Winter op het zuidelijk halfrond 2024

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In gebieden zoals Potrerillos, El Salto, Las Vegas, Las Cuevas, Puente del Inca, Punta de Vacas en Uspallata heeft het gesneeuwd, terwijl er in het Grote Mendoza constant regenval is geweest. Vanwege het slechte weer zijn de lessen op sommige van deze plaatsen opgeschort.

Als reactie op deze situatie heeft de Civiele Bescherming waarschuwingen uitgegeven voor de departementen Malarg�e, San Rafael, Tunuy�n, Tupungato en San Carlos. Ze adviseren om extra voorzichtig te zijn bij het reizen over wegen en paden vanwege de slechte weersomstandigheden.

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Als gevolg van de sneeuwval wordt de doorgang naar Chili morgen uit voorzorg gesloten. De afsluiting begint om 00:00 uur Argentijnse tijd en 23:00 uur Chileense tijd.

"Overeenkomstig de afspraken tussen beide co�rdinaties zal de doorgang bij Uspallata en Guardia Vieja worden gesloten," meldde de instantie.

De preventieve sluiting is het gevolg van de instabiele omstandigheden in het hooggebergte, zoals voorspeld door verschillende weersmodellen, die de veilige doorgang zouden be�nvloeden.

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De Pehuenchepas in Malarg�e zal deze zondag preventief vanaf 15.00 uur gesloten zijn, waardoor reizen niet mogelijk is. Deze maatregel geldt voor alle soorten voertuigen.

Het besluit van de co�rdinatoren van beide landen is gebaseerd op de voorspelling van slecht weer deze zondagmiddag. In Chili wordt de maatregel vanaf 14.00 uur ingevoerd, omdat het daar een uur eerder is.

"De verschillende meteorologische modellen verwachten overvloedige sneeuwval en sterke wind, met een grotere intensiteit in het berggebied van Chili, wat een veilige doorgang zal verhinderen," aldus Justo B�scolo, de co�rdinator van de pas in Argentini�.

https://mediamendoza.com/(...)enche-desde-que-hora

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De Nationale Weerdienst (SMN), onderdeel van het Ministerie van Defensie, heeft een code oranje uitgegeven voor sneeuwval in verschillende gebieden van Argentini�, waaronder het gebergte van Neuqu�n en Mendoza.
Aanstaande zaterdag wordt de koudste dag van het jaar, waarbij het (misschien) tot sneeuw kan komen in Buenos Aires.

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Om de problemen aan te pakken van vrachtwagenchauffeurs die dagenlang moeten wachten op de heropening van de Internationale Pas vanwege zware weersomstandigheden, heeft de regering van Mendoza, in samenwerking met de Algemene Co�rdinatie en Beheer van de Grenscentra van het Systeem van de Internationale Pas Cristo Redentor, het Noodprotocol voor Langdurige Sluitingen van de internationale corridor ingevoerd. Dit protocol omvat een ambulance, medisch personeel en hulp in het Chrabalowski-ziekenhuis voor chauffeurs die dat nodig hebben.

"We hebben drie opvangplekken in het hooggebergte. E�n bevindt zich bij het ACI waar de douane is, een andere naast het YPF-station in Uspallata, en een derde in Do�a Carmen. Deze drie opvangplekken kunnen samen negenhonderdtachtig vrachtwagens herbergen," verklaarde de onderminister van Industrie, Handel en Logistiek, Alberto Marengo. Hij voegde eraan toe dat "tot nu toe alleen de opvangplek bij het ACI volledig bezet is."

https://www.mdzol.com/soc(...)rdillera-429534.html

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A polar jet stream is set to bring a chill across most of the country in coming days, including more snow for the South.
Crown agency Niwa said autumn "is ending as it started - with below-average temperatures".

It said a southerly change would usher in colder air over the weekend, which "will begin a period of gusty, brisk wind for parts of the country, making it feel even colder".

"Sunday looks to have a wind chill across most of the country which may be reinforced toward the middle part of next week."

