The need for improved documentation of severe thunderstorms and tornadoes in South America, Preprints

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P1.18 THE NEED FOR AN IMPROVED DOCUMENTATION OF SEVERE THUNDERSTORMS AND
TORNADOES IN SOUTH AMERICA.
Ernani de Lima Nascimento* and Charles A. Doswell III**
* Instituto Tecnológico SIMEPAR, Curitiba/PR, Brazil
** Cooperative Institute for Mesoscale Meteorological Studies, Norman/OK, USA
1. INTRODUCTION
The subtropics and mid-latitudes of South
America, east of the Andes Mountain Range, have
been recognized as prone to severe convective
weather for quite some time (Fujita 1973; Velasco
and Fritsch 1987; Silva Dias 2000; Brooks et al 2003;
Nascimento 2004, 2005), including the occasional
occurrence of tornadoes (Schwarzkopf 1982; Antonio
et al 2005; Nascimento and Marcelino 2005a,b; Held
et al 2005a,b; among others).
Despite that, there is no institutionalized
procedure for a systematic documentation of severe
thunderstorms in that part of the world, and the few
efforts for documenting severe weather episodes are
conducted by individual initiatives with little or no
formal support (Schwarzkopf 1982, Nechet 2002,
Torena 2003, Antonio et al 2005, Nascimento and
Marcelino 2005a). The availability of a reliable and
standardized archive of severe weather reports is
fundamental for any quantitative investigation of
severe storms. This is particularly crucial in South
America, where mesoscale observing systems ―
including weather radars ― are far from adequate,
being confined to localized regions in the continent
(e.g., Nascimento 2004).
Building on the North American experience in
documenting severe weather reports, we discuss the
relevance of maintaining such archives to the study
of severe thunderstorms in South America, including
the development and testing of techniques to predict
severe weather in that continent. We also describe
possible ways to start addressing the generation of a
severe weather data bank based upon the infra-
structure already existent in at least a few countries,
such as Brazil.
2. SEVERE THUNDERSTORMS IN SOUTH
AMERICA
Severe deep convection has been observed in the
entire South American continent, except perhaps over
* Corresponding author address: Ernani L.
Nascimento, Inst. Tecn. SIMEPAR, Centro Politéc.
UFPR, Cx. Postal 19100, CEP. 81531-990,
Curitiba/PR, Brazil; e-mail: elnascimento@ufpr.br
the Andes Mountains and the far southern Patagonia.
However, a number of studies (Velasco and Fritsch 1987;
Silva Dias 2000; Brooks et al 2003; Zipser et al 2004;
Held et al 2005a) suggest that the most significant
severe weather episodes  associated with large hail,
damaging winds and tornadoes  are concentrated within
the 20-40°S latitude range, east of the Andes (Figure 1).
Figure 1: Map of the approximate geographical region in
South America where severe convective weather is most
frequent (inside the red curve). Several important
metropolitan areas are located in this sector, including
Buenos Aires (Argentina), Montevideo (Uruguay), Asunción
(Paraguay), Curitiba, Porto Alegre and São Paulo (Brazil).
The combination of ingredients for severe convection:
low-level moisture, convective instability and vertical
wind shear, necessary for severe storms, is occasionally
found in that region, especially from late September to
May (a more detailed discussion and additional references
can be found in Silva Dias 2000, Barnes 2001, and
Nascimento 2004, 2005a).
The threat that severe weather episodes pose to the
society is evident in subtropical South America. Figure 2
displays a rather simple ten-year statistics (from 1990 to
1999) of the main natural disasters that occurred in Paraná
state, in southern Brazil, based on the archive of reports
from the Civil Defense (CD) System of that state.
Considering only hail events and thunderstorm-induced
damaging winds (phenomena more clearly related to
severe storms), nearly 50% of the natural disasters

Figure 2: Statistics of the main natural disasters
reported in Paraná state (southern Brazil) from
January 1990 to December 1999. (Adapted from
www.pr.gov.br/defesacivil/calamidades.html)
reported by the CD were associated with severe
convective weather. Hence, noting that they are
relatively rare compared to other atmospheric
systems, severe storms are responsible for a
disproportionally large number of high-impact
episodes for the society, as recognized for other parts
of the world as well (e.g., Doswell 2005).
