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Cold Snap hits southern South America. UPDATE: my 'big fish' story!;-)

By: Christopher C. Burt, 9:10 PM GMT on July 26, 2013

Cold Snap hits southern South America. UPDATE: (and 'Big Fish in Living Room' story!)

It has been a wild week for temperature extremes with the amazing heat wave in north central Siberia juxtaposed with an unusual cold spell in portions of Brazil, Bolivia, and Argentina occurring simultaneously almost exactly opposite one another on the planet. Scroll down to end of blog for my fishy story! It actually has some context considering the amazing rainfall record set at Chantaburi, Thailand this past week.

South American cold snap

Between 20-25th July a mass of very cold air suddenly froze a large area of southern South America (where temperatures had been running above average for weeks prior to the abrupt change).

Snow was recorded for the first time since 1996 at Catamarca, Argentina (28°S and located at about 500m/1,650’), and cold rain (temperatures of 5-6C/41°-43°F) at sea level altitudes like Florianopolis, Brazil. Montevideo, Uruguay also experienced rain with temperatures as low as 3C (37°F). The town of Campos Novos, Brazil (at an elevation of 947m/3,100’) had a high temperature of just 3.6°C (38.5°F) and low of -2.7°C (27.1°F) on July 23rd, a daily average of almost freezing (0.9°C/32.8°F). There was no precipitation at the site that day, if so it probably would have been snow. In fact, a little snow was reported in Brazil in the hills above nearby Curitiba for the first time since 1975.



Snowfall in the mountainous region of Santa Catarina, Brazil is not so unusual. Above is an image of a deep snowfall near Rio Grande do Sul during the cold wave of July-August 2010. Ironically, this occurred at the same time as the famous Moscow heat wave of that summer, a somewhat similar situation as is now occurring. Photographer not identified.

There were incredible temperature contrasts in Bolivia (which isn’t unusual given the complex Andean topography) but what was unusual was that it was actually colder at the low elevations in the Amazonian jungle than in the higher mountainous terrain of the country: temperatures at Bolivian locations above 4000m (13,000’) on 23 July were higher than those in the Bolivian portions of the Amazon jungle at low elevations. For instance, the temperature at Reyes (located at 14°S and 140m/462’ elevation) had a maximum of 9.3C/48.8°F while at El Alto Airport, La Paz (elevation 4,000m/13,200’) the temperature maximum reached 13.9°C (57°F). Temperatures in the Chaco region of Bolivia were remarkably chilly with a reading of -5.8°C (21.6°F) observed at Villamontes.

Some places in the middle of the Andes, protected by mountains on all sides, like Cochabamba didn't experience a single degree drop in temperature, while low areas experienced drops as high as 22-25°C (40-45F) in 24 hours. In Paraguay sleet was recorded in Itapua and the minimum temperature reached -5.2C (21.6°F) at Prats Gill on 24th, not far from the all-time national record of -7.5C (18.5°F) (also set in Prats Gil) on July 13, 2000

The cold air actually filtered as far north as the western part of the Amazon jungle near the Equator, with 7°C (44.6°F) at Rio Branco, Brazil (10°S latitude) and 16°C (60.8°F) at Leticia, Colombia (4°S latitude). Both are low-level sites in the Amazon Basin.

The most exceptional cold wave, in regard to how north cool air has ever penetrated, was that of July 1975 when air of polar origin reached the Caribbean affecting the whole of South America (including the extreme western part of Amazon in Peru, Brazil, Colombia, Venezuela, the Guyanas, and even Trinidad and Tobago. Unlike other cold waves (such as those of 1955, 1973 and 2010) the July 1975 event didn't stop south of the Equator, but continued well into the Northern Hemisphere. This remains unique and the only documented occurrence of such an event. The surface high pressure reached 1044 hPa (30.82”) over central South America on July 15, 1975, the highest yet measured (modern records) on the continent (REF: Markgraf, Vera Interhemispheric Climate Linkages p. 37)




500 mb MAP

Surface air temperature anomaly for the week of July 19-24 (top map) and 500 mb height anomalies for the same period (bottom). Note how the cold air over South America is almost exactly on the opposite side of the world from the heat dome over north central Siberia. NCEP/NCAR maps, courtesy of Stu Ostro.

