Model Output Discussion; into 2015

[egret]

take my word for it john - there is no technical SSW currently predicted. The reason for the lack of posts on that thread is

1) andrej is visiting his girlfriend

2) the ECM charts have backed off the evolution that would have led to a SSW

there may be something within two weeks but as far as the situation only two days ago where some wee musing as to whether a SSW as was imminent - it isn't now.

That doesn't preclude the upcoming warmings doing some damage to the trop zonal flow so don't give up hope.

IDO, I don't see any extended ens evidence yet that the vortex will be on the move from Canada in week 2.

this is where my thoughts re possible scandi height rises comes from. A move back east from Canada to Siberia of the vortex would indeed not allow that.

And finally, I'm no strat expert. very few are which is why we got suckered into the ECM solution from a couple of days ago. We don't have enough data info.(especially when andrej isn't around)

So Andre J is still going for a non technical warming  even if ECM has backed away from a technical one.  Or am I simply getting confused? LoL

[bobbydog]

I would imagine their own models at that range are not agreeing with some others, Ian may help out here?

hopefully john, as he's just thrown a bit of intrigue into the mix!

[bluearmy]

Where andrej is, I imagine there are plenty of warmings !!

[BlueHedgehog074]

The models do seem confident that the Atlantic will be on a mission to swamp the UK in a mobile, Westerly, dominated, pattern... along with the Vortex over Canada blasting a horde of Low Pressure systems towards the UK. Unsettled and windy weather at times, especially to the North, but probably more changeable further South where higher pressure should be more influential. It's always possible things could change and improve for cold weather prospects (e.g: obtaining more amplification in the generally, flattish, Westerly flow) and Northern areas, at least, should experience periods of chilly Polar Maritime flows.

In the meantime, this is what the UK is likely to experience for the next few days, though slight alterations are to be expected - GFS charts used as examples...

Types of charts used for this summary: HGT500 and Sea Level Pressure; T850 and Sea Level Pressure (the 850 hPa temperature charts); UK Max/Min Temperature; UK Precipitation; UK Precipitation Type (mm).

Tonight:

The High Pressure system that we have had over the UK in the last few days bringing cold, frosty, weather, gets knocked to our South-East into mainland Europe. You can see on the charts below that this allows a less cold South-Westerly flow to establish for the whole of the UK. This is reinforced by the fact that milder 850 hpa temperatures get drawn North-Eastwards over us (although 850 hPa temperatures aren't always a great indicator of how warm or cold the temperatures will be at the surface). The temperatures are expected to be in single figures for places, so could feel quite chilly, although there will be some rain about in Western areas. Temperatures will also be a little milder towards the South-West. Perhaps getting into double figures in Cornwall.

Thursday Daytime:

The South-Westerly flow strengthens for the UK with even milder 850 hPa temperatures getting drawn up from the South-West. It will be quite windy, too. Low Pressure to the North-West will drag in a band of rain from the West reaching North-Western areas by mid-day. Temperatures quite mild for most places, but cooler over Northern Scotland, where temperatures will be in single digits. Drier, and perhaps brighter, towards the South-East.

Night-time:

The rain will sink South-Eastwards as a cold front, which will be heavy at times, with colder, clearer, air following behind from the West. The 850 hPa temperature chart illustrates this well, with -5*C hPa temperatures reaching Western Scotland. This colder flow from the West will bring some wintry showers over North-Western areas. These areas of which will see the coldest temperatures of the night, perhaps with a touch of frost over sheltered places. Further South and temperatures could still be in double-digits for places with a wet night for Southern UK.

Friday Daytime:

Friday shows the colder Westerly or North-Westerly flow affecting the whole of the UK with the weather looking quite dry and bright for places. Some showers for North-Western areas, though, and the GFS Precipitation Type chart shows these could be wintry in places, especially over high-ground. The mild 850 hPa temperatures are pushed away Eastwards into the continent and most of the British Isles experiences a chilly day, especially over Scotland, with temperatures into single digits. South-Eastern areas looking to cling onto milder temperatures.

