Evidence of Tornadoes and Microbursts in São Paulo State, Brazil: A Synoptic and Mesoscale Analysis

Abstract

Synoptic and mesoscale analyses indicate environmental conditions favorable to the development of tornados and downbursts in Eastern Sao Paulo State, Brazil, between 16 May and 06 June 2016 under El Nino Sothern Oscillation (ENSO) condition. A subtropical jet stream strengthened by the 2015/2016 El Nino event over southeast Brazil and low-level moisture advection from the Amazon induced mid-level mesoscale vorticity and strong updrafts, respectively. These synoptic summer-like conditions yielded high dynamic and thermodynamic instability, producing deep convection and supercells with high lightning and precipitation rates with golf ball-sized hail stones and high winds at the surface, causing damages to trees, houses, towers and other structures with debris features associated with tornadoes and microbursts. Cellular phone photos and movies of severe weather events in Campinas and Janiru cities on 05 and 06 June 2016 suggest wind damage features caused by tornadoes ranked in the enhanced Fujita (EF) wind scale as EF1 (38–49 m s−1) and EF2 (49–60 m s−1), respectively. Similarly, cellular phone movies of Embu-Guacu City severe weather event on 16 May 2016 suggest a microburst case. The present study is based on quantitative and qualitative records of three high-impact rainfall, hail, lightning and wind gust episodes in the extra tropics during late fall 2016.