Winter Model Discussion 18Z 19/2/13 onwards.

[legritter]

Shiver me timbers ,cold continental air with a stiff wind ,cant believe that some of us Crave for this synoptic situation .a very interesting period coming up going by todays data and modells and an interesting weekend with possible snow chances but luck needed on that one .a strong possibility of low pressure being pushed south across us in the further outlook .i just hope that many of us can catch something that would be a good end to a mixed winter .catch up later after the ecm and uk met ,

[Isolated Frost]

When you see output like this 7 days out, you take notice. EC promotes big retrogressive signal- and with that the first true arctic outbreak... I'm sure 264/288 would be an unstable Scandi vortex- ridging GL heights and a conveyor belt of weak modified low pressure systems across Iberia; north and north-easterlies dominating with low thicknesses and high convection levels. If we see anything of the sort, then perhaps I'll keep my cold goggles on for at least a few more weeks; anything beats this low cloud and wintry drizzle easterly!

[snowking]

Let the battle of the troughs commence then!

Will post in more detail after the 12z's but at present, the ECM EPS suite is the most progressive with the Scandinavian trough (not a bad suite to have on side - I would be more concerned if it was only the GFS suite on board)

The issue, though, remains that if we see the battleground take place, as nick has said, the colder air really just gets mixed out. At current face value I would be really rather excited if I was in the north of Scotland/n Ireland, but elsewhere given the time of year, I wouldn't be holding my breath just yet

Of course should we find that the Atlantic jet has been overplayed (a recurring theme this winter) then the battle is likely to take place much further S and W of the UK, allowing us all to stay on the colder side of the jet stream and bringing fun and games for all - more especially our northern contingent.

The ensemble means edging towards the idea of the Scandi trough winning is an encouraging sign - now lets see the GFS/GEM come fully on board with the idea

Lets also not get too hung up on 850 temps this far away - pushes from the north always tend to get watered down inside 144 hours, but encouraging to see -12's and 16's in there - even watered down to -10c we would see some real fireworks up in the north

SK

[Nimbus Nix]

If we see anything of the sort, then perhaps I'll keep my cold goggles on for at least a few more weeks

That 500mb pattern looks rather like some goggles too at first glance

[No Balls Like Snow Balls]

OMG GFS has overtaken UKMO in the day 5 verification stats. Haven't seen GFS in 2nd place for a fair old while.

[No Balls Like Snow Balls]

I have been searching for some verification stats for the GEM and JMA and came across the below:-

If I am reading this right then at the last verification date the best rated model is as follows

(this is for America only I believe)

1, ECM

2, UKMO

3, GFS

4, GEM

5, JMA

Hopefully I am not reading it upside down. It made me wonder why the METO hold the JMA in such high regard.

[pip22]

Is any of the models showing any unsettled weather on its way?

Im kind of bored on settled weather now.

Dont tell me theres a drought coming up.

Edited February 21, 2013 by DavidCameronSucks

[SMU]

I have been searching for some verification stats for the GEM and JMA and came across the below:-

If I am reading this right then at the last verification date the best rated model is as follows

(this is for America only I believe)

1, ECM

2, UKMO

3, GFS

4, GEM

5, JMA

Hopefully I am not reading it upside down. It made me wonder why the METO hold the JMA in such high regard.

Its meaningless. Because its NH.

Look at the regionals for GFS & you soon realise that its shizzle.

S

[No Balls Like Snow Balls]

Its meaningless. Because its NH.

Look at the regionals for GFS & you soon realise that its shizzle.

S

I don't understand lol, explain please

[Frosty.]

Is any of the models showing any unsettled weather on its way?

Im kind of bored on settled weather now.

Yes they are, probably becoming more unsettled by the end of next week or start of following week from the northwest and of course it will be more unsettled in southern britain for the next 4-5 days with occasional light to moderate snow flurries/showers, perhaps some heavier snowfalls locally during saturday & sunday, kent in particular looks a hot spot for significant snow, I noticed RJS got mocked yesterday for suggesting several inches of snow but he could end up being closer than some of those who scoffed at him.

Edited February 21, 2013 by Frosty039

[Summer Sun]

Is any of the models showing any unsettled weather on its way?

Im kind of bored on settled weather now.

ECM and GFS look unsettled in FI for the start of spring

But up-to next Thursday at least this sums up what we can expect

[pip22]

ECM and GFS look unsettled in FI for the start of spring

But up-to next Thursday at least this sums up what we can expect

Thats looks interesting, looks like the ECM charts are showing Northerly winds coming our way. Looking quite good. Unless there is a warm sector involved. Edited February 21, 2013 by DavidCameronSucks

[Frosty.]

Thats looks interesting, looks like the ECM charts are showing Northerly winds coming our way. Looking quite good. Unless there is a warm sector involved.

Yes it would be nice to think we can eventually swap a very cold Easterly to an Arctic Northerly, the latest ecm and gfs are looking promising in FI and hopefully that trend will continue to firm up in the days ahead.

Edited February 21, 2013 by Frosty039

[Frosty.]

Well, the met office are not expecting the cold snap in early march shown on most of the models so far today, a change to more unsettled and less cold weather from the northwest is what they anticipate, actually they have been saying this for days, even when the models were showing continued high pressure so it's probably best to NOT get suckered into thinking that an arctic outbreak is likely after next week because according to the experts, it won't happen, it's not even hinted at.

Edited February 21, 2013 by Frosty039

[Peejayem]

Frosty...a bit of revisionism from you there re RJS predictions. He was suggesting more than 'several inches'.....20-30 cms in a Great Lakes type event was being mooted!

