Model Output Discussion - Spring Has Sprung

[damianslaw]

Very quiet in this thread generally recently, but not surprising I guess given how benign the synoptics have been and continue to be forecasted. This week sees heights to the south holding influence meaning very mild but also quite dull and wet for some. 

ECM keeps heights strong to the south into next week, preventing the trough cleanly moving east, GFS does move it east eventually but its all rather messy, with low pressure and fronts turning in on themselves as heights build strong to the NW a theme it has been playing with for some time now, possibly MJO and SSW induced.

Its all just a bit uninteresting. 

[WYorksWeather]

Definitely looks like a milder period on the cards now for the next 10 days.

We're not about to get two ridiculously mild months back to back, surely? But it's certainly looking like an option that is on the table. Of course a cooler spell at the end of the month can't be ruled out at this range.

[stodge]

Evening all

The week's pattern - a long fetch TM airflow with an elongated trough positively aligned towards Scandinavia and heights over Iberia. Mild if not warm with above average early spring temperatures but unsettled away from eastern and southern areas with rain at times and I suspect considerable orographic rainfall for the usual suspects.

By the weekend, hints the trough might start pushing east into Europe - obviously now we're outside reliable so just a few bits and pieces to watch. Heights over Greenland start to manifest but what pushes the jet south is the trough setting up just to the west of northern Scandinavia - that generates a cold N'ly which meets the warmer airflow to the south and generates LP which cross the British Isles so those hoping for a prolonged drier and warmer period look to be out of luck as we move into the final third of the month.

12Z GFS OP then brings in some quite cold air (-8 850s) with the trough over southern England while other models point to an unsettled and chilly approach to Easter.

All conjecture at this point. 

[feb1991blizzard]

Some reversal this - but we could have done with it flatlining for a bit longer.

[Snowman.]

 feb1991blizzard and 2 months earlier

[feb1991blizzard]

 Snowman.

Quite, and i still don't think its perfection (its good) for bringing cold to uk, i must admit i've come to the conclusion you need a far and wide split with a ridge from Canada to Scandinavia with poleward flux to override everything and guarantee a belter, although didn't 2013 deliver with a wave 1 initial setup? if anyone's got the geop. height charts from 6th -13th Jan 2013 for 10-30mb, i'd like to see them please.

Edited March 11 by feb1991blizzard

[Daniel*]

No mistaking the exceptional cold to our north in models indeed it was prevailing theme through winter deep cold not far to our north, Iceland experienced its coldest winter since 1994/95.

 

 

Edited March 11 by Daniel*

[WYorksWeather]

18z continues with the mild theme. Towards the end perhaps trending back towards average at 850hPa, but the mild nights mean that in reality mean temperatures are likely to still come out above average.

This can be seen pretty clearly in the ECM 12z meteograms as well.

[Kirkcaldy Weather]

Overall very happy with the above post.

Starting with the modelled movement of the Tropospheric Vortex we can watch as it moves into a position between the Greenland and Kara seas generally over the next week or so.

On 29/02/2024 at 21:11, Kirkcaldy Weather said:

Into Mid March this will be part of the main 500hpa setups with our retrograding block moving into Greenland which gradually continues westwards as this is a big part of the El Ninò pattern as I showed prior, main focal points will be how strong we get into the negative NAO plus the energetic connection with the cyclone from Northeast US into our current UK trough which moves into the Atlantic as discussed plus as these join and link to the emerging trough toward Scandinavia ie the Tropospheric Vortex.

 

On 29/02/2024 at 21:11, Kirkcaldy Weather said:

Fitting with the MJO composites in my post above we are beginning to see the feedback of the next opportunity for a possible snowy system into Northeast America with this currently looking to be devdloping around March 8th - 11th though not a huge emphasis on precise dates.

 

 

 

Very happy with the overall timing as this storm system merges with the Atlantic troughing which feeds into the Tropospheric Vortex as discussed prior.

This pattern of cyclonic systems running to the North Northwest of the UK and Ireland is feedback from recent MJO progression particularly February phases 1 through 2 with good representation including the Tropospheric Vortex positioning.

Pairing with feedback of the Super El Ninò we can see this is supportive of a warmer pattern including the development of high pressure from Africa which extends into Europe again bringing increased temperatures at surface and 850hpa levels.

Linking this to the feedback of phases 2 through 3 during February and March again nice representation here for an above average temperature setup.

Further nice temperature representation particularly in Australia, South America and USA + Canada.

