Model Output Discussion 29th December - Into mid-Winter.

[booferking]

2 thirds of winter nearly gone and we are still chasing this i think we could go to next christmas and we still would,nt land an Easterly..

[Troubleatmill]

17 minutes ago, Seasonality said:

High pressure still looking strong.

Signs of a strong southerly jet starting to appear on that chart....may do us a favour mate

[Seasonality]

30 minutes ago, jvenge said:

Toasty...

A long way out, though, and PROBABLY wouldn't get that warm.

Amazing contrasts. Toasty UK and Scandi. Chilly central and south east.

13 minutes ago, Nicholas B said:

Signs of a strong southerly jet starting to appear on that chart....may do us a favour mate

Could do too! Northerly jet has been a uk party pooper this winter.

[Ali1977]

The GEFS are really trying to hold onto the block to our East at 204, just wondering if this could actually turn into something much better if it can hang on long enough to then get some MJO/Strat help.

[snowray]

Might be just as well not to look too far ahead, we have a very cold weekend coming up with some colder uppers and snow flurries around, and its not going to warm up early next week. I am no fan of this Euro Slug to be honest, it seems to have been there forever, but with the SSW coming up and the AO/NAO potentially starting to go negative it would only take an undercut of some sorts to shift everything North. This could produce a very memorable longer lasting cold spell as the cold builds as we go into Feb and with the effects of the SSW potentially starting to show up as early as the second week of Feb.

[Ali1977]

Some crazy NH patterns in FI on GEFS...SSW effect maybe 

Edited January 19, 2017 by Ali1977

[KTtom]

4 hours ago, D.V.R said:

There's no south-westerly showing in the reliable.. right?  I'm talking about trends and the ECM shows that there is a possibility of an easterly later on.. if you can't see that then fair enough.

What you sorry about?

I was commenting on the charts you posted which show the entire country bathed in south-westerly winds...  I think every-time some people see a bit of yellow to the north east they think an easterly is imminent! Its not.

Edited January 19, 2017 by KTtom

[stodge]

Just skimmed the 06Z GEFS - fairly solid out to T+240 and, as you might expect, much increased scatter from there.

As Ali has already pointed out, some very odd looking synoptics at the far reaches of FI.

P10 is a peach - the displacement of the PV to Hudson Bay sets up a monster Greenland HP.

All a very long way off at this stage.

[gottolovethisweather]

On 12/01/2017 at 12:32, gottolovethisweather said:

A cold ole spell is ahead of us guys n gals; those homebound don't forget to feed and water the garden birds and try to assist other wildlife where you possibly can, as it is not all about us and our welfare when cold weather hits. 

 

 

 

 

 

Wow, a week since I posted in here and back then my eyes were fixed firmly on watching a few flakes fall from the dull looking skies, ended up with a slight dusting which was very welcome but nothing terribly exciting for us snow lovers. Before then, some six days beforehand, my analysis of the ECM had hinted at a watch period from the 12th through to the 16th January, which in reality became cut short by around about a day. Now, having studied the ECM outputs in the meanwhile, I feel we are looking at a mainly cold and dry period down South in particular right through to about the 26th January, of that we can be reasonably sure. An oddly HP dominated settled winter we have had and continue to have, so anyone looking for wintry stuff might have to back off from the models for another week yet until any likely changes come into realistic timeframes. Personally, I don't mind these conditions at least where the winter sunshine breaks through, and sparkly crisp frosts persist throughout in some parts of the local countryside and even in the shaded back garden. Another cold day today with Air Temperatures struggling below 3c as a Maximum in Newbury and the highest Temperatures not breaching 6c over the past few days. Expect more of the same for now. My comments above concerning the wildlife etc. still applies so please think of them as, and when you're able to, despite this being chilly at home, of course, it is nothing like compared to most of Europe right now where it is brutally cold in places.  

Edited January 19, 2017 by gottolovethisweather

[Seasonality]

28 minutes ago, stodge said:

Just skimmed the 06Z GEFS - fairly solid out to T+240 and, as you might expect, much increased scatter from there.

As Ali has already pointed out, some very odd looking synoptics at the far reaches of FI.

P10 is a peach - the displacement of the PV to Hudson Bay sets up a monster Greenland HP.

All a very long way off at this stage.

What about the nailed on 2 weeks of Atlantic dominated weather you were touting this morning? Looking at latest output it looks like there will be little reprieve for much of Europe right out to approaching the end of the month and even in the south of the UK this period goes out until the 26th. That is a week away so who know where we'll go from there. I think any talk of an Atlantic onslaught is overstated as things currently stand.

