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Model Output Discussion 4th Dec.2013-12z onwards.


phil nw.

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Posted
  • Location: Castle Black, the Wall, the North
  • Weather Preferences: Spanish Plumes, Blizzards, Severe Frosts :-)
  • Location: Castle Black, the Wall, the North

Every cloud has a silver lining, a bit more tinkering with this chart from the GEFS 06z control run we would be in business for a more prolonged cold outbreak, I think christmas week will see a change with high pressure to the east/se subsiding and allowing a colder unsettled pattern for the uk.

post-4783-0-35934900-1386421550_thumb.pn

post-4783-0-34771500-1386421562_thumb.pn

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Posted
  • Location: Exile from Argyll
  • Location: Exile from Argyll

Amazing but.... What were the background signal etc compared to now ??? Anyone...

 

Well, a wQBO and around solar maximum, just as now - I don't know what the ENSO state was.

 

There was a Canadian warming in December 1978 though - turnaround in synoptics probably a response to that - no such hero in the wings for this year.......yet.

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Posted
  • Location: Reigate Hill
  • Weather Preferences: Anything
  • Location: Reigate Hill

Probably been posted already but the GEM in FI offer's some hope for us coldies.

 

Hi, nice thought but only one other ensemble member out of the other 21 supports that outlook:

 

post-14819-0-13876700-1386424823_thumb.p

 

There are many more that have a flat zonal pattern, so no surprise the mean is as such:  

 

T180: post-14819-0-53729700-1386424872_thumb.p

 

The London ECM ens: post-14819-0-03171200-1386424958_thumb.g post-14819-0-27472800-1386425039_thumb.g

 

No obvious trends there, though the mean suggests dry with a few members hinting at something more unsettled.

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Posted
  • Location: Fazendas de,Almeirim, Portugal
  • Weather Preferences: The most likely outcome. The MJO is only half the story!
  • Location: Fazendas de,Almeirim, Portugal

Over the next two weeks there is a strong likelihood that we lose the n pacific ridging ( be it Alaskan, Aleutians,kamkatchkan), it looks a cert on the extended modelling but the feature has been semi permanent so it's possible the models are getting rid of it too quickly. Will be interesting to see how the zonal winds respond to what should be less wave activity strat wise. Theoretically, it should help ramp up the vortex even more! If it does happen, will be an interesting watch to see if the theory is borne out.

Tropwise, looks grim today as the sceuro edges closer to losing its first two letters. Methinks this is a tad overdone but be aware that the anomolys are showing heights, not pressure patterns and also the deviation away from the norm. The higher heights will always be exaggerated over scandi as Europe is normally under higher 500dam. We could easily have an upper ridge over Scandinavia with a strrong sou'wester surface flow across much of the north of the area.

Almost time for nick to break out the straws!

Yes, that follows my own thoughts atm wrt this change in pattern. I think that much as the models tried to over amplify the pattern while the Aleutian Pacific poleward ridge has been present, there is a chance that they will over also react to the change of signal the other way over that region of the Pacific as well. I think that, although this is uncertain atm, the pattern change and relocation of the vortex has a reasonable chance of being a relatively temporary one before reverting back to a seasonal default Pacific ridge once again - and in turn sending the vortex core back eastwards again in the longer term where it can assist our wave breaking fortunes and return the jetstream more NW-SE once more in our part of the NH.

 

Its a case of watching and waiting with a bulk part of December looking uninspiring for upper cold, but maybe then things could start a gradual road to much more interesting prospects.

 

Get set. It's coming.  *disclaimer: in february*.

 

Edit: Its the last frame of the GFS 12z and thus completely in deepest FI with all the usual obvious caveats - but it does illustrate what was said above about transient patterns, with the pattern reverting back to the recent one and pressure starting to rise towards the Aleutians and the bulk of the polar vortex relocating back to Siberia (where we want it for longer term prospects) and a return to polar maritime amplified potential to come even though the chart at face value has mid latitude high pressure

 

Posted Image

Edited by Tamara תָּמָר
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Posted
  • Location: Newbury, Berkshire. 107m ASL.
  • Weather Preferences: Summer:sunny, some Thunder,Winter:cold & snowy spells,Other:transitional
  • Location: Newbury, Berkshire. 107m ASL.

