Model Output Discussion 12hrs. 01/10/13

[Iceni]

Charles Dickens was born on 7th February 1812

 

 

Yes I know. That is why I put 'also'. Do you really imagine that one Victorian novelist could influence how everyone thinks of Christmas? Most people couldn't even read in those days.

 

BTW in the Times 13.07.2013: "Yet, as Britons bask in the hottest weekend of the year, with temperatures expected to reach 31C (87.8F), Mr King, 74, has been busy making predictions for the next six months: another hot spell at the end of July; an extremely cold and frosty October; snow on Boxing Day, followed by the harshest winter in decades, with snaps of snow and ice to continue until Easter. “Nature tells you what is coming,†he says. “You’ve just got to get out and look.â€

 

http://www.thetimes.co.uk/tto/weather/article3815693.ece

 

Looking good Dave "the Weather" King.

Edited October 9, 2013 by Iceni

[Summer Sun]

Latest from Gibby

 

Good morning. Here is this morning's account of the midnight outputs supplies by GFS, UKMO, GEM, NAVGEM and ECM for today Wednesday October 9th 2013.

All models show colder air sweeping South down over the UK today reaching all areas by midnight tonight following a band of showers. Thereafter the rest of the week and weekend are cold and rather showery days in the East where gales may affect Eastern Coastal Counties from the North tomorrow. The North and West become largely fine and dry with bright days and chilly nights with some frost in places. In the SE and South cloud will invade from the East through Friday and the weekend as the Low to the SE interacts with the Easterly flow on the underside of a large High North of Scotland bringing occasional rain, dull and misty conditions to these parts where it will feel distinctly raw, especially when compared with conditions of late.

 

GFS then shows slack Low pressure over Southern Britain well into next week with occasional rain and overcast conditions most likely though the cold wind will fall out early in the week so it may feel less chilly. The North stays dry and fine under a ridge still clinging on from the North which extends further South midweek away from the SW. Later in the week some unusually cold air over Northern Europe becomes scooped up by Low pressure from the Atlantic which sets up a more mobile airflow with Low pressure close to the NW sending troughs NE across Britain in a blustery SW wind. A temperature division is shown across Britain on this morning's output with the South becoming less cold while the North stays chilly with the dividing line edging South at the end of the run with Low pressure by then down to the SW.

 

UKMO today continues to maintain the chilly conditions of the weekend going across the UK early next week with a lot of cloud and occasional rain over England and Wales while the North stays dry with the odd bright spell and light winds by then for all.

 

GEM shows a complex pattern developing next week as the breezy and unsettled weekend in the South gives way to drier and quiet weather for a few days. However, Atlantic fronts will be trying to push up from the SW with winds slowly settling South-west or South with occasional rain gradually extending NE to all parts late next week. Average temperatures would be likely in the South then while the North stay rather chilly at times.

 

NAVGEM keeps cloudy and cool weather in the South well into next week as shallow Low pressure maintains it's position over Southern England with occasional rain. Some very cold air flirts with the East for a time midweek with a trough moving NE into SW areas with occasional rain here by soon after midweek.

 

ECM today shows much slacker conditions developing next week with no one pressure system having overall control of the weather over the UK. As a result it will be a very quiet and benign pattern of weather similar to recently but with temperatures much lower with some quite overcast, rather chilly and misty conditions looking likely with the chance of a shower. In any clearances in the cloud overnight extensive fog would readily form and would be slow to clear in the morning's.

 

The GFS Ensembles show a rather cold period for the next 4-5 days, especially over the SE where it quickly becomes unsettled with rain at times. The rest of the run shows temperatures gradually returning to normal with rain at times for all. The operational was a milder member of the pack than the average.

 

The Jet Stream shows the main flow well North over the Arctic while an off shoot from it dives down over the UK and sets up a circulation close to the SE for a couple of days. Then a Southern arm of the Jet crossing the Atlantic becomes the dominant player as the flow to the North weakens away. The flow then absorbs the Low cell to the SE and flows across or South of Britain later next week.

 

In Summary the weather is turning colder as I type. Northerly winds around a developing High to the West and then North of the UK will feed cold North then NE and East winds across Southern areas. The Low slipping South to the East then pulls West across Southern England with some rain at the weekend. As we move further out into the new week conditions look likely to become rather grey and benign with the chance of a little rain still and temperatures largely still suppressed. The Atlantic is waiting in the wings and there are some suggestions that this could engage with the cold air bottled to the North strengthening the Low pressure areas and pushing troughs, cloud, wind and rain across the UK later next week while other output keeps things fairly uninspiring and boring meteorologically speaking with light winds, plenty of cloud and some areas of mist and fog to complete the gloom in quite cool conditions at the surface.

 

http://www.norton-radstockweather.co.uk/Model-Analysis(2859336).htm

[Summer Sun]

Potential for 60mph+ gusts for parts of NE Scotland tomorrow.

 

13100915_0812.gif

 

Weather warning's out from Netweather but nothing from the met office?

 

After watching the 22:35 forecast last night it appears the worst impact will be high sea's so away from coastal sea fronts the impact of the winds won't be much hence no warnings

[nick sussex]

Both the ECM and GFS this morning are showing a bit more interest for those of a cold persuasion, we had a few runs where the GFS wanted to start moving the core of heights further to the west.

They do agree on keeping a chunk of the PV to the east and ne but as yet we don't see a clear trend to transport that cold into the UK, but the ECM and GFS throw a bit more more energy under the block as can be seen by that shortwave energy coming off the main troughing to the west.

I think we're in somewhat of a holding pattern here, cold building to the ne, troughing to the west, heights still holding to the north and nw, as yet we don't see the favourable cut back in the jet.

