SAO PAULO, July 29 (Reuters) – Temperatures fell in swathes of Brazil on Thursday – with rare snowfall overnight in some places – as a polar air mass advanced toward the center-south of the global agricultural powerhouse, threatening crops with frosts. Unusually cold weather in Brazil has already sent and sugar higher and Friday was forecast to be the coldest day of the year, according to Marco Antonio dos Santos, a partner at weather consultancy firm Rural Clima.
