Model Output Discussion

[MAF]

it can be either sometimes one model appears to be a better guide than another and at other times, and this is not uncommon, the 'middle' ground can be used. In this set up that might be difficult so its a case of wait and see for a day or two. The middle term drivers, AO and NAO both suggest a colder rather than a milder spell is likely. Also the 500mb anomaly charts, from whichever centre, also suggest a 500mb flow north of west, again suggesting cold rather than mild. Contour values are being suggested of about 534DM, over the middle of the UK,rather below the early March average.

thanks John, nice to see how the models are interpreted when there is ambiguity amongst them.

[Snowaddict]

it can be either

sometimes one model appears to be a better guide than another and at other times, and this is not uncommon, the 'middle' ground can be used.

In this set up that might be difficult so its a case of wait and see for a day or two.

The middle term drivers, AO and NAO both suggest a colder rather than a milder spell is likely. Also the 500mb anomaly charts, from whichever centre, also suggest a 500mb flow north of west, again suggesting cold rather than mild. Contour values are being suggested of about 534DM, over the middle of the UK,rather below the early March average.

Indeed John, I have noticed that in recent days the teleconnections have been displaying more increasing support for colder rather than mild into March.

Also, there are signs of the PNA pattern in the States becoming at least neutral (or close to it) after a protracted period of negative territory.

The 30mb temperature still remains anomolously warm, despite a cooling in recent times.

At present at least, there is definately more support for cooler, even colder conditions into March than there is for mild.

Although, as we all know these factors are subject to change.

Regards,

SA.

[Frosty.]

I think it's safe to say the uk will be colder and more unsettled next week, those are the broad brush strokes only though because detail will be hard to pin down with positioning and potency of low pressures still unclear. A big change from the stagnant mild cloudy rubbish of the last few weeks though is guaranteed.

[BLAST FROM THE PAST]

So the BFTP storm is on! This will be a notable event though folks and damaging winds for many so needsto be watched and its track of importance. I've been looking at the chances and development for 9 days now and it looks like being a nasty affair and for sure a cold setup is digging in behind it and for March 'cold' will be appropriate description. I rather fancy that southern half of the UK could get a battering and heart of England in the firing line...having said that it is a big storm so pretty widespread gales.

BFTP

[yamkin]

Anyone noticed the 'Finger' pointing towards the UK It's as if the 'Finger' is directing the colder air towards us

[MAF]

or is the cold air just giving us the finger?

sorry off topic

[Shadow]

or is the cold air just giving us the finger?

sorry off topic

Thats funny :o :lol: :lol: :lol:

[Eugene]

I'm really starting to get excited over mid to late next week, this chart is an everything but the kitchen sink chart :lol:

http://www.wetterzentrale.de/pics/Rtavn1501.png

Meaning all different types of weather on offer apart from warmth of course

Nice direct feed from that greenland cold pool too

[Guest North Sea Snow Convection]

At last something more interesting to watch is showing - at least beyond the wind and rain that is. The sort of charts that were more in line with what was expected two to three weeks ago. Still, March can be a fun month and very welcome to see these changes starting to gather a bit of pace after the awful synoptics of the last fortnight.

A lot of blocking with winds between an easterly and northerly quadrant coming for the first half of Spring I think

[Eugene]

And the charts for next week also highlight to me why do people want warm anticyclonic weather this early when there is potential for exciting active weather, spring even May can offer exciting weather types, summer is quite boring really because we lose polar maritime airmasses to our north/west.

July/August apart from occasionally usually have much slacker synoptics which don't really produce nowhere near as much excitement as winter, spring or autumn with only southerly plumes to look forward to which rarely deliver away from the midlands and south, i'm sure actually northern members especially scottish much prefer late spring to summer, summers are very poor up there and there best warmth is usually in May.

Edited February 27, 2009 by Eugene

[nick sussex]

At last something more interesting to watch is showing - at least beyond the wind and rain that is. The sort of charts that were more in line with what was expected two to three weeks ago. Still, March can be a fun month and very welcome to see these changes starting to gather a bit of pace after the awful synoptics of the last fortnight.