NZ Weather Forecast - Friday 24th May 2024

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De wintertemperaturen zijn in het hele land ongeveer even waarschijnlijk rond het gemiddelde als boven het gemiddelde. Er wordt een periode van warmer dan gemiddelde temperaturen verwacht in de eerste helft van juni, gevolgd door een terugkeer naar meer typische omstandigheden in de tweede helft van de maand. Hoewel er gedurende het seizoen af ​​en toe koudegolfjes worden verwacht, zullen deze waarschijnlijk van korte duur zijn.

https://niwa.co.nz/climat(...)ook-june-august-2024

NIWA Seasonal Climate Outlook: June-August 2024

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In the past 24 hours, South Africa has witnessed at least two tornadoes north of Durban, hail in Umhlanga, snow in the Northern Cape and heavy rains and strong winds in the Western and Eastern Cape. So far, seven people have lost their lives in Eastern Cape and at least five people were confirmed killed in KwaZulu-Natal on monday
Winter is setting in as severe weather batters parts of the country. More cold, wet and windy conditions are expected throughout this week, with snow falling in some areas.

Downed trees and destroyed homes were reported in the Tongaat area north of Durban on Monday afternoon after tornadoes tore through the area.

https://www.dailymaverick(...)d-high-winds-hit-sa/

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Christchurch and Timaru recorded their lowest ever average minimum temperatures for May, with averages of 0.5�C and 0�C respectively.

Rainfall was below or well below normal for most of the South Island, Bay of Plenty, and parts of Waikato and Northland, but above or well above normal for isolated parts of Auckland, Gisborne, Hawke's Bay, and southern Wairarapa.

The highest one-day rainfall was 130mm recorded at Leigh, north of Auckland, on May 20.

The highest wind gust of 152 km/h was detected at Secretary Island near Doubtful Sound on May 29.

Warm in Auckland, wet in the capital
Of the main centres, Auckland was the warmest, Tauranga was the sunniest, Dunedin was the driest and least sunny, Christchurch was the coolest, and Wellington was the wettest.

Of the available sunshine observation sites, the sunniest four locations in 2024 were Marlborough with 1265 hours, Nelson with 1251 hours, Bay of Plenty with 1220 hours and Taranaki with 1218 hours.

https://www.1news.co.nz/2(...)ay-in-15-years-niwa/

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Several other places have also experienced their coldest temperature in more than 10 years during this event.

Some of the highlights include:

Longerenong, Victoria. Maximum of 7.9C on Friday 14th June — coldest day in 27 years
Nhill, Victoria. Maximum of 8.3C on Friday 14th June – coldest day in 22 years
Keith, South Australia. Maximum of 8.9C on Friday 14th June– coldest day in 18 years
Westmere, Victoria. Minimum of -5.7C on Wednesday 19th — coldest temperature on record (data to 2006)
Strathbogie, Victoria. Minimum of -6.6C on Wednesday 19th — coldest morning in 18 years
Mortlake, Victoria. Minimum -3.5C on Wednesday 19th — coldest morning in 18 years
Strahan, Tasmania. Minimum -2.9C on Thursday 20th — coldest morning in 41 years

https://www.abc.net.au/ne(...)-cold-snap/104006148

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De stad La Plata registreerde deze woensdag de laagste temperatuur in 57 jaar. Te midden van de koudegolf die La Plata teistert, heeft de Nationale Meteorologische Dienst de laagste temperatuur sinds 1967 in de stad geregistreerd.

De stad La Plata ervaart een koudegolf die een nieuw record van laagste temperatuur in 57 jaar heeft bereikt. Op woensdag 10 juli gaf de thermometer -5,7�C aan, een cijfer dat sinds 14 juni 1967 niet meer was geregistreerd, volgens de Nationale Meteorologische Dienst (SMN).

De foto's en video's die in de vroege uren van de dag werden gedeeld, tonen de impact van de extreme kou in de stad. Bevroren zwembaden en parken bedekt met een witte laag rijp zijn de afgelopen dagen een veelvoorkomend verschijnsel geworden.

https://www.0221.com.ar/l(...)-baja-57-anos-n94860

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Op donderdag 11 juli 2024 21:25 schreef flipsen het volgende:
Mja, het is nog steeds frisjes ja qel iedere middag heerlijk, volop zon, maar wel koud.

