Partnering Research, Education, and Operations via a Cool Season Severe Weather Soundings Program

Abstract

Recent research has improved our knowledge and forecasting of high-shear, low-CAPE (HSLC) severe convection, which produces a large fraction of overnight and cool season tornadoes. However, limited near-storm observations have hindered progress in our understanding of HSLC environments and detection of severe potential within them. This article provides an overview of a research project in central North Carolina aimed toward increasing the number of observations in the vicinity of severe and nonsevere HSLC convection. Particularly unique aspects of this project are a) leadership by student volunteers from a university sounding club and b) real-time communication of observations to local National Weather Service Forecast Offices. In addition to an overview of sounding operations and goals, two case examples are provided that support the potential utility of supplemental sounding observations for operational, educational, and research purposes.

The Development of Severe Vortices within Simulated High-Shear, Low-CAPE Convection

“…(03lr) affect the structure, evolution, and intensity of HSLC convection. The control thermodynamic and kinematic profiles were subjectively designed to capture the typical characteristics from prior HSLC composites (Sherburn et al 2016)…”

“…These high-shear, low-CAPE (HSLC) environments support approximately half of the significant (EF21) tornadoes in the CONUS (Schneider et al 2006), either within miniature supercells or quasi-linear convective systems (QLCSs; e.g., Smith et al 2012;Davis and Parker 2014). However, HSLC convection is also associated with low probabilities of detection (PODs) and high false alarm rates (FARs) of tornado watch and warning products (Dean and Schneider 2012;Anderson-Frey et al 2016;Sherburn et al 2016).…”

“…Recent work has improved our knowledge of the ingredients and settings favoring severe HSLC convection (Sherburn and Parker 2014;Sherburn et al 2016;King et al 2017). Severe HSLC environments tend to exhibit steeper low-level lapse rates, larger low-level shear vector magnitudes, and stronger synoptic-scale forcing for ascent than their nonsevere counterparts.…”

“…Based on this prior research, the strength of low-level updrafts and associated rotation in mesocyclones or mesovortices influence the likelihood of tornadogenesis. It is important to consider the means by which environmental variables with documented discriminatory skill in HSLC environments (low-level lapse rates and shear vector magnitudes 1 ; Sherburn and Parker 2014;Sherburn et al 2016) could impact each of these features. The sensitivity of vortexgenesis to low-level shear vector magnitude has been documented in both QLCSs and supercells within high-CAPE environments, as reviewed above.…”

“…Overview of 1-km reflectivity (dBZ; rainbow shading), surface potential temperature perturbation (K; tan to dark blue shading), 1-km w (5, 7.5, 10, 12.5, 15, 20, 25, and 30 m s 21 ; black contours), and 1-km z (0.02, 0.04, 0.06, 0.08, and 0.1 s 21 ; white contours) for the control simulation from (a) t 5 150 min through (i) t 5 270 min over 15-min intervals. typical in cool-season HSLC environments (e.g., Schneider et al 2006;Sherburn et al 2016).…”