A lot of blocking with winds between an easterly and northerly quadrant coming for the first half of Spring I think

Yes for cold lovers in the uk the last two weeks must have been totally boring although for down here its almost like summer with warm sunshine. Agreed March can provide some very interesting weather with hints of summer and reminders of winter, the ecm was especially interesting this morning but it still takes a leap of faith to see a decent easterly set up, its a race against time for easterlies in March with the continent warming quickly with the right set up so I think we'd need to see that PV drop into Russia and the correctly orientated high, I would prefer though to see an Arctic flow as thats great for snow showers and lots of convection even inland during March with frosty nights, I remember a few years back when I was still in the UK a couple of well timed March snowfalls and clear nights really was a reminder of winter, the worst thing is if we see one of those dull damp spring easterlies so if its going to happen lets hope its a more showery variety. It will be interesting to see the ukmo further outlook today if theres any mention of wintry conditions more especially for eastern areas as that would back the ecm output.

The latest ecm ensembles for the Netherlands do show some colder options but nothing majorly cold although the extended ones look better than last evening.

[Thundery wintry showers]

And the charts for next week also highlight to me why do people want warm anticyclonic weather this early when there is potential for exciting active weather, spring even May can offer exciting weather types, summer is quite boring really because we lose polar maritime airmasses to our north/west.

There is quite a bit of IMBY-ism at the moment, people in the sunny areas noting what a lovely spell it's been, and people in the cloudy areas noting what a boring spell it's been. There appears to have been a somewhat uneven distribution of sunshine across the country, but I expected no different with the high pressure rooted to the south. Central, southern and eastern areas are always favoured in this setup for sunshine, and the north and west often goes for long periods without a solitary sighting of the sun.

Polar maritime airmasses still exist to the north/west in summer, and although the setup has been rare in recent years, a potent northerly with a maritime source in summer can bring sunny spells, towering Cb cells, thunder and large hail. The most memorable example for me was 27th August 1995, if anyone remembers it. What we do lose is the cold upper air over the continent, so that when this air passes over the north Atlantic and/or North Sea, it ends up stable rather than unstable, and thus we get cloud and drizzle in the east and sunshine in the west, rather than sunshine and showers. In spring this impacts significantly upon easterly setups- which combined with the greater convection inland during showery setups, causes Arctic northerlies to be by far the most reliable source of "sunshine and snow showers". In summer, it impacts upon northerlies as well, as even north Scandinavia is relatively warm then.

It looks like it will be classic early-March weather into early March- basically windy and showery, March definitely coming in like a lion. While the GFS is almost certainly overdoing that low, I notice that the Euro models are shifting towards it, and it won't surprise me if the GFS turns out to be nearest to the mark on this occasion.

[Guest North Sea Snow Convection]

Yes for cold lovers in the uk the last two weeks must have been totally boring although for down here its almost like summer with warm sunshine. Agreed March can provide some very interesting weather with hints of summer and reminders of winter, the ecm was especially interesting this morning but it still takes a leap of faith to see a decent easterly set up, its a race against time for easterlies in March with the continent warming quickly with the right set up so I think we'd need to see that PV drop into Russia and the correctly orientated high, I would prefer though to see an Arctic flow as thats great for snow showers and lots of convection even inland during March with frosty nights, I remember a few years back when I was still in the UK a couple of well timed March snowfalls and clear nights really was a reminder of winter, the worst thing is if we see one of those dull damp spring easterlies so if its going to happen lets hope its a more showery variety. It will be interesting to see the ukmo further outlook today if theres any mention of wintry conditions more especially for eastern areas as that would back the ecm output.

The latest ecm ensembles for the Netherlands do show some colder options but nothing majorly cold although the extended ones look better than last evening.

Yes there is no point dwelling on what could have been, we all know that the days are longer now and so limitations are taken as read. But last April showed what is possible with the right synoptics and that lead to the sort of perfectly timed heavy snowfall and frosty night you refer to, so on that basis there is plenty of time yet

I think there is a good chance now that the colder ensemble options will gather pace over the coming days. The basic trend is there in the models, esp ECM and GEM, for low pressure to transfer SE with time into europe - just where it is needed, and that is all that matters for the here and now.

[PB22]

As others have mentioned, still differences between the main models over the development and positioning of the low which will make some differences in terms of where the strongest winds are likely to occur. However, regardless of where the low does track, an increasingly cool, breezy and showery week is on the cards for next week with spells of rain or blustery showers - it could well be a case of April showers coming early!

