9. QLCS Reflectivity Signatures Davis and Parker (2014)

10. Credit Jason Davis

11. 11 SHERB Parameter

12. 12 Maximum TSS of Composite Parameters by Geographic Region

13. 13 SHERB Distributions

14. SHERBS3 Availability for Forecasters AWIPS-1 Volume Browser addition code & instructions https://collaborate.nws.noaa.gov/trac/nwsscp/wiki/AppsAwips/Sherb (AWIPS-2 code under development) AWIPS-1 and AWIPS-2 GFE tool coding & instructions https://collaborate.nws.noaa.gov/trac/nwsscp/wiki/Gfe/Smarttools/Sherb Real-time SHERB plots from NC State Real-time RAP – http://storms.meas.ncsu.edu/users/mdparker/rap Real-time NAM – http://storms.meas.ncsu.edu/users/mdparker/nam Real-time GFS – http://storms.meas.ncsu.edu/users/mdparker/gfs SPC SHERB mesoscale analysis plots Nationwide SHERBS3 – http://www.spc.noaa.gov/exper/mesoanalysis/s19/sherb3/sherb3.gif Nationwide SHERBE – http://www.spc.noaa.gov/exper/mesoanalysis/s19/sherbe/sherbe.gif SHERB is expected to be added to Bufkit in an upcoming release

15. How not to use the SHERB To forecast convection Must be used with a confident forecast of convection All data points used to develop the SHERB were associated with either severe or non-severe convection Therefore, cannot be used to forecast convection! Where convection is not expected Values potentially above guidance threshold where convection will not occur In isolation Composite parameters (e.g., STP, VGP) still exhibit skill, though potentially at lower values than in high-CAPE environments Credit Jonathan Blaes

16. SHERB Feedback HSLC “One Stop Shop” http://www.meas.ncsu.edu/mdparker/sherb/index.html

17. SHERB Optimization Continuing to test different formulations of the SHERB Statistical and observational tests New combinations of parameters Operational tests

18. Davis and Parker (2014), “Radar Climatology of Tornadic and Non-Tornadic Vortices in High-Shear, Low-CAPE Environments in the Mid-Atlantic and Southeastern U.S.” Sherburn and Parker (2014), “Climatology and Ingredients of Significant Severe Convection in High Shear, Low CAPE Environments” Both in Weather and Forecasting (August 2014) HSLC CSTAR Articles

19. CSTAR Program NOAA Grant NA10NWS4680007 AMS/NOAA NWS Graduate Fellowship AMS/NASA Earth Science Graduate Fellowship Program NSF Grant AGS-1156123 WFO Collaborators Storm Prediction Center Acknowledgements 19

20. Clark, M. R., 2009: The southern England tornadoes of 30 December 2006. Atmos. Res., 93, 50-65. Dean, A. R., and R. S. Schneider, 2008: Forecast challenges at the NWS Storm Prediction Center relating to the frequency of favorable severe storm environments. Preprints, 24th Conf. on Severe Local Storms, Savannah, GA, Amer. Meteor. Soc., 9A.2. Dean, A. R., and R. S. Schneider, 2012: An examination of tornado environments, events, and impacts from 2003-2012. Preprints, 26th Conf. on Severe Local Storms, Nashville, TN, Amer. Meteor. Soc., P60. Lane, J. D., and P. D. Moore, 2006: Observations of a non-supercell tornadic thunderstorm from terminal Doppler weather radar. 23rd Conf. on Severe Local Storms, St. Louis, MO, Amer. Meteor. Soc., P4.5. Schneider, R. S., A. R. Dean, S. J. Weiss, and P. D. Bothwell, 2006: Analysis of estimated environments for 2004 and 2005 severe convective storm reports. Preprints, 23rd Conf. on Severe Local Storms, St. Louis, MO, Amer. Meteor. Soc., 3.5. References 20

21. Contact Information Webinar Presenter –Keith Sherburn (kdsherbu@ncsu.edu) Principal Investigator –Dr. Matthew Parker (mdparker@ncsu.edu) NWS contributors –Jason Davis (BMX) jason.davis@noaa.gov –Justin Lane (GSP) Justin.Lane@noaa.gov –Jonathan Blaes (SOO RAH) jonathan.blaes@noaa.gov