Model Output Discussion

[Lewis]

This is how it could have been if GFS 06z from last Monday turned out correct. Don't think there would have many snow reports for today!

Good point! I think a lot of people expect too much, then when you look at that chart, it should bring people back to reality.

lewis

[Frosty.]

it's looking wintry for the far southeast corner later this week, chance of a cm or two from the look of the latest models, maybe 5cm on high ground, most of the uk looks quite benign though with high pressure in control but with overnight frosts, it should feel pleasant enough in the strengthening february sunshine though.

[Guest]

it's looking wintry for the far southeast corner later this week, chance of a cm or two from the look of the latest models, maybe 5cm on high ground, most of the uk looks quite benign though with high pressure in control but with overnight frosts, it should feel pleasant enough in the strengthening february sunshine though.

Aye, it's going to be a long week in some parts of the UK with not much happening. Some late teasers from the models with plenty of potential once the HP lifts anchor:

[aspire27]

Nothing exciting for the rest of week up to friday with that HP stuck NW of Scotland looking at the 6z run.

It seems to me and im sure lots of you will disagree but run after run now seems to be a downgrade for us in the UK.

EDIT:

Also next week the models are going for a west based -ve NAO which could let the atlantic straight back in. This colder spell could be long gone by next week.

Edited February 8, 2010 by aspire27

[Totoro]

From a general, overall UK perspective I have to say that going from the various model outputs we appear to be enduring a particularly insipid and uninspiring spell of 'weather'. Anything particularly interesting is generally a week away. The problem is that it's almost always a week away.

Some in the south east may get moderate snow at times, but the rest of us are stuck in nothingness.

[Bobby]

Nothing exciting for the rest of week up to friday with that HP stuck NW of Scotland looking at the 6z run.

It seems to me and im sure lots of you will disagree but run after run now seems to be a downgrade for us in the UK.

EDIT:

Also next week the models are going for a west based -ve NAO which could let the atlantic straight back in. This colder spell could be long gone by next week.

The ECM and UKMO are better for this week than the GFS 06z, which one is right who knows.

A west based -ve NAO has been forecast for a while, depends on how far West though. Is fine margins and we won't know til the time, a risk though certaintly that it's too far West.

[Frosty.]

Aye, it's going to be a long week in some parts of the UK with not much happening. Some late teasers from the models with plenty of potential once the HP lifts anchor:

Hopefully the high will lift anchor in FI but it's all a bit of an anticlimax this week with the only interesting weather in the southeast, I had expected more from this cold spell than a slight overnight frost and sunny days but FI does look more action packed.

[cooling climate]

Intersting ECM...16th onwards it shows the LP diving south from our NNW and we become cyclonic. The timing seems about right as I said the other day don't be suprised if the block doesn't hold beyond the 14th. It gives way because it retrogrades so far NW and that is the correct signal. This cold spell will be pretty ok BUT I said and still believe that the coldest part of winter has been and gone and this spell won't match January but it will be cold to very cold at times.

BFTP

lol, thats not what you said at all, talk about back tracking. Please don't get me

wrong I am not being argumentative but what ever signals you use to predict the

weather must be all over the place.

Northern hemispheric patterns + MMW all signal a prolonged cold spell perhaps

very cold spell for at least the next 10 days.

[karyo]

The met office further outlook is interesting with snow possibilities for next week apart from the southwest where it will turn milder. I would have thought the southeast would be morelikely to turn mild with the west based -NAO rather than the southwest, so I find that a bit puzzling!

Frosty, I was considering to say the same thing! I am glad you posted first! lol

Karyo

[Guest FireStorm]

I had expected more from this cold spell than a slight overnight frost and sunny days but FI does look more action packed.

I Think that is where a lot of people are being caught out and saddened by the models. I Fear that some people are hope-casting more then looking at the models for what they show realistically (although I am quoting you I am not suggesting this to be you or anyone in particular).

Isn't F.I more renowned for epic thrillers and action packed, even more so where GFS is usually concerned on anything +216 any ways?