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A rare sudden stratospheric warming event is beginning to occur above Antarctica, and it may influence Australia’s weather in the coming weeks.


The term sudden stratospheric warming (SSW) refers to an abrupt increase in air temperature high above either of Earth’s polar regions, typically on the magnitude of tens of degrees Celsius in a few days. This warming occurs in a layer of the atmosphere called the stratosphere, roughly 30 to 40km above the surface.


While warming in the stratosphere does not immediately (or always) affect weather patterns near the ground, SSW events can filter down through the atmosphere and influence tropospheric weather in the weeks following the initial SSW.


If an SSW event does make its way down to the troposphere, it can cause the tropospheric polar vortex to weaken, which allows cold polar air to drift further away from Antarctica (or the Arctic if in the Northern Hemisphere) and spread towards the mid-latitudes.


Through this domino effect, SSW events can cause the Southern Annular Mode (SAM) to shift into a negative phase, which can have the following impacts in Australia during winter:


More cold fronts and low pressure systems over southern Australia

Increased rainfall and snow potential in southwest and southeast Australia

Reduced rainfall in parts of eastern Australia

Stronger winds in the southern half of Australia


The Southern Annular Mode (SAM) is an index used to monitor the position of the westerly winds that flow from west to east between Australia and Antarctica. When the SAM is in a negative phase, these westerly winds, and the cold fronts and low pressure systems they carry, are located further north than usual for that time of year. When the SAM is positive, the westerly winds, cold fronts and low pressure systems are located further south than usual.


Sudden Stratospheric Warming underway

Warming has been detected in the stratosphere above the Antarctic region over the past week, revealing that an SSW event is starting to occur in the Southern Hemisphere. Some forecast models predict that this stratospheric warming will continue over the next week and start to filter down through the atmosphere later this month.


The graph below shows observed stratospheric temperatures in red and the forecast from one model in green. From these lines you can see a sudden increase in the temperature beyond the normal range, potentially getting even warmer than any other observed event at this time of year.


Image: Observed and forecast 10hPa temperature over the Southern Hemisphere’s polar region (90�S to 60�S) according to the GFS model.


It is currently unclear whether the stratospheric warming will influence weather closer to the ground in the coming weeks. However, some models are already showing signs that the SSW signal will descend to lower altitudes during the second half of July. If this trend continues, it will increase the likelihood of a shift towards a negative SAM in late July or August.


Videos: Forecast temperatures at the 10hPa (top) and 100hPa (bottom) levels in the atmosphere, according to the GFS model. The first animation shows warming over East Antarctica during the middle of July, which displaces the cold air within the stratospheric polar vortex. The second animation shows warming predicted to the south of Australia later in the month, indicating the downward progression of the SSW signal.


Since April, Australia has been affected by a stagnant long-wave ridge pattern, leading to persistent high pressure in the Bight. As a result, there has been drought in WA and SA, abnormally wet conditions along the east coast, and very low wind over western Vic. This SSW event may disrupt this pattern for the Australian region.


The images below show one forecast model predicting a shift towards lower sea level pressure near Australia in August, and an associated increase in precipitation for southern Australia, which are both consistent with a shift towards negative SAM.


Image: Forecast mean sea level pressure anomaly in August 2024 according to the ECMWF SEAS5 model.


Image: Forecast precipitation anomaly in August 2024 according to the ECMWF SEAS5 model.


What causes Sudden Stratospheric Warming?

SSW can be caused by large atmospheric ‘waves’ propagating upwards through the atmosphere and crashing into the stratospheric polar vortex. These waves can warm the polar stratosphere and weaken, or even reverse, the westerly winds that typically circulate above the poles in winter.


An SSW event can be classified as minor or major based on the magnitude of warming and changes to the wind speed and direction in the stratosphere:


A minor SSW occurs when the polar temperature increases by 25�C or more within one week at any stratospheric level

A major SSW requires an increase in temperature AND a reversal of the westerly winds at the 10hPa level in the polar regions.


