Model Output Discussion 1200 hrs 15/11/14

[BLAST FROM THE PAST]

Have models got it right yet?  Might we see more agreement to a rapid and sudden onset of cold?  Or will this be a phantom set up.

 

For me its starting to come together and we are seeing what IMO December will be like and the 'sudden' change to cold and I doubt we will need to wait until week 3 of December for our first real cold shot.  5th-8th is Apogee/Full moon timing thus imo a good timeslot for the sudden switch to be in full fruition and the pattern of Atlantic ridge ridging north to link to greenland / Iceland to be in place.  Remember cold direction from N initially....then NE and then E.

 

BFTP

Edited November 28, 2014 by BLAST FROM THE PAST

[ITSY]

The only thing that I think is worth adding into the debate at this point is that the 00Z ens on the ECMWF run had a significant (in fact the largest) cluster heading cold after the midway point. I raised it as something to pin this morning, so with the UKMO and the ECM showing some interesting developments, this is worth bearing in mind as we await the next ensemble release for the 12Z - though I can never seem to access them.

[Banbury]

http://www.meteociel.fr/ukmo/runs/2014112812/UN144-21.GIF?28-18

 

A chart full of potential, allow to LP to swing NW / SE , let the HP squeezing into Greenland and we would be in the ideal position.......................it is the 144 though

[chionomaniac]

Have models got it right yet?  Might we see more agreement to a rapid and sudden onset of cold?  Or will this be a phantom set up.

 

For me its starting to come together and we are seeing what IMO December will be like and the 'sudden' change to cold and I doubt we will need to wait until week 3 of December for our first real cold shot.  5th-8th is Apoge/Full moon timing thus imo a good timeslot for the sudden switch to be in full fruition and the pattern of Atlantic ridge ridging north to link to greenland / Iceland to be in place.  Remember cold direction from N initially

 

BFTP

Hi Fred, 

 

How does the fact that the moon is furthest away from the Earth at that point influence the amplitude of an Atlantic wave giving a link to Greenland? And is not apogee a bit later anyway?

 

http://www.timeanddate.com/astronomy/moon/distance.html

 

I'm sorry but I have never really understood that.

 

c

[knocker]

The last three days of the GEFS 12z anomaly starting at T240. You can see upstream is much the same and the relevant re-alignment of the low and HP areas.  But wait what do I spy at the very end of the run. Nah won't verify of course.

Charts courtesy weatherbell

[Barry12]

The UKMO and ECM have been far better than the GFS/P recently, so I'm definitely going to believe them.

Things are starting to get very interesting, I predict snow will have fallen to lowland parts of the UK in two weeks time.

[Frosty.]

Full steam ahead to a colder spell according to latest output and once again, nothing mild in MO update today, rock solid support for below average temperatures with frost and fog with a risk of wintry ppn for some areas too. A month of considerable wintry possibilities is just around the corner...long suffering coldies..our time has cometh :-)

Edited November 28, 2014 by Frosty.

[knocker]

The vagories of the ECM ops and British weather. Just move the low from Cannes to Oslo in 144 hours.

Charts courtesy weatherbell

 

[nick sussex]

Trying to get some more clarity about which output NCEP prefer upstream is proving difficult.

 

The NCEP extended discussion still preferred solutions with more "flow amplitude" but that looks very similar to the morning update so I'm not sure whether the forecasters did  a quick paste job and rushed out to spend some money on Black Friday.

 

Looking around the State forecasts a few bits and pieces came up, issues surrounding timing  the quicker solutions in terms of clearing precip away from the eastern USA will likely be less amplified.

 

The NCEP maps done by the duty forecaster are more amplified than the GFS solutions though not quite as amplified as the ECM operational run,

 

Overall the fog has just cleared into a mist at present! If you go on past experience of the GFS its much more likely to hang onto a flat solution well into T144hrs, the ECM upto T144hrs is more likely to have the correct solution for the USA, putting aside its recent ramblings at T168hrs onwards theres already a divergence at T120hrs, if pushed at that timeframe on an amplification issue upstream you'd side with the ECM.

