Model Output Discussion

[Guest North Sea Snow Convection]

The very gradual trend towards an eventual possible very end of season cold easterly is continuing in the modelling. GEM and UKMO on the 12z's this evening have both continued to show the phasing of the southerly tracking lows taking place,half inch by half inch, further south. This would be noticeable if one compared the models now to a couple of days ago.

With the very surpressed jet stream continuing with no sign whatsoever of that changing, plus further disruption to the energy circualtion in the NH with further negative zonal anomalies depicted to support blocking more in our own locale, rather than western Greenland, then it is only a matter of time before the -NAO signature becomes more favourable for UK and NW europe. It won't happen quickly, if it is to happen, but I don't personally believe that this west based -NAO Uk cyclonic phase is either long term sustainable or going to last as long as some have expressed on here, certainly not another fortnight.

The modelling, I think, is only going to get more interesting over the coming days.

Just my modest pennyworth as very much a non forecaster

Edited February 16, 2010 by North Sea Snow Convection

[thegreat316]

well i think on a personal note there are alot of people from the south ie portsmouth that would dare not post because they feel there such a tiny minority in this thread,

my post sometimes show charts and my thoughts tonight i have not bothered because talking from a SOUTHCOAST perspective theres nothing really exciting for us.

im not trying to whinned anyone up im just say my thoughts,

although its cold in parts after reading through regional threads for most of the day its clear to see how marginal everything is there is no deep arctic air being dragged in theres north real eastern source or siberian so it all very watered down,

agree i will sit and wait for the news reports of snowfall around the country im not disputing snowfall for anywhere apart from the southcoast,

im simply saying from what im seeing the marginal air is being shifted around this system eventually this air will become mixed out with the wintry stuff becoming less wintry over time.

as for fi well,

i cant really understand why we bother its absolutely far fetched and unrealistic.

im not throwing my toys out of the pram i am dissapointed though and yes tim as you keep saying im aware of the differences of living on the southcoast other than the yorkshire moors,

but funny how after the last cold spell the major players in this thread are not posting there thoughts because theres not truely much to be excited about.

i stand by what ive said the model outputs from today do not suggest a true arctic blast neither do they suggest a deep cold easterly for the southern half of england including wales,other than midlands north everything cold overtime moving north.

Hey BB

looking at the 12z GFS up to +180 it shows several Possible snow events in the south from tonight. The far south coast i.e ten miles from the sea may not see much snow, but those further inland will if it verifys.

The gfs upto 180 clearly brings the uppper temps further south then what was showing a few days ago and is showing that as we head into the weekend marginality will reduce.

i would be surprised if even us on the south coast dont see SOME falling snow in the next 7 days.

[kent]

The very gradual trend towards an eventual possible very end of season cold easterly is continuing in the modelling. GEM and UKMO on the 12z's this evening have both continued to show the phasing of the southerly tracking lows taking place,half inch by half inch, further south. This would be noticeable if one compared the models now to a couple of days ago.

With the very surpressed jet stream continuing with no sign whatsoever of that changing, plus further disruption to the energy circualtion in the NH with further negative zonal anomalies depicted to support blocking more in our own locale, rather than western Greenland, then it is only a matter of time before the -NAO signature becomes more favourable for UK and NW europe. It won't happen quickly, if it is to happen, but I don't personally believe that this west based -NAO Uk cyclonic phase is either long term sustainable or going to last as long as some have expressed on here, certainly not another fortnight.

The modelling, I think, is only going to get more interesting over the coming days.

Just my modest pennyworth as very much a non forecaster

A very balanced and thought out post, its a shame youre input isnt greater.

[The PIT]

ECM not following the lead of GFS while UKMO is similar to the GFS at T144. FI land I know so anything could happen. So once again everything really up in the air as too how it actually pans out.

[cuckoo]

Here is the chart I should have posted! Sorry for that confusion.

You got me excited there with the -10°C uppers over parts of northern Britain!

If only we could tempt some of that Scandinavian cold pool over the North Sea. -20°C uppers over Norway. Hoping the low will go further south and east than is progged at the moment.

Looking deep into to FI the door looks open for an Atlantic attack, if we could get some of that cold here first winter 2010 could go out with a bang!

Alas it is unlikely to be so. Can't help but feel we've been a bit unlucky so far this February.

[cooling climate]

From t96 onwards I think the ECM 12z loses its way and the error just

gets progressively worse. Best to ignore in my opinion.

