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

Abstract

The recent Weather Surveillance Radar-1988 Doppler (WSR-88D) network upgrade to dual-polarization capabilities allows for bulk characterization of microphysical processes in northeastern U.S. winter storms for the first time. In this study, the quasi-vertical profile (QVP) technique (wherein data from a given elevation angle scan are azimuthally averaged and the range coordinate is converted to height) is extended and applied to polarimetric WSR-88D observations of six Northeast winter storms to survey their evolving, bulk vertical microphysical and kinematic structures. These analyses are supplemented using hourly analyses from the Rapid Refresh (RAP) model. Regions of ascent inferred from QVPs were consistently associated with notable polarimetric signatures, implying planar crystal growth when near −15°C, and riming and secondary ice production at higher temperatures. The heaviest snowfall occurred most often when ascent and enhanced propagation differential phase shift ([Formula: see text]) occurred near −15°C. When available, limited surface observations confirmed heavy snowfall rates and revealed large snow-to-liquid ratios at these times. Other cases revealed sudden, large melting-layer excursions associated with precipitation-type transitions near the surface. RAP analyses failed to capture such complex evolution, demonstrating the added value of dual-polarization radar observations in these scenarios and the potential use of radar data for assessing model performance in real time. These insights are a preliminary step toward better understanding the complex processes in northeastern U.S. winter storms.

Toward Exploring the Synergy Between Cloud Radar Polarimetry and Doppler Spectral Analysis in Deep Cold Precipitating Systems in the Arctic

“…The signature of needle and/or columnar crystals in a temperature range from À8 to À3°C, where ice particles seeded in the MPL and secondary ice formation via the Hallett-Mossop ice multiplication mechanism (Hallett & Mossop, 1974) could be active, is often observed in Arctic mixed-phase clouds in linear depolarization ratio measurements . Similar signatures were observed in midlatitude winter storms and convective systems (e.g., Giangrande, Toto, Bansemer, et al, 2016;Kumjian et al, 2016;Kumjian & Lombardo, 2017;Sinclair et al, 2016;Zawadzki et al, 2001). Kumjian et al (2016) observed K DP enhancements produced by needle and columnar crystals in secondary ice formation regions.…”

“…Schrom et al (2015) suggested a polarimetric technique to separate contributions from aggregates and dendrites in the DGL of midlatitude winter storms. Polarimetric signatures of the secondary ice mixed with aggregated and rimed snow in layers with temperature around À5°C were found by cloud and precipitation radar measurements in high-latitude deeper snow clouds Sinclair et al, 2016), midlatitude mesoscale convective systems Kumjian et al, 2016), and midlatitude snowstorms (Kumjian & Lombardo, 2017). However, combining polarimetric measurements with the analysis of Doppler spectra yields a much better chance to identify and separate different types of ice, and to quantify their amounts if their corresponding fall velocities are associated with separate peaks in the Doppler spectrum.…”

Atmospheric Research Over the Western North Atlantic Ocean Region and North American East Coast: A Review of Past Work and Challenges Ahead

“…As noted earlier in section , ETCs are of importance to the U.S. East Coast. A substantial body of work has examined aspects of East Coast winter storms, which have major societal impacts ranging from commerce to public safety over the mid‐Atlantic and northeastern United States (e.g., Brennan & Lackmann, ; Charles & Colle, , ; Evans & Jurewicz, ; Ganetis & Colle, ; Hirsch et al, ; Kocin & Uccellini, ; Kumjian & Lombardo, ; Nicosia & Grumm, ; Novak et al, ; Novak & Colle, ; Root et al, ; Sanders & Bosart, ; Zhang et al, ). In fact, the oldest study identified in this review paper is related to cyclogenesis over the East Coast, which is relevant to the modeling and forecasting of such storms (Miller, ).…”

Examining Storm Asymmetries in Hurricane Irma (2017) Using Polarimetric Radar Observations

“…Dual‐polarization radar has been instrumental in improving quantitative rainfall estimation (e.g., Cifelli et al, ; Giangrande & Ryzhkov, ; Ryzhkov et al, ), hydrometeor classification (Dolan & Rutledge, ; Chandrasekar et al, ; Park et al, ; Ryzhkov et al, ; Vivekanandan et al, ), microphysical fingerprinting (Kumjian & Prat, ; Kumjian & Ryzhkov, , ; Schrom & Kumjian, ), and advancing our understanding of organized precipitation systems including supercells (e.g., Kumjian & Ryzhkov, ; Snyder et al, ), mesoscale convective systems (e.g., Zrnić et al, ), and winter storms (e.g., Griffin et al, ; Kumjian & Lombardo, ). All of these studies have focused on storm systems that occur predominantly over land.…”