Model Output Discussion - Stormy Period Inbound...

[Summer Sun]

GFS P suggesting some snow is possible for northern England and Scotland Monday night and Tuesday with some elevation the south may also see some snow later Tuesday and into Wednesday once temperatures begin to fall

 

 

Temperatures are too high for the south at first but by late Tuesday they begin to fall

 

 

Snow totals up-to 7am on Wednesday show a light covering is possible for parts of the south and Wales whilst parts of NW Scotland are coming close to 1ft of snow

 

[nick sussex]

Slightly better outputs from the 06hrs GFS's upto T192hrs, a little move towards the GEM.

 

Its still difficult to pin down what exactly will happen because the details upstream keep changing, although perhaps a full move towards the GEM is unlikely lets see if we can squeeze out a bit more interest.

 

It would be nice to see outputs that  can deliver more UK wide, although its always difficult in the UK to get those set ups the more people that can see some snow the better.

Edited January 10, 2015 by nick sussex

[PolarWarsaw]

Speaking entirely from a personal perspective I think the track and depth of the mid week depression far more important than a few snow flakes.

 

Indeed. Speaking from the majority of people in here though, the chance of seeing snow (which can happen every couple of years for some, especially in the south) is more important than a few gales, a bit of rain and a wheely bin flying down the street, we see wind, rain and wheely bins about twice weekly! Much like in the summer, people search for a hot day or Thunderstorm regardless of the output, it's human nature. Personally, I couldn't care for a storm, bar the fact it's not just boring dry/dull days. 

 

The output continues to look volatile this morning, I expect some will be sick of rain/wind by the end of the week and others snow and blizzards. Personally, I'd call Scotland the focal point of anything white and wild this week, but expect reports of 'flakes' as far south as Wiltshire across to North London etc. 

 

Enjoy, stay safe!

[knocker]

Indeed. Speaking from the majority of people in here though, the chance of seeing snow (which can happen every couple of years for some, especially in the south) is more important than a few gales, a bit of rain and a wheely bin flying down the street, we see wind, rain and wheely bins about twice weekly!

 

 

 

If you have experienced storms as seen on this mornings charts twice weekly you must have spent your formative years living in Commonwealth Bay. Mind you would have had the best of both worlds.

[BARRY]

Indeed. Speaking from the majority of people in here though, the chance of seeing snow (which can happen every couple of years for some, especially in the south) is more important than a few gales, a bit of rain and a wheely bin flying down the street, we see wind, rain and wheely bins about twice weekly! Much like in the summer, people search for a hot day or Thunderstorm regardless of the output, it's human nature. Personally, I couldn't care for a storm, bar the fact it's not just boring dry/dull days. 

 

The output continues to look volatile this morning, I expect some will be sick of rain/wind by the end of the week and others snow and blizzards. Personally, I'd call Scotland the focal point of anything white and wild this week, but expect reports of 'flakes' as far south as Wiltshire across to North London etc. 

 

Enjoy, stay safe!

[Frosty.]

The Gfs 06z op run shows plenty of polar maritime and also arctic sourced air with hail, sleet and snow showers, perhaps thundery and a distinct lack of any lasting mild air throughout, so there is a good chance of snow. Later the 6z throws a curveball, but a pleasant one with a cold high bringing widespread sharp frosts. The week ahead looks very disturbed with bouts of very wet and potentially stormy weather and cold enough for sleet and wet snow at times, especially further north and with elevation.

Edited January 10, 2015 by Frosty.

[TEITS]

Overall im disappointed in the output with regards to the medium/longer range.

 

Once again the Met O appear to be spot on and reminds me that when we seek a significant cold spell you need this forecasted in the Met O 30 day forecast. I have been wrong on numerous occasions so far this winter and this is because I have believed the GFS F.I charts. Reason for this is sheer desperation following a rubbish winter last year and so far this year.