[igloo]

looking at this evenings ECM it goes into its usual mess after +144 i sometimes wonder why the models go beyond this time frame

[Thundery wintry showers]

Not sure about that, it looks quite plausible to me? The lows sweep up from the SW bringing temporary pulses of milder air into the south and east but the cold air to the NW wins out each time.

However I don't agree with Ian Brown's assessment regarding the mild air winning out- this is probably influenced by the "modern winter trends" in the 1990s and early to mid 2000s. I tend to agree with John Holmes, there's more like a 30% chance of the mild air winning, a lesser chance of very cold air eventually making it in from the NE, while the most likely is that we stay in a moderately cold, unsettled pattern with milder air making temporary visits to the south.

[MR EXTREMES]

From t96 onwards I think the ECM 12z loses its way and the error just

gets progressively worse. Best to ignore in my opinion.

of coarse ignoring it at t96 when thats in the range of reliable could well misslead others when theres nothing to suggest its wrong,

its very much in line with the messy outlook that ive been trying to explain,

shoot me down im sure you will but 4 or 5 days maybe your see what i mean.

edit: yes TWS i think thats about right i dont agree mild either but i dont agree with very cold from what the models are showing.

ofcoarse i could be missleading the new posters but then so could cooling climate.

Edited February 16, 2010 by badboy657

[Geordiesnow]

From t96 onwards I think the ECM 12z loses its way and the error just

gets progressively worse. Best to ignore in my opinion.

Where does it go wrong in your eyes CC? Looks as plausiable as the GFS and UKMO too me. I have a feeling its not showing what you want too see, you want to dismiss it although the ECM is not that bad of a run in all honesty.

Trend has been for the last few days is the weather will be dominated by low pressure and with cold air in place then the risk of snow is there for some.

[Guest North Sea Snow Convection]

Might be worth looking at the NH map on that ECM and see what is happening to fragments of the polar vortex

Outcomes beyond t144 -t168 could evolve quite differently I think

[Glacier Point]

hi Frosty

The 30mb temperature (my brief look in the Stratosphere indications and by no means a definitive one; best read those posts by ch and GP and others for that), and its still way above normal, or was last evening.

The AO and NAO are well below zero with the PNA now showing indications of becoming above the zero line.

Turning to the 500mb anomaly charts and NOAA, along with ECMWF and GFS versions, all suggest a similar pattern. That is a very long track along the Atlantic having originated way north at 500mb. There is almost no sign of any blocking returning to an area which would favour a significantly colder spell. The upper air pattern seems, if not locked, then very reluctant to change, both in the actual charts and in the predictions of 10-14 days ahead-taking us almost to the end of February.

At some point that wavelength must change but its probably going to be towards the end of the first week in March before we can realistically expect that.

Agree with these time scales and I would strongly go down the below average line for March.

The inter-seasonal wavelength changes are really the key here. Both Nino and -AO composites for February support the west based -NAO.

Moving into March, the wavelengths change and become more amplified in the North Atlantic. The signal for a persistent Scandinavian trough remains. That would logically argue for heights to rise to our NW. Continued lagged downwelling from the stratosphere pinning the upper ridge towards southern Greenland and Iceland. Bob's your uncle - another cold shot.

In the meantime, the atmosphere really has stalled - but that includes strong jet flow underneath the UK which will blow away any ridge trying to build to our south.

[MR EXTREMES]

well the ens look like a sw attack also the ecm looks like something wants to push in from the sw aswell,

whether t144 is realiable is the question but its most likely the outcome in my opion.

nh ecm at t144 ::lol:

is not much really apart from t144 system shift from the sw,

this by no means say northern areas wont hold on to cold but most of the uk will be fairly cool but by no means cold.

unsettled cool be theme for sometime.

Edited February 16, 2010 by badboy657

[Bristawl Si]

of coarse ignoring it at t96 when thats in the range of reliable could well misslead others when theres nothing to suggest its wrong,

its very much in line with the messy outlook that ive been trying to explain,

shoot me down im sure you will but 4 or 5 days maybe your see what i mean.

edit: yes TWS i think thats about right i dont agree mild either but i dont agree with very cold from what the models are showing.

ofcoarse i could be missleading the new posters but then so could cooling climate.

There will be no very cold now. Cold in the North, less cold in the South although wet snow still possible.

Deep cold, and by that i mean daytime temps of 1 or 2 celsius are very rare in southern england past mid feb; maybe in northern england and Scotland esp in mountains and hills. I still think we'll see a wintry mix of cold rain, sleet and snow over the next 10 days or so,with northern areas favoured. Possibly the odd disruption from Midlands southwards, whereas the North will see more wintry conditions.

