Sudden Stratospheric Warming Event (SH) 2019

[NZ Thunderstorm Soc]

Roll on September and October to see what results from this event.
Looking forward to the low status and drizzle with every southerly change, like today

[Cyclone Tracy]

NASA GEOS observation from 1.15am NZT today. Upper stratosphere outer edge of the Polar circle has broken the August mean temperature record. Inner polar circle is projected to break the August record tomorrow. Temperature is measured in kelvin. Records date back to 1979.

[snowchaser01]

The more I research I do on this, the more concerning, yet remarkably interesting it becomes. IMO, nothing is off the able when it comes to possible events that could occur as a result of this SSW...

[Cyclone Tracy]

2 cents worth of model highlights from 00z and 12Z

GFS is displaying a maximum temp of +13c @ 10 hPa and +41c @ 1 hPa on 13 September over the south pole. GFS has a strong push of the anomalies into the mesosphere.

EC is again producing the sinister twin daughter circulation within the lower stratosphere @ 100 hPa on 9 September. This can be a precursor to a complete vortex split.

North American ensembles of 60+ models (GEFS, GEPS, EFS) are suggesting a possible further peak of the event around 12 to 15 Sept.

SAM index is remaining between negative -4 to -7 in the stratosphere for the next 14 days. An initial minor negative SAM is making its way to the surface this weekend before trending neutral or positive. There is no clear sign yet of the downward coupling from stratosphere to troposphere which could trigger a violent release of the polar jet stream towards the equator.

[Avalanche]

CT and Tony T, Do we have a weather model map of Antarctica with what's happening right now with the warming event, what are the consequences of the polar jet stream heading towards us? Things are increasing for a southerly outbreak end of next week but models dont suggest it being too severe at this point? Or are the models telling fibs and things could be alot worse than what they are showing. Thanks guys really appreciate your knowledge. Very fascinating,

[Cyclone Tracy]

Hot off the press Avalanche, from EC's latest run 18Z as of midday NZT. 86c temperature gradient over Antarctica 30km above the surface.

Next week is a minor first phase but it's still a sizeable deep low pressure system that needs to be closely watched. The extreme part of the SSW is still unfolding in the stratosphere.

[TonyT]

CT and Tony T, Do we have a weather model map of Antarctica with what's happening right now with the warming event, what are the consequences of the polar jet stream heading towards us? Things are increasing for a southerly outbreak end of next week but models dont suggest it being too severe at this point? Or are the models telling fibs and things could be alot worse than what they are showing. Thanks guys really appreciate your knowledge. Very fascinating,

IMHO next week's COL and following southwest airflow won't be influenced by the SSW event - too soon. Look to 20th September onwards, and maybe even after then, to start to see any impacts on surface weather patterns.

[Avalanche]

Are ha, i see, thank you both for answering those questions.

[Cyclone Tracy]

NIWA's 2 cents worth around lunchtime today.

[Razor]

So much conflicting information and rubbish reporting in the NZ herald https://www.nzherald.co.nz/nz/news/arti ... d=12263419

[harleyb]

Amazing isn't it. Nothing but cut and paste click bait with next to no thought going into what is being cut and pasted. Sadly, this is our news media these days...

[snow101]

The GFS is putting out some truly incredible numbers at the 10mb level. Above 10 degrees celcius in 00Z, and runs prior in 1 1/2 weeks time. Would be extraordinary if it eventuated.

image.png

[Cyclone Tracy]

NASA GEOS observation from 1.15am NZT this morning. Upper stratosphere both inner and outer polar zones have set new August mean temperature records.

Temperature is measured in kelvin. Records date back to 1979.

[Storm Struck]

Im just sitting back waiting to see what will happen as a result of this SSW.
Something i have noted and this happens with general northern lows at any given time, is the low from the north mid week coming down the country is like a pin to the hand grenade below.
The northern low passes to the south deepens and draws up the roaring 40,s, the strong NW to SW increases from Friday onwards with deepening lows and passing strong cold fronts.
Im not sure whether it has any infleunce on the SSW as Tony has mentioned more or so from the 20th there abouts, but this wobble will still be reasonably significant should it all eventuate from what we see in the projected model outputs.

[Cyclone Tracy]

The continual nuking of the upper stratosphere in the next 2 weeks is now projecting the SAM (AAO) index into negative -10 territory. A truly remarkable number and will break the global record if it verifies.

