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

[bobbydog]

1 minute ago, feb1991blizzard said:

No but that's when the models predicted blocking, when they're predicting mild, they will verify.

Fortunately, right now, they are predicting everything....

[blizzard81]

2 minutes ago, feb1991blizzard said:

No but that's when the models predicted blocking, when they're predicting mild, they will verify.

That's usually the case unfortunately, not always, but usually!

[karlos1983]

1 minute ago, bobbydog said:

Fortunately, right now, they are predicting everything....

exactly

[legritter]

Well if the complex workings of our planet are not going to support a proper northern block for our island this winter ,I would prefer v cold zonal run instead .at least we will have some snow shots ,but very very early days ,past about 168 hrs is very uncertain at the moment ,even the pros are unsure ,but the hunt is still truly on gang .

[phil nw.]

With the current NH profile ie.low heights to the north, then any chance of a seasonal turn to something colder rests with the GFS  which is showing  better ridging towards the UK at the end of next week.

The gefs still have plenty of members favouring a high further north with a cell over or near the uk and a chance of getting a continental cold feed.

 

ECM can't be ignored though and it is a disappointing op run this evening looking flatter and showing mobile westerlies across the UK out to day 10,any heights are further south over the continent.This is more in line with it's overnight ens mean which is an added disappointment.

Until the main model suites come closer together it's difficult to see a clear way forward in week 2-will it be a cold frosty high or a flatter westerly setup with any high further south and only transient ridging?

We are now looking for crumbs as it currently stands unfortunately and a UK high would at least give us some frosts and colder days.

Edited December 8, 2016 by phil nw.

[northwestsnow]

Not a great ecm, it has to be said, really ramping up the atlantic.Have to say as a coldie if its not going to be snowy, then a cold high is second prize,really dont want a mild and wet December, had my fill of them over the last few years..

[Matthew.]

5 minutes ago, legritter said:

Well if the complex workings of our planet are not going to support a proper northern block for our island this winter ,I would prefer v cold zonal run instead .at least we will have some snow shots ,but very very early days ,past about 168 hrs is very uncertain at the moment ,even the pros are unsure ,but the hunt is still truly on gang .

Yes a cold zonal run was thought about this morning by the ECM i think. The thing is do we go for the dry frosty high by GFS or cold zonal? 

[bluearmy]

The interest on the ecm 00z was the draining of low heights from n America by day 10. Not the story on the 12z which is a shame as these outlier type ops have to repeat or they are tomorrow's chip wrappers 

[karlos1983]

4 minutes ago, bluearmy said:

The interest on the ecm 00z was the draining of low heights from n America by day 10. Not the story on the 12z which is a shame as these outlier type ops have to repeat or they are tomorrow's chip wrappers 

would it not be fair to suggest that the 12z could also be an outlier, just at the other end of the graph....vinegar destined also perhaps? 

Edited December 8, 2016 by karlos1983

[nick sussex]

1 hour ago, Singularity said:

Look at that low crossing the southern U.S. early-mid next week. It's so fast on the ECM and UKMO runs despite having to overcome a marked ridge ahead of it... does that seem excessive to anyone else or is it just me?

Its an important detail as a faster arrival directs energy into the N arm of the jet - hence over our ridge - before disruption of the trough beforehand is able to occur. Notice the small shortwave shooting over the ridge whereas GFS drops it down west of the ridge.

Not often we see GFS favouring the S arm of the jet in a split setup when the other models are having nothing to do with it!

NCEP discussion may be revealing  this eve - hint hint Nick; you're the go-to source for this

Do you mean the earlier low which the ECM/UKMO run quickly into the troughing to the west  between T96 and T120hrs? Well it starts out as a Pacific shortwave and heres what NCEP think. I think you'll like what they say but its bizarre to see the GFS a bit more amplified than the ECM/UKMO. Its normally the GFS which is more progressive.

...NEXT PACIFIC SYSTEM AFFECTING THE PACIFIC NORTHWEST BY SATURDAY
MORNING...
...EVENTUAL SHORTWAVE/SURFACE LOW CROSSING THE MIDDLE OF THE
CONUS...