Several inches in a few spots does seem quite possible, i think

[Thundery wintry showers]

The GFS's temperature projections for overnight minima have been a fair way out during yesterday and today for much of the country- I can only guess that the GFS was 'assuming' clear skies and sunshine when in reality stratocumulus has been very extensive, thus helping the temperature to hold up overnight.

If we look at the forecast skew-t for London we still have an extensive "dry lid" on convection above 850hPa:

http://cdn.nwstatic.co.uk/gfsimages/gfs.20130221/06/60/sound-London-60.png

...but the skew-t forecasts for East Lothian have the "dry lid" temporarily disappear at T+60:

http://cdn.nwstatic.co.uk/gfsimages/gfs.20130221/06/60/sound-EastLothian-60.png

This suggests that NE England and parts of SE Scotland may have a 24-hour window on Saturday and into early Sunday when we see sleet and snow showers develop quite widely, and some bright or sunny intervals are likely to develop in between. Showers are likely to start off generally as snow but will then turn to a sleety mix, especially near the east coast, as slightly milder air comes around from the south-east. The milder air will also be more stable and the "dry lid" will return above the 850hPa level which suggests a return to dry cloudy weather away from the west by Monday.

Projections suggest that high pressure will become more strongly established over Scotland into next week which may result in generally sunnier skies over Scotland, Wales and the western side of England, but eastern England is likely to have a cloudy week.

For the long-term, the ECMWF is showing a west-based negative NAO and cold air coming down from the W and NW. That setup can bring sunshine and wintry showers when we don't get much secondary low development, but when secondary lows track over the south we can end up with grey wet weather, and possible snow on the northern flank of the systems. It's all a long way off and how cold remains uncertain, but chances are that when we get the attempt at a northerly, the weather will generally turn more unsettled.

[Frosty.]

Frosty...a bit of revisionism from you there re RJS predictions. He was suggesting more than 'several inches'.....20-30 cms in a Great Lakes type event was being mooted!

Several inches in a few spots does seem quite possible, i think

No it's not, if there are several inches in places, there will be some deeper drifts caused by the fresh/strong Easterly/NEly winds, probably drifts over over 2 foot (24 inches), the point is, there has been an upgrade and some areas towards the east and southeast look like having significant snow in the form of frequent showers in the next 4-5 days, it sounds all white to me if you live in the favoured areas, bitter cold and snow showers is what most of us dream about, sadly it's not a nationwide event with the north being more settled with freezing fog and sharp frosts.

[492]

Well, the met office are not expecting the cold snap in early march shown on most of the models so far today, a change to more unsettled and less cold weather from the northwest is what they anticipate, actually they have been saying this for days, even when the models were showing continued high pressure so it's probably best to NOT get suckered into thinking that an arctic outbreak is likely after next week because according to the experts, it won't happen, it's not even hinted at.

But with ''A large degree of uncertainty''.

[Frosty.]

But with ''A large degree of uncertainty''.

yes but no mention of Northerlies at all was surprising considering the large greenland high and scandi trouging shown on the latest ecm and gfs.

Edited February 21, 2013 by Frosty039

[SomeLikeItHot]

Well, the met office are not expecting the cold snap in early march shown on most of the models so far today, a change to more unsettled and less cold weather from the northwest is what they anticipate, actually they have been saying this for days, even when the models were showing continued high pressure so it's probably best to NOT get suckered into thinking that an arctic outbreak is likely after next week because according to the experts, it won't happen, it's not even hinted at.

Fergie mentioned the northerly solution was in the met office ensembles, yesterday I but a minority solution. I made a comment yesterday that this type of single forecast they issue is fairly useless in many cases as its either an average of two very different outcomes - and averages can be less informative than individual solutions in a bi-modal situation.

Looking through models and ensembles today, I can at around 10-15 days either a northerly, the atlantic getting in, or continued high pressure on a few solutions. Giving the rough weightings of these three solutions would be more useful information in my opinion than just some single estimate with words about great uncertainty.

[Frosty.]

Fergie mentioned the northerly solution was in the met office ensembles, yesterday I but a minority solution. I made a comment yesterday that this type of single forecast they issue is fairly useless in many cases as its either an average of two very different outcomes - and averages can be less informative than individual solutions in a bi-modal situation.

Looking through models and ensembles today, I can at around 10-15 days either a northerly, the atlantic getting in, or continued high pressure on a few solutions. Giving the rough weightings of these three solutions would be more useful information in my opinion than just some single estimate with words about great uncertainty.

A breakdown from the northwest after next week is likely, and less cold is probable relative to the freezing cold we will have in the coming days.

[mushymanrob]

a cold spell in early march? pm air with snow showers? possible but not an uncommon event. atm thats a long way off, but the chances of a prolonged cold spell (as in freeze) is pretty remote. atm theres no sign of any spring warmth, but thats only a question of time.

[Mair Snaw]

Just a quick post to inform that we have been seeing a few snow grains blowing in the wind here in the peak district for the past few hours. strange as the bbc were showing light snow all week here today until it changed this morning to mainly cloudy and no sign of snow.....not expecting to see very much here in the next few days but i do hope that some in the south get to see some fun for a change. having lived in Essex as a child i grew up knowing mainly the warm winters of the late 80's and 90's so i guess the south is due some . good luck to all the lamp post watchers this weekend, i for one will be keeping my eyes peeled

[SomeLikeItHot]

I take it not much to be said by the silence on here!!

Or more likely there has been little model output for hours and the current runs are just starting to roll out to the interesting part ie where they may differ from the prior runs at say +120 hours.

[Severe Siberian icy blast]

This was me when I woke up one morning in January

I couldn't believe my eyes

Lets hope we all have some surprises in store this wkend !!