Could be an entirely different type of scenario developing on this 12z GFS run with the Jetstream diving South mid-Atlantic and a split flow, all at only t+60 hours range. A much better setup potentially effecting the other side of the pole in the Pacific. All ifs, buts and maybes so early in the run, but a weird one from the GFS which isn't always a bad thing.

Edited by gottolovethisweather
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Posted
  • Location: Cardiff/Reading Uni
  • Weather Preferences: Snow, Sun, Heat, Cold,T/storms via Spanish plumes *rare*
  • Location: Cardiff/Reading Uni

This developing shortwave could be the main subject next weekend...

 

post-17320-0-19487700-1386433640_thumb.p

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Posted
  • Location: Near Keele, North Staffs
  • Location: Near Keele, North Staffs

A strongly zonal set-up establishing on the GFS, we are now in the sort of situation where charts out to around T216 will have a reasonable level of accuracy.

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Posted
  • Location: Orpington Kent.
  • Location: Orpington Kent.

Could be an entirely different type of scenario developing on this 12z GFS run with the Jetstream diving South mid-Atlantic and a split flow, all at only t+60 hours range. A much better setup potentially effecting the other side of the pole in the Pacific. All ifs, buts and maybes so early in the run, but a weird one from the GFS which isn't always a bad thing.

2 posts in 45 minutes on the 1st Saturday of December as the 12z runs emerge... Speaks volumes, shall I assume nothing came out of the above :) Edited by TSNWK
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Posted
  • Location: Newbury, Berkshire. 107m ASL.
  • Weather Preferences: Summer:sunny, some Thunder,Winter:cold & snowy spells,Other:transitional
  • Location: Newbury, Berkshire. 107m ASL.

This developing shortwave could be the main subject next weekend...

 

Yes that is currently where FI sits in my opinion, somewhere around t+144 hours or thereabout, where we go from there is yet to be revealed. The further North you are in the British Isles the more likely you will see some rain, darn Sarf, the current GFS default pattern is for HP dominance returning. Not so sure I buy the latter but it does remain a possibility as we head ever nearer to Christmas. Posted Image

Edited by gottolovethisweather
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Posted
  • Location: Brighton (currently)
  • Location: Brighton (currently)

This December must be like a holiday for meteorologists! 

Very easy to forecast and unlikely to shift anytime soon!

 

UKMO and GFS in perfect agreement a tell tell sign of mild weather.

 

Karyo

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Posted
  • Location: Newbury, Berkshire. 107m ASL.
  • Weather Preferences: Summer:sunny, some Thunder,Winter:cold & snowy spells,Other:transitional
  • Location: Newbury, Berkshire. 107m ASL.

2 posts in 45 minutes on the 1st Saturday of December as the 12z runs emerge... Speaks volumes, shall I assume nothing came out of the above Posted Image

 

Can you wait one second Posted Image , literally was one second too, see my judgement of the latest below your own post. Posted Image

Edited by gottolovethisweather
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Posted
  • Location: Bolton, Lancashire
  • Location: Bolton, Lancashire

2 posts in 45 minutes on the 1st Saturday of December as the 12z runs emerge... Speaks volumes, shall I assume nothing came out of the above :)

What is so special about the 1st Saturday of December?
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Posted
  • Location: Newbury, Berkshire. 107m ASL.
  • Weather Preferences: Summer:sunny, some Thunder,Winter:cold & snowy spells,Other:transitional
  • Location: Newbury, Berkshire. 107m ASL.

A strongly zonal set-up establishing on the GFS, we are now in the sort of situation where charts out to around T216 will have a reasonable level of accuracy.

 

Strongly zonal in Southern England? NIMBY AFAIK.

 

FWIW (sorry for all these abbreviations chaps) I could suggest Ian might yet call it right as I have stated previously, however currently zonality (the non-raging type) looks only likely, fleetingly at a range of eight or nine days out IMBY. Thereafter current modelling suggests HP domination will return. I feel a change in general NWP output will rear its head sooner than some many well believe. Tuesday/Wednesday's runs will reveal more, however that is simply my gut feeling. Posted Image

Edited by gottolovethisweather
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Posted
  • Location: Orpington Kent.
  • Location: Orpington Kent.

