Model Output Discussion 18th Nov.2013-12z onwards.

[Panayiotis]

I think a nice FI is coming!! Depends on this low leaving the US.... will it ridge sufficient heights towards Greenland? The PV seems to move quite quickly from the Greenland area between 180hrs and 204hrs:

 >>>>>>>>>>> 

Edited November 25, 2013 by Panayiotis

[Matty M]

Yes an interesting FI coming up here, consistent theme with that Alaskan ridge.

 

However still so far out to bear much reliance on. Although nice to see

[Cloud 10]

Looks like a mortal monday for the pub run. 

 

[Cheshire Freeze]

Evening all, been in work all day but have come back to see things are progressing nicely......I see the doom and gloom merchants from the other day are slowly being silenced. There have been signs that there was everything to be pleased about 2 days ago and that momentum seems to have gathered pace today within the NWP modelling (now coming into the day 9 and 10 range). Of course, as Nick Sussex has pointed out, there are hurdles to overcome and cold is not guaranteed (as it never is with the UK climate) but we have a good shot at something wintry developing within the next 2 weeks.

 

GFS 12z ensembles very encouraging.

Edited November 25, 2013 by CreweCold

[Panayiotis]

Scandi high with an undercut to end the run? Would be very nice run if it occurs....

Edited November 25, 2013 by Panayiotis

[Panayiotis]

Scandi high but no undercut to end the run but im very pleased, one of the best runs of the season! However it is another story whether or not it verifies!

Edited November 25, 2013 by Panayiotis

[Cheshire Freeze]

18z ensemble mean around day 9........awesome

 

 

850s trending cold at day 10

 

Edited November 25, 2013 by CreweCold

[Downpour]

18z ensemble mean around day 9........awesome

 

Some decent charts now appearing in the middle timeframe, good to see as the days shorten to the annual minima and winter beckons.

[Joe Levy]

This set does not disappoint! Continuing on the theme of the 6z and 12z, the ensemble mean 850hpa temps show the -4 line reaching the Bristol Channel again!

[Cheshire Freeze]

Nice control run too

 

 

[draztik]

Agreement between the 2 main ensembles this evening, encouraging.... especially because the trend has been there for last few days.

 

t254 / Naefs, & ext ecm ens 12z

Edited November 25, 2013 by draztik

[Mucka]

A couple of stunners, notably 1 and 14 for my region especially but mostly topplers in FI, some with reload potential some with zonal potential.

Overall the signal for the pattern change continues to strengthen but no way to know how that will play out yet.

[Cheshire Freeze]

A couple of stunners, notably 1 and 14 for my region especially but mostly topplers in FI, some with reload potential some with zonal potential.

Overall the signal for the pattern change continues to strengthen but no way to know how that will play out yet.

 

Ensemble 14.....Us in the NW would be digging ourselves out

 

[Downpour]

A couple of stunners, notably 1 and 14 for my region especially but mostly topplers in FI, some with reload potential some with zonal potential.Overall the signal for the pattern change continues to strengthen but no way to know how that will play out yet.

I can only be a matter of time before certain members "urge caution" - but calling a cold spell is what it's all about...

[SMU]

I think some of us pointed out the potential stemming from the Aleutian high around 2 days ago.

Its not all plain sailing as the road to sustaining something more than a typical 2 day northerly is the aleutian high cutting across the pole to support the atlantic ridging to the max and whilst the models have firmed up on the development of this high there is to much interun variability to be to confident just yet-S

[Joe Levy]

http://www.meteociel.fr/cartes_obs/gens_display.php?ext=1&x=190&y=179 Exeter ensembles. Other than a freakish technical fault showing temperatures plummeting off the edge of my computer screen, the ens are slowly clustering towards the colder side of the spectrum, which is good. Not only are we getting colder runs, but now we have a bit more agreement as well which is always helpful. But still, it's in FI and is a trend that needs watching

[Cheshire Freeze]

I think some of us pointed out the potential stemming from the Aleutian high around 2 days ago.Its not all plain sailing as the road to sustaining something more than a typical 2 day northerly is the aleutian high cutting across the pole to support the atlantic ridging -S

 

 

Brilliantly put Steve. As I said, the potential has been there to see for a little while.

[Paul_1978]

Is it just me or are things looking similar to Jan/Feb 1984?

