Model Output Discussion - Cold spell ending - what next?

[That ECM]

Just now, Mike Poole said:

Different outcome on GFS 12z, but the same big picture point, by the end of the run, the trop vortex has vacated Canada/Greenland and moved to the half of the hemisphere to our east.  

I just think we are now picking up on a theme, which will leave the door open to height rises in the Atlantic towards Greenland into February.  

Yes, this could be as long a chase as the one just gone.

[blizzard81]

1 minute ago, Mike Poole said:

Different outcome on GFS 12z, but the same big picture point, by the end of the run, the trop vortex has vacated Canada/Greenland and moved to the half of the hemisphere to our east.  

I just think we are now picking up on a theme, which will leave the door open to height rises in the Atlantic towards Greenland into February.  

In tune with Exeter's thoughts as well. 

[AO-]

18 minutes ago, Mike Poole said:

Different outcome on GFS 12z, but the same big picture point, by the end of the run, the trop vortex has vacated Canada/Greenland and moved to the half of the hemisphere to our east.  

I just think we are now picking up on a theme, which will leave the door open to height rises in the Atlantic towards Greenland into February.  

What worries me more is the vortex gaining strength beforehand. I'm not sure about the likelihood of that outcome as it not in line with what we've seen and what other models show. I think the GFS is overplaying it tonight and it may as well be an outlier in that sense. The Rossby wave created by the Aleutian low should be the one to create a ridge in the Atlantic in the first week of so in February. There should be something visible regarding the ATR in the EPS of GFS tonight. 

 

Edit: looking at the different members of GFS at day 10, the operational definitely is not an outlier when it comes to the strength of the vortex. It is gaining power in 80-90 percent of the members. 

Edited January 20 by AO-

[Kirkcaldy Weather]

Lots to cover. 

 

"Now lets dive into the MJO because it carries importance at various levels.

This could have some impact with regard to an important evolution of the cyclonic developments across Canada into the Maritimes I'd still favour mid Jan but might be slightly later should we get the interference a la the CFS."

Hats off to the CFS yet again as it was pretty much the only model keen and picking up on the Indian Ocean Dipole causing some interference which I discussed in my post from Jan 2nd

As the MJO begins crossing through the Maritimes generally from Mid Jan as discussed this works to aid cyclogenisis with 2 main times of interest.

Storm Isha

Come Sunday evening [January 21st] we'll have damaging gusts particularly through the Irish Sea with effects being most impactful toward Wales up across Southwest Scotland and moving Northeastwards 

 

 

Heading toward Monday these highest gust speeds look to shift focus further southeast 

Further potential damaging gusts cannot be ignored as a possibility across Scotland on the back of Isha

Using the 200mb Velocity data we can watch these focal points as the MJO influence works in tandem to aid this initial cyclonic development with Isha 

To understand the next focal point lets go back to my comments from January 7th

 

"Again links with recent MJO phases this links with the PNA heading more into positive territory, door opens for a snowy system into Northeast America from roughly Jan 18th - 21st IMO '

This same system becomes our next area of potential disruption by January 23rd

You can also watch some of the next patterns setting up on the gif above linking to my comments from my post on January 11th

 

'Following the MJO passing across the Maritimes we begin seeing feedback of phases 1 and into 2 as January week 4 gets started a high forms toward the Maritimes which might extend through Canada, also I'm starting to notice the trend toward cut off low development toward Mexico, far Southwest US '

With the above we can see some of the important 500hpa setups developing into our current timeframe and into week 4 of January (and beyond)

Low pressures from Greenland and into the Arctic

High pressure forming across the Maritimes. A secondary high toward the Northwest of the US and Canada which links with PNA behaviour more on that shortly.

Formation of cut off low(s) in that southwestern America > Mexico regions which also will lead into PNA behaviour.

High pressures East of the UK.

'This will have a setup which favours a + North Atlantic Oscillation especially during January week 4, this favours above average temperatures. Initially there is also more of a -PNA which also connects with the above average temperatures across the eastern portion of America / Canada and Maritimes with below average further west.'

Following on from this as the preceeding MJO phases input begins to feed into the setups from week 4 of Jan onward the above remains true with further developments.

Looks like this initial cut off low will develop into a +PNA during the very end of Jan

 

As discussed above there continues to be the trend of the high extending across Canada

As we head into February and again as the preceeding MJO input begins to materialise this will see the high extension into the Atlantic with further developments of high pressure again toward the Maritimes.

This sees low pressure[s] becoming centred toward the north of the UK 

 

 

 

 

As discussed in my post from Tuesday we're seeing patterns favouring above average temperature scenarios across large swathes ie Europe and America particularly Northeast US and Maritimes > Eastern Canada. 

Colder temperatures become focused into Asia in association with these patterns.

 

I'm also looking toward the very last days of Jan and into February for stratospheric warming(s) as this is supported again with MJO feedback. 