In an annual basis, electric power utilities in
South America also report important operational
losses associated with severe weather (Assuncão
2002). Frequent outages associated with power lines
downed by severe thunderstorms have become an
issue of particular interest for the electric power
sector in countries like Brazil (e.g., Lima and
Menezes 2004). Such developing awareness
motivated a recent workshop addressing the impact
of severe convective storms on the operation of
power utilities in that country (www.furnas.gov.br/
rindat/workshop2005.htm).
As in other areas of the globe, a small  but still
to be determined  percentage of the severe weather
episodes in subtropical South America can reach
significant proportions. A recent example was the
large F3 tornado that struck the town of Indaiatuba,
interior of São Paulo state (around 23°S) in Brazil, on
24 May 2005 (Held et al 2005b, Nascimento and
Marcelino 2005b, Amorim et al 2005). Figure 3a,
obtained from a video, shows a broad view of the
Indaiatuba tornado and its parent low-level
mesocyclone; the thick arrow indicates the sense of
rotation. A close-up view of some of the sub-vortices
produced is provided by Figure 3b, from the same
video.
Other tornadoes of F3 intensity (and even
stronger) have been also identified in other regions of
South America (Argentina: Schwarzkopf 1982;
southern Brazil: Marcelino et al 2005). A non-
comprehensive list of severe weather episodes in
southern and southeastern Brazil can be found at
Figure 3: Still frames from the 24 May 2005 Indaiatuba
tornado video (Brazil). Thick arrow in (a) indicates the
clockwise rotation of the tornado and of the parent low-level
mesocyclone. Local standard time is shown on the top of
each frame. The camera faces the north-northeast in (a), and
northeast in (b). Courtesy of Rodovias das Colinas S.A..
(Adapted from Nascimento and Marcelino 2005b).
www.lemma.ufpr.br/ernani/torbraz.html, and brief case
studies of tornadoes in Uruguay are found in Torena
(2003).
The points above refute the perception that South
American severe local storms are too rare to justify a
serious public awareness to the problem and a systematic
research in that area. There is a strong demand for the
assessment of operational strategies aiming at the
identification and prediction of atmospheric conditions
conducive to severe weather in that continent. One of the
issues that make this task particularly challenging is the
lack of a data bank of severe weather events. In the next
section, we discuss the relevance of a standardized severe
weather data archive to the development of research on
the prediction of severe convective storms, based on the
long and successful North American experience on that
area.
3. SEVERE WEATHER ARCHIVES AND
RESEARCH ON SEVERE STORMS
FORECASTING: A NORTH AMERICAN
EXPERIENCE.
The United States (US) has the greatest number of
severe thunderstorms and tornadoes worldwide. A long
history of significant episodes of destructive and deadly
severe convective weather has raised an important public
awareness around the threat posed by these weather
systems. Beginning around 1925, the scientific interest in
understanding and predicting severe storms combined
with public awareness, developed a “culture” of
preparedness for severe weather in the US, where
accurate and timely warnings, and spotting and reporting
severe storms as they occur, became important activities
that are commonplace today (Doswell et al 1999).
The influence of the increasing number of individuals
and initiatives interested in reporting severe storms upon
the number of tornadoes detected each year in the US
during the second half of the twentieth-century is
discernible, as shown in Fig. 4 (from Doswell et al 1999).
The first spotter networks were set during the 1940’s and
Natural disasters in Paraná state (a) (b)
©
2005
Rodovia
s
das Colinas S.A.
©
2005
Rodovia
s
das Colinas S.A.

Figure 4: Number of tornadoes recorded annually in the
US from 1916 to 1995 (solid circles: raw data; thick
solid line: smoothed data; thin solid line: number of
tornado days. From Doswell et al 1999).
1950’s, after which the number of reported tornadoes
increased considerably.
To a given extent, there exists a synergetic
relationship between the (good-quality) reporting of
storm events and severe storms research/forecasting
which is not always recognized, but which is crucial.