[Mucka]

Brilliantly put Steve. As I said, the potential has been there to see for a little while.

 

About a week I'd say.

 

18z ensembles (each set has trended colder than the last through today, be great to see that continue tomorrow)

 

http://www.meteociel.fr/cartes_obs/gens_display.php?ext=1&x=257&y=72

Edited November 26, 2013 by Mucka

[Captain Shortwave]

About a week I'd say.

 

18z ensembles (each set has trended colder than the last through today, be great to see that continue tomorrow)

 

http://www.meteociel.fr/cartes_obs/gens_display.php?ext=1&x=257&y=72

All we need now is for this to continue and not go backwards as the spell hits day 5-7 in the output. Hence why I'm not getting excited yet. Simply put, why is this any different to the last 2/3 times when we could have had a proper high latitude block set up.

 

Edit - I will find an appropriate (grumpy old cynical man) avatar tomorrow.

Edited November 26, 2013 by Captain shortwave

[Gaz1985]

Is it just me or are things looking similar to Jan/Feb 1984?

 

Haha we've had so many comparisons the past 2 weeks, first it were November 2010 then December 1981 and now Jan/Feb 84

[Gael_Force]

Evening all, been in work all day but have come back to see things are progressing nicely......I see the doom and gloom merchants from the other day are slowly being silenced. There have been signs that there was everything to be pleased about 2 days ago and that momentum seems to have gathered pace today within the NWP modelling (now coming into the day 9 and 10 range). Of course, as Nick Sussex has pointed out, there are hurdles to overcome and cold is not guaranteed (as it never is with the UK climate) but we have a good shot at something wintry developing within the next 2 weeks.

 

GFS 12z ensembles very encouraging.

 

The trend has been there longer than that - especially so from the UKMO

 

[Catacol]

Time for a quick post before sleep. Agree with assessment of polar air back in the mix once the current settled spell comes to an end but not seeing anything remarkable yet. A number of different charts pointing to a similar theme but this one from the NOAA is as good as any:

 

 

 

Mid atlantic ridge rebuilding and NW to N air flow on the horizon. However the chances of this turning into a major outbreak are small. The high is likely to be flattened again though not before the north has had a good opportunity for more snow especially at elevation. For the south its a possibility... but if so it looks transitory.

 

IanF update shows MetO sees the W to NW and back to W air flow as likely for a while too. However I must admit I was pleasantly surprised by the contingency planning post put out by the Met that I had missed before SS posted it. I have plumped for a below average winter overall with the core of the cold from mid Jan to mid Feb - but I did not expect a 20 - 25% probability of the overall temps falling into the most severe (20%) category. I know the odds are still against it - but it smelt ever so slightly of a gentle MetO ramp moment. :-)

Edited November 26, 2013 by Catacol_Highlander

[Gibby]

I can see nothing other than transient cold wintry showery NW type air flows alternating with milder sometimes wetter interludes. The atmospheric pattern is is not right for anything other than transient cold for the UK for the forecasted period from anything I've seen tonight including the 18z and certainly nothing to oil the blades of the sledge yet.

Edited November 26, 2013 by Gibby

[Matty M]

There is always potential in the chart for most synoptics, sure we have 20 ensemble members in the GEFS, 50 members in the EC suite  and plus a whole host we can use as a multi-model ensemble.

 

 

I think some of us pointed out the potential stemming from the Aleutian high around 2 days ago,

Its not all plain sailing as the road to sustaining something more than a typical 2 day northerly is the aleutian high cutting across the pole to support the atlantic ridging to the max and whilst the models have firmed up on the development of this high there is to much interun variability to be to confident just yet-

 

S

 

 

 

 

This is a fluid situation and at present there is a heightened risk of a cold outbreak from day 10 but that is it, a potential outcome, just slightly more favoured than other scenarios presented on the ENS. Further to that its length etc hasn't even been considered at this point but i can't find too many members supporting a prolonged outbreak.

 

However we all know that weather prediction at that distance is extremely difficult and the truth is that any outcome is possible.

 

I just like you hope it is a bitterly cold and snowy one! but we just don't know! Let's watch it develop, speculate etc.. but let's not start picking on past posts and trying to get one up on other people as if we were to pick through historic points of view etc, i am sure a lot of people on here would be red-faced including you .

Edited November 26, 2013 by Osbourne One-Nil
You thought that was ok?!