Model Output Discussion 1st Nov.2013

[Summer Sun]

You've been around long enough SS to know we only believe GEM when showing summer heatwaves and winter blizzards..... 

 

TBF GEM did pick up the storm a few weeks back first

[bluearmy]

what are you on gav ? the gem is just another version of the other models. amplified around the 20th and beyond.  as so many have said this morning, where the pattern sets up will dictate what happens to our little part of nw europe and its far too early to know that. the pendulum will swing cold and less cold as the suites come out (and more obviously the ops). the trick is to spot the trend and see the wood for the trees. unless this becomes a 'count down' scenario, we are days away from having a handle on it.

[Frosty.]

The Ecm 00z ensemble mean shows the colder trend locking in from T+168 hours onwards, the jet axis tilting nw-se and with the formation of a mid atlantic ridge and a large complex trough to the north slowly pushing east towards scandinavia introducing progressively colder polar/arctic air, quite an amplified pattern developing with reload potential, just like the op run. I think we are in for a cold shot with widespread frosts and an increasing risk of wintry precipitation during the second half of november, longevity and intensity are currently unknown but this morning's ens mean gives us the broad brush strokes. 

Edited November 10, 2013 by Frosty.

[snowmadchrisuk]

The 6z brings the diving low in to far West allowing to much modification , and as a result the following High pressure doesn't ridge far enough North . A few tweaks and the 6z would have been another perfect run.... Still I will await the ensembles as im pretty sure the 6z on a Sunday morning is not the most reliable run in FI .

[Captain Shortwave]

A key issue is shown on the GFS op there, mainly there is no cold to tap into and the easterly is completely toothless, it would be rather raw but that's it.

Ensembles again showing the Atlantic high not going anywhere quickly so it would suggest colder than average temperatures.

Gavin would love the control run btw..........

Edited November 10, 2013 by Captain shortwave

[weatherguy]

GEM has other ideas going for a deep low instead of any northerlies

 

 

If it went on a bit longer we may well see a northerly developing, possibly gale force winds with it, but in the short term anything from the north remains at t240 or beyond depending on which model you view

 

 

As you correctly say Gavin...Just look at that WAA pumping into Greenland though! 

 

The strength/organisation of the PV looks a tad worrying in terms of prospects of this being a prolonged cold spell, but it could be worse - the core looks to be shifted over to siberia rather than greenland which always gives us a chance.  Only mid November so anything now is a bonus I suppose  

Edited November 10, 2013 by weatherguy

[Frosty.]

The Gfs 06z op run shows we won't have long to wait for our first brief flirtation with cold air from the north before atlantic high pressure pushes east which cuts it off but that is just the opening salvo because even colder weather follows, cold and unsettled with snow for northern hills and frosts becoming more frequent, then we swap the unsettled polar airflow for cold roar easterlies which strengthen, it would be feeling much colder than the 6-7 celsius on the thermometer with showery outbreaks across eastern areas and a high wind chill, the driest and brighter weather further west where there is more shelter to the west of high ground.

Edited November 10, 2013 by Frosty.

[Frosty.]

Attention all coldies..the GEFS 06z perturbations are overflowing with wintry potential from as early as T+168 onwards, and especially between T+240 / 384 hours, there are arctic reloads galore and a lot of snow potential here, and widespread sharp frosts which all amounts to an early start to the winter of 2013/14.. 

[Tim Bland]

Just to add a dose of reality to this thread..before the masses run out to buy sledges...not many of the ensembles south of the midlands show uppers below -5c in the next few weeks. As it is only November IF this cold spell comes off; south of Manchester will see sleet at low levels and snow on highest hills. I would doubt any low ground south of Scotland will see lying snow..Still early days and could upgrade but that's the reality I'm afraid

Edited November 10, 2013 by Tim Bland

[UV-RAY]

Just to add a dose of reality to this thread..before the masses run out to buy sledges...not many of the ensembles doth of the midlands show uppers below -5c in the next few weeks. As it is only November IF this cold spell comes off; south of Manchester will see sleet at low levels and snow on hugest hills. I would doubt any low ground south of Scotland will see lying snow..Still early days and could upgrade but that's the reality I'm afraid

Lucky I'm North of Manchester then.