Night-time:

Wintry showers will continue to affect some Northern areas with snow over the Scottish hills. Drier elsewhere, although the GFS 'HGT500 and Sea Level Pressure' chart shows a cut-off Low to the West running South along the main trough of low heights to our North - this little feature heading Eastwards towards Western UK. The flow turning to the South-West over South-Western UK, which will bring some milder temperatures with it, although most places away from the coasts will see temperatures close to freezing. Possible frost, too.

Saturday Daytime:

The little Low/wave feature over Southern UK brings spells of rain to the South. Milder 850 hPa temperatures accompany this system, but it's only really the far South that sees the milder temperatures, while everywhere else will experience a cold day (probably also thanks to the fact the ridge of High Pressure to our West helps to feed cold air down from the North-West). Perhaps even cold enough for a bit of sleet for those on the Northern flank of the rain band, such as Central and North Midland areas, especially with that slack flow. But most of the wintry stuff will probably likely be over high-ground. Brighter and more showery to the North.

Night-time:

A ridge of High Pressure to the West will start tracking Eastwards and settle most of the UK down with some dry, clear conditions. Chilly air still feeding down South-Eastwards towards the UK on the High Pressure system's Eastern flank. Many inland areas, particularly to the North, seeing temperatures around, or below, freezing with some sharp frosts possible. A little less cold towards far South-Western areas of the UK.

Sunday Daytime:

A fine, dry, calm, crisp, bright day in store for the whole of the UK with the ridge of High Pressure in control, but possibly a little cloudier towards the far North-West. A cold day for many with temperatures in the low single digits. The hilly areas in Scotland struggling to get above freezing.

Night-time:

Similar picture with the ridge of High Pressure gradually tracking further East, but with the centre of the High Pressure over South-Eastern UK, most places should remain dry. There is however some milder 850 hPa temperatures getting dragged North-Eastwards over the UK. But most places staying below freezing with frost and fog likely. Some South-Western areas seeing slightly milder temperatures, especially over South-Western Ireland.

Edited December 31, 2014 by DiagonalRedLine
To make a little correction

[karyo]

Anomalies of the GEFS bia-corrected 6z

 

T192 

T240 

T384

 

To me they at least show the Candian vorticity weakening but do show a very stormy and unsettled period for us in the UK and on the cooler side as the depressions dig further south.

 

It may just be a case of the pattern re-amplifying off the East coast before we see anything. 

Only the 3rd chart looks cooler to me as the Azores high deflates allowing the low pressure to dig further south. Of course, that's in the 384 hour range which is not likely to verify.

[Weathizard]

Took a few days 'model break' as it grows frustrating looking at charts that don't particularly interest me, it seems things have only got worse - stratospheric warming wise especially, with that piece of the vortex in the worse possible place for us, it's difficult to envisage us getting any cold, without a SSW.

The order of the day seems standard winter fayre, with some cold PM incursions for Scotland and the north but nothing out of the ordinary, the GFS ensembles 240+ show a slight cooling trend but at this timeframe I have no faith in them.

Unfortunately at the moment we are stuck in one if them patterns you sometimes get in winter where you just need a break, otherwise that strong vortex lobe will destroy winter, we are only a month into winter but we've seen a fair few times how stubborn that pattern can be, even at 384 the vortex shows no sign of weakening.

[Tom Quintavalle]

Certainly some interest around T144hrs wrt Scandinavian ridging.

It's been showing on the 3 main overnight runs and more so on the 06z GFS so a continuing picture.

If we look at the NH pattern at around day 6/7 we can see how close we get to a proper split in the vortex before later frames show it reforming.

Looking at that angry dark blue/purple blob of the Canadian pv it does look too powerful to think any ridging heights ahead of it would hold,as IDO suggests in his earlier post.

Never say never though just compare our 06z GFS T144 chart with the evolution from a similar pattern in 1991.

 

 

 

 

Yes Phil, like you, something stirred in the synoptic archive memory vaults, when viewing those runs you refer too.

 

At work so will have to be brief but If I may be so bold, you could also add post Xmas 1984 and around 25th/26th Jan 2009 to your synoptic example of 1991.

 

 

Now of course, synoptically speaking, todays runs that Phil speaks of show a much more suppressed Siberian high away to the SE, with a more pronounced portion of the vortex over Russia/Siberia. Its obvious that todays runs also have the pattern that bit further east but I would argue that to the NW the profile looks similar, with a large lobe of the vortex between Canada and Greenland and a weakish Arctic high nosing into the picture. Note in the 2 examples I've cited, how the Atlantic hits a brick wall, if this were to occur in subsequent model runs, I would certainly begin to take notice but at the moment it's just a bit of cursory speculation.

