Assessment of Crystal Characteristics and Snowfall
Impact During the North Carolina Snowstorm of 17 January 2018 (52)
Gail Hartfield, NOAA/NWS,
Raleigh, NC
Frank Alsheimer, NOAA/NWS
Abstract:
Winter storms in the
Carolinas can produce significant impacts, given that such storms typically
consist of a variety of precipitation types, often mixing and changing during a
storm's lifetime. But even the occurrence of a single precipitation type, such
as in the snowstorm of 17 January, 2018, can cause significant problems. In
this event, forecasters were confident that it would feature just snow (albeit
with a rain-snow mix at onset). Predictions of snow-liquid ratio (SLR) were
accurate however, the impacts were greater than anticipated. It is hypothesized
that the character of the ice crystals near the ground promoted significant
aggregation, which allowed for considerable accrual of snow on trees, power
lines, and other elevated surfaces, leading to greater-than-expected power
outages across the area due to snow-laden tree limbs.
In this presentation, we will
examine several observational datasets, including upper-air soundings, dual pol
radar data, GOES-East imagery and products, and surface meso-analyses, along
with high-resolution model output, to assess the microphysical characteristics
of this snowfall during its evolution, in an effort to better understand the
factors leading to this impactful snowfall. It is hoped that the clues provided
in this case will help better anticipate crystal characteristics and subsequent
impacts during future snowfall events in this region.