[Day 10]

Yesterdays 12z UKMO which has been the flattest option lately showing signs of improvement.

Yesterdays 12z & today's 12z

Then at 144 we have GFS, UKMO, and this morning's ECM.

So a move from the UKMO toward the GFS & ECM it would seem. Can we continue to have little improvements for those hunting cold and eventually snow?

 

[sebastiaan1973]

I Think we see the results of the stratospheric warming. 

Cohen wrote: The immediate response from the PV weakening will likely be increasing tropospheric ridging/positive geopotential height anomalies over northwestern North America directly under the stratospheric ridge and a deep tropospheric polar low under the displaced stratospheric PV over the north slope of Asia.
Rising heights over Alaska and Northwest Canada will help force troughing/ negative geopotential height anomalies accompanied by a cooling trend downstream over the Eastern US. Counterclockwise circulation around the polar low over the north slope of Siberia will transport North Atlantic maritime air into western Eurasia including Europe resulting in a trend to milder temperatures across the region.

At 192h we see an area of high pressure by Alaska. 

After that, we have to wait for;
However if there are subsequent pulses of WAFz/poleward heat transport this should further weaken the stratospheric PV and nudge it closer to Europe. This could either turn the winds more northerly across Europe or even force the stratospheric PV into Europe. Both of these scenarios would reverse the weather once again across Europe and result in much colder temperatures.
https://www.aer.com/science-research/climate-weather/arctic-oscillation

Edited January 19, 2017 by sebastiaan1973

[nick sussex]

You can see by the  charts Day 10 posted that the UKMO has had a few days to forget in terms of modelling. Very flat and slowly edging towards the ECM/GFS solutions.

Its a shame we couldn't see a more negative tilt to any approaching troughing as that could have provided some interest depending on how much cold is left to draw on from the se.

With the zonal winds dropping I wonder if the models have got a proper handle on this,  we might yet get some more favourable solutions showing up over the next few days.

Edited January 19, 2017 by nick sussex

[warrenb]

Well to be honest, the GFS is not zonal as the atlantic hits a brick wall about 400 miles to our east and stalls for the entire run.

[Seasonality]

3 minutes ago, warrenb said:

Well to be honest, the GFS is not zonal as the atlantic hits a brick wall about 400 miles to our east and stalls for the entire run.

Back around Xmas week some were touting 4-6 weeks of zonality, it didn't happen. This week some were talking definitively of a fortnight of Atlantic weather. Looking much less likely now. The Atlantic tiger is a mere kitten so far this winter.

[feb1991blizzard]

7 minutes ago, Seasonality said:

Back around Xmas week some were touting 4-6 weeks of zonality, it didn't happen. This week some were talking definitively of a fortnight of Atlantic weather. Looking much less likely now. The Atlantic tiger is a mere kitten so far this winter.

Fine, that's ok but the models were never anywhere near to unanimous on any potent cold spell either, you also need to be balanced and accept that people calling these big easterlies were wrong as well, plus there was still only brief stationary wavelength patterns from USA across the Atlantic to us, so those that say we were nearer to a big easterly than zonality are also wrong, most of the time the pattern has been moving west to east, if not the wind direction.

[IDO]

4 minutes ago, warrenb said:

Well to be honest, the GFS is not zonal as the atlantic hits a brick wall about 400 miles to our east and stalls for the entire run.

It's been inevitable, wet and windy from D5 to D16 (on current run) on the GFS, with GEM on board that Atlantic train. Call it what you like, but it amounts to the same thing, the jet pushing through the UK bringing the usual fronts and lows, so no cold or snow. What part of the UK the jet flows and at what angle makes it look not zonal, but that is what it is.

The UK>Euro high slow movement has meant zero chance of cold uppers or snow and delayed the zonal spurt, so we are looking towards week 2 of Feb for changes rather than a week earlier. Hard to understand why this was looked on as a good thing, but there it is.

We can see from the late GFS charts that once the zonal spurt has finished we get back into a more meridional flow, but now later than I hoped for due to the wasted few days waiting for the euro high to push east. That D16 NH is worth watching, but patience is now needed:

Lets just hope we avoid further delays with the Euro/Russia high, as past winters show this to be a pain for UK snow.

Of course this will all be subject to change if we get a quick trop response to the strat developments, and all remains promising in that area.

 

[mulzy]

Way out in deep FI but first signs of height rises to the NE are being shown in the GEFS mean.  Something to watch going forward...