[Lewis]

The models are up in the air with regards what happens from Wednesday onwards.

The GFS is showing the HP (High Pressure) much further South, with the ECM and UKMO having it further NW. If the GFS output is correct, then we will miss the worst of the weather, with the odd heavy snow showers from wednesday onwards.

If the ECM/UKMO is correct and we get that evolution, we will see more in the way of precipitation (heavy snow showers).

Nail biting times, let's see what the 12z GFS and 12z ECM has to say. I feel if the GFS continues this trend with the HP, and the ECM shifts slightly in favour we will stay mainly dry, but very cold.

From now until wednesday there's going to be plenty of showers about, more especially tomorrow morning onwards, the metoffice are not really showing much interest and have the showers falling as rain/sleet for coastal areas, and snow on higher ground. This could be due to the isothem, in all honesty i don't know what they are doing.

One thing though, i do sadly expect a downgrade on the next fax charts. The current severe weather warning issued for the SE and EA clearly shows the uncertainity. If the HP does sustain it's position according to the GFS (which is much further South) the main risk zone would be of course EA/SE, so the metoffice have issued a severe weather warning for them areas, because the HP is probably showing it's most Southern position, and probably won't push any further South. Nothing dead certain at the moment, the big guns UKMO/BBC are clearly playing their cards close to their chest.

Exciting times ahead, the model discussion continues.

What will it be? a EA/SE event, or more or less an entire U.K event (with all eastern areas doing well). Place your bets now.

Edited February 8, 2010 by Storm Force Lewis

[snowblizzard]

I do feel some require a dose of reality.

For starters this won't be a classic E,ly because frankly I joined this forum in 2004 and I still haven't seen one. So what is a classic E,ly you may ask? well for me a classic E,ly is when you have a huge pool of sub -20C uppers in the continent with around -15C in the UK. The positioning and orientation of the block maintains these very cold uppers over several days.

Make no mistake for some people the week will be just dry, sunny, cold. During the weekend we may actually find temps rise slightly as the HP moves NW. However its what happens after this thats uncertain.

I think it's been obvious for a while that we were never heading for a 'Classic Easterly'

If anything, temperatures have been slowly rising across Central and Eastern Europe during the past couple of weeks.

http://www.wzkarten3.de/pics/Reurmett.gif

It's only around -10c in Western Russia at the moment

For a 'Classic Easterly' severe spell of weather in the UK we need a deep cold pool across Europe

Previous events (1980's) have seen temperatures -30c or lower in Russia & -20c in Poland, Germany etc.

We could then expect a bitterly Easterly with daytime highs in SE around -5c

Edited February 8, 2010 by snowblizzard

[SussexmarkyMark]

Whether it be a 'classic' easterly or a 'modern' easterly, the models certainly seem to be shying away from it. Before the weekend, there were hints that pressure would rise to our NE and NW, with a double centred HP , with easterly winds from Russia right out into mid-Altlantic. Now, although there seems to be a brief attempt at an easterly across SE England later this week, it quickly disappears as the HP dominates and then the possibility of a northerly, before it becomes cyclonic over the UK.

The point I was trying to make yesterday morning (unsuccessfully it seems as I managed to look at the wrong chart) and others have been making this morning is that over recent runs the HP is further south and the coldest of the air seems to be heading for France and so we are unlikely to see widespread snow or anything particularly severe this week over most of the country. The only exception seems to be the extreme South East.

[snowray]

I think it's been obvious for a while that we were never heading for a 'Classic Easterly'

If anything, temperatures have been slowly rising across Central and Eastern Europe during the past couple of weeks.

http://www.wzkarten3.de/pics/Reurmett.gif

It's only around -10c in Western Russia at the moment

For a 'Classic Easterly' severe spell of weather in the UK we need a deep cold pool across Europe

Previous events (1980's) have seen temperatures -30c or lower in Russia & -20c in Poland, Germany etc.

We could then expect a bitterly Easterly with daytime highs in SE around -5c

Must say I would be happy with max of 0c if there was a Strong Easterly and Lots of Snow showers, but at any rate, we are not going to see an Easterly we are seeing a North Easterly which means that any snow showers that are around won't make it so far inland anyway.

