Model Output Discussions 12z 08/03/17

[Summer Sun]

Easy to spot the UK

[Frosty.]

The Ecm 12z becomes much colder from the north for a time next week with showers becoming heavy and more wintry with hail and thunder, cold enough for sleet and snow in some of the showers, especially for northern hills with temps dropping like a stone during showers but then recovering in the sunny spells between and cold nights with frosts and icy patches following late showers but during mid week the arctic maritime flow is cut off and temperatures start to recover. Following a brief ridge it becomes more unsettled from the north Atlantic with the northwest of the uk catching the most unsettled conditions whereas the s / se generally improves by T+240.

Edited April 22, 2017 by Frosty.

[Robin2012]

1 hour ago, knocker said:

I find the quite impressive part of this evening's gfs is the speed it cuts off the Atlantic around the T200 mark. it drops the deep trough spawned in N.Canada into mid Atlantic and rapidly intensifies the east European ridge in conjunction with Azores which disintegrates the trough to our east to set up a surface high cell over Scandinavia.Which of course places much of the UK into an easterly flow.

Not unsupported by the GEFS but I would not expect this evolution to remain unchanged over the next few runs.

Sidney was quite phlegmatic when I mentioned the short lived northerly.

Phew what great news that is !!! I`m almost as happy as Summer Sun when he spots the charts have suddenly changed from cold/cool to mild/warm with this news, actually can anyone be as happy as that??

[snowray]

7 minutes ago, Robin2012 said:

Phew what great news that is !!! I`m almost as happy as Summer Sun when he spots the charts have suddenly changed from cold/cool to mild/warm with this news, actually can anyone be as happy as that??

Generally speaking charts revert back to the UK default as we enter the T48/T72 timeframe, cold air gets shifted further east and hot weather further south in Summer, not always, but most of the time. We generally end up in the middle ground of not too cold in winter and not very hot in summer, its called the UK climate.

And It matters not what shows up on charts post T120, they are as far out today as they were 15/20 years ago. Its all just a bit of fun after all. 

[Frosty.]

53 minutes ago, snowray said:

Generally speaking charts revert back to the UK default as we enter the T48/T72 timeframe, cold air gets shifted further east and hot weather further south in Summer, not always, but most of the time. We generally end up in the middle ground of not too cold in winter and not very hot in summer, its called the UK climate.

And It matters not what shows up on charts post T120, they are as far out today as they were 15/20 years ago. Its all just a bit of fun after all. 

I love the uk climate, warts and all. It's full of variety. Some of us could see snow falling between Mon / Wed, colder in late April than it was at christmas.

[snowray]

8 minutes ago, Frosty. said:

I love the uk climate, warts and all. It's full of variety. Some of us could see snow falling between Mon / Wed, colder in late April than it was at christmas.

Theres more time to go for it still to be colder than Christmas, I have known it to be colder in early June than Christmas, it has snowed in early June, when was the last time it snowed on Christmas day? 

Edited April 22, 2017 by snowray

[Frosty.]

19 minutes ago, snowray said:

I have known it to be colder in early June than Christmas, it has snowed in early June, when was the last time it snowed on Christmas day? 

Yes you're right about June, snow stopped play during a cricket match on June 2nd 1975 at Buxton and then there was a hot summer..can't remember when it last snowed on Christmas day though.

Anyway, cold snap on the way..18z rolling

Edited April 22, 2017 by Frosty.

[knocker]

I notice Matt H considers this frontal wave may cause a few headaches for forecaster Mon/Tues vis significant snow in central areas

Edited April 22, 2017 by knocker

[knocker]

After mid week and a cool showery couple of days, there is brief ridging before the next intense upper tough starts tracking east en route from the energy repository in northern Canada on a strong jet running west-east. The associated fronts with this system will approach N. Ireland and Scotland 00z Saturday and traverse the country tracking SE over the next 24 hours.

And this is where it gets complicated again, The upper trough continues on its merry way but it deconstructs over the UK as the high pressure in eastern Europe/Scandinavia, along with the HP to the south west intensifies creating quite a complex arrangement of cut off lows with the pertinent one to the east. This results in a not bad looking surface analysis with reasonable temps and still not much rain around

This evolution is bound to be adjusted over the next couple of days so not much point in dwelling on detail. So in a nutshell the mid week cool showery weather will give way to unsettled weather from the west by the weekend which in turn will be replaced by more benign high pressure at the beginning of next week with temps on the rise.

[Frosty.]