Storm spotting, conducted by meteorologists, NWS-
trained volunteers, emergency management and law
enforcement officials, in addition to information from
NWS damage surveys, newspaper clipping services
and the insurance industry, have contributed to the
creation of a remarkable archive of severe weather
reports in the US that dates back to 1950, known as
Storm Data. (Storm Data contains reports from all
types of storm hazards, not only from severe
convection).
An example of the standardized information
contained in Storm Data is shown in Figure 5. The
information is compiled by the US NWS every
month (from the sources mentioned above), and
published by the US National Climate Data Center.
The information provided by Storm Data has played
some role on convective storms research (López et al
1995), particularly for climatological studies
addressing the characterization of severe storms
environments (e.g., Davies and Johns 1993,
Thompson 1998, Evans and Doswell 2001).
For example, the classic study by Johns and Hirt
(1987) on the definition and identification of
derechos did use Storm Data as one of the main
sources of information. Other severe weather
archives and documentations are kept by operational
centers such as the Storm Prediction Center, and by
research groups. One quite evident usage of severe
weather archives in research applied to convective
forecasting is regarding the identification of the so-
called “proximity soundings”.
Figure 5: Sample page from the May 1999 issue of Storm
Data (NCDC 1999), highlighting some key information such
as: location, date and time of a given event (left box) and the
character of the severe weather events (right box).
Proximity soundings (PSs) are loosely defined as
atmospheric profiles, obtained from rawinsondes, that are
representative of the large-scale atmospheric environment
in which severe thunderstorms develop (at least, this is
what PSs are intended to represent; Brooks et al 1994,
2003). Hence, before characterizing a sounding as a PS,
one needs to identify where and when the severe weather
event happened, which, in turn, depends on the available
documentation (and on its accuracy).
Many studies have addressed the problem of
forecasting severe convection utilizing the PS approach,
by either using observed soundings or model-derived
“soundings”  see Brooks et al (2003) and Nascimento
(2005) for a long list of such studies. Despite some
serious limitations of this approach (Brooks et al 1994;
Markowski and Richardson 2004), several findings from
climatological analysis of PSs in the US have been
successfully translated into operational tools for
forecasting, such as the determination of sets of
convective indices for the characterization of severe
weather potential (Thompson 2005).
Moreover, the accurate documentation of different
types of severe events (as depicted in Fig. 5) is needed to
meet the goal of developing forecast methodologies that
not only identify environments conducive to severe
weather in general, but that are capable also of
discriminating distinct forms of severe weather (e.g.,
Brooks et al 2003).

The importance of severe storms archives is also
substantial when assessing the accuracy and/or skill
of a given convective forecast methodology: that is,
the forecast verification issue. Accuracy measures
(such as the false alarm ratio) applied to severe
storms forecasting can only be assessed in the
presence of sufficiently large data sets of severe
weather events that allow statistically significant
analysis.
In summary, the long North American experience
with severe convective storms highlights the
relevance of keeping good-quality severe weather
archives. As with Europe (Doswell 2003), we do not
simply propose that the North American severe
storms archiving system be blindly “copied” by the
South American severe weather community, but to be
used as inspiration for similar initiatives. This is
considered in the next section.
4. THE CHALLENGE IN DOCUMENTING
SEVERE WEATHER AND POSSIBLE WAYS
OF ADDRESSING THE ISSUE IN SOUTH
AMERICA
It is important to stress that severe weather is
associated with sub-cloud phenomena that typically
cover small areas and last few minutes, and cannot
be detected by remote sensed observing systems,
except in highly particular situations  e.g., by
literally chasing storms with weather radars adapted
to vehicles; Wurman (2002); Bluestein et al (2003)
 which are not available in a operational basis
anywhere in the world.
Thus, in contrast with the perception that is often
valid for large- and mesoscale meteorology,
improved satellite and radar coverage of the large
data void areas of South America does not solve the
specific problem addressed here: the documentation
of severe thunderstorms. This demands confirmation
of what happens at ground level. More recently, it has
been proposed the use in Brazil of high resolution
satellite imagery to document destruction paths left
by tornadoes (M. A. Antonio, personal
communication). Previously, Dyer (1988, 1994)
identified tornado paths over forest terrain in
northeastern Argentina, Paraguay and southern Brazil
using similar approach. This represents a promising
alternative for documenting tornado tracks,
particularly over low-populated areas. However, such
capability, still in research mode (Yuan et al 2002),
can not replace a detailed in situ documentation of
severe weather events.