Edited February 8, 2010 by snowray

[MR EXTREMES]

Nothing exciting for the rest of week up to friday with that HP stuck NW of Scotland looking at the 6z run.

It seems to me and im sure lots of you will disagree but run after run now seems to be a downgrade for us in the UK.

EDIT:

Also next week the models are going for a west based -ve NAO which could let the atlantic straight back in. This colder spell could be long gone by next week.

yep met o forecast sums it up really the models certainly wernt accurate into fi this time,

absolutely a downgrade and it happened very quickly it goes to show even with good teleconnections it can all go terribly wrong.

so cold this week still possible of a covering in place then cyclonic into next week.

i think there be some with egg on there faces weather online even the country file weekly forecast has dramatically change since 6pm lastnight.

joe b bigging up the cold spell and plenty talking of this lasting for weeks lol.

just shows how changable our weather is im wondering whether theres any point in looking at the models now this was i think our last chance of something good to finish winter with.

still im happy with the overall below average pattern we have witnessed this winter.

[Wayneywoo]

For those that are interested, here is Meteociel.fr translated to English, starting with the GEFS and how much agreement there is between the ensemble members.

http://66.196.80.202/babelfish/translate_url_content?.intl=us&lp=fr_en&trurl=http%3a%2f%2fwww.meteociel.fr%2fmodeles%2fgefs_cartes.php%3fech%3d0%26code%3d22%26mode%3d0%26runpara%3d0

If you start at +0, you'll see most of the screen is Dark Purple. On the scale, that translates to 0-2. 0 being (i think) all ensemble members agree and the further to the right the chart colours go (cycle through the time period) the further spread there is (disagreement) the ensembles.

Very useful to see where the disagreements are!

Hope this is useful to some.

Edit: Sorry the link was incorrect.

Edited February 8, 2010 by Wayneywoo

[BLAST FROM THE PAST]

lol, thats not what you said at all, talk about back tracking. Please don't get me

wrong I am not being argumentative but what ever signals you use to predict the

weather must be all over the place.

Northern hemispheric patterns + MMW all signal a prolonged cold spell perhaps

very cold spell for at least the next 10 days.

CC, Backtracking? You're having a laugh even with the models last week I never backtracked. Always said Cold spell of 7-10 days...could possibly extend to 14 days and the way it has started and set up has been very satsfactory. Even with the block going too far NW it will still be cold but once it move too far NW it will end it and gradually become less cold. Coldest period 9-14 and getting less cold on from there, said that all along and remain with it. Any prolonging will be bonus but if that PV drops after 16th IT WILL end the cold spell as the Atlantic will have a route in.

And just to show that I have not chagned my mind, backtracked OR be all over the place here is my Feb update done on 25th Jan in LRF thread.

Posted 25 January 2010 - 21:39

Well here are my updated general thoughts re Feb. Like I said a couple of days ago they have latched onto the evolution. HP to our W and NW bringing northerly and at times NE'ly winds with trough in Scandi. With a little bumping around the synoptic set up will not break down as progged T168 onwards and watch for models to latch onto this as we get towards end of the week. I think we will see a shift north of the ridge and a strengthening of the block as we get to end of first week of Feb. With the HP being bumped around winds will veer from n'ly to ne'ly to e'ly but into second week 9-13 say we may see our coldest spell of Feb with biting NE'ly airflow. Around mid month we'll see the end of the block to the NW as an LP moves from NW to SE. I think HP will then gradually sink from arctic to Scandi and slowly sink SE as we go to last week with a southerly flow for the last part of the month generally milder/less cold.

For now though look no further than this northerly for model accuracy, things will change, and considerably from what FI shows now. I do believe that we won't match the severe cold of Jan ie -22c etc but -10c should be well within reach on numerous occasions.

Midmonth is the period to look for a chance that it could turn mild though and remain mild. I think the cold signal is there for the first 10-15 days, a very difficult month and usually in past winters Feb IMO was the least difficult.

