Model Output Discussion

[snowmadchrisuk]

The mild signal seems to continue for around the 7th of march but on the ensembles there does seem to be a colder trend in fi this morning IMO.

The operational 6z gfs was one of them FI runs I hate , high low , high , low , high , low. Doesn't usually work out that way though. If we are going to have high pressure over the uk I'd rather it be a mild sunny high , If it's low pressure would rather it had an arctic source. I don't ask for much do I

Edited February 28, 2009 by snowmadchrisuk

[johnholmes]

Well at the time of my post (12z the night before) the top temp it was showing was 13C! Here is the proof, thank you very much:

(chart courtesy of NW Extra)

Now I'm quite happy to admit I was wrong to go along with this model, because clearly that was a mistake, but I don't appreciate virtually being branded a liar.

Would be nice to see a bit more agreement in the medium to long term when the 12z runs roll out but I'm not holding my breath.

NS

I don't think that comment above is a very sensible remark to make. The post you refer to did not by any stretch of anyones'' imagination, apart from your it seems, brand anyone a liar, to me it simply referred you to what that chart showed and then quoted the official Met O highest max.

Can we please keep those kind of comments off the forum please, I'm not a mod so they may decide to make their own comment and to delete my post.

Edited February 28, 2009 by johnholmes

[NorthantsSnow]

NS

I don't think that comment above is a very sensible remark to make. The post you refer to did not by any stretch of anyones'' imagination, apart from your it seems, brand anyone a liar, to me it simply referred you to what that chart showed and then quoted the official Met O highest max.

Can we please keep those kind of comments off the forum please, I'm not a mod so they may decide to make their own comment and to delete my post.

I quote "certainly didn't have a top temp of just 13c for yesterday" which was what I had claimed going by the chart I have flagged up today. So yes, indirectly, he was calling me a liar. And I think most people would wish for the right to respond to that, which is what I have done, in order to make it absolutely clear that that's not what I'm about. As I am sure you will note I ensured I returned to the topic in hand afterwards; I have no interest in detracting from the Model Discussion, but rather justifying the comments I made yesterday with pictorial evidence to clear my name!

Edited February 28, 2009 by NorthantsSnow

[Cheese Rice]

Anyway, too much difference in the models too get a clear idea on what is likely to happen, cooler conditons will spread in next week with the chance of snow etc, but after that who knows really, easterlys appear to be the main outcomne on the ecm and personally i would put my money on the ecm, as the GFS has been to unreliable lately, until the GFS improves drastically, i will side with ecm

[Paul]

I quote "certainly didn't have a top temp of just 13c for yesterday" which was what I had claimed going by the chart I have flagged up today. So yes, indirectly, he was calling me a liar. And I think most people would wish for the right to respond to that, which is what I have done, in order to make it absolutely clear that that's not what I'm about. As I am sure you will note I ensured I returned to the topic in hand afterwards; I have no interest in detracting from the Model Discussion, but rather justifying the comments I made yesterday with pictorial evidence to clear my name!

I wasn't calling you a liar at all, if you look at the chart you've posted there it's not showing a top temp of just 13c, it's showing a top temp of between 13 and 14c. The raw data from the nmm with additional height adjustments which I use to get a snapshot of top temps in certain locations, showed places with highs in excess of 14c, albeit slightly below 15c and some half a degree below the eventual max at charlwood.

[bluearmy]

UK Outlook for Thursday 5 Mar 2009 to Saturday 14 Mar 2009:

A cold flow of air from the north or northwest will bring a mix of sunshine and showers up to and including the first weekend. The showers are likely to be most prevalent and heaviest towards the north and west, where they will often be accompanied by a fairly blustery wind. The air cold enough for the showers to be a wintry mix of hail, sleet or snow at times, although any significant accumulations of snow should be mainly confined to higher ground in the north. Into the following week the current trend is for the weather to gradually become more settled and milder from the southwest. Temperatures will be below the seasonal average at first with overnight frost and ice but will probably recover to nearer average later.

