Model Output Discussion - 28th November - 4th December

[Tim Bland]

GFS 06Z still showing sub -5C uppers and 528Dam right down to the south coast early next week. Would give evryone a chance of seeing some wintry showers and even a temporary covering north of the Midlands. Things then turn milder as the pattern goes flat again. Another ridge develops in Deep FI with some WAA up to greenland could be more than a toppler this time but a long way to go before then.

BTW this is what I call cold zonality!

Edited November 28, 2011 by Tim Bland

[Bobby]

Fierce storm for the north for saturday:

Hurricane force that

[Thundery wintry showers]

Yes, the models are agreed on a significant "window of opportunity" for cold zonality associated with a Euro trough and northerlies pumping cold air into the eastern Atlantic. After a mild start to the week with some rain spreading east on Tuesday, a north-south split looks likely from Wednesday to Friday with sunshine and showers (some wintriness in the heavier showers) and milder conditions with outbreaks of rain in the south. It's really from Sunday onwards that the cold north-westerlies set in, so subject to some change, but all three models are currently agreed on at least a couple of days of sunshine and wintry showers with the chance of lying snow to low levels in parts of Ireland, Scotland and northern England, and a wintry mix in the south. In these situations there is always the chance of northern/eastern flank frontal snow when the next system pushes up against the cold air.

However since the widespread snowfalls don't set in until T+120 or later there is still scope for the outlook to change.

In the meantime, going back to Barb's post, both GFS and ECM are indicating severe winds in the north on Saturday, This is certainly worth keeping an eye on, as while GFS often overdoes these lows, having ECM in support of GFS suggests that there's a high likelihood of something similar coming off.

[BLAST FROM THE PAST]

Having looked through the 18z ensembles from the GEFS, and the individual members, it appears that there is a noteworthy risk of a severe wind event around next Sunday/Monday. It's beyond the reliable but around 4/5 runs produce winds of a similar strength with a similar synoptic set up.

Hi Crewe

Yes a period I've been keeping my eye on, the storm is still being projected for the period 2-4 and its depth seems to remain fairly bullish with the models. Could be a notable weather event.

BFTP

[Liam J]

A very distrubed outlook for the coming week with gales and rain the order of the day, it will be a very windy week with potential for a few noteable wind events to occur over the next 5 days - Tuesday and Wednesday gales or severe gales, particularly Wednesday evening and night. As we get towards the end of the week my attention is drawn to the possibilty of a damaging major storm affecting Northern Britain with storm force winds over coasts and hills with severe gales over land during Saturday. This has been picked up by various models and ens so this event is not without support.

Edited November 28, 2011 by Liam J

[Iceaxecrampon]

Still on for a week today.

If we survive next Saturdays LP that is.

:o

Northern pipeline begins to open at last.

Not exceptional cold but something festive for Ambleside at the weekend.

We live in hope.

A very distrubed outlook for the coming week with gales and rain the order of the day, it will be a very windy week with potential for a few noteable wind events to occur over the next 5 days - Tuesday and Wednesday gales or severe gales, particularly Wednesday evening and night. As we get towards the end of the week my attention is drawn to the possibilty of a damaging major storm affecting Northern Britain with storm force winds over coasts and hills with severe gales over land during Saturday. This has been picked up by various models so this event is not without support.

Yes - This cold run was modelled 10 days or so ago for the beginning of December - still confident.

[nick sussex]

Will the Azores high be a friend or a foe for cold lovers in the extended timeframe?

I've been looking at this from across the models and where it centres is likely to be a difficult call.

Before we get to this problem in the earlier timeframe theres lots going on, basically every type of weather thrown at the UK over the next 10 days, gales, some snow, rain, at least it won't be boring!

There are some uncertainties regarding shortwaves and how far south cold air will get, in terms of the GFS and its snow precip charts together with its 850's projections I would advise people to not read too much into these until within 96hrs.

So upto 240hrs the pattern looks solid overall.

After this we are likely to see the Azores high ridging ne but where will it set up?

The UKMO given todays further outlook seem to think it will set up far enough north to bring some surface inversions especially into southern areas, can we get it a bit further north still?

At this time I wouldn't rule out the high getting far enough north to pull in a colder east/ne flow especially for the se and east.

It's unlikely given the strength of the jet that it will be able to get far enough north and east to develop more interest than that though, three things to watch out for in later output, how long troughing can remain in central Europe, low heights to the north , will they lift a bit further north away from southern Greenland, finally how much amplification will be left upstream in the eastern USA, all these will effect where the Azores high ridges.

