Growth of Ice Particles and Precipitation Development in Wintertime Snowstorms during IMPACTS

Using particle probe from the NASA P3 collocated with the ER-2 aircraft during the Investigation of Microphysics and Precipitation for Atlantic Coast-Threatening Snowstorms (IMPACTS) field programs in 2020, 2022 and 2023, we piece together the development and evolution of ice particles in snowbands and generating cells. The P3 aircraft was equipped with a full complement of particle probes, direct measurements of the condensed water content, and thermodynamic and 3D wind measurements. The ER-2 was equipped with nadir-viewing radars operating at four wavelengths The boundaries of the updraft regions sampled during individual case studies are identified as a function of altitude.

Total ice particle concentrations are not found to be higher in the updraft regions than in the weak to moderately strong downdrafts, however, precipitation rates are markedly higher in the updraft regions. Some of the stronger updraft regions contained heavily rimed particles, including graupel, with reflectivities from collocated ER-2 radars, reaching almost 40 dBZ at X band. Using the collocated ER-2 radar data, we find that the heavily rimed ice particles were suspended in the updrafts and were transported through the snowbands, followed by their fallout in precipitation streamers. Using these observations and penetrations through the snowbands and fallout regions, we investigate the enhanced production of snow within the snowbands compared to regions outside.