Evolution of Multiband Structures Within the 16 February 2023 Midwest Cyclone During the IMPACTS Field Campaign

The Investigation of Microphysics and Precipitation for Atlantic Coast-Threatening Snowstorms (IMPACTS) is a field campaign operated by NASA from 2020-2023 to investigate the structure of mesoscale snowbands through the use of both airborne and ground-based instrumentation. While a climatology and conceptual model of banded events in the Northeast U.S. has been developed by Ganetis et al. (2018), a broader spectrum of precipitation structures exists that do not all fit the rigid categories of primary or multibands. Some multibands last several hours as discrete, convective-like features, while other cases feature transient, weaker-reflectivity structures that rapidly grow and dissipate, or merge with and split from each other.

On 16 February 2023, the IMPACTS field campaign sampled a developing cyclone over the upper Midwest. Between 13 UTC to 15 UTC, multiband features developed in southeastern Iowa and moved into the Wisconsin-Illinois border, east of the low, to the north of the dry slot. These multibands persisted as distinct quasi-linear structures for 6 hours. After 19 UTC, the precipitation evolved into a more primary band-like feature on the north side of the low, with the region of multiband structures moving farther to the east over Lake Michigan. To better understand the thermodynamic environment, WRF version 4.4 was configured and run over the Midwest for the duration of the event. This poster will highlight the vertical structure of these objects, looking at the microphysical differences between the multiband region and the primary band and also investigating the role of shear, diabatic heating, and instability in generating and maintaining the structure of these bands, as depicted by WRF. The microphysical results will also be compared against in situ observations from the P-3 aircraft at various altitudes between 1730 and 2100 UTC.