Divergence is evident between the GFS and European models by as early as T+120 this morning, with GFS still wanting to create a deeper low:

http://www.wzkarten.de/pics/Rtavn1201.html

http://www.wzkarten.de/pics/Recm1201.html

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

What happens next is questionable. GFS still keen on introducing a chilly, blustery northwesterly which would bring wintry showers to almost anywhere, whilst the Euro's aren't quite as cold but are still just as unsettled:

http://www.wzkarten.de/pics/Rtavn1441.html

http://www.wzkarten.de/pics/Recm1441.html

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

Longer term there are increasing signs for northern blocking to become extensive:

http://www.wzkarten.de/pics/Rtavn1921.html

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

Although by then there are no real notable cold pools for us to tap into, so it could just end up being a rather cold and wet start to spring, and any easterly as Nick mentions could well be dull and damp - something along the lines of what some places have had a lot of lately, but just a few degrees colder.

[nick sussex]

Yes there is no point dwelling on what could have been, we all know that the days are longer now and so limitations are taken as read. But last April showed what is possible with the right synoptics and that lead to the sort of perfectly timed heavy snowfall and frosty night you refer to, so on that basis there is plenty of time yet

I think there is a good chance now that the colder ensemble options will gather pace over the coming days. The basic trend is there in the models, esp ECM and GEM, for low pressure to transfer SE with time into europe - just where it is needed, and that is all that matters for the here and now.

Yes last April was a good example of how important timing is in spring with snowfall, I remember seeing some of the great pics from the se which were lucky to get the snowfall late in the day and with a frosty night it was quite a thing for that late in the year. Its funny how the ecm has actually picked up on the gem of a few days back and if we do get low pressure in central europe and with the Atlantic much quieter that could provide some interest, how about we order a nice strong ne flow sourced in the Arctic that would be good.

Edited February 27, 2009 by nick sussex

[PB22]

There is quite a bit of IMBY-ism at the moment, people in the sunny areas noting what a lovely spell it's been, and people in the cloudy areas noting what a boring spell it's been. There appears to have been a somewhat uneven distribution of sunshine across the country, but I expected no different with the high pressure rooted to the south. Central, southern and eastern areas are always favoured in this setup for sunshine, and the north and west often goes for long periods without a solitary sighting of the sun.

OT, but Its been a fantastic spell here, and already at 12.3C today with the sunshine trying to break through.

It looks like it will be classic early-March weather into early March- basically windy and showery, March definitely coming in like a lion. While the GFS is almost certainly overdoing that low, I notice that the Euro models are shifting towards it, and it won't surprise me if the GFS turns out to be nearest to the mark on this occasion.

GFS could well restore some credibility this week after all the bashing it has taken from some quarter's recently.

I have noticed that the GFS ensembles generally are slightly less cold this morning than they were yesterday, with the mean barely making -5C in the south now:

http://www.wzkarten.de/pics/MT8_London_ens.png

http://www.wzkarten.de/pics/MT8_Manchester_ens.png

http://www.wzkarten.de/pics/MT8_Aberdeen_ens.png

[Guest North Sea Snow Convection]

Yes last April was a good example of how important timing is in spring with snowfall, I remember seeing some of the great pics from the se which were lucky to get the snowfall late in the day and with a frosty night it was quite a thing for that late in the year. Its funny how the ecm has actually picked up on the gem of a few days back and if we do get low pressure in central europe and with the Atlantic much quieter that could provide some interest, how about we order a nice strong ne flow sourced in the Arctic that would be good.

The model charts from early April last year are a great example of how sunshades can become snowshoes in a matter of 48 hours. The neighbours were thinking of having a BBQ on the Friday evening (I think they went ahead with it). The same neighbours were pulling a toboggan with their kids around the lawn late on the Sunday afternoon :lol:

I think once the pattern shift comes nearer in the next few days we will see the overall colder trend across the model ensembles increase further. The evolution of this set-up of a breakaway low splitting away from Greenland and sinking SE'wards is very reminiscent of Feb 2006 which led to the Greenland block at the end of the month/early March and some heavy snowfalls. I seem to remember Inverness having very large accumulations over several days. Other, western areas of the UK did well on that occasion too. The east and south east was less well favoured but there none of the trough features that showed up as in April last year

[Frosty.]

If the GFS 6z is to be believed, scotland would be plunged back into winter, especially the northern half with large amounts of snow, gales, blizzards and overnight frosts but elsewhere it looks less severe although a wintry mix is still likely with daytime maxima between 5-7c but falling in heavier showers which could contain wet snow. The track of the lows remain uncertain though and there are big differences between the gfs & ecm in that respect.

