Model output discussion - 5th December 2016 - Into Winter we go

[Banbury]

2 minutes ago, fergieweather said:

The licensing agreement with UKMO, negotiated a few years ago, is for sharing selected items that help offer technical context to forecasts, but social media growth means a risk of items disseminated without permission or proper context and thus possibly not in spirit of original forecast thinking. For now, I'm afraid that means no further sharing of that material aside from more limited ones through twitter, given sensitivities. Back to model discussion.

Shame your posts cant be locked ...............one liners will still be appreciated though

meanwhile , will the block situ over Greenland

[Ali1977]

5 minutes ago, fergieweather said:

The licensing agreement with UKMO, negotiated a few years ago, is for sharing selected items that help offer technical context to forecasts, but social media growth means a risk of items disseminated without permission or proper context and thus possibly not in spirit of original forecast thinking. For now, I'm afraid that means no further sharing of that material aside from more limited ones through twitter, given sensitivities. Back to model discussion.

This is a proper shame, is there nothing that can be done from the techno wizards - I guess locking ians posts wouldn't even work with the availability of screen shots etc. Can the members not sign some agreement that legally binds us not to share!!

anyway, still plenty of brains in here !!

[Summer Sun]

GFS 00z Para in FI would bring widespread heavy snow

Edited December 27, 2016 by Summer Sun

[Weathizard]

I know there's some positivity again this morning but just to bring some balance, the GFS 0z ensembles are actually a further downgrade from yesterday's 12z which had a stonking set. Looking at the period after the initial cold blast most push away the cold and leave us in a cold dry pattern. The GFS Para is a stonker but we've seen this several times already this winter.

 

Definitely surprised by such positivity given the way things get pushed back every time they get into a 'reliable' timeframe, sure there's a transient northerly but it's a rather dry one mostly, don't mean to be a negative nelly I'm not normally! 

 

 

Edited December 27, 2016 by Weathizard

[fergieweather]

3 minutes ago, Banbury said:

Shame your posts cant be locked ...............one liners will still be appreciated though

 

It's specifically re modified fields. Not forecast rationale (we communicate that publically already). Cheers.

[bluearmy]

Couple observations

gfsp again looks west based -NAO but this run gets it far enough east. Would be ironic if the initial bite at the cherry ends up too far to our east whilst the second one heads west!

talking of which, the ens have always been keener on nite two being more successful. Now just about reaching day 10 so we will get to see how ECM op deals with it as it should offer more insight with its higher resolution (though note it is also liable to over amplification for probably the same reasons). The eps this morning lowering those euro heights post day 10 more convincingly than yesterday though coldies should be concerned about the potential for ridging hangback from the Atlantic to our south. The spread on the ECM ens  post day 6 are pretty masssive and indicate that the route to the second bite may well not be too obvious - I wouldn't necessarily write off a surprise on what seems to be the current direction of travel days 6/10. 

Continues to be fascinating !

[Polar Maritime]

Absolutely no more post on Ian's copyright issues via Meto, Please use PM funtion for any more questions on the issue.

Thanks please continue. 

[radiohead]

ECM Vs 06 GFS.  Good agreement for day 10.

Edited December 27, 2016 by radiohead

[January Snowstorm]

Well the new year spell is quickly being watered down to a 24 hour toppler at best. Cold uppers of course after all its the height of Winter. The trend is certainly one of blocking but as has been the case it's in the wrong place

[Captain Shortwave]

Those low heights near Iberia are going to be another element of uncertainty in the model output, especially as these could end up being friend or foe by offering a catalyst to drag cold air a long way south.

Interesting evolution from the 06z

   

A decent Euro trough developing as low heights sink south east through the UK with another Atlantic ridge following. Definitely scope for this to happen from the 00z suite, as also seen from the ECM operational this morning.

[PersianPaladin]

Latest model diagnostics discussions at NOAA seem to prefer the ECM solution for the development of the amplified upper trough out towards NE US/Canada and towards Greenland. Still some difficulty modelling the progression and orientation of that feature, which matters as far as our northerly shot is concerned.