 

Not long to wait until the afternoon runs start filtering out but it's something to keep an eye on, certainly.

 

Another half glass full look at, what undoubtedly could be just a gleam of light in the otherwise current gloomy model output but as Tamara alluded to in her post yesterday, it could well come down to timing of any attempted Atlantic amplification being drawn up to our NE, coinciding with a split in the vortex, to allow heights to rise between Iceland/ Scandinavia.

 

Excuse the rather rushed and rambling post!

 

Tom.

[Frosty.]

I am a fan of yours frosty.l love your winter posts, a man after my own heart.fear not my friend the polar express will arrive.it is just a little delayed..... Happy new year to all on netweather.EW

Thank you and Happy New Year:-)

As for the model output, although there is no sign of sustained cold while we have high pressure anchored across southern europe and persistent low heights to the north, at least there will be incursions of cold air with a risk of snow as well as rPm and Tm airmasses.

Edited December 31, 2014 by Frosty.

[Midlands Ice Age]

Where andrej is, I imagine there are plenty of warmings !!

 

Are we talking about the north pole or the south pole for these latest warmings,    Blue?  

[bluearmy]

Are we talking about the north pole or the south pole for these latest warmings,    Blue?

The next episode of 'carry on stratispherically' will take place ............

Ooh matron!

Not sure andrej will have seen Charles hawtrey et all. Infact, there's probably a lot of you on here wondering what the hell I'm on about!

[bobbydog]

The next episode of 'carry on stratispherically' will take place ............

Ooh matron!

Not sure andrej will have seen Charles hawtrey et all. Infact, there's probably a lot of you on here wondering what the hell I'm on about!

 

he's probably in the warm sector right now BA.

 

ooh... behave!!

[Mair Snaw]

he's probably in the warm sector right now BA.

 

ooh... behave!!

[mushymanrob]

I am a fan of yours frosty.l love your winter posts, a man after my own heart.fear not my friend the polar express will arrive.it is just a little delayed........mushy is lying on the track!!!!!! Happy new year to all on netweather.EW

Ill derail the bugger! *dastardly laugh*

What most of you seasonal peeps wont realise is that for six months of the year me n frosty sing from the same hymn sheet as we both want summer sun and heat. I think we are more like the gallagher brothers then morcombe and wise lol

As for the current outputs, well its looking decidedly average. And that doesnt make for much discussion as anything cold or mild is straw clutching as things stand.

[Paul_1978]

And finally, I'm no strat expert. very few are which is why we got suckered into the ECM solution from a couple of days ago. We don't have enough data info.(especially when andrej isn't around)

 

 

With due respect, Bluearmy is one of those experts. It was nice for him to update us on a busy day.

???? ;-)

[IDO]

 

 

???? ;-)

 

Expert compared to 99% of the rest of us, but of course compared to an elite group of strat Genius' like Andrej, then maybe less so.

 

No change to the Met Update. Zonal through to mid-Jan with baby ridge/trough combos, so PM - v- TM; just average Jan stuff:

 

http://www.metoffice.gov.uk/public/weather/forecast

Edited December 31, 2014 by i'm dreaming of...

[bobbydog]

Expert compared to 99% of the rest of us, but of course compared to an elite group of strat Genius' like Andrej, then maybe less so.

 

No change to the Met Update. Zonal through to mid-Jan with baby ridge/trough combos, so PM - v- TM; just average Jan stuff:

 

http://www.metoffice.gov.uk/public/weather/forecast

nothing has really changed in the models so why would it change?

not sure why you have mentioned that.

[IDO]

nothing has really changed in the models so why would it change?

not sure why you have mentioned that.

 

It was in respect to a slight signal at D6 for maybe a ridge towards Scandi (GFS 06z hi-res); just checking if the Met had that on their radar, but it sounds westerly to me.

 

Ties in with the current GFS bias with respect to over doing heights to the NE: 

[bobbydog]

It was in respect to a slight signal at D6 for maybe a ridge towards Scandi (GFS 06z hi-res); just checking if the Met had that on their radar, but it sounds westerly to me.

