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#1428212 - 17/07/2017 15:23 Shivering in South America - Mid July 2017
ozthunder Offline
Weatherzone Addict

Registered: 23/09/2001
Posts: 3010
Loc: Mt Warrigal, NSW, Australia
Just noted some very cold temperatures in Chile, Argentina, Uruguay, Paraguay and southern parts of Brazil.Many towns struggling to get to double figures, and not just mountain ones.

A quick look at the weather map shows a SW wind fetch from below Tierra Del Fuego all the way into Brazil.

Buenos Aires going for just 8-9C today.

Asuncion in Paraguay at 25S just 13C, normal 23C.

With moisture there would be some parts of southern Brazil with sleet / snow.

In Chile--

https://www.nytimes.com/aponline/2017/07/16/world/americas/ap-lt-chile-snow.html
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#1428213 - 17/07/2017 15:43 Re: Shivering in South America - Mid July 2017 [Re: ozthunder]
Wave Rider Offline
Meteorological Motor Mouth

Registered: 27/01/2014
Posts: 6208
Loc: Wollongong, NSW
But yet Ushaia in the far south at 55S is also going for 8 degrees which is interesting and actually warm for there.

Interestingly Buenos Aires is quite prone to very cold conditions actually. It's almost at the exact same latitude as Sydney but yet there was snow in July 2007 there.


Edited by Wave Rider (17/07/2017 15:46)
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2016-17 season storm total for here= 15

Oct- 21st
Nov- 9th, 28th
Jan- 24th
Feb- 11th, 12th, 17th, 18th(2)
Mar- 13th, 16th, 22nd
Apr- 9th, 26th
May- 24th

The longer you wait for things, the more you appreciate them.

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#1428225 - 17/07/2017 18:01 Re: Shivering in South America - Mid July 2017 [Re: ozthunder]
Blair Trewin Offline
Weatherzone Addict

Registered: 13/07/2001
Posts: 3687
Loc: Melbourne, Australia
Set-up for this was a cutoff low over eastern Argentina with a centre near Buenos Aires.

The Paraguay/Brazil/BA numbers don't seem too far beyond coldest-day-of-normal-winter territory - with land extending so far south, there's more potential for cold air fetches from a long way south than there is at comparable latitudes in Australia. (Conversely, warm air can go a long way south too; Buenos Aires had a day with a max/min of 26/20 late last month). I spent a bit of time in 2014 in Gramado and Canela, in the highest part of southern Brazil at about 1000m; it would be fair to say that they milk their 'winter' features for all it's worth, even though I suspect they probably only get one or two snowfalls a decade.

Where we have seen some really spectacular numbers is on the eastern side of the Andes - first a big snow dump in the SSE flow, then extremely cold minimum temperatures as a ridge formed over the snow cover. The undoubted highlight was Bariloche, which dropped to -25.4, 4.3 degrees below their previous record low. (To place this into some sort of geographic perspective, Bariloche is at 41S and about 800m elevation - similar to the Tasmanian Central Plateau).

Like the interior South Island of NZ (you may recall the near -20 there a couple of years back), optimal conditions for extreme cold - snow cover, clear skies, light winds - don't happen often in Patagonia, and most winters don't see temperatures fall much below -10 (at least in populated areas), but when everything lines up, perhaps once a decade, the result can be dramatic.

Tierra del Fuego, as you might expect, is pretty maritime (and in this case was south of the cold pool anyway). Ushuaia's coastal and doesn't get below -5 that often, although their record low is -21. (There's a valley about 20-30km out of town with a few ski centres which the highway runs through which I suspect gets some really cold nights - I saw ice-covered ponds there in December - but as far as I know there are no observations there).

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#1428232 - 17/07/2017 18:47 Re: Shivering in South America - Mid July 2017 [Re: Blair Trewin]
Nerd65 Offline
Weather Freak

Registered: 30/01/2011
Posts: 402
Loc: Cranbrook, Townsville
Sounds like the well known "friagem" southern cold surge of that region. From the perspective of tropical/sub-tropical areas such as southern Brazil it doesn't seem too different to what we experience in North Queensland when an East Coast Low in combination with a high to the west directs cold southerlies our way, although in this case not as cold.
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#1428233 - 17/07/2017 18:59 Re: Shivering in South America - Mid July 2017 [Re: Blair Trewin]
Wave Rider Offline
Meteorological Motor Mouth

Registered: 27/01/2014
Posts: 6208
Loc: Wollongong, NSW
Originally Posted By: Blair Trewin

Where we have seen some really spectacular numbers is on the eastern side of the Andes - first a big snow dump in the SSE flow, then extremely cold minimum temperatures as a ridge formed over the snow cover. The undoubted highlight was Bariloche, which dropped to -25.4, 4.3 degrees below their previous record low. (To place this into some sort of geographic perspective, Bariloche is at 41S and about 800m elevation - similar to the Tasmanian Central Plateau).

Like the interior South Island of NZ (you may recall the near -20 there a couple of years back), optimal conditions for extreme cold - snow cover, clear skies, light winds - don't happen often in Patagonia, and most winters don't see temperatures fall much below -10 (at least in populated areas), but when everything lines up, perhaps once a decade, the result can be dramatic.


Such a long post and so much info, thanks for that.

Wow 4.3 below the prev record at Bariloche is pretty impressive. Where did you find this stat?

Yeah it's generally too windy for seriously cold minimums in Patagonia I would expect. I think Comodoro Rivadavia on the east coast is one of the windiest towns in the world with constant westerlies coming down the Andes and picking up speed. As a result its average summer max is about 26C despite being at 46 degrees south.
_________________________
2016-17 season storm total for here= 15

Oct- 21st
Nov- 9th, 28th
Jan- 24th
Feb- 11th, 12th, 17th, 18th(2)
Mar- 13th, 16th, 22nd
Apr- 9th, 26th
May- 24th

The longer you wait for things, the more you appreciate them.

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#1428255 - 17/07/2017 23:05 Re: Shivering in South America - Mid July 2017 [Re: Wave Rider]
Blair Trewin Offline
Weatherzone Addict

Registered: 13/07/2001
Posts: 3687
Loc: Melbourne, Australia
Originally Posted By: Wave Rider



Wow 4.3 below the prev record at Bariloche is pretty impressive. Where did you find this stat?



My approximate equivalent in SMN, the Argentine national meteorological service (whom I've worked with a fair bit on WMO things) posting copiously on Facebook :-).

(Actually, the SMN in Argentina has a pretty strong web and social media presence if you know where to look and can read enough Spanish to find your way around; apart from China, I'd regard them as having one of the strongest national climate services in the developing world).

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