Model Output Discussion - 14th Jan 12z Onwards

[Summer Sun]

Much cold air coming in at t192 and t216 on the easterly flow as Helen Willetts said this could be our coldest spell for 2 years

 

 

 

 

As we saw in 2010 the north sea could bring quite a bit of snow to the eastern side

 

Edited January 14, 2015 by Summer Sun

[Djdazzle]

We all know about ECM and its easterlies! Caution advised!

[Mucka]

Well ECM has something for everyone and the SE would be happy with anything like this I'm sure.

 

[Neilsouth]

We all know about ECM and its easterlies! Caution advised!

 

This! And -5 uppers isn't that good, -10 gives a more accurate telling for snowfall

[chris55]

ECM 168, much better than the 00z. Just need to "split the kipper" lol. With a lightly less deep "slider low" at 144, but still digging South East allowing the easterly flow to kick in.

 

[West is Best]

Quick technical question or two: anyone else not getting the GFS 850hPA's on here? And I take it the wetterzentrale source that is still showing tabs for both GFS and GFS Para, the Para is the new op?

 

Also where are folks sourcing their UKMO? Wetter and Meteociel don't seem to be playing ball?

 

Right, that aside these look great runs again. I love the way the ECM evolves. There is bound to be some dicing but I'd much rather have this situation with snowfall in places than not gamble and have a bone dry easterly or, indeed, westerly muck.

 

Oh, and Steve, well done for saying 'BOOM.' I was wondering who would be first to dare after the thread opener about it

Edited January 14, 2015 by West is Best

[Pembroke Dangler]

Belting E,ly at +192 from the ECM.

 

http://www.meteociel.fr/modeles/ecmwf/runs/2015011412/ECM1-192.GIF?14-0

 

I see some are focussed on where it might snow. Honestly do not waste your time at the moment. In all my years of following the weather I don't recall one time when a slider LP has bought snowfall to my location. Just watch how nearer the time the slider will be modelled to be further W.

My thoughts exactly, i think the rounder low is the problem at 144 but the result is the same with that raging eastelry in coming would feel pretty raw by 192 looking at that!! Westward corrections will come over the next few days and the low will be less deep and more sqaushed looking compared to tonights ecm

[Mucka]

This! And -5 uppers isn't that good, -10 gives a more accurate telling for snowfall

 

In an Easterly? Even a NW only needs -6, -7 for snow to low levels. With a continental flow, where the continent has entrenched cold, you can 850's of -1, -2 and get snow.

Edited January 14, 2015 by Mucka

[Neilsouth]

In an Easterly? Even a NW only needs -6, -7 for snow to low levels. With a continental flow, where the continent has entrenched cold, you can 850's of -1, -2 and get snow.

 

I can't remember that many convective snow showers from uppers of -2, many great falls have been between -8 and -10. Unless you want a sleety north sea mix

[ukpaul]

It's the 120-144h transition, the slider low looks likely to elongate but it barrels through intact to sit over France/Iberia, creating an inevitable easterly. I tend to think that, as per other models, that low will elongate and disrupt more creating further sliders but the quick easterly is plausible. It'll be interesting to see what the ECM ensembles show.

[weather_it_will]

ECM @ T216 would give snow across the midlands

 

-8C  850's Nationwide, even -10 in some places

 

[Cloud 10]

We all know about ECM and its easterlies! Caution advised!

 

I'm already thinking about a possible Northerly after the possible Easterly which is a pretty common synoptic pattern.

 

[nick sussex]

There are two choices here. If you're going to get the blown up low like the ECM then you don't want it to head south too far west, this will drive too much milder air into mainland Europe.

 

If its a shallow feature that moves se then that's less of a concern, so I'm afraid its a case of perhaps suffering a short less cold interlude before the low has tracked into the Continent.

 

Preferably I'd prefer to see the shallower feature because theres always that concern that the ECM low might fill and becoming slow moving too close to the UK.

[Mucka]

I can't remember that many convective snow showers from uppers of -2, many great falls have been between -8 and -10. Unless you want a sleety north sea mix

 

Ah right fair enough. Convective snow showers helped with very cold 850's certainly but in a strong flow like ECM there would likely be embedded troughs within anyway.

 

That and the 850's are pretty cold as well.

 

 

All pie in the sky though for now.

Edited January 14, 2015 by Mucka

[SMU]

But Steve how many times has this been shown on the models in previous spells, it very rarely happens. At most it moves off to the east, or fills in situ. I just don't see that happening tbh. Look what happened last time! Low pressure forecasted to dive into france, instead it moved to the east and it rained

Yes, but previous form isn't a precursor of future form..... look at 2009. 35 Cm of snow in Bexley from the easterly...

