Elevated Convection in Snowstorms Using Aircraft and Remote Sensing Instruments During IMPACTS Campaign

Elevated convection in winter cyclones often found to originate in the midtroposphere in the comma head region (e.g. Plummer et al. 2014, 2015; Rauber et al. 2014, 2016; Rosenow et al. 2014, 2018; Keeler et al. 2016, 2017, Murphy et al. 2017, etc.). The Investigation of Microphysics and Precipitation for Atlantic Coast-Threatening Snowstorms (IMPACTS) sampled interesting elevated convection during the winters of 2020, 2022, and 2023 (McMurdie et al., BAMS, 2022). We previously examined elevated convection from 25 January 2020 with the ER-2 radar suite combined with P-3 in situ measurements. This convection initiated well above the freezing level and had updrafts as strong as 12 ms^-1, but more typically a few ms^-1. The reflectivity cores in this convection ranged from 19-26 dBZ, the snow particles within the updrafts were highly rimed with diameters 5 – 10 mm. There was some evidence of supercooled water in the updrafts at higher altitudes (~6 km, -20 C). In this presentation, we will highlight additional cases of elevated convection from the 2022 and 2023 campaigns emphasizing cases with closely coordinated ER-2 and P-3 measurements. We will present results on the characteristics of the convection such as vertical motions derived from the ER-2 radars and P-3 in situ measurements, as well as the associated microphysical structure from P-3 probe data. The multiple frequency radar measurements and the associated non-Rayleigh scattering associated with larger snow are used to derive snow mean diameter and other properties of the snow.