 

Ties in with the current GFS bias with respect to over doing heights to the NE: NOAA_NWS_NCEP_WPC_MODEL_DIAGNOSTIC_-_INTERACTIVE_MODEL_BIAS_PAGE 8.png

they wouldn't change the outlook based on a weak signal, they would have to see stronger evidence. though ian did post earlier that there is some mistrust of the extended zonal signal. he didnt explain why so we'll have to wait and see for ourselves

[joggs]

Well im taking a break for a few days because im sick to death of looking at the models and seeing the limpet vortex slap bang over Greenland lol.

Happy new year to all and thanks for making neatweather a fab place.

Edited December 31, 2014 by joggs

[cyclonic happiness]

Be careful what you wish for CH, for as others have stated, heights to our south are unlikely to lead us to a potentially cold outlook anytime soon.

I would also beg to differ re the later stages of the Ecm. For eg, let's just say the chart showing for Sun 4th of Jan so happened to be the day 10 Ecm chart, it would be a reasonable enough assumption I think for one to perhaps draw a similar conclusion to that of yours re the potential for something more settled. However, the day 10 chart to me shows an all too powerful jet stream to allow anything other than perhaps a transient ridge to follow such a depression as shown.

Well, if it's a choice between frost and sunshine and rebuilding my fences again, I'd go for the frost and sun everytime.

 

And I disagree too, heights to the south can lead to cold synoptics if the Azores high bubbles up and spreads towards Scandi' with low pressure and the jet sinking over southern Europe.

 

It's more encouraging to me to see HP over the southern British Isles 'as it stands' than raging storms.

That was the point I was trying to make :-)

[Continental Climate]

It seems like the 12z is a lot more progressive than the 6z so far http://modeles.meteociel.fr/modeles/gfsp/runs/2014123112/gfsnh-0-126.png?12!!! More influence from the Atlantic conveyor belt on this run. 

[seaside 60]

The models do seem confident that the Atlantic will be on a mission to swamp the UK in a mobile, Westerly, dominated, pattern... along with the Vortex over Canada blasting a horde of Low Pressure systems towards the UK. Unsettled and windy weather at times, especially to the North, but probably more changeable further South where higher pressure should be more influential. It's always possible things could change and improve for cold weather prospects (e.g: obtaining more amplification in the generally, flattish, Westerly flow) and Northern areas, at least, should experience periods of chilly Polar Maritime flows.

In the meantime, this is what the UK is likely to experience for the next few days, though slight alterations are to be expected - GFS charts used as examples...

Types of charts used for this summary: HGT500 and Sea Level Pressure; T850 and Sea Level Pressure (the 850 hPa temperature charts); UK Max/Min Temperature; UK Precipitation; UK Precipitation Type (mm).

Tonight:

The High Pressure system that we have had over the UK in the last few days bringing cold, frosty, weather, gets knocked to our South-East into mainland Europe. You can see on the charts below that this allows a less cold South-Westerly flow to establish for the whole of the UK. This is reinforced by the fact that milder 850 hpa temperatures get drawn North-Eastwards over us (although 850 hPa temperatures aren't always a great indicator of how warm or cold the temperatures will be at the surface). The temperatures are expected to be in single figures for places, so could feel quite chilly, although there will be some rain about in Western areas. Temperatures will also be a little milder towards the South-West. Perhaps getting into double figures in Cornwall.

Thursday Daytime:

The South-Westerly flow strengthens for the UK with even milder 850 hPa temperatures getting drawn up from the South-West. It will be quite windy, too. Low Pressure to the North-West will drag in a band of rain from the West reaching North-Western areas by mid-day. Temperatures quite mild for most places, but cooler over Northern Scotland, where temperatures will be in single digits. Drier, and perhaps brighter, towards the South-East.

Night-time:

The rain will sink South-Eastwards as a cold front, which will be heavy at times, with colder, clearer, air following behind from the West. The 850 hPa temperature chart illustrates this well, with -5*C hPa temperatures reaching Western Scotland. This colder flow from the West will bring some wintry showers over North-Western areas. These areas of which will see the coldest temperatures of the night, perhaps with a touch of frost over sheltered places. Further South and temperatures could still be in double-digits for places with a wet night for Southern UK.

