Polarimetric Radar Observations of Precipitation Type and Rate from the 2–3 March 2014 Winter Storm in Oklahoma and Arkansas

Authors

Matthew S. Van Den Broeke, University of Nebraska-LincolnFollow
Dana M. Tobin, The Pennsylvania State University
Matthew R. Kumjian, The Pennsylvania State University

Date of this Version

2016

Comments

© 2016 American Meteorological Society

DOI: 10.1175/WAF-D-16-0011.1

Abstract

A powerful winter storm affected the south-central United States in early March 2014, accompanied by elevated convective cells with hail and high rates of sleet, freezing rain, and snow. During portions of the event the thermal profile exhibited a shallow surface cold layer and warm, unstable air aloft. Precipitation falling into the cold layer refroze into ice pellets and was accompanied by a polarimetric refreezing signature and numerous crowdsourced surface ice pellet reports. Quasi-vertical profiles of the polarimetric variables indicated an enhanced reflectivity factor Z_HH below the melting layer bright band and enhanced low-level differential reflectivity Z_DR values coincident with surface ice pellet reports. Freezing rain rate was highest in areas with high Z_HH and specific differential phase K_DP values at low levels. High snow rates were most closely associated with 1- and 1.5-km Z_HH values, though K_DP and Z_DR also appeared to show some ability to distinguish high snow rate. Numerous elevated convective cells contained rotating updrafts that appeared to contribute to storm longevity and intensity.Most containedwell-defined Z_DR maxima or columns and relatively high base-scan Z_DR values. Several contained polarimetric signatures consistent with heavy mixed-phase precipitation and hail; social media reports indicated that large hail was produced by some of the storms.