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Severe weather events in Southern Brazil and their similarity with events in the United States Bruno Ribeiro, Lance Bosart National Institute for Space Research - INPE, Brazil SUNY - University at Albany, NY 16th NROW - November 2015
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Purpose:
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Compare severe weather events in Southern Brazil to that in the U.S. and show some forecast issues.
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Purpose: Compare severe weather events in Southern Brazil to that in the U.S. and show some forecast issues. Motivation: - Little research on severe weather in South America;
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Purpose: Compare severe weather events in Southern Brazil to that in the U.S. and show some forecast issues. Motivation: - Little research on severe weather in South America; - Most conceptual models of severe weather for the U.S. are applicable in Southern Brazil;
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Purpose: Compare severe weather events in Southern Brazil to that in the U.S. and show some forecast issues. Motivation: - Little research on severe weather in South America; - Most conceptual models of severe weather for the U.S. are applicable in Southern Brazil; - Look for when these models may NOT be applicable in Southern Brazil.
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Introduction 1) Similarities between North and South America;
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Introduction 1) Similarities between North and South America; 2) Two cases: - A Squall Line in Sao Paulo state on 08 September 2015;
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Introduction 1) Similarities between North and South America; 2) Two cases: - A Squall Line in Sao Paulo state on 08 September 2015; - A EF2-EF3 tornado case in Santa Catarina State on 20 April 2015.
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South America Topography
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’Classic’ severe weather environment
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Elevated Mixed Layers and Supercells
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Bow-echoes
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Squall Line Case
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Affected most of the Sao Paulo state, including Sao Paulo metropolitan region:
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Squall Line Case Affected most of the Sao Paulo state, including Sao Paulo metropolitan region: - Hundreds of downed trees and flooded streets;
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Squall Line Case Affected most of the Sao Paulo state, including Sao Paulo metropolitan region: - Hundreds of downed trees and flooded streets; - Several 5 cm ( 2”) hail reports;
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Squall Line Case Affected most of the Sao Paulo state, including Sao Paulo metropolitan region: - Hundreds of downed trees and flooded streets; - Several 5 cm ( 2”) hail reports; - Wind gusts peaked 120 km/h (65 kt) in the entrance of Paraiba Valley.
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Squall Line Case - Synoptic Environment
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Weak quasi-geostrophic forcing
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Squall Line Case - Synoptic Environment
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Divergent upper-level flow at jet-streak equatorial entrance
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Squall Line Case - Synoptic Environment
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Low-level cyclonic vorticity associated with the front
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Squall Line Case - soundings
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Squall Line Case - satellite imagery
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Squall Line Case - radar imagery
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Tornado Case
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Estimated EF2-EF3 tornado affected the city of Xanxere on 20 April 2015:
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Tornado Case Estimated EF2-EF3 tornado affected the city of Xanxere on 20 April 2015: - 2 people dead and hundreds injured;
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Tornado Case Estimated EF2-EF3 tornado affected the city of Xanxere on 20 April 2015: - 2 people dead and hundreds injured; - Severe damage to about 50% of the city.
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Tornado Case
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Tornado Case - Synoptic Environment
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Weak quasi-geostrophic forcing:
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Tornado Case - Synoptic Environment
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Tornado Case - Forecast issues
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Conclusions
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Large-scale severe weather environments are similar:
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Conclusions Large-scale severe weather environments are similar: 1- Strong low-level jet bringing warm and moist air from the tropics;
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Conclusions Large-scale severe weather environments are similar: 1- Strong low-level jet bringing warm and moist air from the tropics; 2- Severe weather along a low-level baroclinic region.
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Conclusions Large-scale severe weather environments are similar: 1- Strong low-level jet bringing warm and moist air from the tropics; 2- Severe weather along a low-level baroclinic region. 3- Upper-level forcing by the Subtropical/Polar Jet.
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Conclusions Large-scale severe weather environments are similar: 1- Strong low-level jet bringing warm and moist air from the tropics; 2- Severe weather along a low-level baroclinic region. 3- Upper-level forcing by the Subtropical/Polar Jet. 4- South America also have ‘cold season’ and ‘warm season’ patterns;
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Conclusions - Issues and future research
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- Role of drylines (?) and local topography in triggering severe convection;
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Conclusions - Issues and future research - Role of drylines (?) and local topography in triggering severe convection; - Elevated mixed layers
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Conclusions - Issues and future research - Role of drylines (?) and local topography in triggering severe convection; - Elevated mixed layers Observational framework must be improved:
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Conclusions - Issues and future research - Role of drylines (?) and local topography in triggering severe convection; - Elevated mixed layers Observational framework must be improved: - Radars, soundings and surface observations;
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Conclusions - Issues and future research - Role of drylines (?) and local topography in triggering severe convection; - Elevated mixed layers Observational framework must be improved: - Radars, soundings and surface observations; - Severe weather reports network.
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Thank you
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