 

I agree though Tim but the potential is there, which considering how some were saying we'd be looking down the barrel of raging zonality for November I'll take what's on offer with both hands. 

Edited November 10, 2013 by Sceptical Inquirer

[Frosty.]

Lucky I'm North of Manchester then.

 

I agree though Tim but the potential is there, which considering how some were saying we'd be looking down the barrel of raging zonality for November I'll take what's on offer with both hands. 

Yes I agree SI and I also used the word potential, which is all it is right now but with such a lot of cold options popping up now, we would be very unlucky to miss a cold blast in the next few weeks, on balance, I think it's going to happen.

[BlueHedgehog074]

List of positives (+) and negatives (-) for the possible cool down in the near future (summary from the posts I've read, plus any other possible points that may not have been covered).

 

Negatives:

• [*]The potential is still held out in Fantasy Island (so could be room for a number of additional downgrades, or a risk of the cold getting 'watered down'). [*]The Polar Vortex could be too powerful to allow amplified Atlantic Highs to our West to transform into Greenland highs. [*]A risk of a Western Based -NAO type setup occurring and could put us at risk of being on the wrong side of the cold pattern. A High Pressure system backing too far West would mean the UK could miss out on a direct Northerly flow. [*]The cold spell could be short lasting - the lack of devastation done to the Polar Vortex could mean longer term blocking may struggle to establish itself. [*]No guarantees whether it will be a cold and snowy spell, cold and rainy spell, or a cold and dry spell. [*]Like with the Western based -NAO idea, a risk of Lows dropping down in the wrong place, with highs developing, moving and/or amplifying in the wrong place. [*]The fact it's November would mean snow events are more likely to be marginal, especially for the South (unless the cold can be potent enough to turn November into 'Snowvember'). [*]There might not be a big smile on Steve Murr's face if it doesn't materialize.
  

 

Positives:

• [*]Even though it would be ideal to see the cold snap/spell potential reach the much earlier time-frames to increase the chances of it coming off, the idea of it being held out in FI could also mean enough room for a number of upgrades to happen instead. Plus, the models can apparently chop and change quite drastically when trying to detect a pattern change. As such, seeing a mixture of downgrades and upgrades shouldn't be too much of an issue. [*]A short cold spell is better than no cold spell at all if its the type of thing you're after. [*]Some people seem confident that we should at least get some sort of Northerly toppler, with the chances for reloads to occur, along with spells of cool/cold North-Westerly winds. Even a short lasting cold spell can have the potential to deliver UK-wide wintry weather if it's potent enough. [*]Some of the ensembles seem to have been quite positive for a trend to something cooler/colder. Also, the ECMWF's 00Z ensemble mean looks cool overall with the airflow looking as though it would back generally from a cold Westerly or North-Westerly direction. An example at 192 hours:
  

• [*]Despite the fact that the -5*C or colder 850 hPa temperatures may not cover the whole of the UK, other factors in regards to wintry weather could help override this issue. [*]The models are continuing to be keen about the general pattern becoming more amplified with chances of amplified highs to the West of us. (But I suppose again, we would need to be careful that the amplified highs don't back too far West). [*]The chances of High Pressure to pay the UK some visits this week should mean some frosts are possible. [*]Amplification to our West should mean periods where the Jet Stream directs itself from the North-West to the South-East helping to steer some Lows to our East and into Europe (something some members said could help along with the possible cold spell/snap). [*]There could be a big smile on Steve Murr's face if a potent cold spell does materialize.
  

 

(PS: just like to say the idea of saying whether Steve Murrs would be happy or not if the cold spell came off isn't intended to be an insult, even though red lines can be pretty rotten sometimes ).

Edited November 10, 2013 by DiagonalRedLine

[Frosty.]

All coldies can accentuate the positives, there are plenty of them, there might be even more on the 12z. 