Lightning detection networks such as the ones
implemented in Brazil (Beneti et al 2000, Silveira
2005) play a very important role in tracking
convective activity in real time, but, again, cannot
provide unequivocal confirmation of the occurrence of
large hail, damaging winds or tornadoes.
Another argument in favor of an improved system for
documenting severe storms in South America is that, most
often, media coverage is the main information source for
meteorologists regarding the confirmation of a severe
weather event. In many situations, meteorologists are only
aware of the event after the news coverage on TV,
internet, or newspaper, several hours after the severe
weather occurrence. (These statements are based on the
first author’s experience in Brazil, but we believe that
they are also valid in other South American countries
affected by severe weather). Creating a severe weather
data set from media coverage (e.g., Nechet 2002) can be
highly laborious because such reports usually lack
reliability and quantitative information concerning the
meteorological component of the event. It is not rare to
find episodes related to storm-induced damage being
reported as a tornado by the media, when in fact
thunderstorms with damaging straight-line winds were
responsible for the destruction. Another problem is that
any given event of severe weather that does not reach a
certain (unknown) threshold of “importance” to justify a
journalistic coverage will remain unreported by the
media. Thus, while media coverage does contribute to the
documentation of severe storms, we believe that it should
not be considered the primary source of information for
severe weather episodes.
Other sources of information associated with infra-
structures already existent in most South American
countries seem more reliable, namely: damage reports
from emergency management teams and from the electric
power companies, and direct severe weather reports from
airports.
In Brazil (as in other countries), CD teams are
responsible for providing disaster relief to populations
affected by all sorts of hazards, including severe weather
(SEDEC 1999). Usually, these emergency management
teams represent the first technical personnel to arrive at
places affected by severe weather phenomena. By the
time a CD team arrives, the “destruction signature” left by
the weather event is still very clear, as confirmed by some
damage survey photographs taken by CD officials (Figure
6)  it is part of CD’s responsibility to conduct damage
surveys caused by disasters in Brazil (SEDEC 1999).
Hence, an opportunity exists to use the information
collected in situ by the emergency management personnel
as a support for severe weather documentation.
One example of such potential was the study
conducted by Marcelino et al (2005), who utilized the
archive of weather-related damage reports from the CD
System of Santa Catarina State (southern Brazil) as the
main source of information to identify tornadic events in
that state from 1976 to 2000.

Figure 6: Destruction likely caused by a tornado in
Muitos Capões, in Rio Grande do Sul State (southern
Brazil) on 29 August 2005. Picture taken by a state
CD official during the damage survey. (Courtesy of
CD System of Rio Grande do Sul State.)
After careful scrutiny of the damage surveys (and
journalistic records), Marcelino et al (2005) were
able to confirm the occurrence of ten tornadoes and
to identify other eight potentially tornadic events. For
fifteen events, the available information allowed a
damage assessment following the Fujita scale. (Five
waterspouts, identified by means other than the
destruction reports, are part also of Marcelino et al’s
documentation). Figure 7 shows the geographical
distribution of the weather events.
Figure 7: Tornadoes and waterspouts in Santa Catarina
state (southern Brazil) from 1976 to 2000. The Fujita
damage scale is assigned to some cases (From Marcelino
et al 2005).
As stated by Marcelino et al (2005), the true
number of tornadoes in Santa Catarina during that
period was, most probably, substantially higher,
because events that did not strike populated areas
remained unreported. Similar studies for Santa
Catarina have been conducted for hail, flash floods
and non-tornadic wind events (e.g., Marcelino et al
2004).
Damage reports kept by power utilities can also
contribute to the creation of a severe weather archive,
with the caveat that such information is usually
considered confidential by the electric power companies.
These reports often contain detailed information about the
destruction inflicted by the weather event to the
engineering structures (mostly powerlines), including
occasional aerial photography. Meteorology teams
working for power utilities can use the archives to
identify days and times of severe weather episodes.