 

However even with more amplification don't assume any northerly or ne is a done deal, there are complications with an Atlantic shortwave and the ridge over the Continent outstaying its welcome.

 

So I think we're going to have to wait for tomorrows outputs before seeing which model has called the right pattern over the USA, and a bit longer in terms of any possible colder shot from the n/ne.

Edited November 28, 2014 by nick sussex

[MR EXTREMES]

Have models got it right yet?  Might we see more agreement to a rapid and sudden onset of cold?  Or will this be a phantom set up.

 

For me its starting to come together and we are seeing what IMO December will be like and the 'sudden' change to cold and I doubt we will need to wait until week 3 of December for our first real cold shot.  5th-8th is Apogee/Full moon timing thus imo a good timeslot for the sudden switch to be in full fruition and the pattern of Atlantic ridge ridging north to link to greenland / Iceland to be in place.  Remember cold direction from N initially....then NE and then E.

 

BFTP

Yep blast it could well be heading that way either way nothing mild after this weekend.

It's very nice to see gfs although a nightmare we still get a northerly then the ukmo and ecm want to gang up on gfs.

When you see the ukmo and ecm in tandem then you got to start questioning the evolution but what a dramatic flip from yesterday.

I still feel t96 hrs is fi but we have to wait until Sunday evening and if there still there then confidence will blast through the roof but I admit I'm starting to get rather excited.

[BLAST FROM THE PAST]

Hi Fred, 

 

How does the fact that the moon is furthest away from the Earth at that point influence the amplitude of an Atlantic wave giving a link to Greenland? And is not apogee a bit later anyway?

 

http://www.timeanddate.com/astronomy/moon/distance.html

 

I'm sorry but I have never really understood that.

 

c

Hi Ed

The moon is a modulator not a controller [certainly not as strong as solar effect] but solar and lunar phases are probably directly linked [as are planetary phases as per RJS theory?] and although small it causes atmospheric tides as well as ocean tidal effects.  The gravtitational effect is always apparent whether nearest or furthest....centrifugal and centripetal?

 

Excellent LRF by the way

 

BFTP 

Edited November 28, 2014 by BLAST FROM THE PAST

[Captain Shortwave]

To be honest, as nice as the ECM and GEM look, at that range the usual over-amplification of the Atlantic ridge could be an issue again. Personally I am still thinking this move is a little too quick and we might have to wait a little longer.

ECM ens

It could just be a similar PM shot like the one we will see early next week, it could be more.

I think this month will be a slow burner, starting off fairly dry before becoming more unsettled and eventually much colder.

[IDO]

The D10 ECM mean is very similar to the GEFS mean and does not support it's op at that time scale:

 

 

 

Much as expected.

[bluearmy]

ECM op is a synoptic outlier. That's to say that it's outside the spread of its ensembles in respect of the depression (re low thickness and it's too far west). There is a spread that takes this depression through Denmark and then drifts it east from there.

don't expect to see that ECM op run again as close to the uk with the depression.

[Snowmad79]

ECM op is a synoptic outlier. That's to say that it's outside the spread of its ensembles in respect of the depression (re low thickness and it's too far west). There is a spread that takes this depression through Denmark and then drifts it east from there.

don't expect to see that ECM op run again as close to the uk with the depression.

 

How can you call that an outlier with all the support it has from a decent cluster of members ? 

 

I haven't followed the chats all that much and have just followed the postings in this thread.. so I'm a tad confused.

[blizzard81]

How can you call that an outlier with all the support it has from a decent cluster of members ? 

 

I haven't followed the chats all that much and have just followed the postings in this thread.. so I'm a tad confused.

On another note, does anyone know why the 15 day extended ECM ensembles on meteociel haven't updated since yesterday morning's run ?