Only a few SSW events have been observed in the Southern Hemisphere, with the most recent one occurring in 2019.


Weatherzone’s meteorologists will be keeping a close eye on the current SSW signal and updating the Weatherzone News feed in coming weeks.

Note to media: You are welcome to republish text from the above news article as direct quotes from Weatherzone. When doing so, please reference www.weatherzone.com.au in the credit.

Read More: https://x.com/Ben_Domensino/status/1811633854173901211?s=19

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Every winter, the polar vortex forms high above Antarctica in the polar stratosphere. This year, the vortex is showing signs of being disturbed 🐧

During winter in the Southern Hemisphere, a ring of stormy and freezing weather encircles Antarctica. Known as the polar vortex, it is usually very good at keeping harsh, wintry conditions locked up close to the pole.

➡️ Every once in a great while, the polar stratosphere can warm dramatically during a phenomenon called a sudden stratospheric warming (SSW).

These events have specific criteria that need to be met. A minor SSW requires stratopsheric temperatures to rise at least 25˚C in a week. A major SSW requires both warming combined with a dramatic reduction in stratospheric winds.

Right now, a pattern of warming is being observed in the stratosphere above East Antarctica. It is uncertain if it will reach the threshold needed to qualify as a *minor* SSW, but it may be close. A major SSW looks quite unlikely at this point.

When a SSW occurs, it can help to weaken or displace the polar vortex in the stratosphere, which then filters down onto the tropospheric polar vortex and influences our weather patterns.

These events are rare in the Southern Hemisphere. There have only been three in the satellite era: September 2002, September 2010, and August-September 2019. After the SSW in 2002, New Zealand experienced its coldest October in 20 years with below average temperatures covering much of the country and frequent ground frosts. In 2010 – which is classed as minor event – a number of rainfall records were broken with well below normal sunshine and very cold temperatures in parts of the South Island.

This year, there are some signs that the developing anomalies in the stratosphere may indeed couple with the troposphere, ultimately affecting hemispheric weather patterns. The early indication is for above normal pressures to develop over Antarctica during late July. This will force lower pressures across the mid-latitudes of the hemisphere, including New Zealand and Australia, leading to stormier conditions.

The effects can last for up to a month or two, so this unique climate driver may be with us through August.


https://x.com/peakaustria(...)Jw0OOJ6SP09Webw&s=19

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The extreme cold front dumped thick snow on the popular winter playgrounds of Thredbo, in the NSW Snowy Mountains, and Victoria’s alpine slopes, creating an incredible frozen landscape.

Blizzard conditions occurred above 1200 metres in alpine regions, but were expected to ease early Sunday morning.

https://www.thenewdaily.c(...)1/cold-blast-weather

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Op zondag 21 juli 2024 14:54 schreef flipsen het volgende:
Hier in Mar del Plata wordt het de komende week 16-19 graden

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A slow-moving front over the south of the South Island is bringing "significant" snow to Queenstown Lakes, Southland and inland Otago, as well as heavy rain.

The latest forecast came after a heavy dump of snow in the South Island on Friday caused power outages, shut schools and closed roads.

A heavy snow warning is in place until 10pm Sunday for the Queenstown Lakes District south of Wanaka and for Southland north of Mossburn and west of Athol.

MetService said to expect 12-18cm of snow to accumulate above 400 metres, warning that further snow was expected on Monday night and into Tuesday.

Heavy snow was also expected until 5am Monday in Southland, north of Lumsden and from Athol eastwards, as well as inland Otago excluding the Queenstown Lakes District.

In those areas, people could expect 10-20 cm of snow to settle above 400 metres, with lesser amounts down to 300 metres.

The snow could disrupt travel and damage trees and powerlines, and cold conditions may cause stress for livestock, it said.

MetService warned people to prepare for snow, cold temperatures, and possible power outages.

"If you must travel, drive cautiously, and ensure you have snow chains, sleeping bags, warm clothing, and emergency items."

https://www.rnz.co.nz/new(...)r-lower-south-island