Updated: 1133 on Sat 28 Feb 2009

The ensembles are obviously in agreement with the ecm op today, whereas yesterday, they were not. still no sign of cold enough uppers around to ensure precip is lying lasting snow at low levels. without being able to advect a long fetch northerly over a period of several days or the noreasterly of the type shown on yesterdays 12z ecm, i cant see how the next couple of weeks can deliver anything notable of a snowy nature

[nick sussex]

UK Outlook for Thursday 5 Mar 2009 to Saturday 14 Mar 2009:

A cold flow of air from the north or northwest will bring a mix of sunshine and showers up to and including the first weekend. The showers are likely to be most prevalent and heaviest towards the north and west, where they will often be accompanied by a fairly blustery wind. The air cold enough for the showers to be a wintry mix of hail, sleet or snow at times, although any significant accumulations of snow should be mainly confined to higher ground in the north. Into the following week the current trend is for the weather to gradually become more settled and milder from the southwest. Temperatures will be below the seasonal average at first with overnight frost and ice but will probably recover to nearer average later.

Updated: 1133 on Sat 28 Feb 2009

The ensembles are obviously in agreement with the ecm op today, whereas yesterday, they were not. still no sign of cold enough uppers around to ensure precip is lying lasting snow at low levels. without being able to advect a long fetch northerly over a period of several days or the noreasterly of the type shown on yesterdays 12z ecm, i cant see how the next couple of weeks can deliver anything notable of a snowy nature

Yes its hard to see from the current output any sort of decent wintry spell, the ecm 12hrs yesterday was really the best hope in terms of being able to get some cold upper air in and that was still reliant on alot of factors coming together namely the PV dropping some very cold air into Russia and this being advected westwards. There are still some uncertainties with the upstream pattern so perhaps the euros are the ones to follow here seeing as they have more backing from NOAA regarding the pattern over there. But overall at this time of year PM flows don't deliver for lower ground and we really needed an Arctic flow that could hang around for a few days or a decent easterly, theres only so much time to play with now so unless we see a return to the ecm 12hrs output of yesterday then I think its fair to say the boat would have already sailed for any proper reminder of winter for lower ground. Of course theres still chances of some snow but to see this laying for any length of time during daylight hours at this time of year you really need some excellent synoptics and these just aren't out there at the moment.

Edited February 28, 2009 by nick sussex

[bluearmy]

reading a few posts on here, i'm glad you said it nick - reality check necessary

[nick sussex]

reading a few posts on here, i'm glad you said it nick - reality check necessary

Well I sometimes think people forget how late in the season this is and the synoptics needed to deliver for lower ground, no doubt as with any spring theres bound to be some snow falling but for lower ground you really need some great synoptics for this to last. The ecm 12hrs yesterday hinted that there maybe a chance but today we see everything pushed further east. Upper air temps of -5 off a PM flow just isn't good enough for lower ground and we really need to see these close to the -10 mark, next week at the moment looks okay if expectations are for some heavy showers perhaps wintry more especially for the north and some snow over the mountains.

[Snowstorm1]

Well I sometimes think people forget how late in the season this is and the synoptics needed to deliver for lower ground, no doubt as with any spring theres bound to be some snow falling but for lower ground you really need some great synoptics for this to last. The ecm 12hrs yesterday hinted that there maybe a chance but today we see everything pushed further east. Upper air temps of -5 off a PM flow just isn't good enough for lower ground and we really need to see these close to the -10 mark, next week at the moment looks okay if expectations are for some heavy showers perhaps wintry more especially for the north and some snow over the mountains.

whats chances of snow for me as im in the northeast of england so im quite far north im expecting at least a covering for at least 2 -3 days

[dice48]

nick you have to remember that your in the south of france and some people here are in the north of the uk such as me!and also were not on the european continent so we wont warm up as much as you!

Edited February 28, 2009 by dice48

[mcweather]

Looking at the overall broader picture it's very clear the models haven't got a clue where to take the evolution.

Just to sum it up:

GFS shows a westerly

ECM shows an easterly

UKMO shows a northerly

I think that just about sums it up SP. The interesting thing is that the models can't seem to tear them selves away from the cold scenarios which keep popping up from time to time. We shall just have to wait and see.

