South West/Central Southern England Regional Discussion 22/01/13 23z------------->

[Stoxs]

Been snowing since 5pm here and have extra 2cm. Coming down very heavy now, settling on everything.

Was just looking over your post and thought wow thats simliar to here, then noticed your elevation!!

same as here! often snow events are due to elevation weather you get rain, sleet, wet non settling snow or proper snow and this can be within 50 meters extra elevation. all to 2mtr temps and dew points i guess.

[Beast of Plympton]

Ok, this cold snowy spell hasn't even ended yet but I feel this summary from Gibby should be kept in mind, as we enter into what is currently FI, the beginning of February.

http://forum.netweat...60#entry2565065

Even before Gibby had suggested the above, I must say I watched the GFS 12z run today for the first time in over a week and I got the feeling from viewing the NH Jetstream profile, it would like to split once again from full on zonal, around the period from 31st January to 1st February. Should it do so and the Southern arm decides to dive South, it could be GAME ON once again. Today's GEFS 12z ensembles suite loosely back up my gut feelings too. Gibby in particular, highlights the ECM as hinting at possibly picking up the potential for a trend to colder conditions, come next weekend onwards.

All conjecture at this range but Chiono and GP et.al have also mentioned that the projected milder spell may be fairly short lived, thanks to MJO and SSW influences amongst others.

Winter may have only just begun and could be back with a vengeance back next weekend, you have been warned.

Thanks gottolovethisweather, clever man. Nice evaluation from you and Gibby. Hopefully I will have a better understanding of models by next winter and have more input!!

[Bristawl Si]

Light snow falling here - guess one of those showers, that appeared to be fizzling out, has reached here

[festivalking]

If a greenland high kicks in then the chance of cold weather from the north will certainly increase! And I feel cornwall and devon do better snow wise from weather from the north than cold weather from the east. Certainly if the pembrokeshire dangler fires up. An arctic flow from the north west equals cold and moisture. Here is hoping...

[Blizzardof82]

GTLTW got to love your enthusiasm and positive spin, you sure make a coldie like me smile. Keep up the good work as I enjoy reading your posts

[cerneman]

Thanks gottolovethisweather, clever man. Nice evaluation from you and Gibby. Hopefully I will have a better understanding of models by next winter and have more input!!

Wisdom comes with age!

[Bristawl Si]

Light snow falling here - guess one of those showers, that appeared to be fizzling out, has reached here

Oh well, that didnt last long! Lol

[Beast of Plympton]

Wisdom comes with age!

Haha!! I am sure gottolovethisweather has only just had his 21st birthday??!! I must have read that wrong!!

[Iggy912]

Still being fairly new to this site (all of two weeks..!) I have been throughly entertained and superbly well informed, giving guidance and weather prospects to friends and family, based on what I have read from you humorous and dedicated souls and your witty posts. Keep up the good work chaps! I for one am hooked on the weather... !!!

[Bristawl Si]

Light snow again now - sky has that orange tint to it. Radar indicates it wont last v long though.

[AWD]

Ok, this cold snowy spell hasn't even ended yet but I feel this summary from Gibby should be kept in mind, as we enter into what is currently FI, the beginning of February.

http://forum.netweather.tv/topic/58354-in-depth-model-discussion-analysis-and-summaries/page__st__2060#entry2565065

Even before Gibby had suggested the above, I must say I watched the GFS 12z run today for the first time in over a week and I got the feeling from viewing the NH Jetstream profile, it would like to split once again from full on zonal, around the period from 31st January to 1st February. Should it do so and the Southern arm decides to dive South, it could be GAME ON once again. Today's GEFS 12z ensembles suite loosely back up my gut feelings too. Gibby in particular, highlights the ECM as hinting at possibly picking up the potential for a trend to colder conditions, come next weekend onwards.

All conjecture at this range but Chiono and GP et.al have also mentioned that the projected milder spell may be fairly short lived, thanks to MJO and SSW influences amongst others.

Winter may have only just begun and could be back with a vengeance back next weekend, you have been warned.

I agree, just not quite as quick maybe. I think the GFS would follow the ECM T240 chart but at a later stage. Both the GFS, UKMO and ECM want to take the MJO into phase 8;

Phase 8 would evolve into something like this;

Notice from the above though that the ECM is more progressive and races into phase 8 quicker than the GFS and ends up reaching back into phase 1, something like this;

Something not too good for colder weather. However, with a slower evolution supported by both the GFS and UKMO, hopefully we will see a better trend for the phase 8 composite and the ECM to be less progressive. This however might explain the northern hemispheric 240 hour chart;

With the NAO now forecast to remain slightly positive (it hasn't really gone negative despite the cold spell, neutral at best);

I would have to plump for a less progressive solution to the ECM output. The ECM being on the right lines in weakening the vortex to our NW, but currently too quick in doing so. It will likely take a little longer than what it showed in its 12z output.

Below you can see the GFS 500mb height anomaly guidance for the next two weeks;

Slowly but surely you can see a trend for stronger heights to develop in the Mid Atlantic (a mid Atlantic high). This would halt/slow the progression of Atlantic depressions towards the UK, otherwise known as "zonal", and as you can see in the final chart, a good signal for the height anomaly to move and develop toward southern Greenland. Heights around Greenland are a good source for UK cold weather.

Heights to the west of the UK also showing signs here;

All this resulting in something like this developing by mid February;

So my punt FWIW, I don't think were going to see a mega quick return of cold weather just yet, I do think we will be under the influence of less cold SWerly air for around a couple of weeks. However, there is a reasonable amount of data suggesting height rises in the Mid Atlantic moving closer to Greenland, allowing another cold spell around mid February. That's the trend I see developing over the next couple of weeks anyway.