Furthermore, a closer cooperation with power utility
engineers responsible for damage surveys should be
sought. The possibility of training them in specific
techniques which extract information that is particularly
relevant for the characterization of type and intensity of
the weather event (e.g., NWS 2003) should be considered.
Figure 8 shows significant damage inflicted to
powerline structures in the state of São Paulo
(southeastern Brazil) on the evening of 22 July 2002. This
damage was caused by wind gusts from an isolated severe
thunderstorm, as studied by Lima and Menezes (2004).
Ongoing work in Brazil is seeking to build a data base of
severe convective weather events based on damage
reports from an important electric power company
(Daniele O. Lima, personal communication).
Figure 8: Damage caused by convectively-induced winds to
powerline structures in São Paulo State (southeastern
Brazil) on 22 July 2002. (From Lima and Menezes 2004).
Convective weather reports from airports are another
important (and quite obvious) source of weather
information that can play a role on the creation of severe
weather archives. For example, Fogaccia (2001) used a
sort of PS approach to characterize the atmospheric
environments associated with a number of cases of strong
turbulence and windshear reported by pilots during
landing and take-off procedures around São Paulo
International Airport from 1994 to 1999. Although the
events were not necessary related to severe convection
(ordinary “pulse-type” storms produced most of the
episodes), their effect over airport operations were
relevant. Documentation of such events contribute to an
important convective weather archive to research seeking
the identification and prediction of atmospheric
conditions favorable to potentially hazardous aviation
weather (Fogaccia 2001).
©
2000 FURNAS Centrais El
étricas S.
A.

5. CLOSING DISCUSSION
Severe weather phenomena are inherently
difficult to observe and to predict, but they represent
a tangible threat to many human activities. The lack
of good-quality severe weather archives hinders
research on the climatological and synoptic aspects of
severe thunderstorms that are fundamental for
improving convective weather prediction. As severe
thunderstorm archives with meteorologically relevant
information become more readily available, more
research initiatives can work concomitantly,
addressing various topics of severe storms: from
thunderstorm dynamics to severe weather
climatology (including the important interannual
variability issue) and short range forecasting.
In this context, we emphasize that subtropical
South America is among some of most evident hot
spots for severe convective weather in the world
(Brooks et al 2003), and strong demand for
predicting such events does exist (e.g., Lima and
Menezes 2004). Furthermore, any study addressing
the impact of climate changes upon the frequency of
severe thunderstorms (e.g., identification of possible
trends and downscaling of extremes; Brooks 2004)
for any part of the globe requires background
knowledge on the “current climatology” of severe
weather events and of the large-scale atmospheric
environments in which they develop (Brooks et al
2003). These can only be accurately determined after
extensive work on the topic, where the systematic
documentation of severe thunderstorms can play an
important role.
We have discussed some possible ways of
addressing the issue of the creation of severe weather
data banks in South America utilizing infra-structures
that already exist in the continent. Nevertheless, we
do recognize some limitations on the alternatives
presented, which would have to be addressed by the
South American severe weather community.
(Moreover, we did not intend to present an
exhaustive list of alternative forms of creating severe
weather data sets). First, emergency management
officials have an overwhelming set of responsibilities
to be met during disaster relief campaigns, and it is
not their job to conduct weather-related damage
surveys from a meteorological standpoint. Thus, it is
obvious that only after a thorough discussion
concerning needs and capabilities between
meteorologists and CD systems that a reasonable
common-ground can be reached on that matter.
Second, CD teams are deployed to populated
areas affected by severe storms. Hence, severe
weather occurring away from urban areas (which
typically represents most of the cases; Doswell
2003), will not be part of a severe weather archive
that is based on damage reports kept by CD systems,
leading to underreports (Marcelino et al 2005). Similarly,
damage surveys conducted by maintenance teams of
electric power utilities are confined to small areas around
damaged structures, while aviation reports of severe
weather are confined to areas surrounding airports.
Analysis of high resolution satellite imagery of surface
features affected by severe weather phenomena seems a
promising alternative for the documentation of severe
events over broader areas (regardless of the level of
human occupation), but with some caveats briefly
described in this article.
