General Model Output Discussion

[Cecil Hogmanay Melchett]

Yes, been a big thaw going on here since yesterday evening, I'd say we have now lost half of our original snowcover - which stood at 15cm.

UKMO 12Z certainly turns the UK much milder by the end of the week:

http://www.wzkarten.de/pics/Rukm961.html

http://www.wzkarten.de/pics/Rukm1201.html

http://www.wzkarten.de/pics/Rukm1441.html

At odds with GFS somewhat, but I'd think the milder air will win out for most by the week's end.

sorry i should have said many places seeing big thaws some places seeing slight thaws.

UKMO is really poor Paul,i hope its being too progressive.

[snowingtequila]

We need to be realistic here.This cold spell is at an end.Massive thaw going on today with a 1040mb scandy high and a contiental feed.

Anyone else noticed the AO/NAO profile in a weeks time,looks very very positive to my eyes.why is this happening i thought it was supposed to be negative!

please direct me to the model that shows the cold spell to be at an end because all I see is an end to intense cold and still generally below temperatures with some snow as well. I am surprised you have such a massive thaw all it is doing with me is getting wetter on the ground and compacting more because of this, very slow thaw I would say and only on lower ground. The killer if there was one was the upper warm front from the east, a very sneaky move by the atlantic.

corrention, I have just looked at meto and that does suggest pretty mild on the way, apologies

Edited January 10, 2010 by snowingtequila

[Winter Monsoon]

We need to be realistic here.This cold spell is at an end.Massive thaw going on today with a 1040mb scandy high and a contiental feed.

Anyone else noticed the AO/NAO profile in a weeks time,looks very very positive to my eyes.why is this happening i thought it was supposed to be negative!

Not thawed much hear and im not that far from you. Model showing ppn getting further east, However the question remains will it remain as snow or turn to rain?

[Optimus Prime]

Looks to me odds on for high pressure to retreat slowly into the continent allowing a more westward progression of low pressure and rather unsettled in the west with rain and hill snow around late next week. Rather drier in the east with a few showers thereafter into the weekend. Intitially very cold for the east with a temporary pickup of continental air nbut more transitional later on.

I really can't wait to see the back end of this. It was ok for a few days but then gets utterly boring. Shame this isn't February or we could be looking forward for the next 20c

[PB22]

GFS operational 12z run is one of the colder options on the table, so I think we all know where we will be headed during the week and that is to much milder conditions for many areas.

Its something when a chart like this is bringing 2C and a steady thaw to this part of the world in January:

http://www.wzkarten.de/pics/Rtavn001.html

http://www.wzkarten.de/pics/Rtavn002.html

[swfc]

GFS operational 12z run is one of the colder options on the table, so I think we all know where we will be headed during the week and that is to much milder conditions for many areas.

Its something when a chart like this is bringing 2C and a steady thaw to this part of the world in January:

http://www.wzkarten.de/pics/Rtavn001.html

http://www.wzkarten.de/pics/Rtavn002.html

Good post and shows how quick the cold air is soon gone even given a great chart like that

[Cecil Hogmanay Melchett]

GFS operational 12z run is one of the colder options on the table, so I think we all know where we will be headed during the week and that is to much milder conditions for many areas.

Its something when a chart like this is bringing 2C and a steady thaw to this part of the world in January:

http://www.wzkarten.de/pics/Rtavn001.html

http://www.wzkarten.de/pics/Rtavn002.html

those charts look brilliant dont they paul.

What on earth is causing all the melt higher dews etc? We are under -7 / -8 uppers and a great big scandy high!!

Im with you i know where this is going paul if we are getting sleet/rain/snow under this setup it doesnt imspire hope for the rest of the week.

still,for all of that its been a brilliant cold spell since mid december here and im happy with how the winter has gone even if it goes rubbish from now on.

[swfc]

GFS operational 12z run is one of the colder options on the table, so I think we all know where we will be headed during the week and that is to much milder conditions for many areas.

Its something when a chart like this is bringing 2C and a steady thaw to this part of the world in January:

http://www.wzkarten.de/pics/Rtavn001.html

http://www.wzkarten.de/pics/Rtavn002.html

Good post and shows how quick the cold air is soon gone even given a great chart like thatJust to note we also have quite a thaw now taking place with rain and sleet.

[Optimus Prime]

Its something when a chart like this is bringing 2C and a steady thaw to this part of the world in January:

http://www.wzkarten....s/Rtavn001.html

http://www.wzkarten....s/Rtavn002.html

We all know the reason for that. We've used up the cold pool and hasn't been refuelled from the NE. Happened many times in the past where it was initially cold but progressively turned wet despite the air originating from the same place that was giving the extreme cold.

