In Depth Model Discussion, Analysis and Summaries

[Glacier Point]

bit of both there Geoff, with the potential for a north-easterly and easterly further down the line.

[lorenzo]

With tropical convection (MJO) looking to weaken and become disorganised for the next 2 weeks, allied to scrubbing of westerlies from the atmosphere, not least from an addition of easterly wind anomalies across the middle and high latitudes, we should see angular momentum continue to fall (note frictional torques are still working to remove westerlies).

http://www.esrl.noaa...gcm/gwo_40d.gif

That should ensure the GWO moving through phases 8-1 in the next 2 weeks. This phase teleconnecting to height rises in the mid Atlantic and northward.

Thanks for the quick response..did you roll forward the analog for October MJO to Feb?

[geoffw]

so the op ECM is likely, just over progressive? also should we expect similar conditions for feb?

[damianslaw]

The concept of mid atlantic heights does look very plausible as we head towards the latter part of January thanks to the trough digging southeastwards into the heart of europe coupled with a weakened PV. This will be the trigger to a much more conducive set up for sustained much colder weather as we end the month and head into February as the heights build northwards joining those heights over NW Russia - a NW then N then NE then E airflow....

[Glacier Point]

Thanks for the quick response..did you roll forward the analog for October MJO to Feb?

oh yes.

[Alex]

oh yes.

I have a feeling the analogues fit 2005 quite nicely which would fit in with a cold Feb and start to March?

Can I ask whether we can delay the snow until after the 5th Feb though GP as I have a wedding and honeymoon to attend to first!

[lorenzo]

oh yes.

No point in dropping that in the model thread, best off here for people to find

[geoffw]

No point in dropping that in the model thread, best off here for people to find

why do you say no point dropping it in the model thread? is it not a good chart?

[chionomaniac]

why do you say no point dropping it in the model thread? is it not a good chart?

It is a very good chart Geoff. As good as you are likely to see.

[lorenzo]

why do you say no point dropping it in the model thread? is it not a good chart?

It is an excellent chart, much easier to find here ! Would have to keep posting and re-posting in the model thread is what I meant. Apologies for any confusion.

[Midlands Ice Age]

It is a very good chart Geoff. As good as you are likely to see.

Guys,

I am an avid lurker to this thread.....

Presumably this analogue has not been spotted yet!!!!.

How would it compare to a certain Feb during the 194ss

Looks very similar to me.

MIA

[Glacier Point]

Well, clear evidence of a pattern change with the operational models jumping around however the mists maybe clearing somewhat.

Relative angular momentum remains stubbonly high, indeed still reflective of a strong El Nino rather than La Nina with values of +2 to +1SD:

Much of this is 'westerlyness' is coming from the tropics and now more in the southern hemisphere. Within the northern hemisphere, the +ve U-wind anomalies across 60N have now ceased and been replaced by a negative U-wind anomaly which is what is causing the NWP all these problems in resolving the North Atlantic pattern over the next 5 days.

In the longer term, I still see a drop in angular momentum as the most likely evolution taking the global wind oscillation through phase 8-1 type orbit favouring height rises in the central / western Atlantic. Part of my thinking here is that the negative zonal winds making their way down from the stratosphere (or the weakening in westerlies) will further impart a fall in angular momentum.

With regard to the stratosphere, the current cross section shows an impressive atmospheric response through the tropopause which has effectively halted the strong cold vortex event. There is more of this to come, several more days at least including a sharp response at the 30 hPa layer in the last few days so expect this plot to look even more impressive, and likely to favour a negative AO.

During the programmed transition out of the first half of the winter and cold vortex event, the GFS ensembles were too bullish in bringing the negative AO. However, both GEFS and parallel GEFS are now going for a negative AO and also a negative NAO to develop (interestingly the Canadian model is also onboard with this whereas during the last week it wasn't interested in it).

Long range model tools are in good agreement depicting a strongly amplified pattern over North America and remnant polar vortex centred over Alaska. In the Atlantic, the models agree on a shallow trough over or just west of the UK and developing ridge across the top extending from Siberia across Svalbard towards northern Greenland. Pictured here CPC 8-14 day and ECM ensemble mean for day 10:

I would good for this as a good guide for the next 10 days. Unsettled with temperatures below or slightly below average although not spectacularly so, and the potential for an easterly feed not totally ruled out.

Beyond this, ECM extended ensembles suggest little change. Not so sure of this myself. If the -AO/-NAO regime develops, it should only be a matter of time before colder air filters into the mix, probably from the east or north-east.

A quick word for any in the 'well this is just more of the same...' brigade. No chance. We were staring into the abyss with that deeply +NAO / +AO regime. That has now gone. Why ?

Edited January 16, 2012 by Glacier Point

[Isolated Frost]

Very well informed post again GP- a good amount of detail into the individual factors causing any change and a nice clear explanation to why the NWP are struggling to forecast the upstream pattern as well.

[Crocodile23]

Very well informed post again GP- a good amount of detail into the individual factors causing any change and a nice clear explanation to why the NWP are struggling to forecast the upstream pattern as well.

And what about this?

http://www.3bmeteo.c...valide----55900

(It's in Italian.)

Any official news about this? From NOAA for example that refers to.

Here is a super crappy translation from GOOGLE:

The GFS model maps from Elaborate and ECMWF are not valid perched vitiated by error of data initialization. May seem like a joke, my hand is pure truth, so much so that NOAA Reed announced yesterday, through an official note, the disadvantage occurs.

