A Polarimetric and Microphysical Investigation of the Northeast Blizzard of 8–9 February 2013

Abstract

On 8-9 February 2013, the northeastern United States experienced a historic winter weather event ranking among the top five worst blizzards in the region. Heavy snowfall and blizzard conditions occurred from northern New Jersey, inland to New York, and northward through Maine. Storm-total snow accumulations of 30-61 cm were common, with maximum accumulations up to 102 cm and snowfall rates exceeding 15 cm h 21 . Dual-polarization radar measurements collected for this winter event provide valuable insights into storm microphysical processes. In this study, polarimetric data from the Weather Surveillance Radar-1988 Doppler (WSR-88D) in Upton, New York (KOKX), are investigated alongside thermodynamic analyses from the 13-km Rapid Refresh model and surface precipitation type observations from both Meteorological Phenomena Identification Near the Ground (mPING) and the National Weather Service (NWS) Forecast Office in Upton, New York, for interpretation of polarimetric signatures. The storm exhibited unique polarimetric signatures, some of which have never before been documented for a winter system. Reflectivity values were unusually large, reaching magnitudes .50 dBZ in shallow regions of heavy wet snow near the surface. The 08C transition line was exceptionally distinct in the polarimetric imagery, providing detail that was often unmatched by the numerical model output. Other features include differential attenuation of magnitudes typical of melting hail, depolarization streaks that provide evidence of electrification, nonuniform beamfilling, a ''snow flare'' signature, and localized downward excursions of the melting-layer bright band collocated with observed transitions in surface precipitation types. In agreement with previous studies, widespread elevated depositional growth layers, located at temperatures near the model-predicted 2158C isotherm, appear to be correlated with increased snowfall and large reflectivity factors Z H near the surface.

Geographical Distribution of Thundersnow Events and Their Properties From GPM Ku‐Band Radar

“…The observed lightning flashes were located downstream of high value of reflectivity core (> 35 dBZ) and higher reflectivity aloft, which are ascribed by graupel. Griffin et al () found exceptionally high value of Z H (>55 dBZ) and corresponding enhanced differential reflectivity during 2013 northeast United States winter blizzard. Those enhanced differential reflectivity indicated the updraft and generation of the supercooled water in the convective storms that are associated with atmospheric electrification.…”

Insights into the Evolving Microphysical and Kinematic Structure of Northeastern U.S. Winter Storms from Dual-Polarization Doppler Radar

“…The historic 8-9 February 2013 northeastern blizzard has been studied extensively (Griffin et al 2014;Picca et al 2014;Ganetis and Colle 2015), and produced some of the most extreme winter storm polarimetric radar signatures thus far observed (Griffin et al 2014). This includes vigorous planar crystal growth regions called dendritic growth zones (DGZs) in the literature, which polarimetric radars can detect as enhancements of specific differential phase K DP and/or differential reflectivity Z DR near 2158C (Kennedy and Rutledge 2011; Andrić et al 2013;Bechini et al 2013;Schneebeli et al 2013;Schrom et al 2015).…”

“…Further, intense coastal lows often produce high winds and waves that can damage coastal structures (Picca et al 2014). Recent blizzards labeled as ''historic'' have individually cost tens of millions of dollars in damage and significant loss of life (e.g., Griffin et al 2014;Picca et al 2014). Even when major cities are spared the extreme weather, there can be an enormous economic toll: an estimated $200 million was lost in January 2015 when New York City (NYC) shut down its transit system based on forecasts of a major snow event (Dokoupil 2015).…”

“…In contrast, dual-polarization radar data can provide information about the bulk microphysical structure in storms across a larger areal extent. However, to date only three studies have used dual-polarization radar data to explore the microphysical structure of northeastern coastal winter storms (Griffin et al 2014;Picca et al 2014;Ganetis and Colle 2015). Griffin et al (2014) analyze polarimetric radar data in the historic 8-9 February 2013 storm, which ranks among the top five worst the northeastern United States has experienced.…”

“…However, to date only three studies have used dual-polarization radar data to explore the microphysical structure of northeastern coastal winter storms (Griffin et al 2014;Picca et al 2014;Ganetis and Colle 2015). Griffin et al (2014) analyze polarimetric radar data in the historic 8-9 February 2013 storm, which ranks among the top five worst the northeastern United States has experienced. The authors highlight a number of signatures associated with precipitation transitions, vigorous dendritic growth, and even a flarelike echo resembling a threebody scattering signature.…”