BFTP

There we go CC...I think that is consistency and zero backtracking..time to move on with further model analysing I think.

BFTP

Edited February 8, 2010 by BLAST FROM THE PAST

[dale leigh]

my goodness are we are are we not going to have the cold spell with snow we are hereing in the media and tabloids . why are the models changing so much. very conflicting information regardind the weather for this week. must say very entertaining watching the models change so much. we have had a great winter so far so i suppose we can not grumble if the rest of feb is mild.

[Glacier Point]

yep met o forecast sums it up really the models certainly wernt accurate into fi this time,

absolutely a downgrade and it happened very quickly it goes to show even with good teleconnections it can all go terribly wrong.

Uh ? Seems to me the modelling is very consistent with the interpretations being offered this week (high centred to our north and west) followed by retrogression towards Canada and western Greenland opening up a definate window for cold and unsettled weather week 2. Very much in line with the MetO longer range discussion.

Maybe the west based -NAO is causing confusion - it's one of those occasions where northern blocking can deliver milder weather pattern for the UK and is particularly associated with February.

Longer range, the synoptic discussion still looks to revolve around how far west the -NAO block will be. No ensemble mean guidance projects the removal of the trough to our east, only slow filling which will keep a north south divide to the lows approaching from the south-west during week 2. The exact positioning of that boundary will be crucial and at this range, difficult to say where that will be.

[chionomaniac]

I have to say that I am constantly amazed at how often people describe the models predictions as if they are describing something that occurred last week! If that was the case then I would be sitting here in a howling wet Swesterly with temps into the low teens. Yet I am not. It is snowing outside with the temperature just above freezing. The models are still showing promise for colder scenarios which is still supported by favourable background teleconnections probably for some time to come yet. There is no raging zonality and no Bartlett on the horizon and the bigger picture still needs to be assessed. One sometimes cannot tell what a painting will look like from the first few brushstrokes!

Edit I see GP beat me to it as usual!

Edited February 8, 2010 by chionomaniac

[nick sussex]

The uncertainty today isn't in the pattern but how far west this will go, theres very good support for the high retrogressing towards Canada and trough developing over Scandi. In a nutshell looking at the model output the further west the pattern goes the more chance that the cold Arctic air will spill into the Atlantic with slow moving low pressure over the UK phasing with low pressure over southern Europe, once this happens I'm afraid its game up at least for southern areas as this will pull less cold air in.

http://www.wetterzentrale.de/pics/Recm1921.html

As you can see here low pressure dropping south, low pressure slow moving over Spain.

http://www.wetterzentrale.de/pics/Recm2161.html

We see phasing with both lows and then the low pressure near the UK becomes stuck, the cold Arctic air heading into the Atlantic in line with a western based negative NAO.

http://www.wetterzentrale.de/pics/Recm2401.html

Here we see the low still over the UK.

This is often the problem with a negative western based NAO, even though you have also a negative AO.

To avoid this we need to see the models pull the pattern further east and either not phase those lows or do this much further east,I hope people don't think i'm being unduly negative here but that is a plausible outcome and we should bear this in mind. Now that I've got that out of the way theres still at least a week of cold weather to come with snow chances more especially towards the east and se, also initially as the low drops south next week a chance of some snow for other areas.

What we possibly could find with the further outlook is the cold air hangs on for a while circulating around that low before this becomes modified especially towards the south. Northern areas may hang onto the cold a while longer. Overall though we need to see a big shift eastwards in the pattern to extend the cold UK wide.

[TEITS]

Funny how some keep on referring to downgrades and yet my summary on Saturday hasn't changed today. Always said E areas especially E Anglia/SE are most likely to see the most frequent snow showers from Wed-Fri and that outlook hasn't changed. Maybe some didn't properly read this because they were too busy complaining about being biased towards the SE. The only difference is the showers might not move as far inland as I currenrly thought. However at no stage did locations such as Bristol ever look favoured because with a convective E/NE,ly they never will be!!