 

Apologies if this appears off topic but the gist of what I am saying is the outlook appears to be as suggested by the Met O i.e unsettled with alternating milder/colder spells. I would ignore any GFS F.I eye candy which is what I should of done! I also have to say well done to John Holmes because like the Met O he has also been spot on.

 

I might be a hard core ramper who always predicts bitter E,lys but I am always willing to admit when I get it wrong and also praise those who are correct. I think I shall stick to my other hobby of watercolour painting rather than forecasting lol.

[knocker]

The dynamic trop chart down the line would seem to indicate a similar pattern to the ext anomalies with warmer air into the Atlantic.

Chart courtesy weatherbell

Edited January 10, 2015 by knocker

[Ali1977]

Next weekend looks about the best chance for a Country wide snow event with a potent Northerly - this could develop further and be a slightly sharper colder snap than this Tuesdays one.

[Froze were the Days]

Well done TEITS - I do remember you predicting an easterly in the New Year. As we all know very difficult to predict a couple a weeks a head in 'normal' circumstances but when we have a strong jet stream, a PV which wants to assemble itself in a reoccurring position and an ever present Azores high it takes some shifting for a pattern change.

As I mentioned the other day reminds me of chart watching back in the mid to early 2000's when FI on the GFS charts never got any closer, there 'might' be one or 2 sniffs of colder snaps in the medium term from more amplification of the Azores HP but certainly nothing too note worthy.

Hats off to you Dave for being honest! 

[IDO]

The Gfs 06z op run shows plenty of polar maritime and also some arctic air and a distinct lack of any lasting mild air throughout, so there is a good chance of snow for some of us. Later the 6z throws a curveball, but a pleasant one with a cold high bringing widespread sharp frosts. The week ahead looks very disturbed with bouts of very wet and potentially stormy weather and cold enough for sleet and wet snow at times, especially further north and with elevation.

 

The MO update (14-23):

 

This alternating pattern of wetter weather, with brighter showery interludes will then continue, although turning gradually less windy. Temperatures will also vary from mild to very mild during the wetter spells, to cold at times, perhaps with overnight frosts, during the clearer interludes.

 

I think it will turn out more like the GFS with alternating PM and TM rather than the ECM uppers cold flow. The MET's update suggests like the GFS has been showing that any frontal precipitation will be accompanied by a warm sector to its fore so snow will be back edge or more likely be showery, so hit and miss and as a whole, and at sea level probably nothing sticking around.

 

I think nothing for the south for 16 days plus, but for the north with good ASL, some transient snow. Over all though rather poor if we were going to psycho-analyse it as we head towards Feb?

[Frosty.]

There are reasons for coldies to be optimistic, I mean John Holmes has mentioned this morning of a colder pattern in the next few weeks and I see no downgrades to the pm / arctic shots which the models are still showing, should be some good lamp post and radar watching in the coming week or two. :-)

Edited January 10, 2015 by Frosty.

[winterof79]

Short cold spells?

Got you, cheers.

[johnholmes]

There are reasons for coldies to be optimistic, I mean John Holmes has mentioned this morning of a colder pattern in the next few weeks and I see no downgrades to the pm / arctic shots which the models are still showing, should be some good lamp post and radar watching in the coming week or two. :-)

Come on Frosty I did not think I wrote or even implied as you quote?

[winterof79]

Probably because your post came accross that way John

.quote:

"I suspect on balance it may help for the colder spell to be longer than 5-7 days, possibly we MIGHT be looking into 10+ days and of course in that time the feed backs from such a situation will have impacts on how any of the teleconnections will then show.

So enjoy the colder spell and keep your fingers crossed that in that time some snow may fall on you, enjoy any frosty mornings and see what old man weather actually does. He may well make a complete fool of me but never mind."

Edited January 10, 2015 by winterof79

[kumquat]

There are reasons for coldies to be optimistic, I mean John Holmes has mentioned this morning of a colder pattern in the next few weeks and I see no downgrades to the pm / arctic shots which the models are still showing, should be some good lamp post and radar watching in the coming week or two. :-)[/quote

 

Come on Frosty I did not think I wrote or even implied as you quote?