The cold snap this past week was caused by a strong upper-level low centered over the southern third of the continent. Curiously, it has been unusually mild over the portions of Antarctica opposite South America with a high of 7.8C (46.0°F) being recorded at Base Esperanza (63°S), higher than the normal summer average maximum and just 1.5°C less than the Amazonian maximum of Reyes in Bolivia at 14°S latitude!

Meanwhile on the other side of the world…

The unrelenting heat wave in north central Siberia continues with Svetlogorsk (on the Arctic Circle) recording its 13th consecutive day (as of July 26) with temperatures above 30°C (86°F). Meanwhile, all eyes are turning to Western Europe where a potentially historic heat wave is expected to develop this weekend and continue into next week! There is a chance that some all-time national heat records may fall in some countries like Germany, Liechtenstein, Austria, Slovakia, Slovenia, and Hungary when all is said and done.

Phenomenal Rainstorm in Thailand

On a side note, a historic rainstorm has caused serious flooding in portions of southeastern Thailand. Chantaburi picked up 445.7mm (17.55”) of rain on July 23rd with an amazing 385mm (15.16”) of this falling in just 12 hours and an even more amazing 297 mm (11.69”) in just 6 hours! This may be one of the (if not the) heaviest 24-hour rainfall on record for Thailand (previous record was 414.8mm (16.33”) at Ko Samui on March 28, 2011. A famous flood in Bangkok occurred on May 9-10, 1986 when 401.1 mm (15.79”) of rain fell in just 8 hours. The ensuing floods almost cost the mayor (Chamlong) his job.

My 'fish story'

I lived a few blocks from the Bangkok Met office at the time (during the storm of 1986) on Soi 49 Sukhumvit Rd. and caught a 15" fish that swam through a break in the screen porch door off my living room which flooded about half a meter deep at one point. My girlfriend at the time and I trapped the sucker hiding under the water-logged couch in the living room. We grilled it later that same day (after the water receded) and it was delicious (no idea what kind of fish it was). I think I must be one of the only people who have caught a large live fish swimming around their living room and then cooked it in their kitchen just 10 feet away hours later :-). I'd love to hear from other WU friends if they have had a similar experience!



METARS for Chantaburi, Thailand July 22-23 when a peak 24-hour rainfall amount of 445.7 mm (17.55”) accumulated, a possible national record. Flooding continues as more rain has since fallen over this region of southeastern Thailand. From OGIMET.

KUDOS: Thanks to Maximiliano Herrera for much of the above information about the cold wave in South America.

Christopher C. Burt
Weather Historian

Extreme Weather Cold

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

Reader Comments

I remember reading about equator crossing cold fronts in South America in high school sometime in 1974 or early 1975 prior to the 1975 event. It was documented as an unusual feature of the South American Continent and attributed to the Andes which are the highest North South extending
mountain range in the world and create a synoptic scale extreme of what happens with cold air damming in the eastern U.S. and Plains Northers in the Great Plains east of the Rockies. 1975 was not the only occurrence but penetration all the way to the Caribbean probably
is a record event.

These temperatures in the Amazon rainforest are amazing. Many tropical plant species are sensitive to chill WELL ABOVE freezing especially if of long duration (over 24 hours).


Perhaps I need to stock up on coffee or as I used to call it in Grad School
"Sleep Substitute"

And to go off topic but get out an important message to students, one of the most important things you can do to preserve your education is to get enough sleep while you're getting it. If not your retention will be much less, what you gain studying late nights will more than be compensated by the loss from not enough sleep.

I wish I'd slept more at FSU grad school. It wasn't a problem for me as an undergrad at PSU where I maintained very stable study habits
but more of my grad school knowledge base has decayed and it isn't
the fault of the institution! I was actually much happier in grad school and that was part of the motivation to push past where I should have slept.


According to the synoptic reports on Ogimet, Curitiba Airport itself reported snow (presumably it didn't settle). My Brazilian contacts tell me it was the most significant event there since 1975.