[TillyS]

All 3 main 12z models are clear this evening. Wild and windy westerly weather.

There’s really little else to say about the medium term outlook because the Atlantic is resurgent. Any attempt at height building is steamrollered. And for those looking for cold, the pummelling of these warm winds into Scandinavia is pretty eye watering. ECM and GFS of like mind:

So really our focus is on the short-term for now. A big storm tomorrow night, and a second hot on its heels. Batten down the hatches folks. It’s going to be wild.

[ItNeverSnowsInWindsor]

The op is on the mild side at times so hopefully too progressive this time.

[Mike Poole]

ECM clusters T192-T240:

In this timeframe clusters 1 and 3 build a ridge to the NE, while cluster 2 remains generally flat.  

T264+:

Cluster 1 collapses the nascent Scandi ridge to flat.  Cluster 2 builds a strong Atlantic ridge.  Cluster 3 looks like it might flirt with an Atlantic ridge after the end of the run.  Cluster 4 has a decent attempt to ridge into Greenland, falling back to an Atlantic ridge. So the idea of a build of heights to the NW continuing to gain ground in this timeframe, consistent with the move on the 0z EPS.

[Frosty.]

Please god let the Cfs be right about wintery potential beyond the upcoming mild stormy dross??!!!…I’m not ready to sign the death warrant on winter 2023 / 24 just yet! … there’s plenty of time left.. even into March / April… .. I’ve convinced myself now, I’m deluded perhaps.. but.. you never know.. I might not be! .. up here at castle black, there’s a few nice photos from this winter so far!..  

 

 

[Methuselah]

Just now, Frosty. said:

Please god let the Cfs be right about wintery potential beyond the upcoming mild stormy dross??!!!…I’m not ready to sign the death warrant on winter 2023 / 24 just yet! … there’s plenty of time left.. even into March / April… .. I’ve convinced myself now, I’m deluded perhaps.. but.. you never know.. I might not be! .. up here at castle black, there’s a few nice photos from this winter so far!..  

 

 

Nae bad! 

[Bricriu]

2 hours ago, blizzard81 said:

In tune with Exeter's thoughts as well. 

So have they dropped the idea of Easterly winds now? They had that as the direction of travel  for days. 

[Daniel*]

Exceptionally mild average next week? I’m not wholly sold on that. Looks quite alternate on ECM 12z with nearer normal temps in second half of week.

 

Birmingham fairly representative of CET zone mild days but cool nights.

 

 

Edited January 20 by Daniel*

[bluearmy]

11 minutes ago, Bricriu said:

So have they dropped the idea of Easterly winds now? They had that as the direction of travel  for days. 

No

46 again trends better with retrogression of the ridge second half feb 

 

[StretfordEnd1996]

It may of been a little quieter in here today than earlier in the week when the signs of a Scandinavian High may of presented themselves - but considering only a handful of operational runs from the GFS FI or GEM liked the idea, I'm not losing sleep over the collapse of this signal. 

The various ENS from the GFS and ECM also to me never showed a Scandinavian high with a full blown Easterly - often just showing lots of HP over the top of the country extending up there but nothing more than that..

But, while there's not much going on at the moment on the look out for colder weather, the GFS 12z ENS surprised me a little with the amount of members beyond D10 flirting with the -5'C uppers. Yes there's a huge amount of scatter but it shows there are options on the table. (I acknowledge these ENS are specifically for my town, may be slightly different elsewhere) 

GFS ops last few runs also showing signs of attempted height rises to W/WNWish, I don't take anything in FI usually but it does just paint a slight picture of what may happen if we are to get another colder spell. 

ECMWF extended also kind of hints at this trying to push those heights further to the W of us - and likely quietens the Altantic considerably 

(The week after these weak heights do end up notably to the NW of us but this is well towards mid Feb now) but that's just the direction I sense things may be going

1 hour ago, TillyS said:

All 3 main 12z models are clear this evening. Wild and windy westerly weather.

There’s really little else to say about the medium term outlook because the Atlantic is resurgent. Any attempt at height building is steamrollered. And for those looking for cold, the pummelling of these warm winds into Scandinavia is pretty eye watering. ECM and GFS of like mind:

So really our focus is on the short-term for now. A big storm tomorrow night, and a second hot on its heels. Batten down the hatches folks. It’s going to be wild.

Yes things look shocking don't they for the next few days! 

 

Km/h ^ for clarification.. !

[sebastiaan1973]

EC46 offers some hope, for those with patience.

[blizzard81]

1 hour ago, Bricriu said:

So have they dropped the idea of Easterly winds now? They had that as the direction of travel  for days. 

As others have already said, the Exeter update today is a slight upgrade for wintry potential but patience required. Isn't it always in the UK?

[blizzard81]

50 minutes ago, sebastiaan1973 said:

EC46 offers some hope, for those with patience.

