[Model Output Discussion - Snow for some, but what else is in store?]

It’s certainly interesting the next few weeks, the prospect for cold and snowfall for the next few weeks is very much alive for the UK, or at least parts of it.

Afterwards in February, it’s very much at a juncture. On one hand, we have the MJO Phase 3 pointed out by @Singularity, and signs that the SSW forcing is going to wear off later in the month, which would possibly be destructive for the current -NAO.

However if we stay in the current GWO phases that have been supporting the -NAO for a little while longer, and see the tropospheric polar vortex stay weak into Feb, we might see that period for possible cold and snowfall extend a little more into next month. 
 

But yes, it must come to an end at some point, it’s just a matter of working out when....

More here: https://longrangesnowcenter.net/2021/01/14/europe-on-the-long-term-14th-jan/

 

 

[Stratosphere and Polar Vortex Watch 2020]

1 hour ago, Vikos said:

Zonal winds are slowly (!) weaking in 10hpa and 30hpa, but nothing extraordinary (by now!), maybe at 0 by end of January, but that could (!) than already be the (very early) final warming

Got some decent heat flux into the SPV. It’s just a matter of whether it’s enough for a technical SSW. 
 

At the end of the day, it’s just a technicality and ultimately it’s about whether it’s impacts whether a SSW or just a moderate weakening can be seen on the surface in the NH circulation. And the fact we are already seeing a -AO phase helps.

[Stratosphere and Polar Vortex Watch 2020]

1 hour ago, Nick F said:

Steady as she goes ...

Would like to see EC come on board though, their extended zonal mean zonal wind at 10 hPa updates today, though not sure when we'll get to see it: 

ECMWF | Charts

APPS.ECMWF.INT

Question is, if we do get a SSW, what with the strat decoupled from the trop atm, will we see the effects from it on our weather patterns?

It’s interesting that we already see quite a -AO in the troposphere, before we even start to see the plausible effects downwelling to the surface. So the dynamic there could be interesting.

It’s quite possible that we might have the troposphere try to briefly balance itself out, as the SSW occurs, returning to neutrality or even a slight positive in the first week of Jan. Before the SSW comes down to the surface on the 2nd and 3rd weeks of Jan. And you should be able to maintain a mostly cold -AO/-NAO look through there.

[Model output discussion - Closing in on Christmas]

https://longrangesnowcenter.net/2020/12/20/europe-on-the-long-term-20th-dec/

Climate drivers looking interesting for a cold and snowy late December and early-mid January for the UK, with the potential of a SSW or similar, good extratropical conditions and an already negative AO in the troposphere  

[Model output discussion - into the start of Winter]

18 minutes ago, ghoneym said:

There have been many winters in the past where West based QBO and La Nina influences have been prominent.  Would I be correct in saying these parameters individually tend to bring a milder UK winter but together pose a stronger threat of a SSW and colder than average UK winter? I did have a look at the composites a few weeks back but never saved any at the time as It was a nosey out of curiosity 

Maybe, this was my take on it:

Probably the worse analog (for snowfall) I found on the search for the outlook.

Certainly the QBO is the biggest trouble for this winter, but then again it has been all over the shop in the past few cycles, one cannot really know where it will go.

[Model output discussion - into the start of Winter]

https://longrangesnowcenter.net/2020/12/01/european-winter-outlook-2020-21/

This recent more decent Late Nov/December pattern that is coming into fruition has certainly made the winter forecast more complex, with a number of factors favouring a milder winter.

So I have gone for an average to slightly above average snowfall forecast for this winter (in the UK), not expecting a horrid winter or an incredible winter, but hopefully a half decent one.

Thanks all 

[Early run up to Winter 2020/2021 discussion]

https://longrangesnowcenter.net/2020/10/20/october-preliminary-2020-21-winter-outlook/ 

Looking like for the European winter IMO: 

Moving onto Europe, we see a colder December for the UK, and a pretty average winter overall, with a weaker backend of the season.
The Northern Alps (Northern Europe) should see an average snowfall season, maybe slightly better than normal. 
The Southern Alps (and the rest of Southern Europe) should see a slightly below average season, with the best conditions early in winter. 

