severe weather events in southern brazil and their similarity with events in the united states bruno...

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

Purpose:

Purpose:

Compare severe weather events in Southern Brazil to that in the U.S. and show some forecast issues.

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;

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;

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.

Introduction

1) Similarities between North and South America;

Introduction

1) Similarities between North and South America;

2) Two cases:- A Squall Line in Sao Paulo state on 08 September 2015;

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.

South America Topography

South America Topography

’Classic’ severe weather environment

’Classic’ severe weather environment

Elevated Mixed Layers and Supercells

Elevated Mixed Layers and Supercells

Elevated Mixed Layers and Supercells

Bow-echoes

Squall Line Case

Squall Line Case

Affected most of the Sao Paulo state, including Sao Paulo metropolitan region:

Squall Line Case

Affected most of the Sao Paulo state, including Sao Paulo metropolitan region:

- Hundreds of downed trees and flooded streets;

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;

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.

Squall Line Case - Synoptic Environment

Squall Line Case - Synoptic Environment

Squall Line Case - Synoptic Environment

Squall Line Case - Synoptic EnvironmentWeak quasi-geostrophic forcing

Squall Line Case - Synoptic Environment

Squall Line Case - Synoptic Environment

Squall Line Case - Synoptic EnvironmentDivergent upper-level flow at jet-streak equatorial entrance

Squall Line Case - Synoptic Environment

Squall Line Case - Synoptic Environment

Squall Line Case - Synoptic Environment

Squall Line Case - Synoptic Environment

Squall Line Case - Synoptic Environment

Low-level cyclonic vorticity associated with the front

Squall Line Case - soundings

Squall Line Case - soundings

Squall Line Case - satellite imagery

Squall Line Case - satellite imagery

Squall Line Case - satellite imagery

Squall Line Case - satellite imagery

Squall Line Case - satellite imagery

Squall Line Case - satellite imagery

Squall Line Case - radar imagery

Squall Line Case - radar imagery

Squall Line Case - radar imagery

Squall Line Case - radar imagery

Squall Line Case - radar imagery

Squall Line Case - radar imagery

Squall Line Case - radar imagery

Squall Line Case - radar imagery

Squall Line Case - radar imagery

Squall Line Case - radar imagery

Squall Line Case - radar imagery

Squall Line Case - radar imagery

Squall Line Case - radar imagery

Tornado Case

Tornado Case

Estimated EF2-EF3 tornado affected the city of Xanxere on 20 April 2015:

Tornado Case

Estimated EF2-EF3 tornado affected the city of Xanxere on 20 April 2015:

- 2 people dead and hundreds injured;

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.

Tornado Case

Tornado Case

Tornado Case

Tornado Case

Tornado Case - Synoptic Environment

Tornado Case - Synoptic Environment

Tornado Case - Synoptic Environment

Tornado Case - Synoptic EnvironmentWeak quasi-geostrophic forcing:

Tornado Case - Synoptic Environment

Tornado Case - Synoptic Environment

Tornado Case - Synoptic Environment

Tornado Case - Synoptic Environment

Tornado Case - Synoptic Environment

Tornado Case - Synoptic Environment

Tornado Case - Forecast issues

Tornado Case - Forecast issues

Tornado Case - Forecast issues

Tornado Case - Forecast issues

Conclusions

Conclusions

Large-scale severe weather environments are similar:

Conclusions

Large-scale severe weather environments are similar:

1- Strong low-level jet bringing warm and moist air from the tropics;

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.

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.

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;

Conclusions - Issues and future research

Conclusions - Issues and future research

- Role of drylines (?) and local topography in triggering severe convection;

Conclusions - Issues and future research

- Role of drylines (?) and local topography in triggering severe convection;

- Elevated mixed layers

Conclusions - Issues and future research

- Role of drylines (?) and local topography in triggering severe convection;

- Elevated mixed layers

Observational framework must be improved:

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;

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.

Thank you