Thundersnow in Brazil: a case study of 22 July 2013. (6th August 2015)

• Record Type: Journal Article
• Authors: Dolif Neto, Giovanni; Market, Patrick S.; Pezza, Alexandre Bernardes; Morales Rodriguez, Carlos Augusto; Calvetti, Leonardo; da Silva Dias, Pedro Leite; Escobar, Gustavo Carlos Juan
• Is Part Of: Atmospheric science letters. Volume 17:Number 1(2016)
• Page Start: 26
• Page End: 32
• Publication Date: 2015-08-06
• Subjects: thundersnow -- cold surge -- southern Brazil -- lightning -- radar -- symmetric instability; Atmospheric physics -- Periodicals; 551
• DOI: 10.1002/asl.594
• Languages: English
• ISSNs: 1530-261X

Abstract

Abstract: On 23 July 2013, a snowstorm hit southern Brazil causing material damage and two deaths. Radar reflectivity and lightning data revealed a rare thundersnow occurrence. This study revealed that a Rossby wave propagation followed a typical pattern of cold incursions in South America, but some fundamental differences can be pointed out: (1) further northward Rossby wave amplification; (2) strong upward vertical motion within a deep nearly saturated layer and (3) a conditional symmetric instability layer, in response to strong vertical shear, beneath a layer of weak conditional instability, and above a significant near‐surface vertical depth where temperatures hover around 0 °C.