[SMU]

I think we should earmark the 20-21st as the date to signify wintry potential for the UK  

 

S

[LomondSnowstorm]

Another plus in the cold column is that a northerly at the end of November is pretty common - just taking a look at some of the 'composite' years from my LRF it seems that Arctic air is a fairly frequent visitor to our shores in the last ten days of November:

 

 

 

 

(this one is a corker):

 

 

(this one brought a decent amount of snow to quite a few of us I recall)

[legritter]

Just had a gander at charts and Data ,interesting times coming im sure ,and reading some of the posts i get that feeling the prams are starting to rock, the PRozack is coming out the medicine cupboard ,and razor blades are being sharpened .but lets not get to excited ,lets have some more runs of the modells and get some good looking cold charts all within 6/7 days and of course all singing in harmony .patience is the key as we dont know whats looming during the coming 13 weeks of winter but we do know the following ,282 Runs of the big modells 564 Runs of our friend GFS And thousands of postage size Ensembles and of course our own gut instincts .[weather]your a coldy or a mildy interesting days ahead , im looking forward to the Chase and of course tonights modell discussion ,Bring it on 

[swfc]

Very subtle changes creeping in to the model output atm all be it subject to change .Thanks for the gavin outlook videos too which again add to the said change to a cool down.btw gavin that coughs been dragging on pal??

[Frosty.]

Just had a gander at charts and Data ,interesting times coming im sure ,and reading some of the posts i get that feeling the prams are starting to rock, the PRozack is coming out the medicine cupboard ,and razor blades are being sharpened .but lets not get to excited ,lets have some more runs of the modells and get some good looking cold charts all within 6/7 days and of course all singing in harmony .patience is the key as we dont know whats looming during the coming 13 weeks of winter but we do know the following ,282 Runs of the big modells 564 Runs of our friend GFS And thousands of postage size Ensembles and of course our own gut instincts .[weather]your a coldy or a mildy interesting days ahead , im looking forward to the Chase and of course tonights modell discussion ,Bring it on 

Fully agree legritter, all I can add to the above is  Make it Snow.............and keep watching out for a rare sighting of the beast from the east.

[East_England_Stormchaser91]

Snow is rare IMBY in November with polar Northerlies or NWerlies. Its always a case of seeing the grey 30 miles to the East and seeing Norfolk and E Lincs getting a pasting from coastal streamers, the 30 miles West where I am, not a speckle!! The most I get if I'm lucky is a pushed Cheshire gap light snow shower, thats it! 

The back edge of a cold front with polar air digging in behind it sometimes leaves a dusting behind it. 

Give me A NorthBeasterly or Easterly any day. 

FI keeps churning out promising signs, I must say. However, this Easterly that it is showing as Captain Shortwave mentioned earlier is toothless! Unless it could somehow deliver and become the 'toothless wonder'!

[garbagebags]

Northerly's are vastly superior to easterlys for snow. Everyone knows that.

[Summer Sun]

Northerly's are vastly superior to easterlys for snow. Everyone knows that.

 

I prefer northerlies over easterlies as they can bring sunshine with them in between any snow easterlies just deliver cloudy grey muck of the north sea like they did in March very little snow here just endless days of cloud and raw winds

[P-M]

I prefer northerlies over easterlies as they can bring sunshine with them in between any snow easterlies just deliver cloudy grey muck of the north sea like they did in March very little snow here just endless days of cloud and raw winds

 

Eh?  The easterlies of November 2010 brought endless snow by the shed full with thunder & lightning - dispersed in between with sunshine?  Give me a raging easterly any day (with the upper air cold enough to cause snowy convection of course)

Edited November 10, 2013 by P-M

[garbagebags]

Eh?  The easterlies of November 2010 brought endless snow by the shed full with thunder & lightning - dispersed in between with sunshine?  Give me a raging easterly any day (with the upper air cold enough to cause snowy convection of course)

 

apart from the Fact that the end Nov 2010 event was Greenland blocking and Northerlies...

[Summer Sun]

Eh?  The easterlies of November 2010 brought endless snow by the shed full with thunder & lightning - dispersed in between with sunshine?  Give me a raging easterly any day (with the upper air cold enough to cause snowy convection of course)

 

Yeah that easterly did but the one in March this year didn't bring much snow, its all down to the temperature in the north sea 2010 it was warmer than average, in March it was colder than average

[radiohead]

Eh?  The easterlies of November 2010 brought endless snow by the shed full with thunder & lightning - dispersed in between with sunshine?  Give me a raging easterly any day (with the upper air cold enough to cause snowy convection of course)

 

Yes, a bitter easterly with lows pushing up from the south can produce huge snowfalls.