[NorthernRab]

There will be no very cold now. Cold in the North, less cold in the South although wet snow still possible.

Deep cold, and by that i mean daytime temps of 1 or 2 celsius are very rare in southern england past mid feb; maybe in northern england and Scotland esp in mountains and hills. I still think we'll see a wintry mix of cold rain, sleet and snow over the next 10 days or so,with northern areas favoured. Possibly the odd disruption from Midlands southwards, whereas the North will see more wintry conditions.

True, days below freezing are not that uncommon in Scotland in March, especially in the Highlands and there's often a considerable cold snap in March.

[MR EXTREMES]

There will be no very cold now. Cold in the North, less cold in the South although wet snow still possible.

Deep cold, and by that i mean daytime temps of 1 or 2 celsius are very rare in southern england past mid feb; maybe in northern england and Scotland esp in mountains and hills. I still think we'll see a wintry mix of cold rain, sleet and snow over the next 10 days or so,with northern areas favoured. Possibly the odd disruption from Midlands southwards, whereas the North will see more wintry conditions.

agreed and thats the line im thinking along.:lol:

[Frosty.]

Another cold run from the ECM 12z, especially for northern britain which looks cold throughout with a continuing snow risk and frosty nights, less cold in the south at times but there is no sign of any mild weather. I don't think the ecm loses it's way on this run any more than the other models are prone to do, we are now in a low pressure dominated pattern with below average temps and snow opportunities for some and this should continue well into next week, maybe the next few weeks.

Edited February 16, 2010 by Frosty039

[BLAST FROM THE PAST]

Ok how are we looking? Well a stalled front has brought some very decent precip amounts and lucky ones have seen snow but for most as expected cold rain, wintry mix. I tend to agree that the next week + maybe two weeks is generally below average but not hugely so and chances of snow again for some. 21/22 is looking good for LP possibly to track along the channel but room for manoeuvre north or south but it will be a headache and will bring some poor weather conditions.

As for longer term, average to slightly below start to March and cyclonic with the block to the north nudging away further NW. If LPs attacking from SW build up some zip there could be more hill snow and pretty wet conditions for the UK. There are signs that a temp ridge could build from the south by midmonth mainly affecting the SE bringing ' fairly warm' conditions before being nudged away again as LPs attack from WNW. March just shy of average.

Late weekend and into beginning next week potential for a 'final fling'. Do I think winter's over? No BUT deep cold is....and so are widespread wintry conditions.

BFTP

[weather eater]

From t96 onwards I think the ECM 12z loses its way and the error just

gets progressively worse. Best to ignore in my opinion.

You may well turn out to be right CC but more by luck than judgement, your statement sad to say shows your bias and reveals your lack of objectivity, shame really because you would be worth paying attention to, if you eliminated the bias and gained the objectivity. The models really are struggling and the evolution being show by the ECM is as likely as any other, you may just as well say that all recent model runs lose their way at T96hrs and the errors just get worse. You may well say that events further afield, teleconnection evidence, etc, supports an evolution to colder conditions for the UK, but that is no guarantee. February last year was a case in point, plenty of signs for a cold spell then, that didn’t come off. You may say it’s ok to criticise, how about you put your cards on the table, what’s your opinion. well to be honest I haven’t got a clue for a week’s time, in the longer range the models are as much use at the moment as the seagulls or Mystic Mathew. Not mild SWlys, but near or just under average temps, with a possibility of a change to colder conditions towards the end of the month would be my punt but thats a guess and support from the models is patchy at the moment.

[Bristawl Si]

You may well turn out to be right CC but more by luck than judgement, your statement sad to say shows your bias and reveals your lack of objectivity, shame really because you would be worth paying attention to, if you eliminated the bias and gained the objectivity. The models really are struggling and the evolution being show by the ECM is as likely as any other, you may just as well say that all recent model runs lose their way at T96hrs and the errors just get worse. You may well say that events further afield, teleconnection evidence, etc, supports an evolution to colder conditions for the UK, but that is no guarantee. February last year was a case in point, plenty of signs for a cold spell then, that didn't come off. You may say it's ok to criticise, how about you put your cards on the table, what's your opinion. well to be honest I haven't got a clue for a week's time, in the longer range the models are as much use at the moment as the seagulls or Mystic Mathew. Not mild SWlys, but near or just under average temps, with a possibility of a change to colder conditions towards the end of the month would be my punt but thats a guess and support from the models is patchy at the moment.