 

ECM 240 is out. Still bitterly cold but the cold starting to break up at that point- lucky its 10 days!

 

S

[Man With Beard]

GFS - Easterly bias.

 

UKMO - Further West than GFS

 

ECM - Further west than GFS and UKMO

 

I'd say given the above, the trend is definitely for the low to be further West than the GFS currently projects.

That's the trouble with the UK and cold low pressure, we don't want it too far west or too far east, we need it to be JUST RIGHT! Its painful to watch - is that what keeps us coming back for more??

Cold looking good from D2-D5. That's a good start at least. Such a turnaround from 5 days ago on the op runs.

[fergieweather]

In an Easterly? Even a NW only needs -6, -7 for snow to low levels. With a continental flow, where the continent has entrenched cold, you can 850's of -1, -2 and get snow.

Yes, often folk take the 850hPa prognosis too literally. Chilled continental boundary layer critical.

[shaky]

I personally think the ecm is a snowfest for midlands north!! The -4 line hovers around the area for 48 hours so i assume a band of snow would lie across central england until the colder air sweeps south a day later! !

[Bristawl Si]

So, genuine Q here -

Does the possible slider low scenarios that were shown for the v early part of next week now look somewhat off, so to speak, because the system diving south on Wednesday is now too far West for us in the South?

[frosty ground]

Plenty of uncertainty on how this will unfold, some x-rated, so no done deal yet. The op looks one of the best solutions for snow even amongst the cold ones so we have to hope the ensembles start moving in that direction, otherwise...

 

The control although cold is much drier: gens-0-1-240 (1).png

 

So D5 still remains the FI and although general cold looks guaranteed for 7 days plus from Friday (22% go milder at D5 due to a brief mild sector) what happens next remains very fluid.

You talk of day 5 but post a chart at day 10

[West is Best]

Presumably no-one else can get the GFS 850hPA on here? Paul if you're around, any thoughts why that is? And also if anyone knows which of the wetter tabs (GFS and PARA) is actually the new operational Para I'd much appreciate it. Course, if you're too busy wondering if it's going to snow in Little Missenden next week then I quite understand.

Edited January 14, 2015 by West is Best

[nick sussex]

The turnaround in the UK's cold fortunes is mirrored by the pattern in the USA. Initially the fast zonal flow was expected to set in with the cold lifting out for most of the CONUS for the rest of January.

 

Whats essentially happening is a re-amplification of the flow after a very short flatter period, the east Pacific ridge is set to return, now earlier in the winter this came with an angry PV which kept throwing out low pressure and a super fired jet determined to blast away any blocking.

 

The PV is not as strong as then and so any blocking has a better chance of surviving.

 

The upstream pattern for the critical timeframe when we're hoping to see a ne/e flow after the initial brief northerly is condusive to delivering that however there are some details that at this range are impossible to determine, ie exactly how that transition occurs.

 

At this point in terms of cold opportunities the window of opportunity has been flung wide open and I have everything crossed that the weather will deliver what people in this thread fully deserve for having had to put up with a generally underwhelming first  half of winter and a dismal last winter.

 

If the time and effort and interest shown by members was properly rewarded then at least ten days of good snow and cold is the least that the weather Gods should deliver.

 

So lets hope they do, or are generous and add a bit more to that!

[Great Plum]

Presumably no-one else can get the GFS 850hPA on here? Paul if you're around, any thoughts why that is? And also if anyone knows which of the wetter tabs (GFS and PARA) is actually the new operational Para I'd much appreciate it. Course, if you're too busy wondering if it's going to snow in Little Missenden next week then I quite understand.

Richard, I think it's

http://www.wetterzentrale.de/pics/Rgfs1442.gif etc

[Geordiesnow]

GFS - Easterly bias.

 

UKMO - Further West than GFS

 

ECM - Further west than GFS and UKMO

 

I'd say given the above, the trend is definitely for the low to be further West than the GFS currently projects. 

 

You can't compare the 2 runs though because they are different in how they are dealing with the slider, the GFS looks quite risky too me whilst the ECM is the more 'safe' option. 

 

I have not seen any trends of a west based NAO either and positioning on any potential slider low will be open to quite a bit of doubt but this is part of the drama of model watching because no 2 runs will be exactly the same. 

[ANYWEATHER]

Presumably no-one else can get the GFS 850hPA on here? Paul if you're around, any thoughts why that is? And also if anyone knows which of the wetter tabs (GFS and PARA) is actually the new operational Para I'd much appreciate it. Course, if you're too busy wondering if it's going to snow in Little Missenden next week then I quite understand.

Same here on the 850s