Spring Model Discussion 18Z 6/3/13 onwards....

[TEITS]

The thrill of the chase is what makes many of us tick, well it does for me anyway.

Apart from the ECM shortening the cold spell compared to the 12Z I cannot see much wrong with the output. The bitterly cold E,lys being replaced by a slightly less cold N/NE,ly has always been the trend from the models. This can clearly be seen on the ensembles below.

http://cdn.nwstatic....bridgeshire.png

Personally im just happy with what the models are showing for Sunday/Monday and im not bothered about the duration of this cold spell because it is supposed to be spring anyway.

Edited March 7, 2013 by reef
Quoted post removed

[Liam J]

Still looking at some of the best charts of the winter/spring with the added bonus of them being within touching distance and not post T300 !

[johnholmes]

Im not knocking the Met O but im utterly amazed at the latest fax charts. Why go with the UKMO raw output when the evidence strongly suggests its wrong.

John asked what should the fax look like and the answer is below.

http://www.meteociel...M1-120.GIF?06-0

I watched a Look East forecast earlier which suggested Max temps of 7C, min 4C on Sunday. Well the GFS certainly disagrees with this.

http://www.wetterzen...s/Rtavn9617.png

No doubt some will defend the BBC/Met O but in my opinion both the Fax charts and the BBC Look East forecast are dreadfully wrong. I have saved tonights fax charts onto my laptop such is my confidence that they will change.

Of course they will change Dave that is why I posted the link I use that shows the times as well as the date that the senior man issues them.

[fergieweather]

UKMO now happy with GM out into Sun/Mon with v good consensus between it and EC EPS re handling of frontal zone slipping south into Sunday, with accompanying earlier onset of colder conditions. So, 00z GM accepted with very little modification. Strong signal for transition to sleet/snow on rear edge of front during Sunday, but with forcing being rapidly lost the PPN amounts/rates will be diminishing, so shouldn't be too bothersome. On Sunday, most snow accumulations of any note (i.e. 2+cm) signalled away from windward coasts over high ground, albeit any shower alignment parallel to the flow by Monday could give some patchy issues in E'rn areas. On the coastal fringes, however, the keen flow off N Sea will help inject sensible heat and diminish snow threat here.

Generally, low-level snow accumulations considered to be largely very temporary through Sun-Mon, due to recent rises in depth temperature. Both EC and UK4 show very muted amounts (1cm or less) in patchy distribution for southern UK by later Sunday; highest accumulations on higher ground such as Pennines, parts of Wales and Exmoor.

For Monday, good agreement on drier regime excepting few snow showers around in E/NE, with potential for banding (and thus localised accumulations) the key uncertainty for now.

[tonbridgemole]

Oh what a fax chart.......

[Ian Brown]

The thrill of the chase is what makes many of us tick, well it does for me anyway.

Apart from the ECM shortening the cold spell compared to the 12Z I cannot see much wrong with the output. The bitterly cold E,lys being replaced by a slightly less cold N/NE,ly has always been the trend from the models. This can clearly be seen on the ensembles below.

http://cdn.nwstatic....bridgeshire.png

Personally im just happy with what the models are showing for Sunday/Monday and im not bothered about the duration of this cold spell because it is supposed to be spring anyway.

Yes, I don't really see any downgrade as such, the synoptic development from early Sunday to late Monday remains much the same, with slack winds from the North thereafter. A convective easterly when the push is heights is not West from Scandinavia will never last longer than what we are seeing projected here.

[winterof79]

Has the ECM even updated as both Meteociel and Netweather charts still have yesterdays 12z run?

Ooops... i will edit my post

[Tom Jarvis]

What is wrong with the ECM this morning it hasn't updated on meteociel

[Gibby]

Good morning. Here is the report of the 00z output from GFS, UKMO, GEM and ECM for this morning Thursday march 7th 2013.

All models show a change to colder conditions next week. Currently a SE flow blows across the UK in association with Low pressure down to the SW of the British Isles. Over the coming days this moves slowly East continuing to push troughs of Low pressure slowly North over the UK at the same time as backing winds off towards the East over the weekend and NE by Monday with cold air near Scandinavia flooding SW across all of the UK at this time.