Edited January 19, 2017 by mulzy

[ribster]

6 minutes ago, feb1991blizzard said:

Fine, that's ok but the models were never anywhere near to unanimous on any potent cold spell either, you also need to be balanced and accept that people calling these big easterlies were wrong as well, plus there was still only brief stationary wavelength patterns from USA across the Atlantic to us, so those that say we were nearer to a big easterly than zonality are also wrong, most of the time the pattern has been moving west to east, if not the wind direction.

Not sure about that Feb, I don't recall a single post calling 'big easterlys', only possibilities. Might have more to do with your own interpretation of what you were reading. 

[Polar Maritime]

And back to what the models are 'showing' please. 

[feb1991blizzard]

deleted

Edited January 19, 2017 by feb1991blizzard

[geordiekev]

16 minutes ago, feb1991blizzard said:

Fine, that's ok but the models were never anywhere near to unanimous on any potent cold spell either, you also need to be balanced and accept that people calling these big easterlies were wrong as well, plus there was still only brief stationary wavelength patterns from USA across the Atlantic to us, so those that say we were nearer to a big easterly than zonality are also wrong, most of the time the pattern has been moving west to east, if not the wind direction.

I do recall it was the models calling the easterly,  in particular all 51 clusters on the ECM, so yes on that occasion there was a reason to be sucked in. Personally I think many of the stalwart coldies know not to get Sucked in to far ahead. 

The only persons I've seen getting sucked into long term possibilities recently were those touting weeks of mild. Really should know better IMHO

Edited January 19, 2017 by geordiekev

[Singularity]

39 minutes ago, sebastiaan1973 said:

I Think we see the results of the stratospheric warming. 

Cohen wrote: The immediate response from the PV weakening will likely be increasing tropospheric ridging/positive geopotential height anomalies over northwestern North America directly under the stratospheric ridge and a deep tropospheric polar low under the displaced stratospheric PV over the north slope of Asia.
Rising heights over Alaska and Northwest Canada will help force troughing/ negative geopotential height anomalies accompanied by a cooling trend downstream over the Eastern US. Counterclockwise circulation around the polar low over the north slope of Siberia will transport North Atlantic maritime air into western Eurasia including Europe resulting in a trend to milder temperatures across the region.

At 192h we see an area of high pressure by Alaska. 

After that, we have to wait for;
However if there are subsequent pulses of WAFz/poleward heat transport this should further weaken the stratospheric PV and nudge it closer to Europe. This could either turn the winds more northerly across Europe or even force the stratospheric PV into Europe. Both of these scenarios would reverse the weather once again across Europe and result in much colder temperatures.
https://www.aer.com/science-research/climate-weather/arctic-oscillation

I've read this blog entry closely and I have to question the fact that his stratosphere-troposphere link for N. Eurasia is between 10 hPa and 500 hPa rather than 30 hPa, where the vortex looks to be positioned some 1000 miles further east, placing N. Europe under the western flank of the vortex circulation where there can be deceleration and subsidence to lower levels supporting a tropospheric ridge which would likely be E or NE of the UK.

The result, though, will be largely similar unless the Atlantic jet is diverted underneath the block. The only real difference is that the chance exists to avoid the milder period when looking at it this way - though at this point in time I do see at least a few days under a mild regime as being more likely than not, with a fair chance it will be as long as 4-5 days.

[Gael_Force]

12 minutes ago, geordiekev said:

I do recall it was the models calling the easterly,  in particular all 51 clusters on the ECM, so yes on that occasion there was a reason to be sucked in. Personally I think many of the stalwart coldies know not to get Sucked in to far ahead. 

The only persons I've seen getting sucked into long term possibilities recently were those touting weeks of mild. Really should know better IMHO

As far as I remember, the easterlies were only ever shown for the SE part and from what I see on the XC weather maps, that's exactly what we have. Perhaps 'easterlies' are being interpreted by too many as something snow bearing?

[Man With Beard]

Funny old time on the models. The long range ensembles seem set on it getting milder, eventually. However, it's clear that the block to the east is throwing punches and it really isn't a million miles away from sticking it out.

Look, this isn't a forecast, I've been backing the return to mild for a while, but there's a slither of a chance for something remarkable here. IF that trough next to Iceland can separate itself just a bit more from the main polar vortex. IF a tiny bit of negative tilt can develop on the western side of the high to our east. Then, we may see something incredible happen - the trough dive towards Iberia. Heights don't look desperately strong coming up from the tropics. 

It's not far off. Could this possibly be our lucky moment?? Will the ECM give us a monumental surprise tonight??

Edited January 19, 2017 by Man With Beard