[Cheese Rice]

Yes its hard to see from the current output any sort of decent wintry spell, the ecm 12hrs yesterday was really the best hope in terms of being able to get some cold upper air in and that was still reliant on alot of factors coming together namely the PV dropping some very cold air into Russia and this being advected westwards. There are still some uncertainties with the upstream pattern so perhaps the euros are the ones to follow here seeing as they have more backing from NOAA regarding the pattern over there. But overall at this time of year PM flows don't deliver for lower ground and we really needed an Arctic flow that could hang around for a few days or a decent easterly, theres only so much time to play with now so unless we see a return to the ecm 12hrs output of yesterday then I think its fair to say the boat would have already sailed for any proper reminder of winter for lower ground. Of course theres still chances of some snow but to see this laying for any length of time during daylight hours at this time of year you really need some excellent synoptics and these just aren't out there at the moment.

I think your been far too negative about this tbh, its not as if we are in mid March-late March with these synoptics we have just come out of winter, when the sun isnt that strong at all, i dont see why we still cant get snow with -2-5 upper air, especially in spring, when it is more likely to see snow in spring than autumn, i dont see why the majority of North England/Scotland/N.Ireland cant see a decent wintry spell especially when the majority of these areas are on some what higher ground.

[Cheese Rice]

nick you have to remember that your in the south of france and some people here are in the north of the uk such as me!and also were not on the european continent so we wont warm up as much as you!

Thats what i was thinking, although your posts are intresting and informative i do feel as if you forget you are in the south of France where it is far warmer there than in the UK, just because the same synoptics wont deliver for the south of france it doesnt mean it wont anywhere else

[Cheese Rice]

Well I sometimes think people forget how late in the season this is and the synoptics needed to deliver for lower ground, no doubt as with any spring theres bound to be some snow falling but for lower ground you really need some great synoptics for this to last. The ecm 12hrs yesterday hinted that there maybe a chance but today we see everything pushed further east. Upper air temps of -5 off a PM flow just isn't good enough for lower ground and we really need to see these close to the -10 mark, next week at the moment looks okay if expectations are for some heavy showers perhaps wintry more especially for the north and some snow over the mountains.

I fail to see how this is late in the season, remeber snow can fall and settle all the way upto april, if we were in april fair enough we are late in the season but we have just come out of Winter, and we all know in the UK that winter can prevail throughout march and April

Sorry if i appear to have a go at you but i just dont agree with you on parts of your posts :lol:

Edited February 28, 2009 by 10123

[Thundery wintry showers]

As for "polar maritime flows don't deliver at this time of year", they repeatedly did deliver during the month of March 1995. OK, so there were no lasting accumulations of snow in most of England (brief accumulations that thawed in sunny intervals in between showers) but averaged nationally it ended up as the snowiest March of the 1990s, and apart from the northerly on the 27th/28th, all snowfalls that month came from polar maritime sources. The 3rd March 2008 had a relatively half-hearted incursion that nonetheless brought significant lying snow to the Glasgow area and sleet/snow showers even in lowland parts of south-west England.

There is no major cold being shown on the models in the near term (within about T+144) but plenty of indications for "sunshine and showers" conditions with a wintry mix of showers just about anywhere, the amount of wintriness being positively correlated with how far north and west you are. The cold snowy easterly is still a possibility in a week's time, but a very long shot, as unless we pick up air from the right source it will end up just cold and cloudy.

My guess is that after a week of cool, bright, windy showery weather, it will probably temporarily turn milder from the south-west, but thereafter there could be another reload to a north-westerly pattern, with the jet continuing to track NW-SE.

[MR EXTREMES]

well spring 1917 and 1919 where very cold with deep snow across the country.

i was also just reading about end of feb and start of march 1937 once again heavy snowfall rain sleet hail and very strong winds.

although since then the climate has warmed a fair bit but never say never because in the land of weather anything can happen.

and its also intresting to see a difference in the models predictions west northwest north and east flow so which one will prove correct,

i go with nw and fairly chilly but its always possible of a northeast flow to pop up if this happens then it could be game on.

cant wait to see what the models think later its getting intresting now no time for arguments

[Thundery wintry showers]

GFS throws up yet another scenario, perhaps more in line with the ECMWF with the low stalling out west and then heading south allowing in an easterly. I don't think the easterly is the best bet for cold/snow lovers (or indeed anyone, for that matter) as the genuinely cold snowy air from the NE is unlikely to reach us, and instead the result is just cool and drizzly. But such an easterly is likely to be a transitionary feature anyway.

