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Model output discussion - 1st December onwards


Paul

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Posted
  • Location: Eastbourne and Larnaca,Cyprus .
  • Location: Eastbourne and Larnaca,Cyprus .

In terms of prospects for the rest of the month.

The CPC are resolutely 5/5 for confidence in the upstream pattern , this being a ridge in the eastern USA, troughing in the Atlantic and troughing western USA.

The ridge in the eastern USA does amplify and this could offer some interest later on as generally this would also effect the amplitude of any Atlantic troughing and this of course then effects the Euro high which might morph into the new NW favourite the Sceuro high The Scandi/Euro combo can if orientated favourably can develop some colder drier conditions for the UK.

This could happen before the months end if that Atlantic troughing digs sufficiently south and amplifies in response to the eastern USA ridge.

There is one variable at the moment the MJO which has surprisingly strengthened, the issue of course is whether this can survive the rocky road to a more favourable cold phase for Europe or whether it gets blown off course and weakens.

I think its best to have low expectations for the rest of December and if anything pops up at the turn of the month then great but the NH pattern needs a good re-shuffle. Perhaps the MJO might be able to provide that, we'll see.

 

Edited by nick sussex
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Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.
4 minutes ago, knocker said:

The ecm anomaly at T240 has the trough just to the west of the UK with slight ridging to the east with a familiar pattern upstream. Thus a continuation of the WSW flow over the UK with temps above average. In the ext period at T360 the main difference is the vortex now back over NW Greenland and amplification of the European HP which is now ridging NE to southern Sweden. Thus the UK still in the SW flow and the more settled weather may be influential a bit further north and the temps still above average.

 

ecmwf-ens_z500a_nhem_11.png

I know you being a pro you already know this but that actually isn't a bad scenario for bringing cold into the UK, a pretty strong signal from what you say as well given its a mean of 50 members at T360.

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Posted
  • Location: Camborne
  • Location: Camborne
10 minutes ago, feb1991blizzard said:

I know you being a pro you already know this but that actually isn't a bad scenario for bringing cold into the UK, a pretty strong signal from what you say as well given its a mean of 50 members at T360.

I agree there are a number of options for the evolution but all I can say is that tonight's T360 anomaly is a close replica of the EC32 chart at T408.  It will be interesting to see how this pans out because the EC collapsed the ridging within the next three days.

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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
13 minutes ago, feb1991blizzard said:

I know you being a pro you already know this but that actually isn't a bad scenario for bringing cold into the UK, a pretty strong signal from what you say as well given its a mean of 50 members at T360.

Hopefully something will be stirring in knockers woodshed by the end of Dec / early Jan. ; -)

 

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Posted
  • Location: Carryduff, County Down 420ft ASL
  • Location: Carryduff, County Down 420ft ASL
4 hours ago, Daniel* said:

That is very incorrect I do not have the supportive charts with me however chilly westerly/northwesterly winds were being modelled a chilly blip.

As of late with negative uppers in the mix enough for snow in places.

A couple of GFS ops run had it but there was no support from the GEFS or anywhere else and were quickly dropped.

And even then the air was heavily modified.

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Posted
  • Location: Surrey and SW France.
  • Location: Surrey and SW France.
10 minutes ago, mountain shadow said:

A couple of GFS ops run had it but there was no support from the GEFS or anywhere else and were quickly dropped.

And even then the air was heavily modified.

There was support for it from ECM ensembles -  cold zonality with upper air cold enough for snow on high ground. The signal is less so now but the ensemble for the SE still shows scope for cooler weather; the det is near the top of the spread for the 25th.

epsgram_at_reading!epsgram.gif

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Posted
  • Location: Broxbourne, Herts
  • Weather Preferences: Snow snow and snow
  • Location: Broxbourne, Herts
2 hours ago, bobbydog said:

actually, the charts we are seeing now are not a million miles away from 1947. in reality, having read up on it, be careful what you wish for..

i know references to the winter we had in 1947 are hopeful and tongue-in-cheek for the most part, but its worth remembering that while some very mild temperatures did precede the bitter cold, before that the December had been the coldest for 9 years and the building blocks were in place, albeit they had to keep being restacked.

If we had this kind of chart at this time of year as there was in 1946, there wouldn't be the doom and gloom  around that there is at the moment

Rslp19461215.gif

This forum in 1946-7 would have been high in anticipation throughout that winter....regrettably I think there are justifiable reasons why no such optimism exists this winter

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Posted
  • Location: Kings Norton, West Midlands
  • Weather Preferences: Thunderstorms, Cold & Snowy
  • Location: Kings Norton, West Midlands

Something a bit different. You have to be 3200m above sea level in order to reach 0°c on Thursday, in DECEMBER. 

nmmuk-37-37-0.png?16-00

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Posted
  • Location: Camborne
  • Location: Camborne

The GEFS anomalies this morning still looking to retrogress the Atlantic trough and build heights to the east. The interest I feel is in the next few days after this period. Will the HP to the east collapse and as a corrollary is the GEFS over amplifying this? Anyway it guarantees the continuation of the very mild weather into the NY and on that subject Friday/Sat on the cards to be the warmest.

 

gefs_z500a_5d_nh_41.pnggefs_z500a_5d_nh_65.thumb.png.4b568d94cagfs_t2m_a_f_uk2_16.thumb.png.590a9408f8d

 

 

Edited by knocker
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Posted
  • Location: Derbyshire Peak District South Pennines Middleton & Smerrill Tops 305m (1001ft) asl.
  • Location: Derbyshire Peak District South Pennines Middleton & Smerrill Tops 305m (1001ft) asl.

