Winter Model Discussion - Cold Hunting -12Z 06/01/13

[Troubleatmill]

Come on you big fat lazy lump of High Pressure move northward or dissapear and let the lps track south, anywhere but there !!!

Edited January 7, 2013 by Nick JB

[East Herts Snow]

One thing I am noticing is that GFS wants to introduce an E/NE winds at some stage. However what keeps changing is when it will happen and for how long it will remain in place. On this run they appear sooner, but turns into a Northerly in the longer run.

[swfc]

The area around the tip of greenland is proving a real ball ache regarding the forming of low pressure.the pv will not give way thereon this run at all

[TEITS]

Let battle commence.

The only trend I see in the medium range is the potential for Europe and the US to be in the freezer. Whether this includes the UK I have no idea!

[Weathizard]

GFS trending towards what we've been told is trending on the ECM/MOGREPS then. Not being a negative sausage but its difficult to see how we can get a sustained easterly there, a few days ago it looked plausible but with all the shortwaves being picked up at short range (again) it doesn't look good for longevity! Still its not game over yet, as I said earlier 120 is realistically as far as we should look and we are seeing quite large changes there so post 168 who knows!

[Methuselah]

The nearest thing to certainty I can see is that FI will be colder, as governed by the expected upper-air pattern...The details are academic?

[Timmytour]

The one consistency about the GFS is, the earlier it brings the easterly in, the quicker it evaporates.

[TEITS]

The area around the tip of greenland is proving a real ball ache regarding the forming of low pressure.the pv will not give way thereon this run at all

The only thing I will say about the PV is the models might be good at predicting warming of the Stratosphere but when it comes to how this affects the PV is nowhere near as certain; The PV you refer to over Greenland is thankfully often being modelled just to the W of Greenland. Aslong as it stays on the W side then an E,ly is possible for the UK. However this lobe of PV W of Greenland is causing headaches in my opinion because some runs have this weaker and backing even further W.

Edited January 7, 2013 by THE EYE IN THE SKY

[Nick F]

Well, if it's worth putting much faith in output beyond t+144, 06z GFS seems to follow along the lines of the 00z ECM in showing a strong ridge over the E Atlantic building ahead of a deep trough over the NW Atlantic. This tends to prevent a full-blown easterly developing unfortunately.

Ideally you want low pressure to the SW to get a prolonged easterly, instead shortwaves are sliding SE across the UK, thanks to high pressure to the SW.

Edited January 7, 2013 by Nick F

[Frosty.]

I reckon we would now have to be extremely unlucky to miss out on some kind of cold spell, the models are showing very wintry weather evolving over the course of the next 7-10 days, the gfs and ecm take different routes to get there and the gfs 00z in particular has some astonishing FI charts which are even better than we had during that dec 2010 freeze, it shows the dramatic effects of sudden stratospheric warming very clearly. This week starts mild, temps of 9-12c today, similar tomorrow but then colder from midweek with frosts becoming more widespread, then by the end of the week and especially by early next week, it could be turning much colder with an increasing risk of snow and severe frosts as bitter cold air spreads in from the east or northeast. After the dross we had over christmas/new year, the models are making up for lost time. Unlike last time when the models were teasing us with a potential freeze, the background signals are far superior this time around.

[nick sussex]

It looks like a shortwave will develop and head around the periphery of the Azores high before travelling se/s towards the UK.

This seems to be the latest trend from the GFS. So if this happens then its really the track into the UK re how far west/east that will determine any snow potential.

We'll see how long this trend lasts this evening!

[bluearmy]

well each run does little to clarify anything. the 00z gfs op trended blocked atlantic in fi. the 06z trends mobile. the inconsistency remains the only consistent ! would be nice to be able to place faith in the anomolys at least. big sympathy for ian and those pros who HAVE to make a forecast. the rest of us can watch and enjoy the ride !

[UV-RAY]

Let battle commence.

http://modeles.meteo...snh-0-264.png?6

The only trend I see in the medium range is the potential for Europe and the US to be in the freezer. Whether this includes the UK I have no idea!

Looks similar to what was being modelled in December to me, with all hope of the low pressure sliding under the block and we all know what happened then.

[Timmytour]

While I don't think the 06z GFS run is particularly bad, in view of how it compares to the 0z, I'm making a Steve Murr-like decision to bin it!

[Catacol]

I am still an anomaly junkie - all this op run analysis just makes my brain sweat.

