Winter Model Discussion 12Z 15/1/13 onwards.

[SMU]

er no murk south east of the m4 with temps well below freezing.....

Also this is now teh chart at T96 where we could see -10c widespread across the south & midlands

with sub -15c in prone areas- benson etc

S

Edited January 16, 2013 by Steve Murr

[IDO]

er no murk south east of the m4 with temps well below freezing.....

S

NAE has temps rising for that weak band Thursday:

[Guest]

the NAE doesn't make sense to my very amateur eye - if you look at thursdays nights weak rain / snow band below the M4 corridor ish it has rain but if yuo look at the 850's on the south coast they are -5 at least and the dew point is -5 so how could that possibly fall as rain ???

The light blue and light pink tend not to give much if any precip, also all the NAE precip charts will show a band of blue round the pink (if that makes sense). It's probably more to do with the precip not being intense enough than anything else.

[jake_83]

er no murk south east of the m4 with temps well below freezing.....

Also this is now teh chart at T96 where we could see -10c widespread across the south & midlands

with sub -15c in prone areas- benson etc

http://www.meteociel...M1-96.GIF?16-12

S

Morning Steve. Interesting how low those temps are....very far from an expert myself but struggling to reconcile such a cold night followed by suggestion of "rain" by MetO in London and the SE on Sunday. Wondered what your thoughts are on that?

[nick sussex]

Morning all

I see the NAE continues to cause consternation, this will not effect snow chances off the main front.

The flow ahead of the front will be east/se as it approaches which if you look at the dew points for northern and ne France supports snow.

After that as you can see from the big changes in the fax charts from T96hrs last night to T84hrs today its still very uncertain.

Some interesting longer range output from the ECM, as long as you get a clean separation of energy from the eastern USA trough then the later ECM output has a very good chance of verifying.

Overall lots of uncertainty in the shorter term, and some interesting potential after that.

[SMU]

I did say SE of the M4 ...

Ukmo says

However when the winds bend just 12 hours later & the main band hits

T60 -06z in the morning

the undercut well in place

& t72

T72 12pm Sat PPn band

snowline WAYYY back towards the SW...

so its a typical event for the SW turning to rain- the rain as Ive highlighted in the westcountry & wales etc-

the NAE MAY end up further east with the snowline ( not to london)- but remember theres no NAE 60 which would bend the isobars back SE-

S

[the lad sharp]

er no murk south east of the m4 with temps well below freezing.....

Also this is now teh chart at T96 where we could see -10c widespread across the south & midlands

with sub -15c in prone areas- benson etc

S

Ah a voice of reason at last. There seems to be a lot of people on here being negative in the face of stunning charts and huge potential.

[Ali1977]

Graphics on bbc so show snow more central and north uk compared to GFS graphics which keep it more central and SW...wonder if bbc graphics have taken any 06z runs into account!

[IDO]

Latest fax for Sat noon:

The front crosses to the east so snow for most. The 528 dam on the M4 corridor. Dew points look good apart from Cornwall:

and uppers ditto:

So snow risk down to sea-level: Apart from Cornwall.

[phil nw.]

A number of posts from through the night have been removed or put into the Ramp/Moaning thread because they added nothing to model discussion.

Please some of you think before posting in here-let`s keep this thread informative and useful in relation to the Model outputs.

Thanks all.

[Severe Siberian icy blast]

Latest fax for Sat noon:

The front crosses to the east so snow for most. The 528 dam on the M4 corridor. Dew points look good apart from Cornwall:

and uppers ditto:

So snow risk down to sea-level: Apart from Cornwall.

I can't see that fax when I go to the fax charts ?? So that to me looks progressive?

[Troubleatmill]

The GEM is quite ridiculous for snow and continued cold out to t240, with low after low diving SE under the block which is going nowhere, if anything building, quite amazing and would result in more snow than any of us have seen before, myself included at 40 years of age. wasnt around for 63 but lots in the 80's and this would be more.

