Relationship of snow microphysics and precipitation generation to vertical motions in extratropical cyclones: Results from IMPACTS

This study analyzes in situ aircraft microphysical measurements in deep snow-producing clouds during the Investigation of Microphysics and Precipitation for Atlantic Coast-Threatening Snowstorms (IMPACTS) field programs in winter 2020, 2022, and 2023 to characterize and compare the microphysics in the updraft and downdraft regions. Measurements were acquired from the NASA P-3 aircraft equipped with a full complement of particle probes and instruments for direct measurements of condensed water content and thermodynamic and 3D wind measurements.

We identified the P-3 aircraft flight days collected within snowbands, generating cells, and peripheral regions from 14 flights. These are composited and used for the analysis. Temperatures sampled ranged between −27° and +1°C. The data are partitioned by air vertical velocity, with strong updrafts defined as >0.5 m s −1 , very strong updrafts as >1 m s −1 , and strong downdrafts as <−0.5 m s −1 .