FINAL PREFERENCE: BLEND OF THE 12Z GFS/ECMWF
FORECAST CONFIDENCE: SLIGHTLY BELOW AVERAGE

AS THE PARENT CLOSED LOW LINGERS BACK NEAR COASTAL WA...ADDITIONAL
JET ENERGY OFF THE PACIFIC BEGINS TO TAKE AIM AT THE NORTHWESTERN
U.S. THIS WEEKEND. ALL OF THIS PACIFIC SHORTWAVE ENERGY WILL SWING
INLAND CARVING OUT A MORE AMPLIFIED RESPONSE OVER THE CENTER OF
THE COUNTRY. ALL OF THE ENSEMBLE MEANS ARE QUITE FLAT WHICH MAKES
IT DIFFICULT TO UTILIZE ANY OF THESE GIVEN SOME AMPLIFICATION IN
THE FLOW IS EXPECTED. ENSEMBLE LOW PLOTS ARE QUITE MESSY WITH NO
DISTINCT CLUSTERS NOTED AS MEMBERS ARE GENERALLY SCATTERED ABOUT.
THE 12Z NAM/09Z SREF MEAN DO RESIDE WELL NORTH AND ARE QUICKER
THAN ANY AVAILABLE SOLUTION. OF COURSE THE EXACT PLACEMENT OF THE
SURFACE CYCLONES AND WEST-EAST FRONTAL BOUNDARY WILL PLAY A ROLE
IN WHERE OVERRUNNING PRECIPITATION WILL FALL. UNTIL THE GUIDANCE
BEGINS TO SHOW A BIT MORE CONSISTENCY...THE PLAN WILL BE TO
CONTINUE SPLITTING THE DIFFERENCE BETWEEN THE 12Z GFS/ECMWF.
 

The thing is Singularity we'd need a lot more amplification than even the GFS shows to help sharpen up that troughing to the west and its being fed by the PV lobe over Greenland. It will be however interesting to see what this evenings NAM/SREF do because they are the flattest solutions, if they become more amplified maybe that's a better sign.

Edited December 8, 2016 by nick sussex

[karlos1983]

4 minutes ago, nick sussex said:

Do you mean the earlier low which the ECM/UKMO run quickly into the troughing to the west  between T96 and T120hrs? Well it starts out as a Pacific shortwave and heres what NCEP think. I think you'll like what they say but its bizarre to see the GFS a bit more amplified than the ECM/UKMO. Its normally the GFS which is more progressive.

...NEXT PACIFIC SYSTEM AFFECTING THE PACIFIC NORTHWEST BY SATURDAY
MORNING...
...EVENTUAL SHORTWAVE/SURFACE LOW CROSSING THE MIDDLE OF THE
CONUS...

FINAL PREFERENCE: BLEND OF THE 12Z GFS/ECMWF
FORECAST CONFIDENCE: SLIGHTLY BELOW AVERAGE

AS THE PARENT CLOSED LOW LINGERS BACK NEAR COASTAL WA...ADDITIONAL
JET ENERGY OFF THE PACIFIC BEGINS TO TAKE AIM AT THE NORTHWESTERN
U.S. THIS WEEKEND. ALL OF THIS PACIFIC SHORTWAVE ENERGY WILL SWING
INLAND CARVING OUT A MORE AMPLIFIED RESPONSE OVER THE CENTER OF
THE COUNTRY. ALL OF THE ENSEMBLE MEANS ARE QUITE FLAT WHICH MAKES
IT DIFFICULT TO UTILIZE ANY OF THESE GIVEN SOME AMPLIFICATION IN
THE FLOW IS EXPECTED. ENSEMBLE LOW PLOTS ARE QUITE MESSY WITH NO
DISTINCT CLUSTERS NOTED AS MEMBERS ARE GENERALLY SCATTERED ABOUT.
THE 12Z NAM/09Z SREF MEAN DO RESIDE WELL NORTH AND ARE QUICKER
THAN ANY AVAILABLE SOLUTION. OF COURSE THE EXACT PLACEMENT OF THE
SURFACE CYCLONES AND WEST-EAST FRONTAL BOUNDARY WILL PLAY A ROLE
IN WHERE OVERRUNNING PRECIPITATION WILL FALL. UNTIL THE GUIDANCE
BEGINS TO SHOW A BIT MORE CONSISTENCY...THE PLAN WILL BE TO
CONTINUE SPLITTING THE DIFFERENCE BETWEEN THE 12Z GFS/ECMWF.
 