GFS shows the flow backing slowly towards the North through the working days of next week as High pressure slips slowly South to the west of the UK. The bitter winds of Monday will decrease with the cold moderating somewhat from then on. Nevertheless, in the Northerly flow there will be bright spells and showers or hail, sleet and snow, especially near North and East Coasts but inland elsewhere through the afternoons. Frosts will be widespread and sharp at night. Through next weekend and onward the flow backs more Westerly bringing milder winds in from the Atlantic with any showers, chiefly in the North only at this stage turning back to rain. Later in the run the weather becomes more akin to where we should be at this time of year with High pressure to the SE and mild SW winds wafting across the UK with some rain, chiefly in the NW.

The GFS Ensembles show a four or five day cold spell starting from Sunday and lasting through the working week before most members bring rather less cold weather across the UK from the West accompanied by rain at times as High pressure to the NW collapses and allows the Jet to move North.

The Jet Stream forecast itself continues it to blow West to East well South of it's regular March position before a portion of it ridges North into the UK later next week flowing NW to SE over the UK then. The main punch of it though remains well South.running East across Northern Africa.

UKMO shows Low pressure over Europe and a direct Northerly feed over the UK with an inverted ridge of High pressure to the West of the UK from High pressure centred to the NW. A typical Spring mix of sunshine and scattered but locally heavy snow showers would occur with widespread and sharp overnight frosts with some accumulating snow in places over the hills and temporarily overnight in other areas too.

GEM shows a complex and slack cold Northerly flow over the UK later next week before winds fall light and back West with low pressure to the West bringing milder air across the UK later with rain preceded by snow in places.

ECM has watered down the cold this morning with it too showing just a slack Northerly flow next week with snow showers here and there before high pressure kills these off and eventually brings in rather milder air courtesy of Low pressure moving in at more Northern latiudes. feeding in milder and rainier SW winds across Southern areas at least towards the end of the run.

In Summary a cold spell is on the way. On comparison with previous output the cold is quickly modified as we go through next week and it may well be that Monday is the coldest day in the strong NE flow following the exit of the depression from the South. Through the week daytime's may not feel too bad in the South though bright and sunny intervals could be punctuated by some scattered but potentially heavy snow showers especially towards the middle of the week. Longer term it does now look that milder air makes inroads back into the UK from the West next weekend with a return to more average conditions again later in the period.

[fergieweather]

Hi Gibby: your summary pretty much replicates Exeter views. They also call for milder/wetter inroads being made later into 10-15d period but possibly earlier.

[mushymanrob]

..... and its gone... well the deep cold uppers anyway.

nice to see this mornings models in broad agreement, timing might be an issue, but the ukmo wasnt all that much out, the gfs and ecm have modified the severity of the cold and snow chances for many have diminished. which model was right? none of them. yet again 'middle ground' looks like becoming reality. the ukmo was right not to ramp the extreme cold.

after a dull wet and windy weekend a breif very cold day or so on monday into tuesday is likely, some snow? well showers for favoured exposed eastern areas, maybe some light ones further inland. but then a 'normal march cold' week ahead, some sun, night frosts. all models and the ensembles suggest a slow return to normal by next weekend.

[Gibby]

Hi Gibby: your summary pretty much replicates Exeter views. They also call for milder/wetter inroads being made later into 10-15d period but possibly earlier.

Thanks Ian. It's nice to have your backing that I'm reading through the charts correctly and not driven by hype of some of the media.

[Frosty.]

Turning much colder and very wintry is the message from the 00z models with bitterly cold air sweeping westwards from Scandinavia, by march standards, next week looks very cold and even by the end of next week, the ecm 00z is showing sub -10 T850 hPA into the far northeast and far southeast, next week will be cold with widespread sharp frosts and there will be snow showers, more especially for the n and e and also a risk of more persistent sleet and snow at times. The general pattern next week is for a block of high pressure to the north to transfer to the west of the uk and low to the northeast with a feed of arctic air, not a strong blast but within that flow there could be disturbances (troughs) so the most severe cold will probably be on mon/tues followed by some moderation but perhaps another surge of very cold air as troughs run south. Away from the showers there will also be some sunny weather next week.

As for the next few days, the south looks like having a lot of rain, just over an inch in places, so a big contrast to the last 2-4 weeks which have been generally very dry.

[fergieweather]

Thanks Ian. It's nice to have your backing that I'm reading through the charts correctly and not driven by hype of some of the media.

If you'd called for either -25C or +25C it might have been queried ;-)

[johnholmes]

Yes, I don't really see any downgrade as such, the synoptic development from early Sunday to late Monday remains much the same, with slack winds from the North thereafter. A convective easterly when the push is heights is not West from Scandinavia will never last longer than what we are seeing projected here.