 

I think it is quite clear that  a colder overall pattern is developing, the anomaly charts, links below, have been reasonably consistent on this over the last 2-3 days

???

[nick sussex]

My definition of decent cold.

 

It doesn't have to be two weeks of severe cold it can be just 4/5 days but has to include the following.

 

Snow falling, laying without a problem at sea level, overnight frost doesn't have to be harsh but enough to keep the snow intact, even if temps creep up above zero during the daytime low dew points mean little thawing.

 

So far this winter how many parts of the UK have enjoyed this? the post Christmas spell saw some lucky areas in the north Midlands/ north/nw England have something close to that. For the rest of the UK its been crap, for this reason the type of synoptics I'm looking for in the outputs is something that can produce that 4/5 day spell more UK wide. .

 

So lets hope the outputs can deliver that in the next few days.

Edited January 10, 2015 by nick sussex

[MR EXTREMES]

Well I'm sorry that one run this morning has caused the confusion.

Turning progressively colder uk mo update very mild absolutely could be right but any very mild air looks to be very short lived.

All the models suggest the Azores heights to be displaced and lower pressure to our East se and South although not perfect yet it's still small baby steps I'm still confident of a more sustained deeper cold situation before months end.

Someone had a little pop at the cold heart of winter suggestion well it's cold and snow is in the forecast widely at times.

Very stormy period remember the calm after the storm all that energy being sucked out of the atmosphere and alantic will eventually recede.

I'd say from last night it's not a downgrade and am suprised by the negativity in this forum.

I'm 80% confident on a cold sustained spell after the already cold alternating pattern.

[Frosty.]

There are reasons for coldies to be optimistic, I mean John Holmes has mentioned this morning of a colder pattern in the next few weeks and I see no downgrades to the pm / arctic shots which the models are still showing, should be some good lamp post and radar watching in the coming week or two. :-)[/quote

Come on Frosty I did not think I wrote or even implied as you quote?

I'm confused now, I thought you mentioned a colder pattern?

Edited January 10, 2015 by Paul
Fixed quote

[JoeShmoe]

 

The MO update (14-23):

 

This alternating pattern of wetter weather, with brighter showery interludes will then continue, although turning gradually less windy. Temperatures will also vary from mild to very mild during the wetter spells, to cold at times, perhaps with overnight frosts, during the clearer interludes.

 

I think it will turn out more like the GFS with alternating PM and TM rather than the ECM uppers cold flow. The MET's update suggests like the GFS has been showing that any frontal precipitation will be accompanied by a warm sector to its fore so snow will be back edge or more likely be showery, so hit and miss and as a whole, and at sea level probably nothing sticking around.

 

 

 

That would tie in with IanF's comments last night suggesting the continuation of a strong jet and deep depressions shown on the EC clusters right out to end of Jan

 

Good for here, been snow showers this morning 

[Frosty.]

A more detailed post than the one I gave last evening.

I think it is quite clear that a colder overall pattern is developing, the anomaly charts, links below, have been reasonably consistent on this over the last 2-3 days. Again similar to their over/post Xmas predicted change, it was the ECMWF-GFS version that first gave this idea. In the 5 years I have made daily notes on the 3 it is usually NOAA at 6-10 sometimes even the 8-14 that picks up pattern changes first. Although it may be a moot point if it is actually a pattern change. To me it is a sufficient shift in the long wave pattern to say it is. Time will tell if it is a major one or a minor one.

Above doubt is that the 500mb flow WILL change from its westerly, twitching a touch south and a touch north of to a touch south of west over the past weeks or two, to a quite definite north of west direction. This will mean that ‘most’ of the time fairly cold and relatively deep Polar Maritime air will affect most of the country, at least in the 6-10 day time scale. So far the 8-14 NOAA does not indicate this moving into a more northerly Arctic air mass. There is still no signal for a general height rise Iceland to Greenland for this to look feasible. It may develop but it certainly is not showing yet.