Middle of Feb is exactly when those inflated southern Euro heights dissipate. Only then do we see the opportunity for the white stuff we are all craving. 

[Severe Siberian icy blast]

54 minutes ago, blizzard81 said:

Middle of Feb is exactly when those inflated southern Euro heights dissipate. Only then do we see the opportunity for the white stuff we are all craving. 

Mid feb is 2 is wks of winter left. 

It wouldn't surprise me to see this years tease to peter out into another year of potential but never quite lit the cigar, we were talking about predominant northerly blocking with small windows of zonal Atlantic influence. In reality it look like we face a longer period of sustained westerly weather. 

Do i believe it all? No.

But a drop in AMM along with a vortex shake up that didn't go our way when we already had a favourable pattern, add into the mix a very cold winter period over USA which we all know is like a spark to an engine igniting the pond resulting in a +nao, 

Give it another 10 days and we're all be turning to March for the fix i just hope this year does us proud we all deserve it.

From a synoptic perspective its been fascinating.

Lets hope our beloved background drivers bounce back but mid Feb is not good enough considering how promising its looked.

Stoke north, great winter and for the Northwest with two big snow events in from first wk of Dec and the last one i know some places were buried and parts of Scotland and NI have done well too but for places brum south it's been pants from a snow respective.

 

Edited January 20 by Severe Siberian icy blast

[WYorksWeather]

ECM 12z continues to look pretty mild for the foreseeable. Yes, there are interludes in there where the mean drops to perhaps only a little above average, but 850hPa temperatures at 5C are going to be either very mild under a westerly, or if more anticyclonic, possibly frosty by night but reasonably mild by day.

The ECM meteogram for Reading above illustrates this quite well. The wind direction over the next two weeks is forecasted to be at various points south-westerly, westerly, and southerly. The exceptionally mild interludes coincide with south-westerlies (turbocharged by abnormally warm SSTs over the Azores), nearer normal temperatures under southerlies, and the westerlies somewhere in between.

It does at least look like it won't be a relentlessly wet pattern, with some quieter interludes. Cold may still return in February, but nothing much of interest from a cold perspective on the horizon.

More locally, I'll be keeping an eye on Storm Isha which may have some impacts at my location depending on track, so I may post a little less in here.

I will be back for the GFS 18z ensembles though.

 

[Purga]

Now when have we seen a chart like this? Déjà vu

[damianslaw]

Surprised no real mention of GFS18z this eve, yes way beyond reliable but it pulls in   a cold northerly and advects heights NW. I do take notice of the GFS when these type of synoptics might be the likely destination, as it has a habit of being first to sniff them out - namely because it goes out to 2 weeks plus. 

For a mid Jan Sat eve, tonight in this forum has been as subdued and as quiet as they come. Mid winter blues..

Edited January 21 by damianslaw

[WYorksWeather]

45 minutes ago, damianslaw said:

Surprised no real mention of GFS18z this eve, yes way beyond reliable but it pulls in   a cold northerly and advects heights NW. I do take notice of the GFS when these type of synoptics might be the likely destination, as it has a habit of being first to sniff them out - namely because it goes out to 2 weeks plus. 

For a mid Jan Sat eve, tonight in this forum has been as subdued and as quiet as they come. Mid winter blues..

To be fair, it is a ridiculous outlier on the ensembles. Doesn't mean it's wrong, but taking with a pinch of salt for now!

[Don]

3 hours ago, blizzard81 said:

Middle of Feb is exactly when those inflated southern Euro heights dissipate. Only then do we see the opportunity for the white stuff we are all craving. 

Maybe, but I thought the EC46 was a further upgrade on yesterday.

[IDO]

Just highlighting the GFS in FI. The next 8 days:

The FI charts of the last week suggest that the models overplay Scandi heights. This bias and the UK high has disappeared, with the northern arm of the jet too powerful.

The retrogression of the Euro heights back to the Azores continues to be the outlook from the GEFS as the tPV moves west to east to our north. D8-16 mean:

  

There is potential in week 2 for Atlantic Heights. Still, I do think we may need help from background signals as there is no sign of upstream forcing by the end of week 1 of Feb. And still a Siberian block making it difficult for the tPV to leak to the Asian/Pacific side of the NH, which would allow more room for trop wave breaking in the Atlantic if we do not get tropical forcing.

Overall a typical mix of zonal Winter weather for the next two weeks See the sine wave of 850s and pressure for London:

Average winter weather UK-wise. The usual caveats.

[northwestsnow]

Potential emerging at the end of EC 00z

 

 

 

 

[mulzy]

2 minutes ago, northwestsnow said:

Potential emerging at the end of EC 00z

 

 

 

 

Yes, maybe a glimmer of light at the end of the tunnel here.  The PV looks less organised in this frame - we need to see this trend continuing over the next few days.