 

Quote

UPPER TROUGH AMPLIFYING FROM THE NORTHWEST TO THE EAST COAST THROUGH THU NEW ENGLAND COASTAL SURFACE LOW DEVELOPING THU NIGHT ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: 00Z NAM...12Z ECMWF...00Z CMC BLEND CONFIDENCE: AVERAGE THE 00Z GFS IS TOWARD THE FASTER SIDE OF THE GUIDANCE REGARDING THE UPPER TROUGH PROGRESSION...IMPACTING THE POSITION OF A SURFACE LOW WHICH DEEPENS RAPIDLY THU INTO FRI NEAR THE NEW ENGLAND COAST. THE PAST 2 CYCLES OF ENSEMBLE SCATTER LOW PLOTS HAVE SHOWN RELATIVE AGREEMENT WITH A BLEND OF THE 00Z NAM...12Z ECMWF...00Z CMC CLOSEST TO THE CENTER OF THE ENSEMBLES. WHILE ALL OF THE MODELS SHOW RELATIVELY GOOD AGREEMENT...THE 00Z ECMWF ADJUSTED A BIT STRONGER AND SOUTH/WEST WITH THE 12Z/30 LOW POSITION NEAR THE MAINE COAST. THIS SUPPORTS THE STRENGTH OF THE 00Z NAM...BUT GIVEN THE SOUTHWESTWARD DISPLACEMENT OF THE 00Z ECMWF FROM THE LATEST ENSEMBLE LOW CLUSTERING BETWEEN CWSS AND BHB...ITS 12Z/26 RUN IS CONSIDERED MORE FAVORABLE.

http://www.wpc.ncep.noaa.gov/discussions/pmdhmd.html

[MR EXTREMES]

43 minutes ago, Cloud 10 said:

Worth posting a Northern hemisphere chart from the GFS 00z P run,just to show an example of a pretty much perfect Greenland high.

 

You could only dream that this chart will happen.

There's no question a cold snap is on its way,

through heights sinking over the uk is not the worst thing after cold air is in place so  possibly a cold high but the Canadian vortex segment and higher heights to south of uk sèem to be a player and where it's all placed.

09/10 winter had heights from the azores that ofter started out into the Atlantic into Greenland then retrograde to Scandinavia but then this winter not really anything like that special winter.

I do believe cold snaps could feature through the remainder of winter but not really anything prolonged.

[Polar Maritime]

The 6z showing colder daytime temps into mid-next week. Before another Northerly pushes South for the weekend. The detail will continue to change, But the Wintry theme continues.

 

 

[Paul_1978]

23 minutes ago, January Snowstorm said:

Well the new year spell is quickly being watered down to a 24 hour toppler at best. Cold uppers of course after all its the height of Winter. The trend is certainly one of blocking but as has been the case it's in the wrong place

You appear to be concentrating solely on one output and not considering the overall bigger picture that lots of people have been telling us about. 

I think there's an awful lot to be positive about. 

[Scandinavian High.]

by looking at this we have high to the north and low pressure to the south so we have a easterly flow heavy snow for the south of U.K. .

Edited December 27, 2016 by abbie123

[Methuselah]

31 minutes ago, January Snowstorm said:

Well the new year spell is quickly being watered down to a 24 hour toppler at best. Cold uppers of course after all its the height of Winter. The trend is certainly one of blocking but as has been the case it's in the wrong place

I think that's because the models are hunting for the right solution and what, to us, may appear to be a massive (inter-run) swing is, in the general scheme of things, no big deal? Apart from that, I think it's fairly safe to say that a pattern-change is underway...

[johnholmes]

43 minutes ago, January Snowstorm said:

Well the new year spell is quickly being watered down to a 24 hour toppler at best. Cold uppers of course after all its the height of Winter. The trend is certainly one of blocking but as has been the case it's in the wrong place

The perils of watching each run churn out

Edited December 27, 2016 by johnholmes

[bluearmy]

Note that the 06z GFS op is a reasonable run in week 2 in respect of the extended means/anomolies. a dumbelling mid Atlantic high which never quite allows a full on deep cold blast is quite plausible. would still give below av temps, sometimes well below and the chance of some of the white stuff. 