Also an interesting coincidence that the Julys of both 1975 and 2013 have been notably warm in large parts of Australia. Indeed, Melbourne had its warmest July day on record (23.3 C) on the 18th, breaking the record set in 1975 - although the sequencing is different (the 1975 warm spell was two weeks after the South American cold outbreak, not just before it as in 2013).
Quoting 2. blairtrewin:
According to the synoptic reports on Ogimet, Curitiba Airport itself reported snow (presumably it didn't settle). My Brazilian contacts tell me it was the most significant event there since 1975.

Also an interesting coincidence that the Julys of both 1975 and 2013 have been notably warm in large parts of Australia. Indeed, Melbourne had its warmest July day on record (23.3 C) on the 18th, breaking the record set in 1975 - although the sequencing is different (the 1975 warm spell was two weeks after the South American cold outbreak, not just before it as in 2013).


Thanks for this Blair!

I'm wondering if there is some relationship (climatologically) between extreme temperature antipodal events that seem to occur concurrently between the northern and southern hemispheres. We now have 1975, 2010, and our current situation as examples (small but determined examples). Maybe just coincidental, but it would make for a nice thesis for some doctoral student!

Hard to understand how climate patterns across hemispheres (north-south) could relate to specific extreme weather events happening concurrently on both halves of the planet. I know nothing about this, so just a muse on my part.
Thanks for the interesting blog, including the glimpse to sweltering Europe:


Temperature highs for today, July 27, in Celsius. But the colour says it all.

Of course it's once again the jet stream which turned on the heater, probably in Siberia, too.
From the department of probably unrelated coincidences, mid July 1975 in the Mid Atlantic was dominated by a decaying very strong midwest trough, and a moderately strong bermuda high which gradually intensified and built west as the trough weakened. This is a common heavy rain producer for the middle atlantic region and some parts of the DC area got over 10", mostly in the middle of the month. I learned about drainage that summer when my poorly drained vegetable garden was severely damaged by flooded soils and plants died.

The pattern this mid july was somewhat similar but the midwest troughing was not nearly as strong and was smaller scale. Th slow transition from deep very moist southerly flow to westerly flow associated with the strengthening bermuda high and increasing stability and drying, was very similar to mid July this year. I'm only remarking because I noted a similarity to 1975 in the U.S. pattern BEFORE I read this blog entry.

The fact I'm old enough to remember 1975 is itself disturbing :-)

I strongly suspect this is coincidental and not a marker of a pattern that produces summer South American cold outbreaks.
Quoting 4. barbamz:
Thanks for the interesting blog, including the glimpse to sweltering Europe:


Temperature highs for today, July 27, in Celsius. But the colour says it all.

Of course it's once again the jet stream which turned on the heater, probably in Siberia, too.


Reached 35C (95F) in Stuttgart today, a little less than predicted. We had severe thunderstorms three days this past week due to the heat. Some tree and crop damage in the area.

Tomorrow should be 33C (93F), but Monday will be sharply cooler with only 20C (68F) for a high, with heavy rain perdicted. Afterwards, though, the temps will shoot up again and be back in the nid 30´s C (mid 90´s F) by next weekend.

I see no advantage to "staying indoors" during this heat. I, nor anyone I know, has air conditioning in their home. An upstairs bedroom can be unusable in the evening. I do have air conditioning at work, so I am not complaining about going to work this week.
Iin this blog you may see a lot of pictures of the snow in southern Brazil - http://www.metsul.com/blog2012/Home/home/350/Espet acular_e_memorável_nevada_entra_para_a_história_ do_Sul_do_Brasil

Their meteorologists do an outstanding job, helping to warn people about the weather.

I live in Brasilia, in the center of Brazil, but this month I'm staying at Piaui, a State in the northeast. Here, we have highs of 36C every day. The house I'm staying has ar conditioning, but we turn it on just in the evening, because of the high cost of electricity.
Quoting 2. blairtrewin:
According to the synoptic reports on Ogimet, Curitiba Airport itself reported snow (presumably it didn't settle). My Brazilian contacts tell me it was the most significant event there since 1975.