The large number of good-quality severe thunderstorm
reports in the US is due, in part, to the existence of a
relatively large body of trained storm spotters (Doswell et
al 1999). Such volunteer groups do not exist in South
America, at least not officially. While we do not
recommend untrained individuals to chase severe storms
for the seek of reporting weather phenomena (a dangerous
activity), the severe weather research community in South
America could consider training volunteers to spot severe
thunderstorms from their own homes and report the
events in a standardized form.
South America’s atmospheric sciences community can
contribute to the effort in understanding severe
convection, as already shown from studies addressing
tropical and subtropical convection, like the remarkable
field campaigns in the Amazon (Large-scale Biosphere-
Atmosphere Experiment, LBA) and subtropics (the South
American Low-Level Jet Experiment, SALLJEX; and the
Tropical Convection and Cirrus Experiment in Brazil;
TrocciBras). A coordinated effort for an improved
documentation of severe thunderstorms is needed, though.
For now, we do not have a reasonable estimate of how
many severe thunderstorms and tornadoes occur each year
in South America; we still do not have a solid knowledge
on the seasonal and interannual variabilities of severe
convection in that continent; and there still is a long way
to go in transferring the knowledge acquired from severe
weather research to forecasting products in support of
operational meteorologists (Nascimento 2005).
ACKNOWLEDGEMENTS
The first author’s work was partially supported by
Brazil’s Conselho Nacional de Desenvolvimento
Científico e Tecnológico (CNPq), under grant number
476904/2004-8, and by Instituto Tecnológico SIMEPAR.
We acknowledge Rodovia das Colinas S.A., FURNAS
Centrais Elétricas S.A., and the CD from Rio Grande do
Sul State, in Brazil, for providing photographs and video
still frames utilized in this article. We wish to thank
researchers Isabela Marcelino and Daniele O. Lima for
enlightening discussion on some of the issues addressed
in this paper.

6. REFERENCES
Amorim, W. C. M., C. A. R. Morales, R. I. Albrecht,
and R. M. Rosa, 2005: Yes, we do have tornadoes
in São Paulo, Brazil. From the mesoscale models
to the radar reflectivity point of view. Preprints,
32nd Conference on Radar Meteorology,
Albuquerque,NM. (http://ams.confex.com/ams/
32Rad11Meso/techprogram/paper_97176.htm)
Antonio, M. A., C. A. A. Antonio, and J. C.
Figueiredo, 2005: Tornadoes of the 2004 autumn
season in the countryside of São Paulo. Preprints,
12th Brazilian Symposium on Remote Sensing,
Goiânia/GO, Brazil, 2819-2826. (In Portuguese).
Assunção, L. A. R., 2002: Powerline structures
downed by winds. Preprints, International
Seminar on Wind Effects on Powerlines, Belo
Horizonte/MG, Brazil. (In Portuguese).
Barnes, G., 2001: Severe local storms in the Tropics.
Severe Convective Storms, C. A. Doswell III (Ed.),
Meteorological Monograph, 28 (50), Amer.
Meteor. Soc., 359-432.
Beneti, C. A., E. A. Leite, S. A. M. Garcia, L. A. R.
Assunção, A. Cazetta, Fo, and R. J. Reis, 2000:
RIDAT – Rede integrada de detecção de descargas
atmosféricas <Integrated network for detection of
lightning discharges>: perspectives and future.
Preprints, 11th Brazilian Congress on Meterology,
Rio de Janeiro/RJ, Brazil,
Bluestein, H. B., C. Weiss, and A. L. Pazmany, 2003:
Mobile Doppler radar observations of a tornado in
a supercell near Bassett, Nebraska, on 5 June
1999. Part I: tornadogenesis. Mon. Wea. Rev., 131,
2954-2967.
Brooks, H. E., 2004: Downscaling of Severe
Thunderstorms from Reanalysis Data. Project
abstract, University Corporation for Atmospheric
Research, 3pp. (www.assessment.ucar.edu/2004
review/brooks.pdf)
Brooks, H. E., C. A. Doswell, III, and J. Cooper,
1994: On the environments of tornadic and
nontornadic mesocyclones. Wea. Forecasting, 9,
606-618.