NOAA 6-10 and 8-14, also have a read of the NOAA forecasters assessment, they can give some guide to what the main wave pattern is likely to be in their view. This can sometimes help in giving a bit more guidance for the eastern Atlantic/western Europe area.

http://www.cpc.noaa.gov/products/predictions/610day/500mb.php

ECMWF-GFS output

http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

Looking at the synoptic models and those that show this idea out to at least 240h are pretty close to the overall upper pattern. The surface detail, troughs, even the much loved (!) short wave features are not discernible this far out on the anomaly charts but remember it is the upper air that is the major cause of these not the surface, although like much in meteorology there are times when it is not easy to separate one from the other. How much snow, where, when again is for the synoptic models at no more than 72h and more likely 12-24 h to give this detail.

Below is the link on Wetter which gives a quick glimpse of how GFS and ECMWF suggest things may look at 240h

http://www.wetterzentrale.de/topkarten/fsecmeur.html

As you might expect with small features running in this flow then timing is going to be problematical at this time range, hence the differences between the 2 GFS versions and ECMWF, but all 3 really following the idea suggested above.

Turning to further out than 10 days and we can see how the AO and NAO are looking although they are not drivers but indicators of what the atmosphere is being suggested by the other outputs. The link below show AO, NAO and MJO data (actual and forecast)

http://www.cpc.ncep.noaa.gov/index.php

I tend to mistrust AO, NAO and PNA much after about 7 days, as mentioned they are really only showing what the synoptic models are giving and are as likely to be incorrect at the range of much beyond about 7 days.

Turning to the GFS MJO it currently is in phase 5/6 in reasonable amplitude. The link below shows how this tends to fit in at 500mb in January

http://www.americanwx.com/raleighwx/MJO/MJO.html

Both of them show much as one should expect, that is a 500mb pattern not that far removed from what we have had over the past week or more.

What of its forecast?

This suggests with a lower amplitude but possibly still sufficient to have some effect on northern hemisphere weather edging into phase 7, follow the link above to see what it suggests for the 500mb pattern?

It does suggest a colder upper air pattern with ridging occurring N-E-SE of the UK with –ve heights out west.

That leaves the problem what sort of surface flow might get IF this is correct, and is the upper pattern likely to be that? This is where I leave the stage as I have not enough knowledge to be able to make sensible and constructive suggestions on this. I suspect on balance it may help for the colder spell to be longer than 5-7 days, possibly we MIGHT be looking into 10+ days and of course in that time the feed backs from such a situation will have impacts on how any of the teleconnections will then show.

So enjoy the colder spell and keep your fingers crossed that in that time some snow may fall on you, enjoy any frosty mornings and see what old man weather actually does. He may well make a complete fool of me but never mind.

Colder pattern? Yes I agree Edited January 10, 2015 by Frosty.

[IDO]

???

 

 

Yes a cold upper flow as a whole from D3+ has been evident for a while but nothing major and how that translates on the surface is more important. Alternating cold and warm fronts is not great for snow hanging around and also makes any frontal snow borderline. So yes a seasonal period coming up with maybe uppers 1-2c below normal. However in the heart of Winter I do not expect anyone would be happy with those prospects, most are looking for some heavy lasting snow. That is not being modelled up to D16:

 

 

You can see from the 850s that the sine wave action of alternating PM and TM, like D8, and as the Met Office suggests, is now trending. ECM when it gets into the D7 period should also flip back to this IMO. The GEM ensembles are also in line with the GEFS and there is no support for it's op (no surprise there):

 

 

GFS D8 snow totals: 

Edited January 10, 2015 by i'm dreaming of...

[Frosty.]

Let's clear this up, what did I say to annoy John Holmes..I demand an answer..lol

I pm'd you Mr h :-)

Edited January 10, 2015 by Frosty.

[Paul]

I pm'd you Mr h :-)

 

Good plan Karl, think we'd all prefer to get back to the models and leave John & Frosty gate behind now

[tinybill]

i  hope there a downgrade  before wednesday    935  mb  over scotland