The models are NOT struggling!

This wintry mix of rain, sleet and snow with a slack area of LP over the UK has been modelled for the last week now and it was progged over a week ago that it would last right thru' this week. The North of the UK was always 'favoured' for colder, snowier weather - yes, there will be some 'minor' snow events further south, but that was also forecast.

Detail, on a regional basis, always change in the UK because we're only a few hundred miles wide and a 1000 miles or so long - not particularily 'large' in weather terms as a land mass.

[LomondSnowstorm]

The models are NOT struggling!

This wintry mix of rain, sleet and snow with a slack area of LP over the UK has been modelled for the last week now and it was progged over a week ago that it would last right thru' this week. The North of the UK was always 'favoured' for colder, snowier weather - yes, there will be some 'minor' snow events further south, but that was also forecast.

Detail, on a regional basis, always change in the UK because we're only a few hundred miles wide and a 1000 miles or so long - not particularily 'large' in weather terms as a land mass.

Firstly, I love the role reversal weather eater has taken from about three weeks ago when the battleground between the atlantic and easterlies were going on when the models weren't struggling, when with even smaller differences they apparently are! I agree with BB's summary here, that particular events as usual will only be forecast in short timeframes but overall things look fairly similar up to around +144 with cold air generally in the north, slightly less cold in the south with lows pushing northeast at times bringing the risk of frontal snow for some and sunshine and showers at other times.

LS

[Geordiesnow]

The models are NOT struggling!

This wintry mix of rain, sleet and snow with a slack area of LP over the UK has been modelled for the last week now and it was progged over a week ago that it would last right thru' this week. The North of the UK was always 'favoured' for colder, snowier weather - yes, there will be some 'minor' snow events further south, but that was also forecast.

I agree, the models may have varied quite a bit from run to run in terms of positioning of the lows but in general as we knew for a while, cool to just slightly below average conditions with rain/snow at times. Low pressure will be the driving force of our weather although strong winds on a widespread scale should be fairly low i would of thought. One thing has changed is that this week is forecast to be colder by the models than previous output.

[weather eater]

The models are NOT struggling!

This wintry mix of rain, sleet and snow with a slack area of LP over the UK has been modelled for the last week now and it was progged over a week ago that it would last right thru' this week. The North of the UK was always 'favoured' for colder, snowier weather - yes, there will be some 'minor' snow events further south, but that was also forecast.

Detail, on a regional basis, always change in the UK because we're only a few hundred miles wide and a 1000 miles or so long - not particularily 'large' in weather terms as a land mass.

The models are struggling with the LP as we head in to next week, nothing strange about that, I'm not your granny you dont need to teach me how to suck eggs, Im well aware of how minor detail changes in the shorter term effect a country the size of the UK thank you very much. Those minor detail changes are very important as to whether we see the low move away or whether as is perfectly possible the whole thing hangs about for a second week, it is there that the struggle is not in the next five days.

Edited February 16, 2010 by weather eater

[January Snowstorm]

It's almost impossible to follow the thread tonight.

Most seem to be talking about what will happen in March.

Am I losing my mind, we are on the cusp of cold and snow this week, and we look to March? I could understand it if we were currently under a bartlett, who cares what March brings, all I know for certain is it brings an Ice melting strong sun!!!!

[MR EXTREMES]

It's almost impossible to follow the thread tonight.

Most seem to be talking about what will happen in March.

Am I losing my mind, we are on the cusp of cold and snow this week, and we look to March? I could understand it if we were currently under a bartlett, who cares what March brings, all I know for certain is it brings an Ice melting strong sun!!!!

to be honest i very much agree march is spring and so is april snow will fall in the north it always does in spring at some point.

my focus is with people that are not being bias towards cold and showing there thoughts by what the models are showing.

not once have i pointed towards blowtourch but average or slightly below is the likely outcome for sometime i really dont agree that an upgrade is happening right now on this unsettled cool spell.

whether eater your post is spot on and BFTP excellent input once again from you.

models are going to flip flop all over the place for awhile i expect,

but are bang on with the general trend and thats cold then cool and unsettled.

northern areas always in the best place for wintry stuff,

although the next couple of days could have suprises from midlands north but after this rather normal febuary weather.

still this is better than blowtourch i firmly think that march is not going to be as some might hope for.

Edited February 16, 2010 by badboy657