Brooks, H. E., J. W. Lee, and J. P. Craven, 2003: The
spatial distribution of severe thunderstorm and
tornado environments from global reanalysis data.
Atmos. Res., 67-68, 73-94.
Davies, J. M., and R. H. Johns, 1993: Some wind and
instability parameters associated with strong and
violent tornadoes. 1. Wind shear and helicity. The
Tornado: its Structure, Dynamics, Prediction, and
Hazards, C. Church, D. Burgess, C. Doswell III,
R. Davies-Jones (Eds.), AGU Geophysical
Monograph 79, 573-582.
Doswell, C. A., III, 2003: Societal impacts of severe
thunderstorms and tornadoes: lessons learned and
implications for Europe. Atmos. Res., 67-68, 135-152.
Doswell, C. A., III, 2005: Progress toward developing a
practical societal response to severe convection.
Submitted to Natural Hazards and Earth System
Science.
Doswell , C. A., III, A. R. Moller, and H. E. Brooks,
1999: Storm spotting and public awareness since the
first tornado forecasts of 1948. Wea. Forecasting, 14,
544-557.
Dyer, R. C., 1988: Remote sensing identification of
tornado tracks in Argentina, Brazil, and Paraguay.
Photogramm. Eng. Remote Sens., 54, 1429-1435.
Dyer, R. C., 1994: A review of tornado activity in Brazil.
Proceedings, Int. Soc. Photogramm. Remote Sens.,
INPE, São José dos Campos, Brazil, Vol. 30, Part 7a,
203-213.
Evans, J. S., and C. A. Doswell, III, 2001: Examination of
derecho environments using proximity soundings. Wea.
Forecasting, 16, 329-342.
Fogaccia, A. J. P., 2001: Analysis of turbulence and
windshear events in the vicinity of São Paulo’s
International Airport. Master’s Thesis, Department of
Atmospheric Sciences, University of São Paulo, 131pp.
Fujita, T. T., 1973: Tornadoes around the world.
Weatherwise, 26, 56-62.
Held, G., A. M. Gomes, E. L. Nascimento, O. Pinto Jr., K.
P. Naccarato, C. A. Antonio, and A. B. P. da Silva,
2005a: Tornado signatures for nowcasting using radar
and lightning observations in Brazil. Geophys. Res.
Abstracts, 7, 10221, 2005 General Assembly of the
European Geosciences Union, Vienna, Austria.
Held, G., A. M. Gomes, K. P. Naccarato, O. Pinto Jr., E.
L. Nascimento, A. A. Correia, and I. P. V. O.
Marcelino, 2005b: Analysis of tornado characteristics
in the State of São Paulo for the improvement of an
automatic alert system. Preprints, 32nd Conference on
Radar Meteorology, Albuquerque, NM. (http://ams.
confex.com/ams/32Rad11Meso/techprogram/paper_
96729.htm)
Johns, R. H., and W. D. Hirt, 1987: Derechos: widespread
convectively induced windstorms. Wea. Forecasting, 2,
32-49.
Lima, D. R. O., and W. F. Menezes, 2004: Downed
powerline structures in Cachoeira Paulista (SP) and the
occurrence of severe thunderstorms. Preprints, 13th
Brazilian Congress on Meteorology, Fortaleza/CE,
Brazil. CD-ROM. (In Portuguese).
López, R. E., R. L. Holle, and T. A. Heitkamp, 1995:
Lightning casualties and property damage in Colorado
from 1950 to 1991 based on Storm Data. Wea.
Forecasting, 10, 114-126.

Marcelino, I. P. V. O., M. Mendonça, and F. M.
Rudorff, 2004: On the occurrence of hailstorms in
Santa Catarina State. Preprints, 1st Brazilian
Symposium on Natural Disasters, Florianópolis,
Brazil, in CD-ROM. (In Portuguese).
Marcelino, I. P. V. O., M. L. P. Herrmann, and N. J.
Ferreira, 2005: The occurrence of tornadoes in
Santa Catarina State, Brazil. Submitted to Austr.
Meteor. Mag.