Friday Daytime:

Friday shows the colder Westerly or North-Westerly flow affecting the whole of the UK with the weather looking quite dry and bright for places. Some showers for North-Western areas, though, and the GFS Precipitation Type chart shows these could be wintry in places, especially over high-ground. The mild 850 hPa temperatures are pushed away Eastwards into the continent and most of the British Isles experiences a chilly day, especially over Scotland, with temperatures into single digits. South-Eastern areas looking to cling onto milder temperatures.

4 gfs h500's.png4 gfs 850's.png4 gfs max temps.png4 gfs ppn.png4 gfs ppn type.png

Night-time:

Wintry showers will continue to affect some Northern areas with snow over the Scottish hills. Drier elsewhere, although the GFS 'HGT500 and Sea Level Pressure' chart shows a cut-off Low to the West running South along the main trough of low heights to our North - this little feature heading Eastwards towards Western UK. The flow turning to the South-West over South-Western UK, which will bring some milder temperatures with it, although most places away from the coasts will see temperatures close to freezing. Possible frost, too.

Saturday Daytime:

The little Low/wave feature over Southern UK brings spells of rain to the South. Milder 850 hPa temperatures accompany this system, but it's only really the far South that sees the milder temperatures, while everywhere else will experience a cold day (probably also thanks to the fact the ridge of High Pressure to our West helps to feed cold air down from the North-West). Perhaps even cold enough for a bit of sleet for those on the Northern flank of the rain band, such as Central and North Midland areas, especially with that slack flow. But most of the wintry stuff will probably likely be over high-ground. Brighter and more showery to the North.

6 gfs h500's.png6 gfs 850's.png6 gfs max temps.png6 gfs ppn.png6 gfs ppn type.png

Nigt-time:

A ridge of High Pressure to the West will start tracking Eastwards and settle most of the UK down with some dry, clear conditions. Chilly air still feeding down South-Eastwards towards the UK on the High Pressure system's Eastern flank. Many inland areas, particularly to the North, seeing temperatures around, or below, freezing with some sharp frosts possible. A little less cold towards far South-Western areas of the UK.

7 gfs h500's.png7 gfs 850's.png7 gfs min temps.png7 gfs ppn.png

Sunday Daytime:

A fine, dry, calm, crisp, bright day in store for the whole of the UK with the ridge of High Pressure in control, but possibly a little cloudier towards the far North-West. A cold day for many with temperatures in the low single digits. The hilly areas in Scotland struggling to get above freezing.

8 gfs h500's.png8 gfs 850's.png8 gfs max temps.png8 gfs ppn.png

Night-time:

Similar picture with the ridge of High Pressure gradually tracking further East, but with the centre of the High Pressure over South-Eastern UK, most places should remain dry. There is however some milder 850 hPa temperatures getting dragged North-Eastwards over the UK. But most places staying below freezing with frost and fog likely. Some South-Western areas seeing slightly milder temperatures, especially over South-Western Ireland.

9 gfs h500's.png9 gfs 850's.png9 gfs min temps.png9 gfs ppn.png

It seems to me that there seems to be a lot more high pressure over us this weekend that hoped for over the last few days.???

Edited December 31, 2014 by seaside 60

[chris55]

GFS 6z with some changes to previous runs, back this west a bit and pump up that WAA and a cold easterly wouldn't be out if the question !

[johnholmes]

? some snow for higher hills Pennine/N Wales areas north if GFS is correct on Saturday?

[phil nw.]

Yes GFS P goes with flattening the attempt at Scandi ridging quite quickly at T144hrs.

http://modeles.meteociel.fr/modeles/gfsp/runs/2014123112/gfsnh-0-144.png?12

 

GFS Op a slower evolution with a better attempt.

http://modeles.meteociel.fr/modeles/gfs/runs/2014123112/gfsnh-0-144.png?12

Until we get closer it is difficult to assess how mobile the pattern ends up further on.

 

UKMO at t144 also thinking about Scandi ridging. 

http://www.meteociel.fr/ukmo/runs/2014123112/UN144-21.GIF?31-17

 

At least while there is this uncertainty there is room for a less zonal outlook.

 

Now over to the ECM.