i wish we got these sort of updates regularly. I know Ian gives us his musings when he can, but this would be great to digest and unpick every evening.

cheers Nick

Karl

[SMU]

6 hours ago, Summer Sun said:

 

 

I will try to do a longer post in a while however it would appear the EC seasonal model is broken. That would be along side the Glosea. 

This isnt a dig @ Matt or Ian- however how can we maintain northern blocking that we dont aready have?

How can we have a distinct -NAO for December when its been neutral since the start- the key word here being 'distinct'- suggestive of something lower than -1.5 on the scale-

well sadly theres nothing within the next 8 days that suggests that so as a minimum we will be halfway through December with no trace of any blocking that had been forecast all the from the outset of November-

Also, another reason why I must assume that is the inference that the trop vortex is running disconnected to the strat one-

It looks pretty connected to me, At the end of Nov the 10HPA 60N zonal mean forecast a steady rise from the outset through to the middle of the month & beyond & thevtrop vortex has followed- The AO which is the best measure has had a smooth increase from negative values to a current mean that is in touching distance of +2 in a couple of days, thats a hefty rise of 3 sigma in 2 weeks- it mirrors the strat perfect-

The dates are mirrored

 

Excluding the GFS ensembles which will always throw out a few peachy runs theres been nothing to indicate that there would be anything other that a 1/2 day transitory cold shots all the way to xmas...'

I will look at the zonal mean forecasts today but I fear it makes poor viewing...

S

[bluearmy]

One difference in the 12z eps is more amplification towards Svalbard by day 10 with the Siberian vortex looking toward a little segment in e Siberia rather than its Canadian cousin 

[karlos1983]

By 'maintaining' I'm pretty certain Matt H meant the signal, not what was actually occurring, he is fairly knowledgeable in his field I'm lead to believe, as in not seeing something that isn't there! But then I guess to be sure you would need to ask him. I'm sure he's approachable.

but the strat disconnect comments do seem to be contradictory given the evidence you've posted. But thats me taking it at face value, as its a tad beyond me to debate otherwise.

Edited December 8, 2016 by karlos1983

[Iceberg]

Some insane temps being forecast for the states over the next 2 weeks. Lots of cold for most states. This is a sample though forecasting temps below -40c at surface. Might even be a few news stories about this before Christmas. 

For us the pattern was always suggesting the possibility of cold Christmas onwards patience needed as we are only 8 days into winter. !

[Ali1977]

2 minutes ago, Iceberg said:

Some insane temps being forecast for the states over the next 2 weeks. Lots of cold for most states. This is a sample though forecasting temps below -40c at surface. Might even be a few news stories about this before Christmas. 

For us the pattern was always suggesting the possibility of cold Christmas onwards patience needed as we are only 8 days into winter. !

This forum over there would be insane!! All the luck ( cold lovers anyway)

[Singularity]

Thanks @nick sussex

The part about the ensembles being flat where amplification is expected catches my eye. Could a similar situation be occurring with the EC ens. and ECM... and UKMO for that matter?

Curious stuff. Get the slower outcome with a trough disruption able to unfold ahead of it and at least we have a better and higher latitude block to fight then next Atlantic trough with. Well, I say that, but upstream events will be the true deciders on whether we can turn that one into a disrupting feature as well. Not sure if the newly picked up 6-7-8 MJO signal will have any influence soon enough to affect that particular outcome (residual IO activity could be leading to projected MJO on Henson-Wheeler diagram appearing weaker in the Pacific than it actually is).