Edited January 16, 2013 by Nick JB

[cyclonic happiness]

I do seem to get the feeling that this cold 'spell' has snuck up on us somewhat, either that or we've just been dissapointed so many times this winter that no-one was really taking any notice??

Anyways, it's a fabulous outlook for snow over the next dare I say 'couple of weeks' as it stands and maybe even a longer cold spell once the SSW kicks in properly.

Friday is looking excellent for the majority of the UK and once that snow falls, I can't see anywhere in the latest runs that would melt it.

Truly could be a classic cold spell (and I've already out-done 2010 with it's poxy 1" of snow, we had 2 1/2" here, 1" of which is still lying).

[Gibby]

Good morning. Here is this mornings review of the 00z output from GFS, UKMO, GEM and ECM for today Wednesday January 16th 2013.

All models show a continuing cold output this morning. The next few days show a cold and frosty spell with some sunshine in the East with some snow showers near Eastern coasts. In the West the weather will be cloudier for much of the time and consequently less cold with some light rain at times with some hill snow. On Friday all models show an active trough moving in from the West with widespread snowfall for many Central areas through the day, turning to rain in the SW later. Many Easternmost areas may not see the snow till late in the day either.

GFS then shows the weekend being one of continued cold weather with further snow at times, especially in the North and East while the SW continue to more likely see rain and sleet rather than snow. Through next week and FI the Atlantic does win through with showers or longer spells of rain rather than snow for many in strong and gusty winds at times too with any cold weather restricted to the far North and Northeast.

The GFS Ensembles show a slow rise in average uppers over the next few weeks but for much of the time but with a large spread later in the run in the South some colder options are shown late in the run as precipitation under Low pressure remains ever present from the end of this week.

The Jet Stream shows the flow strengthening over the Atlantic towards a position South of the UK where it remains for quite a while. There are signs of it wanting to lift North through the Atlantic in a week or so.

UKMO shows the weekend as being cold and unsettled as a trough moving into the UK on Friday disrupts and slips away SE over the weekend. Snow will continue for many into Saturday leaving cold and cloudy conditions into the latter end of the weekend. As we move into next week the model shows a further surge of Low pressure move in from the SW with further snowfall in Northern Britain while Southern areas become less cold and wet at least for a time.

ECM today shows the snow of Friday dying out slowly over Saturday as the energy from the front slips away SE and decays. It would stay cold and cloudy for most areas. By Monday as per UKMO a new surge of Low pressure moves in from the SW with a further area of snow and strong winds moving NE over the UK turning to rain in the South as less cold air moves slowly North. The change is temporary with the cold air flooding back South over the following days with further cold and wintry weather for all before a UK High brings cold and frosty weather to end the run with somewhat milder SW winds in the far NW.

In Summary the UK battleground is set for Friday. Most areas will see some snow and some areas, particularly in Central districts could see a lot with drifting and major disruption for many. Through the weekend and beyond the cold continues its battle over the UK with further snowfall in places, more likely in the North and East while Southern and Western areas see less cold air with rain at times rather than snow. There is still plenty of variability between the models and I have deliberately kept the details on specifics to a minimum as the details can and will change still over the coming days.

[allenar]

I do seem to get the feeling that this cold 'spell' has snuck up on us somewhat, either that or we've just been dissapointed so many times this winter that no-one was really taking any notice??

Anyways, it's a fabulous outlook for snow over the next dare I say 'couple of weeks' as it stands and maybe even a longer cold spell once the SSW kicks in properly.

Friday is looking excellent for the majority of the UK and once that snow falls, I can't see anywhere in the latest runs that would melt it.

Truly could be a classic cold spell (and I've already out-done 2010 with it's poxy

1" of snow, we had 2 1/2" here, 1" of which is still lying).

SSW has already kicked in I recon

[WhiteFox]

Graphics on bbc so show snow more central and north uk compared to GFS graphics which keep it more central and SW...wonder if bbc graphics have taken any 06z runs into account!

