Severe Weather in South America: Tornadoes and Severe Storms

[Alexandre Aguiar]

Two more deaths today due to severe weather in Southern Brazil. In some towns it rained 9 inches in just two hours. Here are some pictures of Porto Alegre, Brazil, late in the afternoon this Sunday.

Since Thursday, 4 people died in Brazil and 2 in Argentina. I must also mention Bolivia has for weeks facing catastrophic flooding. Over 300.000 people are homeless and 50 died. The UN is asking for international help.

 

[Alexandre Aguiar]

SOUTH AMERICA FORECAST DISCUSSION - INTERNATIONAL DESKS
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
1258 PM EST THU MAR 08 2007

GFS DATA AT FTPPRD.NCEP.NOAA.GOV/PUB/DATA/NCCF/COM/GFS/PROD/

NOTE: CONDITIONS FOR SEVERE WEATHER DEVELOPMENT ARE EXPECTED TO
CONTINUE ACROSS BUENOS AIRES PROVINCE-URUGUAY-RIO GRANDE DO SUL-
MESOPOTAMIA VALLEY AND CORDOBA IN ARGENTINA...WHERE A RAPIDLY
INTENSIFYING SURFACE LOW WILL FAVOR GENERATION OF MESO SCALE
CONVECTIVE SYSTEMS. FAVORABLE JET DYNAMICS...STRONG
BAROCLINICITY AND VERTICAL WIND SHEAR WILL LIKELY FAVOR TORNADIC
CELLS TO AFFECT BETWEEN CORDOBA/CHACO ARGENTINO AND URUGUAY ON
DAY 01. DAILY RAINFALL MAXIMA OVER THIS REGION WILL EXCEED 75MM.

 

[Alexandre Aguiar]

MOST RECENT EVENTS

Tornado affects the Cascavel Airport (Parana) on February 28th:

Tornado levels dozens of homes in Peruibe (Sao Paulo) on March 9th:

Downburst last weekend in Campinas (Sao Paulo):

 

[Alexandre Aguiar]

Sao Paulo, the mosyt populated city in South America, is under water at this hour after a major rain storm.

 

[Alexandre Aguiar]

Severe weather affected the Argentinian capital this week with localized urban flooding. The lightning uin Buenos Aires was incredible in TV pictures. One photo from skyline Buenos Aires early in the evening April 17th.

Also from Buenos Aires, Argentina, is the most incredlibe lightning photo I ever saw in urban environment. It was taken last December 16th. 2006.

Radar, flooding and other pictures from this week's storm in Buenos Aires here.

 

[Alexandre Aguiar]

Tonight's sounding from a town in my state.

Station latitude: -29.78
Station longitude: -57.03
Station elevation: 74.0
Showalter index: -4.11
Lifted index: -9.02
LIFT computed using virtual temperature: -10.28
SWEAT index: 306.22
K index: 40.40
Cross totals index: 24.20
Vertical totals index: 27.10
Totals totals index: 51.30
Convective Available Potential Energy: 5518.46
CAPE using virtual temperature: 5838.75
Convective Inhibition: -11.39
CINS using virtual temperature: -5.39
Equilibrum Level: 135.75
Equilibrum Level using virtual temperature: 135.73
Level of Free Convection: 892.68
LFCT using virtual temperature: 909.63
Bulk Richardson Number: 98.98
Bulk Richardson Number using CAPV: 104.73
Temp [K] of the Lifted Condensation Level: 296.53
Pres [hPa] of the Lifted Condensation Level: 929.50
Mean mixed layer potential temperature: 302.81
Mean mixed layer mixing ratio: 19.99
1000 hPa to 500 hPa thickness: 5757.19
Precipitable water [mm] for entire sounding: 50.78

If you were about to chase and have this sounding, what would you conclude ?

 

[Lori Meyer]

Wonderful photos! Thanks for sharing. I always think it is cool to see anticyclonic tor pics.

 

[MatthewCarman]

Very nice pictures

 

[MJ Poore]

Impressive pictures and that CAPE looks explosive. I am interested to know how the low level winds or jets and moisture feeds work there?

 

[Alexandre Aguiar]

It was in fact explosive. Two people died after severe thunderstorms last night in southernmost state of Rio Grande do Sul in Brazil.

 

[Alexandre Aguiar]

A cold front stalled last week over Uruguay. Some 20 inches of rain fell in just 72 hours. Yesterday the government declared a "state of national disaster" (Declarado Estado de Desastre in Spanish). This is the headline from today's El Pais newspaper in Montevideo.

Uruguay is a poor, beautiful and friendly country. This video illustrates the scenario in the region of Mercedes.

http://www.youtube.com/watch?v=A8oG-MQluNo

There are some reports (and photos) of the flooding in these links:

http://www.metsul.com/secoes/visualiza.php?cod_subsecao=28&cod_texto=710

http://www.metsul.com/secoes/visualiza.php?cod_subsecao=28&cod_texto=702

In some areas is the worst flooding since 1959, but in some states the flooding this week is the worst in history.

 

[Alexandre Aguiar]

IT IS SNOWING TONIGHT IN SOUTHERN BRAZIL.

Also watch a news report on the snow from a local television station.

 

[Grant Gutierrez]

What is the peak month of severe storm/tornado occurances? I have been thinking about heading down to Brazil, so it may be cool to get in some storms down there.

 

[Alexandre Aguiar]

Grant

The peak time in Brazil and northern Argentina is late spring and summer.

 

[Menno van der Haven]

The peak time in Brazil and northern Argentina is late spring and summer.

Interesting topic. I like it very much to read about severe storms on other continents !!!
I regularly watch the GOES-satellite images and see often large TS-complexes over Argentina and Brazil.

When you look at the following graph, I guess your area can perhaps be considered as the MCC-capital of the world !

The global distribution of mesoscale convective complexes (MCCs), based on satellite imagery as described in Laing and Fritsch (1997). Small squares indicate location of MCC at time of maximum extent; adapted from Laing and Fritsch (1997).

Is it true that very steep lapse rates can be seen developing over the Andes mountains and being transported eastward over a moist, warm airmass ? So creating high instabilities?