CSTAR High-Shear Low-CAPE Conference Call Notes – July 2015

July 2015 CSTAR High-Shear Low-CAPE Conference Call Notes

The call occurred on Tuesday, July 28th, from 11AM to around 1145 AM EST. There were participants from NC State, AKQ, BMX, CAE, GSP, HUN, LWX, RAH, RNK, and SPC.

1) Research update from Keith Sherburn on the HSLC process study using idealized modeling and emulated radar sampling project. The slide deck is available for downloading at https://goo.gl/0iJUna

  • imageSubtle changes in low-level hodograph shape and orientation have a large impact on convective evolution in HSLC environments, as shown by a matrix of 12 simulations.
  • Streamwise vorticity/storm-relative helicity in lowest levels is critical for strong, rotating updrafts and intense low-level vortices due to enhanced dynamic lifting.
  • The amount of line-normal flow even in the lowest 1 km affects the ability for convection to move off of an initiating boundary.
  • Hodograph shape aloft plays a role in precipitation fallout, ultimately altering the proximity of adjacent updrafts/downdrafts from neighboring cells, potentially influencing the life cycle of low-level vortices.
  • Future work will examine the development and failed development of intense, long-lived, low-level vortices in these simulations and compare their origins to those in higher-CAPE environments.

2) Research update from Lindsay Blank on the operational NWP resolution and sensitivity study using HSLC event hindcasts project.

The slide deck is available for viewing at https://goo.gl/er5HZS

  • Lindsay is focusing on three metrics: radar reflectivity, hourly precipitation, and rotational tracks.
  • The new model setup is being used. It appears that the model is overactive in the coarser the domain.
  • Preliminary results indicate that WRF produces more hourly precipitation than Stage IV observations.

 3) Discussion of QLCS Tornado Warnings Work in central Region at WFO Springfield MO

Jonathan previously passed along some notes on the work that WFO Springfield MO and other partners have been doing relating to efforts to improve QLCS Tornado Warnings. Jason Schaumann, SOO NWS Springfield, MO, provided much of the information shown below. Based on some initial feedback, we are planning on inviting Jason to present some of his work in a future conference call.

The initial work: Operational Application of 0-3 Km Bulk Shear Vectors in Assessing QLCS  Mesovortex And Tornado Potential by Jason Schaumann and Ron Pryzbylinski describes a three ingredients method for anticipating mesovortex genesis and rapid intensification. This methodology applies for both the cold and warm seasons. A statistical research project was conducted by a Hollings Scholar student to show the statistical significance of the three ingredients method.

Subsequently they worked to identify additional mesoscale and radar signatures which represent an increased probability for damaging winds and tornadoes from mesovortices. The recent culmination of these efforts includes guidance for issuing severe thunderstorm and tornado warnings for mesovortices.  Most recently, Michael Mathews from Bismark, ND developed a two page handout and video condensing and highlight this work. Jason has constructed a Google Site which summarizes all of this work. Included on this site are two recent webinars that were given to Central Region (and a few Southern Region) offices. The first presentation covers the three ingredients method while the second presentation covers radar and warning strategies.

4) Next Conference Call

Since many of the NC State students have different schedules this semester because of classes, we will need to identify a time to have regular monthly calls. Please keep an eye out for an email requesting input.

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