[PB22]

Slightly off topic, but somewhat related to model out...the Met Office update is rather at odds with some of the model output, notably the ECM:

UK Outlook for Wednesday 4 Mar 2009 to Friday 13 Mar 2009:

A cold flow of air from the west or northwest will bring a mix of sunshine and showers up to and including the weekend. The showers are likely to be most prevalent and heaviest towards the north and west of the United Kingdom, where they will be often accompanied by a fairly blustery wind. The air will remain cold enough for the showers to fall as hail, sleet or snow at times, although any significant accumulations of snow should be mainly confined to higher ground in the north. Temperatures are expected to be slightly below the seasonal average, with frost likely at night. Beyond the weekend, the current trend is for the weather to gradually become more settled and slightly milder from the southwest.

Updated: 1208 on Fri 27 Feb 2009

Certainly doesn't tie in with the operational ECM for beyond next weekend:

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

It will all change of course, but it suggests at the moment that the Met Office aren't calling for too much of a prolonged colder spell despite some of the indicators.

For me we could see a much milder mid-March after a cool start to the month, and the GFS ensembles do show a few milder options from the 7th:

http://www.wzkarten.de/pics/MT8_London_ens.png

All in FI though and in the meantime we can look forward to a lot of weather activity next week which will be very interesting indeed.

[Altohumorous]

At last something to watch, for me here this has been a generally boring winter, the beginning of December and a bit of February was exciting, and there was some nice, sunny, frosty weather for a while in December, other than that there has been alot of very tedious weather, with very few storms at least, whatever about cold.

Im always amazed how a major cold, stormy blast from Greenland/the Arctic comes at the end of Feb/first week of March almost every year like clockwork. One of the best was (I think) in Feb/March 2001, producing a 24 to 36-hour blizzard here

[NorthantsSnow]

Models not sure about this storm yet so details will change over the next few days in the short term, but getting progressively colder and more unsettled is the theme with the risk of sleet/snow returning to areas with a bit of elevation :lol:

GFS is frustrating because we almost tap into a very cold easterly. All FI anyway of course but this nonsense about there being no cold pool to tap into is not at all true, on this run a very cold block indeed forms to our east as the run progresses but sadly doesn't quite reach us.

Still, ECM looks tasty at +240 and there are plenty of cold solutions on the GEFS ensembles.

Fascinating times with interesting weather making a very welcome return.

[snowmadchrisuk]

In recent days some have asked what am I on about saying my area has been in constant cloud, but the latest sat pics show what they have been showing all week , an area of cloud over the midlands refusing to budge

If next week turns out to be a sunshine and showers setup then I will be very happy , as may get some sunshine and some hail and some snow you get the picture , anything is better than what my area has at the minute.

[Frosty.]

Slightly off topic, but somewhat related to model out...the Met Office update is rather at odds with some of the model output, notably the ECM:

Certainly doesn't tie in with the operational ECM for beyond next weekend:

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

It will all change of course, but it suggests at the moment that the Met Office aren't calling for too much of a prolonged colder spell despite some of the indicators.

For me we could see a much milder mid-March after a cool start to the month, and the GFS ensembles do show a few milder options from the 7th:

http://www.wzkarten.de/pics/MT8_London_ens.png

All in FI though and in the meantime we can look forward to a lot of weather activity next week which will be very interesting indeed.

Agreed,

It looks milder after next week which would make 3 mild weeks out of 4, quite impressive given it's been a colder winter than usual by uk standards. :lol:

[snowmadchrisuk]

Agreed,

It looks milder after next week which would make 3 mild weeks out of 4, quite impressive given it's been a colder winter than usual by uk standards. :lol:

I wouldn't base things on the met office 16 day. Remember they had to make a massive back track on the current mild spell , they were saying in the days leading up to it that it was going to get cold and then very cold , and in 2 days had backtracked to very mild.

They can only say what the models show to be fair, the only time I think there personal experience is useful when they have to forecast snow in england and wales.

[Yeti]

If the GFS is right, there could be some extreme snowfall over the Pennines and other Northern hills next week:

http://www.wetterzentrale.de/pics/Rtavn1144.png

http://www.wetterzentrale.de/pics/Rtavn1141.png

A bit of a cold zonality setup really, which obviously is always good in terms of chances for northern blocking later (such as happened in January this year). Low level snow looks highly unlikely unless this blocking does develop perfectly, but with the storm taking a track like that, above 400-500m conditions could be absolutely horrendous with prolonged, driving snowfall giving blizzard conditions and drifting in the strong winds.

I will definitely be heading to the Dales next Sunday if the storm does track as per GFS, as conditions could be quite incredible over the hills :lol: