Model output discussion - into the start of Winter

[Radiating Dendrite]

14 minutes ago, mushymanrob said:

hello WIB

Im not buying the ops quick return to a zonal Atlantic driven pattern. The Anomaly charts are consistent and are gradually building towards mid/high latitude blocking. There may be a short lived Westerly spell but overall IMHO the outlook is decidedly promising for cold weather lovers. Id expect and Easterly after next weekend, which may not start out as being overly cold, but as the film tag says "build it and they will come" .

I reckon the current outlook is the best "winter" (discounting the march, spring, cold spells of 13,18) outlook for ten years.

 

Do not think I have ever seen such a positive post from you mushy in regards to a possible cold outlook.

You are usually the one who always keeps feet on the ground and highlight the first sign of a model going off on a fantasy cold run.

[Radiating Dendrite]

11 minutes ago, General Cluster said:

But, following the 'flat' blip, things do end on a more interesting note: not all that far from 'square one' in fact... a nice build-up of cold air over Europe, too. Garden paths aplenty?

    

Nice to see the colder air in Europe at that point.

This is starting to feel like a second / third bite of the cherry. Poor initial starter but very sticky chocolate fondant pudding for desert  

[Climate Man]

25 minutes ago, joggs said:

The 06z always seems to flatten out the pattern before the 12 and 18z re-amplify.

Seems to have the iron on full steam in an effort to flatten the pattern.  Huge variation currently from model to model and from run to run for the same model. Russian Roulette at the moment. 

[mushymanrob]

6 minutes ago, Radiating Dendrite said:

Do not think I have ever seen such a positive post from you mushy in regards to a possible cold outlook.

You are usually the one who always keeps feet on the ground and highlight the first sign of a model going off on a fantasy cold run.

Thanks.. my feet are on the ground, im interested in what the weather is doing regardless of personal preferences. Ive been following the charts for over 50 years, long before the internet and models were so freely available. Ive lived through many cold winters and now recognise the signs.. im looking at the synoptic pattern and the expected synoptic pattern along with my faith in the NOAA charts, they "fit" with the type of synoptic patterns that lead us into 78/9 and 84/5 for eg.

Of course this isnt a "done deal" but imho the charts are heading that way, which this season holds far more potential for then many previous and apart from December 2010 is the most promising since i joined this site 15 odd years ago. (ignoring march 13 and 18 as they were technically spring)

[IDO]

The op def the most progressive in flattening the pattern according to the short ens:

  

The Control similar in design but less dramatics. Some ens still more convincing with the longevity and degree of those lower heights but the signal (UK trough) is a transient one taking the mean as a guide? The above are for London and temps wise nothing cold, looking dry and average seems the call up to D6, until the cold front arrives.

[johnholmes]

59 minutes ago, johnholmes said:

My input using the 500 mb anomaly charts

Ec-gfs and noaa as usual

Ec-gfs similar to each other but not the same, over usa or how treat European trough; ec changes over n America are perhaps about how 2 days on might be expected to look; gfs has lost  the ridge between the troughs so trough from ne Canada does just about link with one over s’ern states

Noaa has ridge over w’ern n America bit more pronounced also trough to east, now shows ridge e of this and higher +ve values than 2 days ago; this in turn creates more marked troughing in uk area, c of g about on 10 w and very little contour flow into Europe.

Well make of these what you will, not a set of charts to suggest anything that will last for many days but the 8-14 does keep the 6-10 pattern/strengths into its period. Noaa is usually closest to what actually occurs and ec lately has been almost as variable as gfs, so go with noaa.

The contour heights predicted over the uk are ‘about’ average for this time of year and there is no indication of deep cold air being advected over the country, from any other area, be that NW-N-NE-E so temperature wise around, perhaps a touch below, at times countrywide. No likelihood of any low ground snow from any ppn. Higher northern ground if anything falls. The far NW of the UK most unsettled/changeable and possible gales if any surface lows deepen close to that part of the country with temporary snow in the colder air behind the systems. But nothing unusual for late November/early December in the 6-14 day outlook in my view. With such a slack flow over southern areas then fog and frost could develop on suitable clear sky nights.

http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

http://www.cpc.ncep.noaa.gov//favicon.ico Climate Prediction Center - 6-10 Day 500mb Outlook

WWW.CPC.NCEP.NOAA.GOV

 

http://www.cpc.ncep.noaa.gov//favicon.ico Climate Prediction Center - 6-10 Day 500mb Outlook

WWW.CPC.NCEP.NOAA.GOV

 

[johnholmes]

Just now, johnholmes said:

http://www.cpc.ncep.noaa.gov//favicon.ico Climate Prediction Center - 6-10 Day 500mb Outlook

WWW.CPC.NCEP.NOAA.GOV

 

Not sure why they are not giving the link to the site-sorry

[Eskimo]

Some consistency between the 3 'major' models up to +144h (next thurs). Obviously some small variances with regards to the depth of the low in the Atlantic and the position of the Scrussian high. 

ECM                                                                   GFS                                                                    UKMO

                  

Fast forward just 24 hours, and it's just embarrassing (I've used GEM as the UKMO doesn't have a +168h). 

ECM                                                                 GFS                                                                     GEM

                  
                   

Until that low is resolved, the output is going to be all over the place, from run to run and from model to model. I wouldn't start worrying until ALL the models start reflecting the GFS 06z solution. 

 

 

Edited November 27, 2020 by PerfectStorm

[Gypo]

YUM!

[Met4Cast]

December 4th is the tipping point. The ECM is much sharper with the ridging both in the Atlantic and across Scandia/Russia allowing for much greater trough disruption & ejection of low pressure southwards into Europe, as a result the pattern remains sluggish and rather amplified later on in the run.

The GFS is much flatter in the Atlantic and has more positive ridging over Scandinavia resulting in far less trough disruption SE into Europe & a much faster return to a flat, Atlantic like pattern. Thankfully, the Det appears to be on the more progressive side of the ensemble pack at this stage.

[Snow lover 2020]

20 minutes ago, Gypo said:

YUM!

What’s this mean 

[Ali1977]

16 minutes ago, Snow lover 2020 said:

What’s this mean 

The chart shows the average/mean of the ECM ENS pressure charts at day 15 , showing a high pressure to our NW and a LP to our S/SE. In general it’s pointing towards the good chance of very cold weather in the U.K.

It’s never quite as straight forward as that as means are skewed by outliers etc, however you won’t see many charts better than that. 
On face value that chart points towards a Beast from the East with plenty of moisture and low pressure systems bumping into the cold air from the south - lots of snow

Edited November 27, 2020 by Ali1977

[I remember Atlantic 252]

6 minutes ago, Ali1977 said:

The chart shows the average/mean of the ECM ENS pressure charts at day 15 , showing a high pressure to our NW and a LP to our S/SE. In general it’s pointing towards the good chance of very cold weather in the U.K.

It’s never quite as straight forward as that as means are skewed by outliers etc, however you won’t see many charts better than that. 
On face value that chart points towards a Beast from the East with plenty of moisture and low pressure systems bumping into the cold air from the south - lots of snow

my favourite childhood setup, E'lys with low pressure and snow from the south!

[damianslaw]

Glancing charts, key feature is the trough dropping into Europe and much lower heights, have that in place and any Atlantic attack will have a hard time in getting a foothold, I can see a quick route to extensive block to our north thanks to positioning of the PV.

[Nick F]

Quite a potent storm system developing over eastern U.S. early next week as split northern and southern streams over the U.S. merge, the surge north of Caribbean airmass ahead of the storm colliding with cold polar air swinging in from behind the system likely to stoke up the jet stream downstream over the NW Atlantic next week, hence why the models are trying to flatten the upper flow out over the Atlantic towards NW Europe late next week.

But, 06z GFS is progressive with moving the east coast storm system NE towards Greenland later next week compared to 00z GFS and 00z EC ops, while it seems to be flooding the Canadian arctic with much lower heights than recent model guidance. Seemingly wants to pull an extension of the TPV back towards Canadian arctic and Greenland. Not uncommon for the TPV to seesaw back and forth between Siberia than back to Greenland and Canada in winter, but GFS maybe too progressive with this.

It seems the models this morning are broadly agreeing now how the synoptic evolution pans out after day 6, once the polar trough digs SE from Greenland down across UK / NW Europe. It no longer looks like a cut-off low will develop over S/SW Europe from the trough extension now, with high pressure building over the top across the UK. Instead it looks like a trough will remain ‘intact’ over Europe. While the Atlantic upper flow will become more mobile and energised to the west of the trough.

However, the speed to which the Euro trough pushes east, 06z GFS more progressive pushing east than its 00z predecessor, the angle of the upper trough axis, and the track and the strength the polar jet takes across the Atlantic into the trough over Europe uncertain for now. 00z EC and GEM track the jet furthest south with the Euro trough not budging so quickly east.

Longer term, the omnipresent Ural block, Aleutian Low and western Canada block signal in the extended ensemble guidance will help put strain on the polar vortex, with EC extended range zonal wind at 10 hPa continuing to show a weakened stratospheric vortex from the middle of December. This persistent blocked pattern in parts of the NH until then will perhaps, with help of the passage of the MJO wave through to western Pacific, help keep the TPV in constant state of flux and keep it from getting a strong hold over Greenland.

 

Edited November 27, 2020 by Nick F

[phil nw.]

It looks doubtful that the 06z GFS op has a return to south westerlies in week 2 correct. 

A rather cold ECM mean has an upper trough extending se from Iceland down through the UK into the continent from day 6.

