Model Discussion 12Z 25/02/13

[mushymanrob]

Tbh, I dont see a returning to above average temps for a good while, and whilst the southern half of the uk may see something milder than of late we may well see some battleground situations ie mildvscold over central Britain in picticular. Its very hard to pick up any trend from the models at the moment, and I certainly would not rule out another bash of cold weather over the Uk during March. If youre one to go by the latest metoffice update for March, they say that March is likely to be below average temperature wise. Anyway lets get this mundane,non discript weather out the way, and perhaps later in the week we may see a definiate trend whether it will be milder or colder from the models.....!

i didnt think there would be above av temps, id settle for average! however this morning it does look like we could get something above average next week in the expected southerlies (or southeasterlies) IF the cloud breaks.

I am still confident of higher pressure to the north of the UK and a east/northeasterly flow

into the second week of March.

not being funny, but what do you base that on? theres no sign on the anomaly charts of that set up happening, which it should start to do very soon if that was a strong possibility.

maybe there is some data that can be interpreted that way, i dunno, imho theres too much data and its easy to cherry pick the bits that suit a position. this morning the models have drifted away from anything cold. even the ecm has now started to agree with what the gfs had first suggested. airflow from the southern quadrant next week as this high drifts southeastwards might see some pretty warm days if theres any lengthy sunny spells. then a gradual slip into something more unsettled is expected.

[ANYWEATHER]

A milder more unsettled trend though, as gibby just posted, can't disagree with an expert and faced with the gfs and ecm 00z ops, there does appear to be a new signal which has shunted the FI cold further north and east and allowed a more unsettled and milder regime to make significant inroads.

Gibby only posts to what the models are showing as of now/today etc, so if the models will paint a much colder outlook in a few days time his day to day summaries will reflect this!

[No Balls Like Snow Balls]

Looks like currently Sunday will be the best day in a fair while for the South of the UK. With quite mild temps and some sunshine. It will feel lovely compared to what we are used to. Hoooorah I hear most of you say lol

Edited February 27, 2013 by No balls like Snow Balls

[chris55]

As Ian mentioned last night the chance of some kind of battleground scenario can not be ruled out as we head through March. V low risk at present going on the models at face value, but with some very cold air to the north and east and a southerly biased Atlantic flow it's not an impossibility.

And BOM is always good for a laugh!

[Frosty.]

Gibby only posts to what the models are showing as of now/today etc, so if the models will paint a much colder outlook in a few days time his day to day summaries will reflect this!

Yes Gibby gives an unbiast view of the op runs and the ensembles plus the mean, it's clear there has been a shift overnight towards a milder and unsettled outlook, unfortunately, because I was hoping for a cold outlook with those unusual deep FI synoptics yesterday but based on the latest data, any suggestion the models are wrong today with their new signal is just hopecasting rather than having anything to back it up.

Edited February 27, 2013 by Frosty039

[Frosty.]

The Gfs 06z shows a mild Sly flow across southern britain next wednesday, temps rather closer to average further north, it also looks more unsettled than recent times with some showers scattered across the uk, even some longer spells of rain and feeling like spring has sprung with pleasant sunny spells and some areas remaining dry.

Edited February 27, 2013 by Frosty039

[Frosty.]

The 6z feels generous in FI and throws in a day or two of colder weather before the mild is back with a vengeance a few days later, the 6z pattern is more west based with all the arctic air flooding into the atlantic which is of course a complete waste and the uk is largely on the mild side of the trough until that colder blip, it's more like typical early spring weather for next week with temps around 11-13c, some sunshine but also showers and longer spells of rain, mainly for the north and west of the uk as pressure looks lowest there, then the trough staggers eastwards and allows a backwash of colder polar maritime air to mix out the mild uppers briefly.

Edited February 27, 2013 by Frosty039

[Captain Shortwave]

Whilst looking at the charts today, it doesn't looks too good on a cold perspective, but taking a looks at the area to our north between Greenland and Russia, the two models are handling things very differently 06z GFS tries to drop a lobe of polar vortex towards Scandinavia and then decides to redirect this to Greenland whilst the ECM just clears the polar vortex to siberia but a new area develops over northern canada and we are just in a normal atlantic set up.