[snowmadchrisuk]

Well let's hope 12z is wrong , the mildest easterly I have ever seen by next thursday . That really would be a damp cloudy awful setup . Mind you does't last 5 mins , the Azores is coming , but what will our little low over iceland do ? Eyes down for gfs part 2

Edited February 28, 2009 by snowmadchrisuk

[Cheese Rice]

GFS throws up yet another scenario, perhaps more in line with the ECMWF with the low stalling out west and then heading south allowing in an easterly. I don't think the easterly is the best bet for cold/snow lovers (or indeed anyone, for that matter) as the genuinely cold snowy air from the NE is unlikely to reach us, and instead the result is just cool and drizzly. But such an easterly is likely to be a transitionary feature anyway.

Agree, i could see it been quite cold on the ground though, wth prevailent fog and temps by day rising to 1.c (under fog), looking at the source of the brief easterly is very warm air over egypt with 20.c uppers so defo not ideal for snow

[nick sussex]

I fail to see how this is late in the season, remeber snow can fall and settle all the way upto april, if we were in april fair enough we are late in the season but we have just come out of Winter, and we all know in the UK that winter can prevail throughout march and April

Sorry if i appear to have a go at you but i just dont agree with you on parts of your posts

I think people are misinterpreting what I'm saying, theres always a chance for snow falling well into spring, I'm not disputing that but if people want snow laying and lasting on the ground then the current output does not suggest this. In terms of the continent warming this is in relation to easterly flows, in most springs the continent will warm quickly so where as these are good for the winter months as we head through March they lose alot of their potency and so instead we look to Arctic flows at this point to deliver the wintry conditions.

Last April some se areas saw some good snowfall which came at the right time and therefore lasted overnight under frosty conditions but was gone quickly the next day. Of course we've seen many Marches produce good snowfall that lasted on the ground but the synoptics at present do not show this as being possible unless you're on a mountain so thats the point I'm making.

[Eugene]

Looking at the GFS 12Z ensembles there is disagreement on the 5th/6th whether an easterly occurs, i also wouldn't write off an easterly just because GFS 12Z OP shows milder air it could easily be a cold easterly if winds just turn slightly north of east.

[multi cellular thunderstorm]

Please stay on topic, any more posts about bbc / metcheck forecasts will be moved or deleted.

Thanks and nice FI on this run!

[dice48]

there seems to have been a bit of a downgrade but the snow risk and low temperatures are stil there.

[damianslaw]

I think people are misinterpreting what I'm saying, theres always a chance for snow falling well into spring, I'm not disputing that but if people want snow laying and lasting on the ground then the current output does not suggest this. In terms of the continent warming this is in relation to easterly flows, in most springs the continent will warm quickly so where as these are good for the winter months as we head through March they lose alot of their potency and so instead we look to Arctic flows at this point to deliver the wintry conditions.

Last April some se areas saw some good snowfall which came at the right time and therefore lasted overnight under frosty conditions but was gone quickly the next day. Of course we've seen many Marches produce good snowfall that lasted on the ground but the synoptics at present do not show this as being possible unless you're on a mountain so thats the point I'm making.

Yes agreed, the synoptics are not showing any really cold uppers so long lasting snow on low ground does look unlikely (but still very good chance of a cover overnight Tues/Wed in north western parts of Britain). As you say we start to need cold uppers near the -10 degree mark for long lasting snow hroughout daylight hours that doesn't quickly thaw as we go through March. Northerlies with a direct arctic flow at this time of year can bring the coldest weather of any winter season as the arctic is at its coldest now and SST's. Easterlies can deliver snowy cold weather right through March if they have a polar continental source i.e. scandanvia or better still from Russia, but if from off the near continent they won't bring such weather as central europe begins to rapidly warm during March.

One good thing about Spring though is that it occurs at the time of year when we see northerlies and easterlies reach there yearly maxim, its rare for a spring to pass without at least one direct northerly fetch from the arctic and even though next week doesn't look like doing such, I firmly believe we will see at least one direct northerly arctic feed at some stage between now and mid April (think back to last easter and around 6th april 08...)