8 day anomaly is still very good:

[Methuselah]

Personally, detail-wise, I'd bin them all after 7-days' or so...

[tight isobar]

Good morning all. New to the net forum, well gfs6z continues to show a colder scenario for uk although seems to now want the cold,(colder!) To our green pleasant land earlier, however with current happenings i,e strat warm, Its only logical outputwill throw out EVO, with wild swings and the like. Personaly im interested in what the 18z will throw up, as i feel by then we may start to see a more positive, start tocross model agree??,i may well be wrong in that suggetion though, but feel with current will start to clasp the upcoming potential cold, that to my eye is ALMOST now certain, whats lesz certain is how prolonged thingscould end up. Again be interested from my gore from 18z onwards...lets see,regards.

[pyrotech]

Caution is the word of the day

the mogreps says westerly influence and Ecm. moving in that direction.

That does not mean game over,but is a warning as mogreps was first to ut us zonal rather than cold five weeks ago. i hope its wrong but this has possible issues for areas where water table is still high as we could repeat that pattern. i am not being negative just realistic. To much inconsistancy at the moment but right now the new trend is wrong way, but that can change. Mogreps later and 12z Ecm will hopefully change the trend.sorry done this on phone

[Met4Cast]

I'd like to bank the CMA please

http://www.meteociel.fr/modeles/cmae_cartes.php

[bryan629]

Monday 7 January—Sunday 13 January

Turning chilly

This week starts with high pressure to the south of the country, allowing southwesterly winds to bring mild, moist air from the Atlantic. By Tuesday a cold front brings brighter but cold conditions with frost by night. The end of the working week looks likely to bring unwelcome rainfall to the southwest at times.

By the weekend the forecast become trickier. Some computer models want to build high pressure to the north of the UK which would lead to northeasterly winds bringing much colder air feeding across the country. This would mean the likelihood of some wintry showers. Alternatively some models suggest that the winds will come from the southwest, bringing Atlantic weather systems and a return to milder conditions.

At the moment the first scenario is perhaps the most likely but the development of these scenarios will be closely monitored throughout this week.

Monday 14 January—Sunday 20 January

Rather cold perhaps?

As we head into the second half of January, the uncertainty in the forecast is greater than normal. At the moment it looks most likely that high pressure to the north of the country will dominate, with easterly winds continuing to feed cold air across the UK.

This set up would probably bring bright but colder than average conditions with overnight frosts. Further wintry showers would also develop, especailly in the north and east. Milder, wetter conditions might affect the south and west at times.

Monday 21 January—Sunday 3 February

Staying cold?

The uncertainties in the forecast continue through to the end of January although the colder trend still looks the most probable scenario. This could continue to bring temperatures lower than would typically be expected at this time of year, with a higher than average chance of some wintry weather.

Edited January 7, 2013 by bryan629

[EML Network]

There's not too much to add that hasn't already been said, the 06z is yet another variation and would start to bring snow to the North as early as Friday night / Saturday morning.

thereafter it's all too close for my liking with the UK always being on the boundary line between cold and milder air, and on this run the REALLY cold air seems to somehow filter out of Europe, not over keen on thus run, but it's still another one trending toward a decent cold shot and snow potential...so overall one can't really complain

[Nick F]

It looks like a shortwave will develop and head around the periphery of the Azores high before travelling se/s towards the UK.

This seems to be the latest trend from the GFS. So if this happens then its really the track into the UK re how far west/east that will determine any snow potential.

We'll see how long this trend lasts this evening!

Yes, tricky for any model to predict this far off with any accuracy the low progged to drop southeast this weekend, needs close watching though, as there's potential for snow on its northern flank based on current parameters for snow to fall.

After the weekend, If we didn't see that pesky high building up from the Azores, ahead of that deepening trough off New Foundland, then I would be more confident on deeper cold setting in from the E or NE, But it gets rather messy after the end of this week, with a ridge building over Scandi and a ridge building NE from the Azores along with a strong equatorward jet edging east on the eastern flank of the Azores ridge - which will bring further shortwave energy down from the NW across the UK.

All getting rather complicated, why can't we have a straightforward easterly!

Edited January 7, 2013 by Nick F

[mountain shadow]

Im liking the anomaly charts, it would good to see them better manifested in the models!!

[Coast]

Good morning all. New to the net forum,

Morning TI and welcome to the forum with that first post. Could you pop your location in your profile for us please?

[Frosty.]

ecm looking pretty rank to be fair

We must be looking at different versions of the ecm, the 00z looks very nice to me.