Climatic factors:

1. A basinwide moderate (possibly strong) La Nina this winter.
2. A positive QBO
3. Solar Minimum
4. Atlantic SSTs favourable for a +NAO
5. North Pacific SSTs favourable for a Aleutian Ridge.
6. Average growth of Stratospheric Polar Vortex into winter, potential for SSWs later.
7. Phase 3-6 MJO centred tropical base state
8. Low sea ice in Barents-Kara Sea.
9. Average snow coverage in Siberia.

Technical analysis in link above :) 

 

[Stratosphere and Polar Vortex Watch 2020]

On 18/10/2020 at 05:28, Griff said:

Suspiciously quiet here... If a record strong PV was forecast I'm sure we'd be writing off winter immediately, but what's to bet that if I post the following and comment 'so far decidedly average' I'll be met by 'just you wait until December'...?  

In any case, average for now. Today is Saturday, last post was Wednesday and this came out on Thursday. 

At this stage of the game, no news is good news.

Average allows for a large spread of potential options, depending on what the climate does.

Looking at the clues we have:

Tropical upper stratosphere is currently colder than average, that indicates a stronger than normal Brewer-Dobson circulation, pushing ozone towards the NH Strat polar vortex.

So again we certainly have the capacity for inducing a SSW, it's just whether the tropospheric factors allow for it.

[Model output discussion - August hot spell - how hot, how long?]

My first seasonal prediction for the NH this season: 
https://longrangesnowcenter.net/2020/09/06/early-september-seasonal-2020-21-winter-preliminary-outlook/

Western & Central US and the Northern Alps to benefit from a Canadian Vortex/Aleutian High and +NAO driven weather outlook for the winter ahead from the preliminary look of factors (still got more to loom at in coming weeks...). 

Not so great for the Southern Alps or Southern Europe in terms of snowfall, and a pretty mild and wet outlook for the UK on the cards.

Take a look at the details above  

[Model output discussion 02/02/20]

https://longrangesnowcenter.net/2020/02/23/europe-on-the-long-term-23rd-feb-2/
My final forecast for the long term in Europe this season. The final days of the month and first 10 days in March look a little more hopeful for snowfall prospects according to models and the tropical drivers. But this will subside in mid-March.

At the end of the day, the season was not that great, and the drivers failed to get us into a conducive state.
 

[Model output discussion 02/02/20]

 

The positive AAM anomalies are resuming in the extratropics (at a similar latitude to the UK), which is partially behind the continued and now reinforced +NAO flow. In order for the UK winter pattern to be changed, we need those tropical +AAM transports to move north and -AAM deposits establish close to the poles to help to dislodge the strong tropospheric polar vortex.

 

Looking at the top chart’s upward trend, which shows a strengthening stratospheric polar vortex, we are running out of options, except looking towards a consistent zonal outlook. However later in February may be more interesting in terms of the strat.

More details here on my blog for UK/Europe:

https://longrangesnowcenter.net/2020/02/03/europe-on-the-long-term-3rd-feb-2/
 

[Model Output Discussion - Happy New Year!]

My latest outlook doesn’t exactly bear very well for the UK, until perhaps mid-late February:

https://longrangesnowcenter.net/2020/01/07/europe-on-the-long-term-7th-january/

A little snippet about the current GWO forecast, more details in the outlook.

“The GWO is currently in Phase 8-1, and is forecast to proceed through the lower phases of GLAAM orbit over the middle two weeks of January. This is likely to keep the current +AO/+NAO phase in a holding pattern, waiting for the next GWO cycle through the positive phases. The past cycle has been so far inadequate in getting the momentum deposits in the right areas for a less zonal outlook. Positive cycle is expected in late January/early February

Frictional torque is currently negative, showing the ability for a negative orbit for the GWO, with the Mountain torque expected to follow“
 

 

[Model output discussion - Winter has arrived and the hunt for cold is on]

2 minutes ago, jules216 said:

@Snowy Hibbo in your blog you mention: Fair to say that the next two-three weeks are likely to feature more potential for cold and snowfall risks for the UK and Southern Europe.

But looking at anomalies over long range, it is not before 26.12 that any meaningful anomalies show anything remotely cold for snow for most of Continent. That would give us a window of opportunity between 27.12 and 06.01? Then you mention things will go zonal again until another chance in February earliest? That is about 10 days of potential blocking and then we have 3 weeks to salvage winter sometime in February. Great 

Yeah, last week of a December looking better and the first 10 days of January. I’m not promising anything, it’s just the drivers look more conducive to better cold and snowfall risks.