ECM T168

GFS (06z) T160

Completely different, whilst both give similar results over the UK. One cannot say that in the grand scheme of things that the two models agree with each other. Just happens that our little speck on the world by coincidence it happens to be the same. All models have handled things over the Arctic poorly this winter, all models have thrown bits of polar vortex here there and everywhere. But I guess that is to be expected if there are less data collection points over that area of the globe.

[Captain Shortwave]

Interesting development on the ECM t144-168 charts perhaps where the low to the north

develops between Iceland and Greenland allowing heights to build to the east of this.

On this run the heights sink back southeast but this could be a new development and

one to watch.

Possibly, GEM shows the same sort of promise with high pressure starting to develop over Norway with the atlantic trough starting to slide east/south east through the channel

Only shown this chart to show the possibilities if the ECM decides to develop things in the mid range further. Would give a good battleground scenario.

If we get cold air over us of course

Edited February 27, 2013 by Captain shortwave

[bradymk]

Possibly, GEM shows the same sort of promise with high pressure starting to develop over Norway with the atlantic trough starting to slide east/south east through the channel

Only shown this chart to show the possibilities if the ECM decides to develop things in the mid range further. Would give a good battleground scenario.

Contintent is too mild though so any SE wind will not be cold, you would have to hope that the colder air that is way over in E Europe is further west. ECM Ensembles are still good for cold though longer term, trending colder. Question is now, do we want cold or would we rather warm sunshine?

[nick sussex]

We've seen today the ECM drop its more wintry tease for northern areas with the pattern pushed much further east and the cold heading into eastern Europe.

However its still showing a totally different set up to the GFS, the spoiler there is the shortwaves and western negative NAO.

It's really a stalemate on the ECM with still decent heights to the ne.Last nights NOAA extended discussions mentioned a chance that the largest positive anomaly could well develop in the east Pacific in week two and as we've seen from the winter this does not correlate well with high pressure over Greenland.

So that western based negative NAO may well be shorter than first thought.Looking at the De Bilt ensembles you've got the majority cluster there turning much milder for a time, the smaller cluster has colder conditions.

http://www.weerplaza...&type=eps_pluim

If you look at the wind direction that shows a cluster of e/ne flows around the 7th March onwards and then if you look at the dew points those go below freezing.

I think the suggestion from those colder ensembles is some form of pressure rise to the ne with low pressure eventually disrupting and sending energy into more southern Europe, that would tie in with the western negative NAO signal weakening as the main positive anomaly develops in the eastern Pacific, this would develop troughing in the USA plains, pull back any high pressure further west and lead to troughing in the Atlantic.

The ECM ensemble mean shows that troughing stuck to the sw and a stalemate of sorts, heights beginning to drop in the ne Canada as that positive anomaly begins to weaken and that strong east Pacific ridge.

I think for those hoping for a last wintry reminder the ensemble mean does show some interest. I'm not sure what the UKMO make of the situation re any cold into the second week of March, their MOGREPS suite might look different to the ECM trend, we'll see from their update soon.

I think what the output clearly shows is that western based negative NAO is a frustration if you're in the UK as the weak point is often in this area as the low pressure tries to edge ne with the cold funnelling sw to the west.

There is still however some uncertainty with shortwaves to the north and also whether there still might be a chance of some colder air effecting the far north.

So I think at the moment realistically its a case of seeing whether the models ditch that western based negative NAO into week 2 and develop troughing in the mid Atlantic with pressure rising to the ne.

To have any real chance of a decent wintry shot you need the coldest source which at this time of the year generally comes from the ne, whilst that cold pool remains relatively close then still a chance that could effect the UK, more especially the north.

If that doesn't happen then lets at least hope for some drier and sunnier weather , the latter has been sorely lacking for the UK in recent months.

[Nick F]

i think the problem ahead for the UK to get back under deep cold air and thus increase the snow potential is that the Polar Front Jet (PFJ) is going to stay way to the north over Sern Greenland and east across the Norwegian Sea into Scandi. This means the deep cold will be bottled up at high latitudes. So even though we are seeing troughing/low pressure so far south over the Atlantic to the west of Iberia - this is a result of strong energy going into to a Sub-Tropical Jet. Between the STJ and PFJ where the UK lies, the air is not particularly cold to depth and will become less cold as we see the current high slip SE into Europe and troughing takes hold to the SW bringing milder air in.