By days 9/10 we are still in the polar air with that feed from North West ongoing. 

Nothing too wintry yet although it will be rather cold and unsettled with probably some hill snow. 

Quite an interesting set up whereby if heights rise further either to our east or west we have a chance of evolving into a colder pattern. 

[Laurence Hill]

Nick F, your graphics on the two GFS charts in your last post are much appreciated, makes it a lot easier for amateur to understand.

[bluearmy]

1 hour ago, Gypo said:

YUM!

 

1 hour ago, Ali1977 said:

The chart shows the average/mean of the ECM ENS pressure charts at day 15 , showing a high pressure to our NW and a LP to our S/SE. In general it’s pointing towards the good chance of very cold weather in the U.K.

It’s never quite as straight forward as that as means are skewed by outliers etc, however you won’t see many charts better than that. 
On face value that chart points towards a Beast from the East with plenty of moisture and low pressure systems bumping into the cold air from the south - lots of snow

Its not a mean - its the ec control from yesterday - it is as much use as the gfsp from yesterday which wasn't far away from it but as nigh on useless at that timescale

[Ali1977]

1 minute ago, bluearmy said:

 

Its not a mean - its the ec control from yesterday - it is as much use as the gfsp from yesterday which wasn't far away from it but as nigh on useless at that timescale

Oh yeah, I seen ENS and just presumed it was the mean - it would be a great mean though  
And you are correct, absolutely useless and never to be seen again unfortunately 

[bluearmy]

1 hour ago, mushymanrob said:

Thanks.. my feet are on the ground, im interested in what the weather is doing regardless of personal preferences. Ive been following the charts for over 50 years, long before the internet and models were so freely available. Ive lived through many cold winters and now recognise the signs.. im looking at the synoptic pattern and the expected synoptic pattern along with my faith in the NOAA charts, they "fit" with the type of synoptic patterns that lead us into 78/9 and 84/5 for eg.

Of course this isnt a "done deal" but imho the charts are heading that way, which this season holds far more potential for then many previous and apart from December 2010 is the most promising since i joined this site 15 odd years ago. (ignoring march 13 and 18 as they were technically spring)

rob, i would temper your thoughts on this for two reasons -

a) there is still no mid atlantic upper ridge on the cpc day 11

b) the w euro trough is a rare thing and if anything is going to fail to sustain on a noaa cpc chart it is this feature ! 

the current op output week 2 of a displaced azores ridge with a tilted trough axis from s Greenland into se Europe and systems crossing nw Europe with warm sectors seems reasonable 

[IDO]

Looking at the verification of the 0z op's and we can see why d9-d10 ECM charts should be treated with caution in setups like this:

d8 >>>  d10>>> 

ECM on top of GFS at D8 as we would expect, then on d10 a reversal and quite a significant difference between them in  favour of the GFS. I am not saying that GFS is right on this occasion but from my experience, technically ECM are not great with any type of ridging at that range. Of course, I doubt pro forecasters take much notice of op runs after D8!

[JeffC]

Am watching things like a hawk at the moment as daughter gets married in Coniston on Fri 4th, so cool and dry preferred over mild and wet!

[mushymanrob]

35 minutes ago, bluearmy said:

rob, i would temper your thoughts on this for two reasons -

a) there is still no mid atlantic upper ridge on the cpc day 11

b) the w euro trough is a rare thing and if anything is going to fail to sustain on a noaa cpc chart it is this feature ! 

the current op output week 2 of a displaced azores ridge with a tilted trough axis from s Greenland into se Europe and systems crossing nw Europe with warm sectors seems reasonable 

a) True, but its trying to build. Over the last several successive runs its gone from a minor positive pressure anomaly to a stronger one, the parent Azores high appears to be stronger shunting the contour lines further North. The pretty strong westerly upper flow has so far failed to disuade this positive pressure anomaly . So i remain optimistic here.

b) True.... not much more i can add to that other then its been a developing feature over the last several runs, im commenting on whats there now, and not passing judgement on whether its believable or not.

However, regardless of the accuracy of, or my interpretation of, there are a lot of signs suggesting mid/high latitude blocking will be a player. Just last weekend it was looking like average unsettled zonal conditions would prevail through into December. Then this settled spell emerged , soon after the other settled spell we had from a coule of weeks ago. High pressure is becoming more of a player, and isnt that what a Nina phase with an eQBO phase supposed to promote high pressure development at these higher latitudes?

To me, these current expected synoptics smack of a more irregular pattern like we had IMHO in those winters like 78/9 and 84/5.

[Frosty.]

Ok..I want snaw..do you want snaw?..does the GEFS 6z show snaw?..well yeah it does actually!...fingers crossed gang, hopefully early meteorological winter will bring us some snaw!!!!!!!   

[That ECM]

The best part of a lockdown day. 12z are on the way. looking for output that shows us a foot of powder that @mushymanrob promised is on its way