Markowski, P. M., and Y. Richardson, 2004:
Multiple-Doppler radar observations of vertical
wind profile heterogeneity in convective boundary
layers. Preprints, 22nd Conf. on Severe Local
Storms, Amer. Meteor. Society, Hyannis/MA.
(http://ams.confex.com/ams/11aram22sls/
techprogram/paper_81183.htm).
Nascimento, E. L., 2004: Identifying severe
thunderstorm environments in southern Brazil:
analysis of severe weather parameters. Preprints,
22nd Conf. on Severe Local Storms, Amer. Meteor.
Society, Hyannis/MA. (http://ams.confex.com/
ams/11aram22sls/ techprogram/paper_81745.htm).
Nascimento, E. L., 2005: Severe storms forecasting
utilizing convective parameters and mesoscale
models: an operational strategy adoptable in
Brazil? Braz. Meteor. Magazine, 20, 121-140. (In
Portuguese).
Nascimento, E. L., and I. P. V. O. Marcelino, 2005a:
Preliminary analysis of the 3 January 2005
tornadoes in Criciúma/SC. Bull. Brazilian Meteor.
Soc., 29, 33-44. (In Portuguese).
Nascimento, E. L., and I. P. V. O. Marcelino, 2005b:
A multiple-vortex tornado in Brazil. To be
submitted to Monthly Weather Review.
NCDC, 1999: Storm Data. Vol. 41, No. 5, 372 pp.
(www5.ncdc.noaa.gov/pubs/publications. html)
Nechet, D., 2002: The occurrence of tornadoes in
Brazil. Bull. Brazilian Meteor. Soc., 26, 29-39. (In
Portuguese).
NWS, 2003: A Guide to F-Scale Damage
Assessment. National Oceanic and Atmospheric
Administration, U. S. Dept. of Commerce, 94 pp.
(http://meted.ucar.edu/resource/wcm/ftp/Final
NWSF-scaleAssessmentGuide.pdf)
Schwarzkopf, M. L., 1982: Severe storms and
tornadoes in Argentina. Preprints, 12th Conf. on
Severe Local Storms, Amer. Meteor. Soc., San
Antonio/TX, 59-62.
SEDEC, 1999: Manual for Civil Defense Planning.
National Secretariat of Civil Defense (SEDEC),
Vol. I, Brasília, Brazil, 70 pp. (In Portuguese).
Silva Dias, M. A. F., 2000: Storms in Brazil. In:
Storms, Volume II, R. Pielke Jr. and R. Pielke Sr.
(Eds.), Routledge Press, p. 207-219.
Silveira, R., 2005: Report on the operational use of
lightning detection methods in Brazil. WMO
Commission for Instruments and Methods of
Observation, Expert Team on Remote Sensing Upper-
Air Technology and Techniques, Geneva, Switzerland,
Doc.5.1(1) Rev. 1, 9pp.
Thompson, R. L., 1998: Eta model storm-relative winds
associated with tornadic and nontornadic supercells.
Wea. Forecasting, 13, 125-137.
Thompson, R. L., 2005: Explanation of SPC Severe
Weather Parameters. Storm Prediction Center (web
page), Norman/OK, www.spc.noaa.gov/sfctest/help/
sfcoa.html.
Torena, F., 2003: Tornadoes in Uruguay. Unpublished
technical note. (http://ar.geocities.com/lapaginaderio
negroyneuquen/temas/uruguay. doc). (In Spanish).
Velasco, I., and J. M. Fritsch, 1987: Mesoscale convective
complexes in the Americas. J. Geophys. Res., 92 (D8),
9561-9613.
Wurman, J., 2002: The multiple-vortex structure of a
tornado. Wea. Forecasting, 17, 473-505.
Yuan, M., M. Dickens-Micozzi, and M. A. Magsig, 2002:
Analysis of tornado damage track from the 3 May
tornado outbreak using multispectral satellite imagery.
Wea. Forecasting, 17, 382-398.
Zipser, E. J., P. Salio, and M. Nicolini: Mesoscale
convective systems activity during SALLJEX and the
relationship with SALLJ events. Clivar Exchanges, 9
(1), 14-19.