The GFS this morning shows an unsettled Christmas eve/day, Especially for the North as lows swing in off the Atlantic bringing gales and bands of rain for the big day..

 

a.pngb.pngc.png

Edited by Polar Maritime
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Posted
  • Location: Reigate Hill
  • Weather Preferences: Anything
  • Location: Reigate Hill

The CFS w3 and w4 show no changes to this entrenched pattern so the MJO signal not showing up at the moment: wk3.wk4_20151214.z500.thumb.gif.20731b0d

The GEFS and GFS continues in FI to downgrade the Scand/Euro ridge and beginning to trend towards another Euro high that gives the UK another repeating warm spell:

d12  mean: 56710fd9300b0_gens-21-1-300(2).thumb.png   5671100fe5324_gens-21-6-300(1).thumb.png

D16 mean: 56710fd857dcb_gens-21-1-384(13).thumb.pn   5671102052f3f_gens-21-6-384(1).thumb.png

 

Subtle differences with timing at D10 on the big three models but all similar synoptics: 

 

567110aa99e2d_ECM1-240(7).thumb.gif.3bcc567110ab5104d_gfs-0-240(10).thumb.png.4d567110ac17333_gem-0-240(11).thumb.png.ff

Still good cross model and run to run support so we can be very confident of the long wave pattern over the next 10 days.

As the experts have said we have to be wary of the MJO signal at the moment. Another tweet:

  anthonywx
Even w/ MJO destructively interfering with ++ENSO signal, strong Nino background state (low freq) forcing prevails. https://t.co/XAFqlcI8G8
15/12/2015, 18:03

Until the longer range forecasts change the pattern and neither CFS or ECM are doing that at the moment then we have to assume the normal MJO composites are outweighed by the current ENSO synoptics. Too early to be conclusive either way but not banking a Scandi/Euro ridge yet.

 

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Posted
  • Location: Cambridge, UK
  • Weather Preferences: Summer > Spring > Winter > Autumn :-)
  • Location: Cambridge, UK

More of the same on the 00z runs, continuing very unsettled, with slightly more cooler sectors crossing the UK than at the moment, but overall on the mild side. Looking like a white Xmas is off the cards unless you've got a house up on CairnGorm, and even then I wouldn't bank on it!

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Posted
  • Location: st albans
  • Location: st albans

I would caution against the expectancy of big warmth in a week or so. Should the sceuro ridge edge closer to nw Europe, a slacker flow would deliver seasonal temps.  Any inversion would be potentially cold.  Currently, the PFJ looks strong enough to keep the UK close enough to the trough to dispel that option but it wouldn't take much of a retrogression of the lw pattern. 

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Posted
  • Location: leicester
  • Location: leicester

Unbelievably mild charts at the moment!!even during the last 2 winters we had better charts to look at around this time even though they didnt actually happen in the end!!scary thing is i thought the last 2 decembers were bad but this is shaping up to be even worse!!wasnt even aware that you could get temps of 17 or 18 degrees in december lol!!lets hope january makes up for the mild mush we having now!!

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Posted
  • Location: Edmonton Alberta(via Chelmsford, Exeter & Calgary)
  • Weather Preferences: Sunshine and 15-25c
  • Location: Edmonton Alberta(via Chelmsford, Exeter & Calgary)
8 hours ago, Timmytour said:

i know references to the winter we had in 1947 are hopeful and tongue-in-cheek for the most part, but its worth remembering that while some very mild temperatures did precede the bitter cold, before that the December had been the coldest for 9 years and the building blocks were in place, albeit they had to keep being restacked.

If we had this kind of chart at this time of year as there was in 1946, there wouldn't be the doom and gloom  around that there is at the moment

Rslp19461215.gif

This forum in 1946-7 would have been high in anticipation throughout that winter....regrettably I think there are justifiable reasons why no such optimism exists this winter

Exactly the set up during December 1946 is nothing like the pattern we have now...as stated elsewhere before the really severe weather hit in the 3rd week of Jan 1947..there had already been a fair amount of cold and snow around in the first part of winter which a lot of people may not realise.

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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

The AC will be on full blast in the woodshed this week according to the Gfs 00z with max temps in the 13-15 celsius range and saturday could be even warmer with low 60's F for some areas, The nights also look exceptionally mild with minima  of 11/12c...very springlike indeed, crazily mild with air sourced from way south, the daffs are loving it!

ukmaxtemp.png

ukmaxtemp (1).png

ukmaxtemp (2).png

ukmaxtemp (3).png

stream_img.jpg

daffodils1-620x348.jpg

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I'm in no way of fan of mild winter weather, but I am a fan of extreme weather and this month looks like falling about as far into the extreme category as we can get in UK. As well as the incredible warmth, we are also seeing a significant lack of sunshine, which again could well end up breaking low records if the model pan out as currently shown between now and months end. It is also extremely interesting imo to witness just how nature is coping with the warmth, there is so much in bloom now even given the dull, darkness, so one can only imagine how things would look if the past 4-6 weeks had been accompanied by even average amounts of light/sunshine. In our rush to see snow, ice and freezing temps we are perhaps taking our eye off the real ball here, which is a significant shift in the climate unfolding in our lifetime, not across millennia...very interesting times indeed, with plenty more to come it would appear. That woodshed might need to install air-con before too much longer:D

Edited by coldcomfort
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