Beyond and to be honest at this stage its a complete and utter mess looking at the ensembles. Some of these suggest turning milder with SW,lys, others suggest heavy snowfalls with LP tracking along the channel, some even suggest an E,ly via a Scandi HP!

Lets be realistic for some locations this week will only bring dry, sunny, cold conditions before turning slightly less cold during the weekend. Beyond and it could be possible that some regions turn much milder. However at this stage I wouldn't come to any assumptions because surely the past 7 days of model output has taught us that. The HP moving to Greenland looks very likely but that is about the only reliable pattern beyond +144.

In some respects I wish the mild SW,lys had occured due to the constant moaning on this thread!!

[nick sussex]

Funny how some keep on referring to downgrades and yet my summary on Saturday hasn't changed today. Always said E areas especially E Anglia/SE are most likely to see the most frequent snow showers from Wed-Fri and that outlook hasn't changed. Maybe some didn't properly read this because they were too busy complaining about being biased towards the SE. The only difference is the showers might not move as far inland as I currenrly thought. However at no stage did locations such as Bristol ever look favoured because with a convective E/NE,ly they never will be!!

Beyond and to be honest at this stage its a complete and utter mess looking at the ensembles. Some of these suggest turning milder with SW,lys, others suggest heavy snowfalls with LP tracking along the channel, some even suggest an E,ly via a Scandi HP!

Lets be realistic for some locations this week will only bring dry, sunny, cold conditions before turning slightly less cold during the weekend. Beyond and it could be possible that some regions turn much milder. However at this stage I wouldn't come to any assumptions because surely the past 7 days of model output has taught us that. The HP moving to Greenland looks very likely but that is about the only reliable pattern beyond +144.

In some respects I wish the mild SW,lys had occured due to the constant moaning on this thread!!

Yes I can see why you'd say that. Peoples expectations have gone into overdrive, to be honest I was thinking twice about including my less than optimistic slant on the western based negative NAO in my previous post in case that was met with more hysteria!

I thought i'd get that out of the way and end with a positive in that its likely to stay cold for at least the next week. To be honest Dave I dread to think what will happen next winter if its an average or mild affair, Dec and Jan have led some people into forgetting the previous mild dross affairs of so many years.

We have been extremely fortunate with the winter so far but some members wouldn't be happy unless it was another 1963!

[TEITS]

To be honest Dave I dread to think what will happen next winter if its an average or mild affair, Dec and Jan have led some people into forgetting the previous mild dross affairs of so many years.

Well judging by some of the posts on here I think I would stop posting on this thread should we have a mild winter!

Going back to the models and I have to say im not oonvinced of a W based NAO. Seen the models suggest this before during this winter but in the end the block was further E than suggested. Also when I think of N,lys in the model output the trend is to always move these further E once they enter the reliable timeframe. So at the moment I feel any LP tracking S is likely to be further E than suggested.

Quickly going back to some of the moanning on here. I do wish members would use their local knowledge of their weather. For instance I have a rough idea of what a NW/N/NE/E/SE,ly brings to Peterborough. Thankfully the NAE will be coming into range very shortly so we might have a better idea with regards to snowfall.

[nick sussex]

Well judging by some of the posts on here I think I would stop posting on this thread should we have a mild winter!

Going back to the models and I have to say im not oonvinced of a W based NAO. Seen the models suggest this before during this winter but in the end the block was further E than suggested. Also when I think of N,lys in the model output the trend is to always move these further E once they enter the reliable timeframe. So at the moment I feel any LP tracking S is likely to be further E than suggested.

Quickly going back to some of the moanning on here. I do wish members would use their local knowledge of their weather. For instance I have a rough idea of what a NW/N/NE/E/SE,ly brings to Peterborough. Thankfully the NAE will be coming into range very shortly so we might have a better idea with regards to snowfall.

Yes the pre Xmas cold spell had a similar signal for a western based negative NAO although Chinio mentioned that the current MMW might lead to a further pulse of negative zonal mean winds which could back the pattern further west. Lets hope the models edge the pattern eastwards with time and we don't end up seeing that low stuck over the UK.

Edited February 8, 2010 by nick sussex