Countless times in February 1986.

[peterf]

2.2c here and the snow and icicles are vanishing fast.thats a major thaw to me. considering wev'e had major ice and snow cover for over 3 weeks.

[Guest North Sea Snow Convection]

No way of knowing what is going to happen beyond mid week. UKMO looks way too progressive and contradicts the GFS. Ensembles will be pretty useless in this sort of situation so little point in looking at them imo.

At the very least, any atlantic encroachment should be temporary as there is every indication of the Scandinavian block reasserting itself very quickly. The models are not going to handle that issue very well - hence the suspicions about the poor and over progressive UKMO. Some dry weather (still cold) would be appreciated actually with frost and winter sunshine. On that basis hopefully high pressure will win out.

Edited January 10, 2010 by North Sea Snow Convection

[Ben_Cambs]

I dont expect a prologned mild spell IMO. The currently -NAO is expected to return to average, and there are signs that a negative NAO could return soon after. This chart shows the change:

[Solar Cycles]

2.2c here and the snow and icicles are vanishing fast.that's a major thaw to me. considering we've had major ice and snow cover for over 3 weeks.

Some have had a thaw, some haven't. Too much whining going on in here, for me still looks cold in the reliable time frame. Looks good IMBY for Wednesday, off course this can and probably will change!

Sorry Pete, that wasn't meant for you!

Edited January 10, 2010 by Solar Cycles

[MR EXTREMES]

UKMO is quite progreesive, I doubt if the ECM will back that scenario.

i dont think ecm will back it either.

we had great event this year but im somewhat confused how this thaw has happened even when the alantic mild air has not reached us.

i think by tomorrow there wont be much left in the south.

as for wed turs event i dont expect anything wintry down here now after todays thaw i think some may be dissapointed with a breakdown but it does go to show the models are not useless even the gfs.

where events will happen is up in the air.

i also think it will be milder than what some maybe thinking unless your north of the m4 but even around th coast around the uk i dont think it will be as cold so thaws becoming more widespread through the week.

higher ground will always fair better in holding on to colder air and snowcover,

i really cant say this is a 63 type setup it was much colder in 63 with overall global temps being cooler and sea temps lower aswell.

i think the upper air temps are to blame for todays letdown in some parts of the country infact catching out the meto aswell,

i also think its silly to have warnings for some much of england for wed but im sure thease will be changed in a dramatic way come mon evening.

ecm most like will still prog mildish,

i think but the idear of a major snow event this week from the alantic unless the low pushes right in is a none runner.

but all the same there are background features that could happen which may help for this mildish to not stick around for to long.B)

Edited January 10, 2010 by badboy657

[swfc]

We all know the reason for that. We've used up the cold pool and hasn't been refuelled from the NE. Happened many times in the past where it was initially cold but progressively turned wet despite the air originating from the same place that was giving the extreme cold.

Countless times in February 1986.

Strange that the meto didnt pick up on that fact last night.???.

[Michael Winston]

The degree of childishness from one or two people this winter has taken my breath away even more than the extreme cold. There has been complete disregard for wise and experienced posters; the actual conditions; the national perspective and finally what the models are really showing.

Well said, WIB. As a frequent reader and infrequent contributor to the model threads, I , like yourself, get very frustrated with this attitude.

My take on this week, after a quick shufty at the fax charts, is that we are in for an interesting week, not least because I live right on Steve Murr's* imaginary line!

Thanks, as always, to the experienced posters (you all know who you are!).

Kind regards,

Mike.

*Edit: Apologies. That should be Nick F.

Edited January 10, 2010 by Winston

[West is Best]

I think the thaw in your part of the world may have something to do with the warmth of the North Sea impacting further inland than would normally be the case ?

Yep it's all down to the still relatively warm North Sea. That's why it was colder and more snowy the further west you went today.

But I give up.

[rich1]

A lot of discrepancies in the output, I think as for what happens midweek onwards is a coin toss, a lot of divergence from very early on so nothing ca be taken as read

in all honesy I suspect a lot of the 'cold spell over' postings hae been from those in areas that got more of a thaw today i.e. the north east and eastern coastal counties...just a hunch

this is an old skool winter with old skool battleground scenarios which tend to be inconsistently modelled and forecasted. Todays thaw in some areas was due to a influx of warmer uppers which isnt that unusual, and not from a creeping atlantic incursion which some people seem to think it is

[Snowyowl9]

sorry i should have said many places seeing big thaws some places seeing slight thaws.