[johnholmes]

51 minutes ago, Weathizard said:

I know there's some positivity again this morning but just to bring some balance, the GFS 0z ensembles are actually a further downgrade from yesterday's 12z which had a stonking set. Looking at the period after the initial cold blast most push away the cold and leave us in a cold dry pattern. The GFS Para is a stonker but we've seen this several times already this winter.

 

Definitely surprised by such positivity given the way things get pushed back every time they get into a 'reliable' timeframe, sure there's a transient northerly but it's a rather dry one mostly, don't mean to be a negative nelly I'm not normally! 

 

 

Another post showing the problems of comparing different runs. Stick to comparisons of the same time down to 144h. Also compare one model with the other for the same time, ie: 00 or 12Z, and until the time scale is below 144h don't complicate matters with the 06 and 18Z.

Honest it does work, probably 70-75 % of the time and also ensures less stress for those searching for cold and snow. But if you enjoy the roller coaster just ignore me.

Edited December 27, 2016 by johnholmes

[BLAST FROM THE PAST]

Looking ok for a spell of below average temps.  One gets the feeling though that it won't be a full on arctic outbreak (not yet) but more of a series of swipes..... but potent swipes.  The Euro heights do bother me a touch on determining the cleanliness of the first cold thrust, enough room there to water the first swipe down.

I've got lower stratos warming pencilled in for early NY which if comes about a lag for mid Jan prolonged arctic outbreak.  Outlook anyway for Jan seems to be 'warming' (pardon the pun) up nicely and with consistency of JH method a good coldie start looks on the cards

Just seen that laymen sunspot count i.e. Same as when used to read sunspots in Maunder and Dalton minimas...shows we have had 17 spotless days.  This cycle 24 is plunging rapidly now and is below cycle 5, it could get interesting this.  Siberia locked into freezer with record cold for Western Siberia.

BFTP

Edited December 27, 2016 by BLAST FROM THE PAST

[tight isobar]

Talk of cold icur being watered down atm' is as un-worthy of mention of upgrades! 

Various' progression and placements of waa' and cell situ's are by far and away not resolved! ..

And WILL obviously have reasonable implications for our final overheads.

Anyway a massive day today I feel for probable outcomes from 1/01/2017-10/01/2017...

Today's suites I feel will be pivotal! !!

[bluearmy]

As nick mentioned yesterday, without forcing from the polar regions, we are relying on upstream patterns to dictate amplification. we know how these can change run to run, day to day. so unless we see a convincing change re blocking establishing well to our north, expact the nwp to co tiniest to fluctuate. 

Frustrating, I know but the reality is thus. 

[January Snowstorm]

27 minutes ago, johnholmes said:

The perils of watching each run churn out

Merely reflecting the changes in the last 24hours across all models. I didn't quote one specific run. Example UKMO was stunning yesterday not so special today. ECM 24 hours ago was showing a full blown Greeny high, not so now. So it isn't the perils of watching one particular run its my educated view of where the models were yesterday to today (educated in my amateur take of watching weather/climate for 40+years)

I do agree though that it could swing back again and at least the atlantic remains subdued

[EML Network]

Don't shoot me down for saying this, but I fear there is going to be a lot of disgruntled coldies by the end of the day, the cracks in the potential cold spell are already beginning to appear on this mornings set of runs and I fully expect things to get watered down as the week progresses. 

Going through the various gfs runs this morning and the form horse is for a return to westerly driven weather post day 10. 

I would upload some postage stamps but I don't have the time.

The models always seem to throw out cold charts over the Christmas period for early January, only for things to get watered down as the data streams increase after the Xmas lull...(well that's my take on it anyway),seems to happen every year.

I do hope this is just a blip, but for me the writing is being etched on the wall in pencil this morning, let's hope someone comes and rubs it back off ...else we'll all end up having chased yet another potential cold spell that only ever existed inside a computer model !!

And how many times have we been here. 

[Summer Sun]