Also an interesting coincidence that the Julys of both 1975 and 2013 have been notably warm in large parts of Australia. Indeed, Melbourne had its warmest July day on record (23.3 C) on the 18th, breaking the record set in 1975 - although the sequencing is different (the 1975 warm spell was two weeks after the South American cold outbreak, not just before it as in 2013).
Quoting 2. blairtrewin:
According to the synoptic reports on Ogimet, Curitiba Airport itself reported snow (presumably it didn't settle). My Brazilian contacts tell me it was the most significant event there since 1975.

Also an interesting coincidence that the Julys of both 1975 and 2013 have been notably warm in large parts of Australia. Indeed, Melbourne had its warmest July day on record (23.3 C) on the 18th, breaking the record set in 1975 - although the sequencing is different (the 1975 warm spell was two weeks after the South American cold outbreak, not just before it as in 2013).


There was no snow in Curitiba downtown (centre), just rain.
The airport is in the hinterland.
Curitiba downtown hardly ever sees snow.
The only snow events with accumulation in the past 100 years have been in 1928 (5cm) and 1975 (1cm on the gardens,trees, roofs, ).
No accumulation but falling snow was recorded in the Observatory in 1912 and 1942.
Quoting 2. blairtrewin:
According to the synoptic reports on Ogimet, Curitiba Airport itself reported snow (presumably it didn't settle). My Brazilian contacts tell me it was the most significant event there since 1975.

Also an interesting coincidence that the Julys of both 1975 and 2013 have been notably warm in large parts of Australia. Indeed, Melbourne had its warmest July day on record (23.3 C) on the 18th, breaking the record set in 1975 - although the sequencing is different (the 1975 warm spell was two weeks after the South American cold outbreak, not just before it as in 2013).


In most of South America the same. This July 2013 has been very warm, in many parts of Brazil the warmest July on record.
Not a single station in the whole South America has set an all-time lowest temperature, while dozens of all-time highest temperatures for July have been set, specially in Brazil, constantly between 36C and 38C all the past days.
While larger parts of Brazil have been above average every day of this month, other parts in the South have just had few days below average always in a very very warm July.
July 2000 was a much colder event for Southern Brazil.
This is nothing compared to the cold events of decades ago when in the South there was snow accumulation up to 2 meters.
I would say Liecthenstein is the most likely national record to fall, than with lower chances Austria, Germany, Czech Republic, Slovakia, Slovenia, Poland.
On Monday a good chance for San Marino is garbino wind will be wild blowing from the Appennins to the adriatic coast.
Are you kidding me?! 49F for the high temperature in the Amazon?? Imagine if a Canadian family went on a vacation to Jamaica and it never got above 50 degrees. Meanwhile it was 50 degrees in Canada where they came from.
Thanks Christopher! That level of rainfall is quite impressive. I remember that Jamaica had about 37 inches of rain from TS Nicole (2010), but this was over a four day period.
Reported tonight on CCTV/China 24:

China scorched by heat
07-28-2013
On Friday, temperature in Shanghai went off the chart, hitting 40.6 degrees Celsius,(105.08 Fahrenehit) a record high temperature in the city for the past 140 years. Some locals took the rare opportunity to take pictures of the giant thermometer on the street.

Anhui province in east China has also reported sustained hot weather. Saturday’s temperature hit 40 degrees Celsius, the highest in this summer. And Luzhou city in southwestern Sichuan province saw a temperature over 40 degrees Celsius. Local weather authorities issued the second highest alert for the heat.
Really nice blog. Thank you.

I'm in Trinidad (11N 61W).
July has been incredibly dry and hot, with no sign that this is going to change soon.

I've never seen the Caribbean Sea and the GOM so devoid of cloud for so many weeks in July before.

Very peculiar weather, everywhere.
Quoting pottery:
Really nice blog. Thank you.

I'm in Trinidad (11N 61W).
July has been incredibly dry and hot, with no sign that this is going to change soon.

I've never seen the Caribbean Sea and the GOM so devoid of cloud for so many weeks in July before.

Very peculiar weather, everywhere.

Hi pottery! We have been having similar conditions here in Jamaica as well. Kingston as well as other areas in eastern Jamaica are having water restrictions at the moment. We had a bit of rain in central and western Jamaica yesterday for the first time in a week or so.
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