Ian can you look at your last sentence please,especially the first part, what did you mean to say?

[johnholmes]

taking a longer term look beyond the expected cold spell

[Frosty.]

..... and its gone... well the deep cold uppers anyway.

No thats wrong mushy, the deep cold uppers are incoming for late sunday and throughout mon and tues, it looks like moderating after that but staying cold all next week with frosty nights and daytime temps well below average, Brrrr and some parts of the uk will have snow during next week.

[Methuselah]

I suspect being afraid it will not show the snowmaggedon he has been going on about for several days, falls of 1 ft widespread etc etc!

Aye, John. And it's not just this year, either...All eyes will tend to home-in on the most dramatic solution; whereas the models are forever homing-in on the only solution - the weather at T+0?

[BLAST FROM THE PAST]

The deepest cold thrust period gets shortened as it clears south on overnight runs, its something that has been seen all winter and looks like happening again. Ok its one run, however I believe that yet again there has been a big overcooking by some models [one would have hoped that for once that wouldn't occur?]. UKMO has moved towards the evolution but the LP to our SW as it moves into France travels further south on the models thus although subtle it is enough to have huge impact on the snow chances and deep cold longevity.

TEITS I wouldn't bother looking at your tv forecast until day before, I think some have been awful this winter too.

I for one am not surprised at what we see happening, it is a downgrade.. It'll be cold...no doubt...but its a small window of notable cold before it becomes a drag of annoying weather.

Another step forward from the UKMO but backward steps from ECM [although ECM 12z had shortened it so looking at the 00z that is now available its not too bad] and GFS......where have we heard that before?

BFTP

Edited March 7, 2013 by BLAST FROM THE PAST

[BLAST FROM THE PAST]

Aye, John. And it's not just this year, either...All eyes will tend to home-in on the most dramatic solution; whereas the models are forever homing-in on the only solution - the weather at T+0?

Yep and that shouldn't be right in this day and age, we have seen this winter some very poor displays by some very powerful computer models....and I'm not talking t168+ either.

BFTP

Edited March 7, 2013 by BLAST FROM THE PAST

[chris78]

No thats wrong mushy, the deep cold uppers are incoming for late sunday and throughout mon and tues, it looks like moderating after that but staying cold all next week with frosty nights and daytime temps well below average, Brrrr and some parts of the uk will have snow during next week.

are they really though...this is very deja vu....epic cold spell predicted...any nay sayers get lots of stick begins to be watered down.......yet some continue to think EPIC and record breaking breaking and Dec 2010 are all on the way.......it may be a cold spell but it is looking less likely to be a spell that will be remebered in 50 years...which is what many were saying yesterday...and in Dec 12 and in Feb.........and every time the models show a cold chart!

we will see what happens...but as ever when I see record breaking chats in 6 days my default is..that wont come off....Im not saying there wont be frosty nights and some snow in the east...but let be honest thats not what your were all getting exited about yesterday.

[Paul]

ECM have finally updated their servers with the data from the latest run, so it's now online

http://www.netweather.tv/index.cgi?action=ecm;sess=

[shaky]

Yes, I don't really see any downgrade as such, the synoptic development from early Sunday to late Monday remains much the same, with slack winds from the North thereafter. A convective easterly when the push is heights is not West from Scandinavia will never last longer than what we are seeing projected here.

i really dont undestand how the ecm is a downgrade though!!its practically same as last night and also the ukmo is better aswell!'some of the comments on here sometimes amaze me!!

[BLAST FROM THE PAST]

i really dont undestand how the ecm is a downgrade though!!its practically same as last night and also the ukmo is better aswell!'some of the comments on here sometimes amaze me!!

Yes I for one took the 12 z as todays 00z and I like the 00z better. Yes the UKMO has moved forward, but the GFS since yest, and ECM since yesterdays 00z have shortened the bitter blast [i think that is the crux that the deep bitter blast moves into France fairly quick]

BFTP

[nick sussex]

Looks like the models are moving to a middle ground solution with the east/ne flow.

The UKMO a little better in terms of potential than last night and the ECM/GFS shortening it. Thereafter it still looks cold but you lose the coldest uppers so some marginality coming into the equation after that point.

The ECM looks like it could bring some very cold nights with that slack northerly, the inference after that is a change to milder conditions as energy runs over the top.

Also there might be some fronts moving south in that northerly flow , with a chance of some snow but this could be a wintry mix on lower ground.

It certainly looks interesting for the next week or so.