We're really looking at the feedback of the above really coming to the fore in particular from Mid March - 15th which becomes most noteable to begin with across Canada as the persistent blocking patterns which have - are a common El Ninò characteristic begin to transition as troughing begins to form into Canada.

From the 15th there are a couple of major developments as discussed above.

The Canadian Blocking starts to transition more into that of a trough dominated pattern.

The increasingly strengthening high develops from Africa into Europe.

As the trough developments begin over Canada this will force the blocking to weaken overall at this stage with signs of the cut off high developments I spoke of currently looking likely somewhere between Greenland and Canada with Baffin Bay a reasonable shout.

On 04/03/2024 at 16:15, Kirkcaldy Weather said:

This is an impressive MJO cycle with a strengthening amplitude from the Indian Ocean which looks to maintain amplification as it crosses the Maritimes and heads into the Pacific. Having discussed upto phase 2 we are beginning to have feedback of phase 3 heading from March week 2 > 3 with the storm track in America gradually shifting northward and the trends into cut off blocking with troughs either side and possibly stormy conditions.

The feedback as we begin to move at a continuous high amplitude across the Maritimes see my post here for further info  

 

This feedback is already becoming noticeable within the models with phase 4 in March having tendency of high pressure building in the Atlantic possibly extending toward the Canadian Maritimes with scope for ridging up into Greenland and a potentially stormy setup with troughing around the UK. 

Thanks for reading.

KW

[WINTRY WALES]

Hey guys just a quick musing whilst this thread is so quiet. We have seen places in Europe ( Scandanavia) and other parts of the World like China experience very harsh and record cold Winters this year. Other parts of the World like Greece and Turkey in recent years gone by experiencing theirs too. For our small part of the globe and most of western europe it seems pretty difficult to see any prolonged decent cold weather due to repeating pressure set ups scuppering some favourable cold weather signals for it to happen.

This to me seems something else maybe other than the general global climate change. Can any one expand on this and maybe help explain?

[Due South]

 WINTRY WALES Personally, harsh winters are still happening around the world, like you've said. Will we be on the end of one of those??. Yes I believe we will. But we are such a small place that everything needs to fall into place. It's not like we are the size of China or USA where there guaranteed snow "SOMEWHERE" within the country.

I feel we will definitely see another cold winter soon enough..

[WINTRY WALES]

I am not so sure, Western to central Europe, which is substantial area in size seems to have suffered a key change to some driver other or something other than the Climate change factor the rest of the world is experiencing. 

[ANYWEATHER]

2 hours ago, WINTRY WALES said:

Hey guys just a quick musing whilst this thread is so quiet. We have seen places in Europe ( Scandanavia) and other parts of the World like China experience very harsh and record cold Winters this year. Other parts of the World like Greece and Turkey in recent years gone by experiencing theirs too. For our small part of the globe and most of western europe it seems pretty difficult to see any prolonged decent cold weather due to repeating pressure set ups scuppering some favourable cold weather signals for it to happen.

This to me seems something else maybe other than the general global climate change. Can any one expand on this and maybe help explain?

You have to remember that the UK only inhabits 0.01% of the Earth's surface. So winters like 1947/63 the 1963 winter the coldest since the era of the little ice age ,makes you wonder why that occurred?  There was a lot of nuclear testing around the world during the 1940s/50s/60's and I have mused that there could be a correlation?  

[Mcconnor8]

I think it is more down to the higher SSTs in the Atlantic hampering the building of high pressure in the specific areas that we need it to get proper cold into this country, which is climate change driven. We are simply more susceptible to the effects of Climate Change than many other areas of the world due to our location. I don't see how there could be any correlation between Nuclear testing and the weather as forces in play weather wise are far greater than could be influenced by that.

[Summer8906]

 WYorksWeather Presumably at this time of year though "ridiculously mild" requires sunshine so if continues as dull and wet as it is now, it will surely just end up something like March 2023.

[JakeWorces]

The last few GFS runs were showing a long dry spell for most of the UK from 20th March onwards. Runs were pretty consistent so I was mildly optimistic. This morning's 6Z is a nightmare; 20-23rd showing multiple systems dumping more heavy rain across all of us. Seems to be history repeating itself since November; every single settled/dry spell it forecasts disappears as it approaches. Is the model now flawed in that it is biased towards dry/settled weather? It seems quite remarkable how many times it has happened now. It never seems to incorrectly call for rain however.

[jamesthemonkeh]

There is hope for dry and warm ahead...albeit anything classified as both in March looks more likely to be fleeting.

[Rain All Night]

On 11/03/2024 at 10:20, Rain All Night said:

0z deterministic runs, out to Mon 18th (day 7)

Outlook about as uninteresting as it gets, from what I can see...