[Model output discussion - Winter has arrived and the hunt for cold is on]

https://longrangesnowcenter.net/2019/12/16/europe-on-the-long-term-16th-december/

Some -NAO prospects over the next few weeks, propped up by the -GLAAM orbit.

Then a +NAO forecast over much of January, per the descending SPV and it’s currently strong status.

Potentially another turn to a -NAO in February, on the back of another GWO cycle and a potential SSW.

Details of my outlooks in the link above  

[Upcoming winter speculation and chat - October edition]

https://longrangesnowcenter.net/2019/11/14/european-winter-outlook-2019-20/

Here is my European and UK winter seasonal forecast for 2019-20. We should see a troughing and more snowy pattern in January and February, with a more average pattern in December IMO.

Thanks everybody  

[Model Output Discussion - Into November 2019]

The current snowy pattern is due to an underlying base state that is still quite negative in terms of AAM and a tropical state which is more progressive in terms of the expansion of momentum.

The combination of a MJO Phase 6-7-8 progression and the underlying negative momentum anomalies have introduced Scandi blocking and potentially -NAO (+ 10 days) responses to the brief tropical momentum progression.

You can see the meridional pattern induced by the negative momentum anomalies in the medium term by the polarised difference between the block and the trough. 
 

Anyway, today I have also released my seasonal winter outlook for the UK and Europe here  

https://longrangesnowcenter.net/2019/11/14/european-winter-outlook-2019-20/

Playing with ideas presented in the short-medium term applied to the seasonal forecast, as well as looking at stratospheric and other factors in terms of applying it to the likes of January and February.

 

 

 

 

 

[Upcoming winter speculation and chat - October edition]

14 hours ago, Mike Poole said:

Well winter is getting closer and soon people (those who are inclined to do so, anyway) are going to have to start making predictions, and it is especially difficult this year, some very relevant factors:

• All long range models giving a highish probability of a mild winter (look forward to the GloSea5 update tomorrow).
• Low solar activity at solar minimum, which the models apparently don't deal well with, this should lead to a more meridional jet. 
• Big strat trop disconnect forecast to continue for the foreseeable.
• SSTs in Indian Ocean favourable for increased westerlies (as per MO Contingency Planners forecast and discussion in teleconnections thread).
• Possibility of an early SSW.
• Low arctic sea ice.  

I've been mulling all of this over, and I wonder if one feature of the upcoming winter for the small locale that is the UK, might be a strong jet stream across the Atlantic but angled further south than normal.  

Here's a couple of charts from CFS 18z T1944 to illustrate the sort of thing I mean.  I place no credence in this run whatsoever, just cherry picking charts to illustrate the point:

In the heart of winter, such a jet pattern with some variability in direction with cold but not very cold air in place over the UK could make for some hefty battleground scenarios.  Just musing of course!

 

I’ve just been going around and around in circles with the European forecast. It’s a bit all over the shop.

I can concur with your idea though, something I have been mulling over. My European forecast for the season should be out later this week  

[Upcoming winter speculation and chat - October edition]

6 hours ago, Beanz said:

Genuine query.  I was under the impression (more than likely the wrong one!) that the Atlantic was warm and not favourable for cold in the UK.  What’s your thinking here? 

As @Met4Cast uses in the chart above, there is a significant cold anomaly right in the middle of the Atlantic. So that could help spur the -NAO and a colder winter for the UK.

4 hours ago, Steve Murr said:

@Snowy Hibbo

Interesting to put a forecast out so early - however in order for that to land your going to need some support from the stratosphere In Nov ( or Early Dec ) - All the blocked AO / NAO winters that startes in Dec ( which you indicate ) all had early warmings - Similar to 1981/ 2009 for example-

If that were me I would have released that forecast in 6 / 7 weeks time when the stratospheric profiles & coupling have become more apparent.

As highlighted earlier in this thread at least the persistence of the -NAO may lend some support to the forecast over & above the norm- Its that AO block - that cannot sustain without the strat...

Good luck anyway.

This isn’t the final forecast, this is just the last one I do for the entire globe, hence the global charts. I do a specific final UK/Europe forecast, where hopefully I have a bit more stratospheric guidance. But yes I am banking on a SSW at some point. I do see perhaps a good chance for some strat warming in November/December though. And there’s plenty of factors supporting the potential for a SSW anyways.