Overall given the teleconnections and the cold stratosphere then if we can see this more seasonal interlude end with a cold surface inversion then IMO that would be making something better out of the pattern than we could have possibly expected earlier.

[kold weather]

I'd say foe Nick, especially with the PV as it is right now...

Anyway lots to get through before then, as some people have picked up on the models really blow up the low on the 3rd, both the ECM and the GFS have a very powerful low developing. Pattern could prove to be very good eventually for the higher ground over N.England and Scotland if we can get a little secondary depresson whizz along.

[Frosty.]

It's now more likely than not that there will be a cold plunge from the arctic arriving by sunday after a stormy spell hits the north on saturday, it could last a few days before a ridge associated with the azores/atlantic high to the south west of the uk spreads north east and cuts off the cold air supply but the ecm may prolong it further although the ecm version is not as potent as the gfs at the moment, expect snow and hail showers to the far north and east if this arctic blast occurs but inland areas could end up sunny and cold with just isolated snow flurries and widespread sharp frosts with heavier more widespread coastal snow showers unless there are any embedded troughs although that seems unlikely given the short duration of the event. It then looks like atlantic high pressure will become the main feature towards the end of next week with low pressure to the north and winds coming around the top of the atlantic high and over the uk, air sourced from mid atlantic which will still feel cool but temps back to average of 8-10c but maybe milder later with occasional polar maritime incursions just grazing northern scotland but the gfs 06z ends with another arctic blast so any anticyclonic spell towards mid dec may be brief.

[nick sussex]

I'd say foe Nick, especially with the PV as it is right now...

Anyway lots to get through before then, as some people have picked up on the models really blow up the low on the 3rd, both the ECM and the GFS have a very powerful low developing. Pattern could prove to be very good eventually for the higher ground over N.England and Scotland if we can get a little secondary depresson whizz along.

Well of course we could end up with the high too far south but at least for the UKMO initially they seem to think it will centre far enough north to pull in some drier and colder air from the continent especially towards southern areas.

I'm not going to rule out the high a little further north than that for the timebeing, we'll see over the coming days, anyway at least there is some weather to discuss for now rather than the tedious last few weeks.

[jonnybradley]

I'd say foe Nick, especially with the PV as it is right now...

Anyway lots to get through before then, as some people have picked up on the models really blow up the low on the 3rd, both the ECM and the GFS have a very powerful low developing. Pattern could prove to be very good eventually for the higher ground over N.England and Scotland if we can get a little secondary depresson whizz along.

I base this on nothing other than a bad feeling but can see this high moving back over Europe, replacing the high thats been stuck there for the last how ever many weeks now

[johnholmes]

In the meantime, however tedious some feel the weather has been, there has been and is predicted to be again quite important changes in the weather-storms, flooding, rainfall, even sowfall for hillier areas?

Another couple of deepening depressions due over the weekend long before manyana land MIGHT happen.

[Backtrack]

In the meantime, however tedious some feel the weather has been, there has been and is predicted to be again quite important changes in the weather-storms, flooding, rainfall, even sowfall for hillier areas?

Another couple of deepening depressions due over the weekend long before manyana land MIGHT happen.

What is manyana land?

[johnholmes]

strictly speaking (its Spanish) for tomorrow, but usually used in the sense of its unlikely to happen!

Edited November 28, 2011 by johnholmes

[P-M]

What is manyana land?

Manyana is tomorrow in erm Spanish is it or something like that? So think he meant tomorrow as is in FI?

[Backtrack]

Oh right.

Thanks guys.

[johnholmes]

not to worry b I was simply trying to steer the model thread into more likely territory. I do find it a touch tiresome that pre T+144 hardly ever gets a mention unless its to mention ejection of short waves or what is happening over the states but with the clear intention of talking post T+144.

Obviously we are all free to chat about what we wish but it does get a bit like a stuck record.

For those interested, the first indication of the low(s) for the weekend can be seen on the T+120 Met O Fax chart, the area with no isobars close by Newfoundland. All the models then treat it rather differently then as it starts to develop, a good intro is to read the post by chio on the dedicated thread to it. Its a result of the very large temperature differences north to south between Greenland and the SE end of the north Atlantic which is causing this run of deep lows tracking across the ocean towards the NW of our shores. As each tracks east so the air is slowly turning a little less mild from the north and this will continue into next week.

Edited November 28, 2011 by johnholmes

[Backtrack]

not to worry b I was simply trying to steer the model thread into more likely territory. I do find it a touch tiresome that pre T+144 hardly ever gets a mention unless its to mention ejection of short waves or what is happening over the states but with the clear intention of talking post T+144.

Obviously we are all free to chat about what we wish but it does get a bit like a stuck record.