0z ensemble means, out to Tue 26th (day 15)

Other than the mean surface low shifting eastwards very late in these runs, there is not a lot to comment on.

0z deterministic runs, out to Tue 19th (day 7)

Nothing interesting in the next week, doesn't look too bad down here for the most part.

0z ensemble means, out to Wed 27th (day 15)

Azores ridge around the equinox, then maybe an Atlantic ridge towards the end of the month?

[raz.org.rain]

 WINTRY WALES maritime bias. Ocean currents or not, large maritime bodies have a moderating effect on surrounding climates due to factors such as the Coriolis effect. They absorb excess heat during the summer and slowly radiate it back out during the winter. Compare that to more continental climates such as inner Turkey and eastern China, which are at the full mercy of cold air masses that build up over the continent and push southwards with ease. Western Europe is unique in that there's no large continuous landmass beyond the 50th parallel, so it can't even be compared to similar climates at the same latitude such as the BC coastline, which has a large landmass to its north which can deliver notably cold weather, and a large mountain range that restricts the maritime climate to the coastline whereas Western Europe is very flat in comparison.

 

For those reasons, extreme cold events are an exceptionally rare event. You could probably argue that climate change factors such as SSTs could potentially make cold winters a lot more difficult here compared to elsewhere in the northern hemisphere.

[Summer8906]

 raz.org.rain Indeed, I would argue that Northwestern Europe has the worst temperate climate in the world. Nowhere else manages to deliver that "killer" combination of boring and unpleasant.

Edited March 12 by Summer8906

[Summer8906]

 JakeWorces GFS 06z does finally bring the high in after the 23rd, though then reverts back to a further deluge by the 26th, yet another unwanted deep slow moving Biscay/west of Ireland low.

35 minutes ago, raz.org.rain said:

or those reasons, extreme cold events are an exceptionally rare event. You could probably argue that climate change factors such as SSTs could potentially make cold winters a lot more difficult here compared to elsewhere in the northern hemisphere.

What is surprising given NW Europe's extreme maritime influence is how we can get 40C north of 50 north. Even Mediterranean climates struggle to get above 40 much. One might think the sea track over the Mediterranean would moderate Saharan air.

Edited March 12 by Summer8906

[WINTRY WALES]

 raz.org.rain  Fantastic and very well explained. But being an avid skiier over the last 30 years in the alps etc... there is a considerable change in the last 10 years or so to the climate in Western Europe that seems noticeably extreme to what most of the rest of the world is experiencing.  

[Mcconnor8]

 WINTRY WALES There are heat record being smashed worldwide though, Northern Africa currently pulverising lots of records, but yes Western Europe particularly vulnerable I think to climate change as highlighted by the comparisons in snowfall during Winter from pre 1980 compared to since which is quite a huge drop.

[raz.org.rain]

43 minutes ago, Summer8906 said:

What is surprising given NW Europe's extreme maritime influence is how we can get 40C north of 50 north. Even Mediterranean climates struggle to get above 40 much. One might think the sea track over the Mediterranean would moderate Saharan air.

Edited 35 min

It sort of makes sense in a way. We've got a relatively flat plain and high salinity sea between us and the Sahara. The continent itself can also see warm and dry air masses build up with relative ease, and there's no major mountain ranges to hinder them when the wind direction is favourable. Variation in how the Atlantic behaves can promote more influence from the south, multidecadal variation influences how atmospheric and precipitation patterns behave and such. On the face of it, it really doesn't take all that much for hotter air masses to be dragged so far north in this part of the world.

This is where theories such as AMOC strength see more nuance. According to the theory, a general absense of a North Atlantic current would promote much hotter and drier summers across Europe. I believe it was Drijfhout et al. who demonstrated that northwestern Europe in particular would see much stronger atmospheric blocking leading to prolonged hotter and drier summers in this part of the world. Another interesting point to note is that much of the more recent AMOC studies don't explicitly mention northwestern Europe when hypothesising a cooling trend in winter, I'm sure one of the more recent ones states that any cooling would be largely restricted to Scandinavia.

Edited March 12 by raz.org.rain

[Norrance]

 WINTRY WALES As it is quiet the off topic posts can stay for now. One thing that I noted is that despite the two record breaking events in Chine the overall winter temperatures in the same areas were well above average. Only really Northern Scandinavia and NW Russia in the NH had sustained under average temperatures over most of the whole winter.

edit. Sorry other mods.

Edited March 12 by Norrance