Wintertime Elevated Convection During the IMPACTS Field Campaign

Elevated convection in winter cyclones has been shown to be rooted above fronts, frontogenetic regions, and other layers of discontinuity in the mid-troposphere (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.). It differs from shallow generating cells that are a common occurrence in winter storms and snow trails that originate near top of deep stratiform clouds. The NASA Investigation of Microphysics and Precipitation for Atlantic Coast-Threatening Snowstorms (IMPACTS) sampled winter storms in the Northeast and Central U.S. during the 2020, 2022, and 2023 winters. The NASA ER-2, with three nadir-looking Doppler radars covering X, Ku, Ka, and W-bands, and the NASA P-3, instrumented with microphysics and other in situ measurements, flew in closely coordinated flight tracks in a variety of storms. This paper will report on the analysis of elevated convection during several elevated convection cases during the 2020-2023 IMPACTS campaigns to highlight the characteristics and origins of this convection. The 20 January 2020 case had an unusually strong convective updraft (> 10ms-1), as compared to previous studies (2-7 m s-1; e.g., Rosenow et al. 2014), that was well-documented by the two aircraft. It was associated with a warm front and a warm occlusion offshore of New Jersey. The 17 February 2022 case was associated with a cold front over New England and New York, and it had weaker vertical motions of similar magnitude to these previous studies. The radar-derived characteristics of these and other elevated convection cases using the multi-frequency ER-2 airborne data will be discussed. Several approaches are used to estimate vertical motions. Reflectivity and vertical velocity data will be supplemented by HRRR and WRF model data and differential reflectivity and polarimetric (LDR) observations to provide additional context into the background and ambient environment for these elevated convective events. Our analysis of the IMPACTS cases aims to provide a better understanding of the microphysical and dynamical characteristics of Northeast wintertime elevated convection that can produce heavier more localized precipitation.