The word "undercutting" could be a regular word come February, with a southerly tracking jet.

Edited January 23, 2013 by AWD

[gottolovethisweather]

I agree, just not quite as quick maybe. I think the GFS would follow the ECM T240 chart but at a later stage. Both the GFS, UKMO and ECM want to take the MJO into phase 8;

Phase 8 would evolve into something like this;

Notice from the above though that the ECM is more progressive and races into phase 8 quicker than the GFS and ends up reaching back into phase 1, something like this;

Something not too good for colder weather. However, with a slower evolution supported by both the GFS and UKMO, hopefully we will see a better trend for the phase 8 composite and the ECM to be less progressive. This however might explain the northern hemispheric 240 hour chart;

With the NAO now forecast to remain slightly positive (it hasn't really gone negative despite the cold spell, neutral at best);

I would have to plump for a less progressive solution to the ECM output. The ECM being on the right lines in weakening the vortex to our NW, but currently too quick in doing so. It will likely take a little longer than what it showed in its 12z output.

Below you can see the GFS 500mb height anomaly guidance for the next two weeks;

Slowly but surely you can see a trend for stronger heights to develop in the Mid Atlantic (a mid Atlantic high). This would halt/slow the progression of Atlantic depressions towards the UK, otherwise known as "zonal", and as you can see in the final chart, a good signal for the height anomaly to move and develop toward southern Greenland. Heights around Greenland are a good source for UK cold weather.

Heights to the west of the UK also showing signs here;

All this resulting in something like this developing by mid February;

So my punt FWIW, I don't think were going to see a mega quick return of cold weather just yet, I do think we will be under the influence of less cold SWerly air for around a couple of weeks. However, there is a reasonable amount of data suggesting height rises in the Mid Atlantic moving closer to Greenland, allowing another cold spell around mid February. That's the trend I see developing over the next couple of weeks anyway.

The word "undercutting" could be a regular word come February, with a southerly tracking jet.

Thanks AWD, I get the gist of what you're showing there but I'm still not as au fait as you with all the charts.

Nevertheless whether I understand everything, perhaps matters not, as you have provided a most useful analysis once again.

[Erbyskerby]

AWD - you are the dog's danglies - thankyou for your analysis and your poetry. Top class.

[Mark Neal.]

Was just looking over your post and thought wow thats simliar to here, then noticed your elevation!!

same as here! often snow events are due to elevation weather you get rain, sleet, wet non settling snow or proper snow and this can be within 50 meters extra elevation. all to 2mtr temps and dew points i guess.

Yes it certainly does help being slightly higher here, there has been many times when we have had snow falling up on Headington Hill, down in the city centre it has been rain/sleet.. :-)

[Mark Neal.]

Yes, i'd also like to say its great to have great Analysis from the likes of AWD, GTLTW, top work gentleman.

And for anyone who thinks this end of the cold spell coming is the end of winter, will be shocked, plenty of time left!!

[kernowman]

So that was winter for me, a dusting of snow, I should be grateful for at least seeing a snow flake this winter. Here's hoping for a 1976 style summer and hopeful for a better winter next season.

Edited January 23, 2013 by kernowman

[George]

So that was winter for me, a dusting of snow, I should be grateful for at least seeing a snow flake this winter. Here's hoping for a 1976 style summer and hopeful for a better winter next season.

No hope for a cold spell in February then?

[Mark Neal.]

No hope for a cold spell in February then?

Very stupid for comments saying that it could be it for winter... February is usually a cold and snowy month overall, this February coming could still come up trumps its a watching situation, i'm expecting to see some interesting synoptics start to show up fairly soon, Mid Feb cold spell returns?

Edited January 23, 2013 by Mark Neal.

[Costa Del Fal]

So that was winter for me, a dusting of snow, I should be grateful for at least seeing a snow flake this winter. Here's hoping for a 1976 style summer and hopeful for a better winter next season.

And where better to spend it but the beaches of Cornwall. Whilst ill be in the Midlands for the core of Summer I cant wait for any nice Spring or Early summer days where I can head down to the likes of Gyllyngvase, Swanpool and all the others for some chill out and a beach BBQ.

[sherrie]

Three years ago there was still snow lying in the first week of march so that must have fallen in february, dont understand why some people think its the end of winter?

[kumquat]

So height rises to the north and undercutting lows. Well, we can't complain that we haven't seen that. I'm just not seeing where that will come from looking at current NWP output.

There are signs that encroachments northwards between low pulses will once again take hold temporarily but this time through the Mid Atlantic as the wave rides around to our POV from the Pacific. I'm predicting week 3 of February will have seen enough WAA surging north to create the Greeny block. But that will not produce anything other than marginal fronts, troughs and incursions from (working around from) NW, N, NE, E and SE.

Winter is over for the South West from this weekend onwards. See you next year!

[Panayiotis]

So height rises to the north and undercutting lows. Well, we can't complain that we haven't seen that. I'm just not seeing where that will come from looking at current NWP output.

Were you able to this cold spell at the start of January? Because I didnt and the results of it can be seen in my signature! Just saying cold spells seemingly pop out of nowhere, so you/others shouldnt call off a whole winter's month. Edited January 24, 2013 by Panayiotis

[iowpompeylee]

A few flurries of snow on the Isle of Wight this morning

[divadee]

Morning all.

Crumbs some posters are doom and gloom In here!! It's not even February yet!! Winter is not over you can't say that till march gets here!! Here's hoping for some colder weather in February as we have seen many a time down here.

[Gleno-South Coast]

Morning all,cheeky little dusting of snow on my car roof bout 6 am this morning,just when u think its over ;-)