Blame some of oceanographic buoys position in the Atlantic, that failure would have provided incorrect data about the current state of the atmosphere. Well everyone knows how apologetic develop a Weather Search more simular it correctly a complex system How long can the atmospheric-land, Should Think So what if I can get is to have many approximations we introduce a cast of a reed error such as wrong initial conditions . In other words we start with a state that is already wrong, by making a forecast that over time can only amplify this error.

The validity notice issued yesterday for all partners in the weeks and could explain the blatant mistakes made in the final period by two models, especially in the medium and long ends, resulting in the often unreliable and ready to change it to run in a run.

We expect all if it systems, refer Went Appropriate checks next week, with the hope that not only has to settle my model Let nature take it's reed due course, in winter, giving us worthy of his name.

Edited January 18, 2012 by Crocodile23

[Hairy Celt]

And what about this?

http://www.3bmeteo.c...valide----55900

(It's in Italian.)

Any official news about this? From NOAA for example that refers to.

Here is a super crappy translation from GOOGLE:

The GFS model maps from Elaborate and ECMWF are not valid perched vitiated by error of data initialization. May seem like a joke, my hand is pure truth, so much so that NOAA Reed announced yesterday, through an official note, the disadvantage occurs.

Blame some of oceanographic buoys position in the Atlantic, that failure would have provided incorrect data about the current state of the atmosphere. Well everyone knows how apologetic develop a Weather Search more simular it correctly a complex system How long can the atmospheric-land, Should Think So what if I can get is to have many approximations we introduce a cast of a reed error such as wrong initial conditions . In other words we start with a state that is already wrong, by making a forecast that over time can only amplify this error.

The validity notice issued yesterday for all partners in the weeks and could explain the blatant mistakes made in the final period by two models, especially in the medium and long ends, resulting in the often unreliable and ready to change it to run in a run.

We expect all if it systems, refer Went Appropriate checks next week, with the hope that not only has to settle my model Let nature take it's reed due course, in winter, giving us worthy of his name.

If when invalids turkeyplopppers we read, expects nothing rather smeared white messiness. Else high altitude balloons mays suddenlys erupt bangwise & leave no datas at alls!!!

[Tim Bland]

Lol it's like a post from crazysnowman from lutons, remember him!

Is the above in reference to last week or current outputs? I know NOA said there was a lack of data but the above seems more extreme. Models seem to have settled down now and are more in agreement - much to the disappointment of the coldies!

[skifreak]

more in agreement - much to the disappointment of the coldies!

I do wonder if some people on here reside on the same planet?

Edited January 19, 2012 by skifreak

[Tim Bland]

I do wonder if some people on here reside on the same planet?

A pointless and derogatory post, the type which ruin this form for the masses.

I was not proclaiming that the models were now in full agreement but as a result or NOA's increased reconasance there is more stability in the general synoptics being shown, IE 5 days ago not 1 of the GFS / GFES ensembles agreed with the ECM OP (which was showing an easterly) during this period the run to run variance of nearly all models was huge. My question was.... Are NOA saying there is still data issues or have we seen the last of this? - Although obviously all models vary and are low in reliabilty beyond 120hrs.

[Paul]

This is the in depth model thread, why does it currently read more like the model banter thread??

[The PIT]

Interesting so we may have been looking at duff data. Would be interesting to know how long this has been going on. Pity we don't have the orginal from noaa. A quick google doesn't reveal anything.

[Paul]

I wouldn't read much into it at all - a few duff buoys is not likely to make a huge difference when you consider the amount of data they pull. They also do QC on data every run and remove anything that is iffy.

[Crocodile23]

I wouldn't read much into it at all - a few duff buoys is not likely to make a huge difference when you consider the amount of data they pull. They also do QC on data every run and remove anything that is iffy.

QC?

[Southern Storm]

Quality control

[lorenzo]

Hopefully GP can provide a summary at some point, am lacking in expertise for the GWO charts. Can see a tendency here though and it isn't for more of the zonal train.. If I am looking at this right the mountain torque figures are hammering into the global momentum.

[summer blizzard]

Decided to post this here since the normal model thread just swamps posts within minutes.

As the prospect of the easterly is now within the timeframe of a few days i believe it is the best idea to drop the models and focus on the FAX charts as these are based on all UKMO and ECWMF ensembles (top 2 global models) in addition to the forecasters knowledge and experience.

I first bring your attention to the actual chart for 12z and the forecast chart for 12:00 tommorow...

You can see from the forecast chart for tommorow that the Russian High is already present, strengthening and retrogressing westward with the low north of the UK split and weakening as it moves south..

That in itself is a crucial development as the processes leading to the potential cold are occurring as we speak.

Perhaps most importantly is the trend in the models though which some have described today as negative however in relation to the close range FAX chart this is not true. You can see from the 0z run forecast for 12:00 tommorow that the Russian High is 2-3mb stronger than previously forecast and the low over the UK is a little stronger which will ultimately prevent the Azores High coming in that bit earlier and enhance cold air advection from the east...

So certainly in the mesoscale timeframe what we see is if anything an upgrade.

I would also add that the Met Office do forecast a snow event on Monday and have the high win..

http://www.bbc.co.uk/weather/2635167#extra-uk-content

http://www.bbc.co.uk/weather/2635167#extra-uk-content