[knocker]

The D10 ECM mean is very similar to the GEFS mean and does not support it's op at that time scale:

 

EDM1-240-9.GIF  gens-21-1-240-7.png

 

Much as expected.

 

Indeed. The anomalies have some differences.

 

The GEFS has a trough north of the UK, greater ingress of the HP into Europe with a weak Russian trough. The ECM does not have the trough north of the UK but a ridge from the HP that is retrogressing westwards in northern Europe, Upstream is similar on both.

Charts courtesy weatherbell

[Captain Shortwave]

How can you call that an outlier with all the support it has from a decent cluster of members ? 

 

I haven't followed the chats all that much and have just followed the postings in this thread.. so I'm a tad confused.

Synoptic outlier meaning a different pressure pattern. Many of the colder ensembles will likely be calm anticyclonic members given the means higher than normal heights over northern Europe.

[IDO]

How can you call that an outlier with all the support it has from a decent cluster of members ? 

 

I haven't followed the chats all that much and have just followed the postings in this thread.. so I'm a tad confused.

 

 

If you compare the op and mean at D10 (or before) the LP system in Holland on the op has no support. In fact the difference in pressure is stark. Even without access to the individual ensembles it would be fair to conclude that the op was a synoptic outlier for that LP system in the Holland area:

 

 

 

Therefore anything after D6 should be treated as unlikely as the conduit for that LP system was another one that triggered the height rise towards Greenland at D5 (north of Azores).

Edited November 28, 2014 by i'm dreaming of...

[bluearmy]

How can you call that an outlier with all the support it has from a decent cluster of members ? 

 

I haven't followed the chats all that much and have just followed the postings in this thread.. so I'm a tad confused.

It's a synoptic outlier. a cluster of runs do have a depression but it's further east than the op and not as low re thickness.

The graphical representation in holland isn't too relevant when the depression on the op is headed right over there.

Perhaps someone could post the reading ens to illustrate. What might be interesting is that the control takes the first depression through Denmark and then finds a second one which follows closer to the op route and with cold air already entrenched.

[Penrith Snow]

.

Back on topic the ECM is superb, ignore the detail it's the trend that matters.

Andy

Edited November 28, 2014 by ajpoolshark
removed the off topic bits and pieces

[nick sussex]

http://www.weerplaza.nl/15daagseverwachting/?r=midden&type=eps_pluim

 

Longer range ensembles developing some very cold members, some will be inversions but also  Scandi high scenarios, a mixed bag towards the end but enough there to keep the interest going.

[blizzard81]

It's a synoptic outlier. a cluster of runs do have a depression but it's further east than the op and not as low re thickness.

The graphical representation in holland isn't too relevant when the depression on the op is headed right over there.

Perhaps someone could post the reading ens to illustrate. What might be interesting is that the control takes the first depression through Denmark and then finds a second one which follows closer to the op route and with cold air already entrenched.

Hi BA, yes, the 15 day extended ensembles have updated and I was immediately drawn to the control run.

Would you be kind enough to tell me what happens to the control run between days 10 and 15.

Sorry BA, it looks as though you have already explained in your post

Edited November 28, 2014 by blizzard81

[bluearmy]

Hi BA, yes, the 15 day extended ensembles have updated and I was immediately drawn to the control run.

Would you be kind enough to tell me what happens to the control run between days 10 and 15.

it brings another depression se around the high which behaves in a similar way to the op run. Difference being that low uppers are in place. I suspect the control would deliver snow to the uk. Once the depression sinks into Europe, the Atlantic ridge builds across the top as the flow upstream flattens

[blizzard81]

it brings another depression se around the high which behaves in a similar way to the op run. Difference being that low uppers are in place. I suspect the control would deliver snow to the uk. Once the depression sinks into Europe, the Atlantic ridge builds across the top as the flow upstream flattens

Many thanks BA