UKMO is really poor Paul,i hope its being too progressive.

Had a little freezing snizzle here this afternoon froze on contact,back to snow now relief.

UKMO just got tired of this cold spell and wants to boot it off,that won`t happen.

[Altostratus]

those charts look brilliant dont they paul.

What on earth is causing all the melt higher dews etc? We are under -7 / -8 uppers and a great big scandy high!!

Im with you i know where this is going paul if we are getting sleet/rain/snow under this setup it doesnt imspire hope for the rest of the week.

still,for all of that its been a brilliant cold spell since mid december here and im happy with how the winter has gone even if it goes rubbish from now on.

The Feb 05 spell contained even better charts synoptically. The problem with that spell was that there were no cold pools to tap into. Pockets of cold air were present this time, however, this has mostly been mixed out now. Indeed, warmer air is starting to be drawn in from the Greece/Turkey region. Also, the curvature of the isobars hasn't been favourable from the outset, with a greater sea track and extended contact time. The resulting air mass gets modified to a greater extent as a result. This is no doubt a contributing factor; particularly as it is early in the winter and the sea temperatures are still cooling. How signifcant a factor it is, is difficult to say.

[swilliam]

It seems to me that as well as the size, depth and position of the 1st low there is 2nd one which has an influence on whether the block is preserved to our NE.

Looking a the GFS this small SW can be seen which heads into France and then the Med. This helps support the block and means in the end it sits at a more Northerly latitude

In comparison the METO model does not have this feature (as well as having the deeper and more Northerly 1st low - this couldbe whty the 2nd low does not appear.

The result is pretty near the end for the block in the medium term with WAA going NE rather than N or NW.

The GEM model has the feature and ends up with a HP of 1045 in S Norway.

JMA has the feature (slightly delayed) and also the best block in the end

GME is similar to the UK Meto but the block is better preserved.

It will be interesting to see what the ECMF shows. It seems the general pattern of a block to our E and an Atlantic trough sending depressions up Northwards and inducing ridges near us and amplifying the block is agreed by most of the models. Whether we are cold or not will depend on the E/W position of the block and the trough.

Sorry for all the charts - I guess you could look for yourselves if you are interested..

Edited January 10, 2010 by swilliam

[ian34]

i think it is fair to say that the big freeze of the last 21 days is over as we have known it we should be thankful for what we have recieved thus far and look forward to further scenarios this winter is far fro over!

[snowlight robbery]

Country file just begun, get ready to watch forecastor conducting most UNENVIABLE job in the world!

[Duane S.]

I can't see from your details whereabouts you live, so am assuming from your post it's probably somewhere like the Canary Isles or perhaps Marrakech? Am I close? Here in the hitherto mild hinterland of north Devon we had 10-15cms of snow overnight and this morning, and it hasn't stopped sending down flakes of snow all afternoon.

As for the 12z GFS run, well that most certainly is not an end to the cold spell. From that run there are still -5C 850hPa uppers appearing a week hence. The sort of extremely low temperatures we have experienced could not last all winter, but that a thaw does not make.

The degree of childishness from one or two people this winter has taken my breath away even more than the extreme cold. There has been complete disregard for wise and experienced posters; the actual conditions; the national perspective and finally what the models are really showing.

Great post again WIB. I think some should use me as a benchmark every time they want to throw a hissy fit about a thaw (we live in the UK not Siberia, thaws happen). I have probably received a massive 1 level cm of snow from this entire winter up to date. Despite that I manage (hopefully) to post in a constructive manner about the charts that I see.

I am not saying I am any sort of expert but when I see some much more experienced members posting such negative dross because we are coming into a well forecast warm(er) period it is annoying at best.

The ensembles have been telling us for at least a week that the VERY cold uppers will be heading away from our shores, forecasts have backed this up recently, charts in the interim have (with their usual wild flucations) shown this too.

Rather surprisingly the METO is more progressive than the GFS tonight, ECM coming out soon so that will be interesting.

As for Tuesday. seriously, who knows? The METO doesn't, I don't and nor does anybody else. Heavy PPN is likely, the SW likely to be hardest hit but whether it falls as rain or snow we will have to wait and see..

[mushymanrob]

looks like my scepticism was proven right... theres hardly any snow left here as temps have risen above 0c, i see nothing in the models that suggest a return to freezing... just 'normal' cold. in my locale attacks from the southwest often ammount to nothing snow-wise as milder air is nearly always shunted ahead of any fronts. freezing continent or not, temps have risen.