The Ecm 00z shows a cold snap incoming from the north , especially for tues / wed with sunny / clear spells and wintry showers, widespread night frosts with icy patches and a chance of temporary lying snow here and there but more especially on hills and further north.

Edited April 23, 2017 by Frosty.

[knocker]

The ecm aong much the same lines as the gfs bringing fronts across the country but thereafter differs somewhat before promoting the high pressure On Monday it whips a small perturbation through the northern half of the country which has rushed in from the south west, spawned by the upper trough that has sunk a fair way south in the western Atlantic.Thereafter it quickly establishes the high pressure with the trough deconstructing in mid Atlantic.

[Frosty.]

Amazing contrast from north to south tomorrow on the Gfs 00z, pleasantly mild in the south and bitterly cold across parts of scotland with heavy snow!

Edited April 23, 2017 by Frosty.

[Summer Sun]

After a chilly few days Thursday is likely to be the transition day with milder air starting to move in

Still chilly in Scotland and NW England to end the week but milder for most other areas

Saturday could see temps drop again before rising on Sunday

[Frosty.]

In a nutshell, the first half of the new working week becomes unseasonably cold from the north with wintry showers and night frosts with temporary lying snow at times, especially on hills and further north.

Edited April 23, 2017 by Frosty.

[Summer Sun]

Quite a pleasant May day from the 06z after a mixed weekend

[Captain Shortwave]

So like others have said, a few very chilly days ahead with an air mass which could produce a mix of hail/sleet or even snow in the heavier showers.

      

Just to show how interesting this Spring has been, the models if correct could switch us from late winter to early summer potentially.

      

It does appear that we will initially build a weak area of heights over Scandinavia which starts to prevent the eastwards advancement of Atlantic weather systems before we see a deep Atlantic trough develop with the winds potentially swing around towards a southerly quadrant. 

GFS similar

      

So a cold week to come followed potentially by a rapid warm up at the start of May, the models possibly hinting at an early taste of summer. We will have to wait and see but given we have seen some unseasonable warmth and then potentially snow falling just about anywhere this week, it is perhaps no surprise that we could see another switch back to a large temperature anomaly.

[knocker]

Getting a handle on the evolution over the next 14 days is no easy matter at the moment using the NOAA, GEFS and EPS anomalies.Although there is agreement on major pattern changes no agreement as yet on how these will run.In the 6-10 period all agree on the Atlantic trough with the eastern European ridge intensify and stretching NW north of the UK and various interpretations of the role played by the Azores, Towards the end of this period the GEFs and EPS retrogress the trough and have the high pressure becoming much more influential and thus more benign and pleasant weather over the UK with temps on the rise.

In general they all continue this theme in the next period but I emphasize in general because it becomes a tad complex, In a sense the EPS is the most straight forward with the trough running a long way south east of Iberia (cut off lows ahoy) and the high pressure ridging just to the east of the UK. Ergo gentle zephyrs from SSW and temps significantly above average. Note the GEFS pays a fair amount of lip service to this idea and NOAA a bit of a nod. I suspect it will take a couple of days or so before the situation becomes clearer. Either way the situation is encouraging

[Frosty.]

It's late April but there are still snow warnings!

A wintry snap on the Gfs 6z with sharp frosts and snow..an echo of winter is on the way.

Edited April 23, 2017 by Frosty.

[Fourty Point Three Degrees]

Some nice barbecue-tastic looking charts for week 1 of May!! A sign of things to come?? we'll see..

[skifreak]

Looks like the I'm in Heathrow about to leave the UK model is correct again and it will snow at home tomorrow ! 

[Frosty.]

15 minutes ago, skifreak said:

Looks like the I'm in Heathrow about to leave the UK model is correct again and it will snow at home tomorrow ! 

Indeed, a spell of heavy snow is expected across northern Scotland tomorrow..weather warnings have been issued.

Looking at the Gfs 12z..it looks snowy up north tomorrow.

Edited April 23, 2017 by Frosty.

[lassie23]

Good to see that no members are cherry picking charts showing their favoured weather conditions.

[Frosty.]

2 minutes ago, lassie23 said:

Good to see that no members are cherry picking charts showing their favoured weather conditions.

It's tomorrow's weather..looks wintry ooop north

[lassie23]

Just now, Frosty. said:

It's tomorrow's weather..looks wintry ooop north

I didn't mean you lol and yes snow for the lucky people up in Scotland

[Frosty.]

1 minute ago, lassie23 said:

I didn't mean you lol and yes snow for the lucky people up in Scotland

Oh I c..I forgive you then.

Edited April 23, 2017 by Frosty.