On January 6, NCSU students Jason Davis and Keith Sherburn visited the Greer, SC (GSP) weather forecast office to discuss a variety of topics related to the HSLC portion of the CSTAR project. The students met primarily with Pat Moore, Justin Lane, and Larry Lee from GSP and Hunter Coleman from Columbia, SC (CAE).
The forecasters first led the group through a series of case studies using the weather event simulator, allowing for discussions of both tornado events and null cases in an operational framework. These case studies included observations of two broken-S radar signatures, one of which produced a tornado and one of which that did not, and an event in which squall line interactions with a supercell produced a tornado. The forecasters stressed the importance of focusing on base scan data due to the need to make quick warning decisions in these fast evolving events. Therefore, it was learned that it is important that research on radar signatures associated with HSLC tornadoes should be applicable to what forecasters see in the base data. The forecasters also discussed how they take a careful look at any radar signature that appears out of the ordinary. Following the case studies, Jason presented some preliminary radar images from HSLC cases and began a discussion on the utility of radar derived products such as the v-r shear tool in AWIPS, the normalized rotation (NROT) product in GR2Analyst, and the azimuthal shear product in NSSL’s WDSS-II application.
Further discussion took place on the role of baroclinicity in HSLC events, the predictability of HSLC events, and comparisons between HSLC events and events with higher CAPE. To wrap up the visit, Keith began a discussion on what the forecasters at GSP could most benefit from in a parameter-based climatology. In general, it was agreed upon that it would be beneficial to synthesize all of the factors for forecasters so that they can easily identify the potential risks prior to the outset of an event. Ideally, this would include knowledge of the storm type along with anticipated radar structures if a QLCS event is expected. This will require determining what impact CAPE has on convective mode, whether SRH is relevant in terms of tornadogenesis, and what the ideal effective layer for HSLC events is.