 

[Upcoming winter speculation and chat - October edition]

30 minutes ago, Summer Sun said:

 

You beat me to it! Thanks @Summer Sun

1. Snow & Ice conditions good for Eastern US, Japan and Europe/UK.
2. MJO largely good for European and UK snowfall, perhaps less so later in winter. Similar for Eastern US and Japan.
3. Oceanic ENSO good for Japan, Southwest US and Eastern US.
4. -AAM good for Europe, Eastern US and Japan, less strong later in winter.
5. Stratospheric conditions favourable for Eastern US, Japan and Europe/UK.
6. Solar minimum favourable for more snowfall for Eastern US, Japan and Europe/UK.
7. Atlantic favourable for a snowy UK winter and colder Europe.
8. QBO favourable for Eastern US, UK and Europe.
9. North Pacific favourable for Eastern US, less so for PNW.

All this is good for a snowy winter IMO, contrary to the models (yes I know, bold, but I have the reasoning to back it up :) ).

[The Seasonal Forecast Thread]

For example, have a look at this -AAM analog I used.

Showing some potential for a -NAO/Greenland block, with the trough lying over Europe, but still with potential for a cold winter for the UK. Though this is just one driver/idea.

[The Seasonal Forecast Thread]

3 hours ago, Jamesjane said:

What is this...... We live in the UK, What is the forecast for us..You have mentioned every continent but have left out the main protagonist

Chill out. The UK could see a -NAO pattern that would bring a colder winter for it and the rest of Europe. I did discuss Europe in the outlook. 

It explored the different model solutions heading towards a winter +NAO, and then I explained why this may not be the case.

[Model Output Discussion - Into Autumn 2019.]

Take a look at my fresh seasonal outlook. Looking at a +NAO in the models and a -NAO in some of the drivers.

https://longrangesnowcenter.net/2019/09/27/late-september-northern-hemisphere-2019-20-winter-outlook/

• Early, good season for Japan, Eastern US and Europe.
• A decent season for California, a poor season for the PNW, Colorado slightly above average perhaps.
• Early Siberian High development, with a potential SSW later in the season.
• Nina-esque atmosphere, cool neutral-weak oceanic La Nina.
  
  EDIT:
  Please use the Seasonal Forecast Thread to respond/discuss this forecast. Thanks. BW.
  https://www.netweather.tv/forum/topic/72635-the-seasonal-forecast-thread/?do=findComment&comment=4084894
   

[The Seasonal Forecast Thread]

Take a look at my fresh seasonal outlook. Looking at a +NAO in the models and a -NAO in some of the drivers.

https://longrangesnowcenter.net/2019/09/27/late-september-northern-hemisphere-2019-20-winter-outlook/

1. Early, good season for Japan, Eastern US and Europe.
2. A decent season for California, a poor season for the PNW, Colorado slightly above average perhaps.
3. Early Siberian High development, with a potential SSW later in the season.
4. Nina-esque atmosphere, cool neutral-weak oceanic La Nina.

 

[Model output discussion - hot spell beckons but then what?]

In terms of the 2019-20 Winter Outlook, so the countdown begins:
https://longrangesnowcenter.net/201...-seasonal-2019-20-winter-preliminary-outlook/
 

Some ideas here:

A strong winter Aleutian low

A +NAO favoured by models and Greenland ice cover.

Perhaps some -EPO blocking

A warm neutral ENSO state.

A good outlook for Japan, Northern Alps and Western North America

An opportunity at a decent winter for the Eastern US, per some indicators.

And probably a wetter and more mild winter for the UK. That said, there is a good environment for SSWs, so we might see more -NAO like conditions later in the winter

 

As for Dorian, per the UKMO and EC, it should move up the coast, rake the East Coast, Georgia, SC and NC. Gets quite close to the Carolinas on both models. And quite deep too.

 

[The Seasonal Forecast Thread]

In terms of the 2019-20 Winter Outlook, so the countdown begins:
https://longrangesnowcenter.net/201...-seasonal-2019-20-winter-preliminary-outlook/
 

Some ideas here:

1. A strong winter Aleutian low
2. A +NAO favoured by models and Greenland ice cover.
3. Perhaps some -EPO blocking
4. A warm neutral ENSO state.
5. A good outlook for Japan, Northern Alps and Western North America
6. An opportunity at a decent winter for the Eastern US, per some indicators.
7. And probably a wetter and more mild winter for the UK. That said, there is a good environment for SSWs, so we might see more -NAO like conditions later in the winter.