[phil nw.]

A few posts have been removed.

To those affected please keep one line comments or those that have no model views to other threads- such as the moan/banter thread.

Let's keep the off topic clutter out of here.

Thanks.

[joggs]

2 minutes ago, Iceberg said:

Some insane temps being forecast for the states over the next 2 weeks. Lots of cold for most states. This is a sample though forecasting temps below -40c at surface. Might even be a few news stories about this before Christmas. 

For us the pattern was always suggesting the possibility of cold Christmas onwards patience needed as we are only 8 days into winter. !

I've said it for years on here,a bitter states most of the time gives us the opposite.

Alot of our best (coldie) spells,82,87,91 have had east America mild.I think records were broken around Washington in Feb 91.Checkout Ian mcCaskill on YouTube. Then drool over what happened in Britain lol.

[bobbydog]

19 minutes ago, Steve Murr said:

 

I will try to do a longer post in a while however it would appear the EC seasonal model is broken. That would be along side the Glosea. 

This isnt a dig @ Matt or Ian- however how can we maintain northern blocking that we dont aready have?

How can we have a distinct -NAO for December when its been neutral since the start- the key word here being 'distinct'- suggestive of something lower than -1.5 on the scale-

well sadly theres nothing within the next 8 days that suggests that so as a minimum we will be halfway through December with no trace of any blocking that had been forecast all the from the outset of November-

Also, another reason why I must assume that is the inference that the trop vortex is running disconnected to the strat one-

It looks pretty connected to me, At the end of Nov the 10HPA 60N zonal mean forecast a steady rise from the outset through to the middle of the month & beyond & thevtrop vortex has followed- The AO which is the best measure has had a smooth increase from negative values to a current mean that is in touching distance of +2 in a couple of days, thats a hefty rise of 3 sigma in 2 weeks- it mirrors the strat perfect-

The dates are mirrored

 

Excluding the GFS ensembles which will always throw out a few peachy runs theres been nothing to indicate that there would be anything other that a 1/2 day transitory cold shots all the way to xmas...'

I will look at the zonal mean forecasts today but I fear it makes poor viewing...

S

To be fair Steve, I think it's just the wording there, the EC maintains its longer term signal for blocking along with GloSea. Whether that actually happens or not is a different story....

I was also of the understanding that the models were struggling with the strat/trop disconnect and trying to stabilise this, hence the 'chaos' (for want of a better word)

Edited December 8, 2016 by bobbydog

[Summer Sun]

As you were then with the uncertainties continuing

 

[legritter]

37 minutes ago, Matthew Wilson said:

Yes a cold zonal run was thought about this morning by the ECM i think. The thing is do we go for the dry frosty high by GFS or cold zonal? 

Dry frosty high would be good ,then let  it migrate north ,not asking much ,we need  some slices  of bread not crumbs ,cheers . 

[Cheshire Freeze]

1 minute ago, Summer Sun said:

As you were then with the uncertainties continuing

 

Either way, disparity cannot carry on indefinitely. I'm inclined to actually side with the GEFS on this one in the long term...Never thought I'd say that! I think the EC ENS will sharpen up in the next week for towards the festive week

[Methuselah]

And anyway (before I lose count) there are still 82 days of winter still to come...So, don't - on the basis of one or two model-runs - call the whole thing off, just yet?

And no-one's perused the Brazilian and Chinese models yet? The Inuit model looks promising!

[bluearmy]

Looking at the extended eps and the news is mixed. The Siberian segment relocates from w Siberia to e Siberia. This will allow more amplification to our ne. The Atlantic low anomoly becomes marked and likely throws a fairly zonal train at us which will split in our vicinity against a sceuro ridge. W Europe is devoid of a high anomoly and no upper ridging is shown from the Azores. Shallow upper trough across Europe as a whole. This would allow for systems to run nw/se towards Iberia and I wonder if such a cluster exists.