A strongly zonal set-up establishing on the GFS, we are now in the sort of situation where charts out to around T216 will have a reasonable level of accuracy.

No arguments there. When we are in this pattern there is lot more slack for changes to have no material impact to our weather subsequently the models can be trusted further out as the tolerance parameters increase. We are entering a zonal pattern shortly and although the Bartlett term is used too frequently, I do believe we must be close to meeting some of the Bartlett requirements. Edited by TSNWK
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Posted
  • Location: winscombe north somerset
  • Weather Preferences: action weather
  • Location: winscombe north somerset

please remove as off topic But sad .sat outside a pub in Somerset last night watching imitation snow falling for over an hour ,it covered the roof and road outside in several inches of snow even car tracks in the snow ,my wife and friend got back to me after shopping and even my wooly hat was covered [the models didnt forecast this so theres hope yet .PS i had a STella cheers .Posted Image

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Posted
  • Location: Newbury, Berkshire. 107m ASL.
  • Weather Preferences: Summer:sunny, some Thunder,Winter:cold & snowy spells,Other:transitional
  • Location: Newbury, Berkshire. 107m ASL.

Just to add to this zonal debate, I am still learning and I know certain members are well versed in Meteorological terms but for the record and simply to aid any newbies and/or novices..

 

Zonal flow

Component of atmospheric circulation along a line of latitude, towards the east or west.Atmospheric circulation along, or approximately along, parallels of latitude ...

 

Above, courtesy of bom.gov.uk

 

Whilst some will speak from their own patch, I am relating my comments to much of the UK away from the Northwest and within the reliable timeframe when I speak of a zonal/non-zonal flow.

 

BACK TO MODEL DISCUSSION NOW PLEASE.

Edited by gottolovethisweather
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Posted
  • Location: Castle Black, the Wall, the North
  • Weather Preferences: Spanish Plumes, Blizzards, Severe Frosts :-)
  • Location: Castle Black, the Wall, the North

I don't mind if the outlook does become strongly zonal, it will increase the risk of cold zonality as time goes on, it wouldn't just be mild. The less time we are in no mans land between high pressure to the east/se and low pressure to the west/nw..the better.

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Posted
  • Location: portsmouth uk
  • Weather Preferences: extremes
  • Location: portsmouth uk

funny how last month and the month before we see a sharp increase in solar activity could be that feb could be our best bet as solar activity has declined a little so mid jan start of feb we could see something more exciting from the model out puts.

I feel uptick in solar activity has a strong effect on the strength of the vortex and jet stream output.

 

I don't believe we are going to see anything exciting for a long time yet.

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Posted
  • Location: Beccles, Suffolk.
  • Weather Preferences: Thunder, snow, heat, sunshine...
  • Location: Beccles, Suffolk.

I don't think that solar activity has got anything to do with it, er...The USA is cold just now?

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Posted
  • Location: Brighton (currently)
  • Location: Brighton (currently)

I don't mind if the outlook does become strongly zonal, it will increase the risk of cold zonality as time goes on, it wouldn't just be mild. The less time we are in no mans land between high pressure to the east/se and low pressure to the west/nw..the better.

 

No, it will make the pattern very flat and hard to achieve any meaningful amplification that is required for a cold spell here.

 

Karyo

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Posted
  • Location: NR Worthing SE Coast
  • Location: NR Worthing SE Coast

I wonder what odds bookies will offer for a white Christmas for anywhere in the UK ?

Looks to be no major change with a surface high and upper ridge anchored around 50N east of the UK and an upper trough somewhere between 10 and 30 west over the next two weeks or so?

But then the weather loves to make idiots of us all-you never know. Take a look at some of the 'classic' winters and what the charts show two weeks or so before some of them started-something to do while some of you bite your nails and hope the charts start to show a snow fest starting?

Posted Image

 

Posted Image

 

Posted Image

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