For those interested, the first indication of the low(s) for the weekend can be seen on the T+120 Met O Fax chart, the area with no isobars close by Newfoundland. All the models then treat it rather differently then as it starts to develop, a good intro is to read the post by chio on the dedicated thread to it. Its a result of the very large temperature differences north to south between Greenland and the SE end of the north Atlantic which is causing this run of deep lows tracking across the ocean towards the NW of our shores. As each tracks east so the air is slowly turning a little less mild from the north and this will continue into next week.

Fully agreed. I'm all for cold and snow, but I love the wind and rain. The Atlantic is such an interesting feature, and such a great influence on our weather, it certainly should not be ignored by people just looking for the prospect of snow.

This type of weather is really exciting. We don't generally get strong winds around my area because it's in a dip, and pretty tightly enclosed. But according to the GFS, on Saturday we COULD see a quite intense storm. Looking forward to it! B)

[jonnybradley]

For those interested, the first indication of the low(s) for the weekend can be seen on the T+120 Met O Fax chart, the area with no isobars close by Newfoundland. All the models then treat it rather differently then as it starts to develop, a good intro is to read the post by chio on the dedicated thread to it. Its a result of the very large temperature differences north to south between Greenland and the SE end of the north Atlantic which is causing this run of deep lows tracking across the ocean towards the NW of our shores. As each tracks east so the air is slowly turning a little less mild from the north and this will continue into next week.

Good post John and thanks for the heads up. Just wondering which thread you are referring to? is it the "29th November - 6th December 2011 Atlantic Storms", hell am off to read it anyhow if not, looks interesting.

Edited November 28, 2011 by jonnybradley

[Andy_]

Very cold Friday morning in Scotland before the next big storm system moves in

[AWD]

GFS 12z still as -5c 850's covering the country this time next week! Should bring some low level snow to Scotland at least, as well as higher ground of northern England!

All in association with the deep area of LP running NE past Scotland at the weekend! Strong winds in the North!

Watch how this LP system develops and tracks in the coming days, as this will determine what kind of pM shot we get afterwards! A more southerly track and the pM airflow may get further south, a more northerly track and the pM airflow may just be reserved for Scotland! Intensity needs to be good too to drag the cold air down on it's western flank when moving NE

into Scandi!

Very little mildness in the reliable at least for now, much more seasonal active weather!

Interestingly, FI is rather more unsettled than previous FI runs have been, especially for the north with more depressions running into Scandi!

Edited November 28, 2011 by Active Weather Dude

[rich1]

Considering the upstream patterns being what they are, a cold looking run for the hi res

Preferable to Euro high guff any day of the week IMO

[kold weather]

Certainly not a promising outlook, with a +ve NAO set-up and deep PV.. I would expect any Northerly incursion to be limited to a very short space of time as secondary depressions are picked up nearer the time.

Any eventual ridging North of the Azores High could settle things down for a time but the only way back is South with the overall NH profile.

The most interesting thing about the 12z GFS is it does develop a secondary low but in the mid-atlantic and then it sweeps eastwards around the upper low near the UK...such a set-up needs to be watched because whilst marginal it could provide some interesting weather, esp if the low got shifted further north over the UK itself.

Good run overall, any cold uppers won't last long but this is SO MUCH better than what we could have had given where we are at right now in the stratosphere. I'd take the whole 12z run in a heartbeat given the state of background conditions right now.

[Zakos]

Still out of what many would say is the reliable time frame,but nonetheless the first time I have had heavy snow non-Fi forecast for my area (Central England) this year.

The fact that this is being consistently forecast by the GFS is also encouraging.

I now agree with what many have been saying - Last December "Spoiled" Cold lovers.

Yes, with a cold PV were not going to get a prolonged cold spell on par with last year until at least the new years.

But, this doesn't mean we cant get a few decent cold snaps, We can get these with a cold PV can we not?

Although I am a cold lover, I am really happy with just falling snow even if it only settles for a few hours. I dont need a 30 cold spell like last year to appease me, A few 3 day cold spells with a few days of lying snow is enough for me! Well until the New Years that is...

[Cecil Hogmanay Melchett]

Hopefully we will see some back up from the ecm this evening because its looking posible that higher ground in the north could indeed some of the white stuff late next weekend and early next week.With NH profile as it is its the best we can hope for at the moment,sadly for the majority esp say south of the midlands theres little cheer at the moment and the real posibilty exists that we could see HP reestablish itself over Europe in the longer term.

All things considered i will gladly take seeing snow falling from the sky as a real unexpected bonus!!

lol zakos you said pretty much the sdame as me!

Edited November 28, 2011 by happy days