Think we need to see the PFJ drift further south if we are going to see any chance of winter's return in the next few weeks.

[No Balls Like Snow Balls]

No sign of any widespread rain until at least Tues/Weds next week. Over 2 weeks of relatively dry weather UK wide hasn't been seen in a fair while. I am ready to move on from dull and benign now though.

[Glacier Point]

I would make the most of next weeks relatively benign conditions, our west based NAO looks like heading towards a more east based solution in the longer term associated with developing heights over Alaska and the Arctic. Spring likely to feel a long way off for the middle part of March when I and 59,999 other people will be enjoying the Cotswold fresh air.

Today's GEFS consolidating yesterday's CPC idea of loosening the block over Canada in favour of Alaska, which builds heights to our north and north-east.

[Bobd29]

I would make the most of next weeks relatively benign conditions, our west based NAO looks like heading towards a more east based solution in the longer term associated with developing heights over Alaska and the Arctic. Spring likely to feel a long way off for the middle part of March when I and 59,999 other people will be enjoying the Cotswold fresh air.

Today's GEFS consolidating yesterday's CPC idea of loosening the block over Canada in favour of Alaska, which builds heights to our north and north-east.

Me too GP, when was it ever warm at Cheltenham mid March?

[TEITS]

I would make the most of next weeks relatively benign conditions, our west based NAO looks like heading towards a more east based solution in the longer term associated with developing heights over Alaska and the Arctic.

Spot on in my opinion GP. Whilst I haven't posted much recently the overall trend towards a cold March appears increasingly likely and a east based NAO has often been hinted at on the models.

Im actually slightly disappointed though. After giving British Gas plenty of my money due to the overall cold winter, it appears they will get even more from me due to the likelyhood of March being a cold month.

[Severe Siberian icy blast]

Spot on in my opinion GP. Whilst I haven't posted much recently the overall trend towards a cold March appears increasingly likely and a east based NAO has often been hinted at on the models.

Im actually slightly disappointed though. After giving British Gas plenty of my money due to the overall cold winter, it appears they will get even more from me due to the likelyhood of March being a cold month.

Sorry but il believe it when I see it . Signals mean nothing until we get inside the 96hr time frame.

[snowmadchrisuk]

Just a quick question what time do the ensembles update on Netweather these days ? 3 hours after the Model run and there still showing the 00z's.

[Summer Sun]

Just a quick question what time do the ensembles update on Netweather these days ? 3 hours after the Model run and there still showing the 00z's.

You can find the 06z ensembles here - http://null/TWO/ensembles/

[Bristawl Si]

Me too GP, when was it ever warm at Cheltenham mid March?

I've experienced a few mild ones in the last 15 years - 2011 Albertas Run, Ryanair Chase - conditions came just right for this sun-loving horse! Nice day!

[snowmadchrisuk]

You can find the 06z ensembles here - http://jp2webdesign..../TWO/ensembles/

Thanks Gavin .

[Captain Shortwave]

You can find the 06z ensembles here - http://jp2webdesign..../TWO/ensembles/

I see there are 2 straw-clutches (I mean massive outliers from early on), go perturbations 10 and 11, I believe in you

[Frosty.]

Spot on in my opinion GP. Whilst I haven't posted much recently the overall trend towards a cold March appears increasingly likely and a east based NAO has often been hinted at on the models.

Im actually slightly disappointed though. After giving British Gas plenty of my money due to the overall cold winter, it appears they will get even more from me due to the likelyhood of March being a cold month.

We better make the most of next weeks mild mixed weather then since winter could bite back towards mid march

[snowmadchrisuk]

I see there are 2 straw-clutches (I mean massive outliers from early on), go perturbations 10 and 11, I believe in you

run 10 still looks to me the obvious solution , if I could put all bias aside , it is all to do with that low to our West , depending on which way it decides to stretch itself alters the outcome with opposite effects. I think as ensemble members are still clinging on to that solution (50% btw maintain some kind of heights to our North and near Greenland) We can not yet discount a colder outlook.

[snowmadchrisuk]

For Iceland this has to be one of the biggest spreads I have ever seen ....