First minor effect is next week according to the chart, then the hint of the chaotic descending trend towards the troposphere is starting to appear mid month.

[talbotmj15]

Latest GFS has the SSW event hitting 20deg plus. This is now pushing towards a 100deg warming event. Im now leaning towards a full polar split. A flood rather than streamers of cold air leaking imo.

Does anyone know what the worst event has been in terms of temperature variation in history?. With such a massive warming event now underway is there any presidence to follow for effects here and Aussie?. There is also the impact on the surface of the ice? Melting etc?

Without sounding alarming this event appears to be beyond anything we have ever seen down there?

[Richard]

They are incredible numbers there - getting up around 100deg

[Dean.]

Latest GFS has the SSW event hitting 20deg plus. This is now pushing towards a 100deg warming event. Im now leaning towards a full polar split. A flood rather than streamers of cold air leaking imo.

Does anyone know what the worst event has been in terms of temperature variation in history?. With such a massive warming event now underway is there any presidence to follow for effects here and Aussie?. There is also the impact on the surface of the ice? Melting etc?

Without sounding alarming this event appears to be beyond anything we have ever seen down there?

Melting of the ice....really? Sounds like a Newshub article

[talbotmj15]

When temperatures reach above 0degrees centigrade the ice will melt. Just incase you needed a refresher Dean. Its was part of primary school learning. I guess you didnt attend.

[Cyclone Tracy]

my 2 cents worth on the above questions.

In recorded times, the current SSW has now set temperature records for August in the SH. Current modelling suggests we could be watching global historical records fall in association with the NAM and SAM indexes in the coming 14 days. Ice melt or gain is an unknown. Taking into account local energy equilibrium between the stratosphere and troposphere, I would think that an ice gain would be the favoured scenario if the models verify, as the southern ocean temperatures near the continent would drop. EC is also suggesting this on the water temp anomalies.

History suggests, synoptic dynamite for NZ is an aggressive negative SAM (AAO) interacting with moisture from the tropics / subtropics. StormStruck yesterday indirectly made mention of how volatile this mix is.
When in isolation, a negative SAM alone can cause significant winds, cold snaps, nasty OZ bushfires. Sub-tropical depressions can cause substantial flooding. In April 1968, the SAM index was around negative -3 when a depression named Giselle arrived. This would be the most devastating weather event for NZ of the 20th century. If the SAM index plummets @700 hPa this September or October, keep a very close watch on southward bound tropical /sub-tropical depressions.

[Bradley]

Latest GFS has the SSW event hitting 20deg plus. This is now pushing towards a 100deg warming event. Im now leaning towards a full polar split. A flood rather than streamers of cold air leaking imo.

Does anyone know what the worst event has been in terms of temperature variation in history?. With such a massive warming event now underway is there any presidence to follow for effects here and Aussie?. There is also the impact on the surface of the ice? Melting etc?

Without sounding alarming this event appears to be beyond anything we have ever seen down there?

Melting of the ice....really? Sounds like a Newshub article

I can’t find any research out there in either the northern or hemisphere which suggests a SSW increases the surface temperature of the pole and leads to the loss of sea ice, from what I can see it generally has the opposite effect of what the name ‘warming’ suggests...

[Dean.]

When temperatures reach above 0degrees centigrade the ice will melt. Just incase you needed a refresher Dean. Its was part of primary school learning. I guess you didnt attend.

You watch too many movies

[talbotmj15]

I was simply asking if ice melting was possible. CT has addressed that.

Your comments about movies and newshub are neither warranted or necessary Dean. Given i thought temperatures at sea surface would be likely to exceed 0 degrees i thought that would lead to ice melt.

Thanks again CT for your knowledge. Its very helpful.

[Richard]

We're not all knowledgble buggers when it comes to weather so there's nothing wrong with asking questions surely. I wouldn't mind knowing why this SSW could lead to ice gain when sea temperatures will drop

[Cyclone Tracy]

We're not all knowledgble buggers when it comes to weather so there's nothing wrong with asking questions surely. I wouldn't mind knowing why this SSW could lead to ice gain when sea temperatures will drop

IMO, No one knows the answer to the ice question, especially with this historical event, so only time will tell us..... but with how energy works in the lower atmosphere, a heating of the stratosphere will lead to a cooling of the troposphere (where the weather happens) through energy equilibrium and air circulation. This event has the potential to drop earths overall temperature for the next 12 month.