6z runs won't be taken into account. They may take note of 6z GFS, but don't make updates until they see 12z runs. I guess they would also look at hi-res output, but again, unless there are big changes they would stick with fax charts and guidance issued following 0z runs.

[weather eater]

I do seem to get the feeling that this cold 'spell' has snuck up on us somewhat, either that or we've just been dissapointed so many times this winter that no-one was really taking any notice??

Anyways, it's a fabulous outlook for snow over the next dare I say 'couple of weeks' as it stands and maybe even a longer cold spell once the SSW kicks in properly.

Friday is looking excellent for the majority of the UK and once that snow falls, I can't see anywhere in the latest runs that would melt it.

Truly could be a classic cold spell (and I've already out-done 2010 with it's poxy 1" of snow, we had 2 1/2" here, 1" of which is still lying).

That’s what you want, not Stella runs in FI, just for a change its seems we are getting up-grades as we approach 0hr and not downgrades. Last night’s runs across the board and this morning’s ECM and GEM runs appear to want to drain the lobe of the PV from Greenland South Eastwards across the Atlantic and the plughole appears to be just SE of UK, could be dramatic.

[swfc]

great mo this morning.just to note the latest bbc forecast has snow pushing well in land friday with heavy falls.ecm looks a cracker this morning and locks everything in place

[mulzy]

Superb output this morning.

This is the ECM day 7 ensemble mean - got a feeling that the operational although pretty good is on the mild side of the whole ensemble suite.

Edited January 16, 2013 by mulzy

[Matty M]

ECM EPS mean further southwest with front at T72hrs

[TEITS]

Stunning set of runs this morning except for the GFS which is pretty rubbish to be honest. Just to highlight the uncertainty here is what the Met O are saying for my region.

"Remaining very cold. A bitter wind developing by Friday with some snow spreading northeast later. Further snow is expected at times on Saturday and Sunday."

This is supported by all the output with the exception of the GFS. This model keeps precipitation to the W and then the cold spell goes out with a whimper. Now my caution is historically either two things happen in my region. We either remain cold and see little snowfall as the fronts are held at bay or we see a brief spell of snow followed by milder weather. What rarely happens is what the UKMO/ECM are suggesting.

Maybe I should forget about the past history and judge the output on its own merits as I often say on here. However until we see agreement from the GFS then I shall remain cautious.

[Wayneywoo]

I think this time round you can ramp it up Fred. As you say, often you get snow to rain as milder air pushes in however, it's not often we have an SSW on our side

I just hope the front gives as much snow to as many as possible while prolonging the cold and not coming too far NW.

To add to the above, the GFS, although it picked up on this cold spell first, has been performing dismally ever since. The UKMO/ECM/GEM combination has been spot on so far...

Edited January 16, 2013 by Wayneywoo

[TEITS]

Without doubt the best ECM mean I have seen so far this winter.

Just to clarify my earlier post. Whilst members are worried about rain or snow my primary concern remains the advancement of any fronts to my region. Still aslong as the ECM continues to suggest this excellent trend then im happy. You can't help but sense that this cold spell could become much colder from the NE towards the end of Jan.

[Methuselah]

Just now, it's hard not to ramp: the charts do rather speak for themselves. When was the last time that the most reliable sources were all suggesting 24 hours' of, at the very least intermittent, snowfall?

And, FWIW, don't be too surprised to find the 06Z a bit of a stand-alone again this morning...

[WhiteFox]

Just now, it's hard not to ramp: the charts do rather speak for themselves. When was the last time that the most reliable sources were all suggesting 24 hours' of, at the very least intermittent, snowfall?

And, FWIW, don't be too surprised to find the 06Z a bit of a stand-alone again this morning...

Yes, delete button at the ready I'm sure! How much further east will the 6z push the mild this morning? I reckon Atlantic back in full control by 72 hours followed by outbreaks of complaining...