Whilst that ridging holds to the north you always have a chance of getting some early season cold in from the ne/east as long as the models don't want to trend to a west based negative NAO,so that's something to look out for in future runs.

[Alexis]

I can't really see where the interest in the models lies at the moment. A lot of still, cloudy weather going by the charts with temperatures near average after this week's cool shot.

[BLAST FROM THE PAST]

Very interesting model watching at the moment. Will we see a holding block. I have latter half being cooler [cold shot looks much colder] and very active with LP track / jetstream shifting south. Well up to FI the Atlantic is getting held at bay but will that change into last 3rd of Oct?. It is nice to see the change gather pace though and to a fairly beefy switch too for time of year and ECM went for it much sooner than the GFS.....a good start.  

 

 

 

BFTP

Edited October 9, 2013 by BLAST FROM THE PAST

[ribster]

Yes I know. That is why I put 'also'. Do you really imagine that one Victorian novelist could influence how everyone thinks of Christmas? Most people couldn't even read in those days.

 

BTW in the Times 13.07.2013: "Yet, as Britons bask in the hottest weekend of the year, with temperatures expected to reach 31C (87.8F), Mr King, 74, has been busy making predictions for the next six months: another hot spell at the end of July; an extremely cold and frosty October; snow on Boxing Day, followed by the harshest winter in decades, with snaps of snow and ice to continue until Easter. “Nature tells you what is coming,†he says. “You’ve just got to get out and look.â€

 

http://www.thetimes.co.uk/tto/weather/article3815693.ece

 

Looking good Dave "the Weather" King.

One Victorian novelist didn't, but the Victorians did, with Christmas cards and carols with the traditional view of Christmas, anyway, completely wrong thread, apologies.

[bluearmy]

 as long as the models don't want to trend to a west based negative NAO,so that's something to look out for in future runs.

 

does it matter at this time of year nick? as long as the lw pattern doesnt realign to bring a thaw to the asian snowcover, if you are going to lose a cold solution to a west based -NAO, far better its in october than NDJF

[Gavin Hannah]

Hey guys n gals, don't come in here much. Anyway, looking through the GFS and the +48hr 850 chart.

 

 

Where I've circled the HP, is it just me or is the GFS being a little too generous with the temperatures?  I'd expect a lot more mixing of the air masses up near Iceland / Greenland.  

 

 

 

 

[Captain Shortwave]

Well this is certainly different

Warm air would be pushing back north east on this chart

I'm torn here

on the one hand it kills the cold for the time being but on the other hand conditions here would improve by a huge margin.

Of course it could be very very wrong.

Wow I wonder how rare it is to see both Greenland blocking and a Bartlett high at the same time

Edited October 9, 2013 by Captain shortwave

[Summer Sun]

Warmer uppers making a quick return early next week for both the UK and more importantly across Scandinavia

 

 

No risk of frosts in the south!

 

 

The first Atlantic low in a long time brings with it milder wetter air

 

 

All in all this cooler snap looks to be just that a snap with a good recovery early next week thanks to the low out west dragging up some warmer air and some much needed rain for some areas

 

 

UKMO seems to be going the way of GFS as well here's t120 from them both to compare

 

Edited October 9, 2013 by Summer Sun

[East_England_Stormchaser91]

Warmer uppers making a quick return early next week for both the UK and more importantly across Scandinavia

 

 

No risk of frosts in the south!

 

 

The first Atlantic low in a long time brings with it milder wetter air

 

 

All in all this cooler snap looks to be just that a snap with a good recovery early next week thanks to the low out west dragging up some warmer air and some much needed rain for some areas

 

Definitely taken this with a pinch of salt. Atlantic overcooking much? Stereotypical GFS!

[Summer Sun]

Definitely taken this with a pinch of salt. Atlantic overcooking much? Stereotypical GFS!

 

UKMO seems to be following GFS though see my post I've edited in a comparison of GFS and UKMO at t120

 

t144 from GFS and UKMO to compare

 

 

The biggest difference is the placement of the high over Spain and parts of France

 

Out to t186 and GFS keeps the UK under uppers no lower than +4

 

Edited October 9, 2013 by Summer Sun

[Captain Shortwave]

Definitely taken this with a pinch of salt. Atlantic overcooking much? Stereotypical GFS!

The UKMO looks a little better but still poor. In fact the UKMO undercuts less energy from the Atlantic low in the early stages.

You would think that the cold air would plunge towards us once the low has cleared eastwards on the GFS

Edited October 9, 2013 by Captain shortwave

[Gavin Hannah]

Definitely taken this with a pinch of salt. Atlantic overcooking much? Stereotypical GFS!

 

Yeah, even if the patterns do verify or to something similar, I think the mods are getting a little out of whack with the upper air temps.  There's a lot of cold air that doesn't seem to do much at all on this run.

[East_England_Stormchaser91]

UKMO seems to be following GFS though see my post I've edited in a comparison of GFS and UKMO at t120

Anything 3 days away is hard enough to forecast. By next week, we could see the cold air to the north make a push South. What actually looks like causing the GFS low to strengthen is a tiny tropical shortwave trapped behind an area of high pressure in the mid atlantic, if that shortwave fails to make it past the high and just dissipates away, then that whole idea of the low powering up towards us is binned off. 

If the current high pressure in the Atlantic now strengthens or makes an unusual movement, the whole pattern currently modelled will alter significantly. Posts nearly 7 days out may as well be totally ignored for realistic talk.

[Summer Sun]

Its not till t240 before we see those colder uppers over Iceland making it down to the UK

 

 

Some snow for NW Scotland

 

 

But if you look west you can see whats coming yes that area of high pressure

 

 

With it the 850 uppers start to ease

 

 

Who fancies a late southerly?

Edited October 9, 2013 by Summer Sun

[Captain Shortwave]

Yeah, even if the patterns do verify or to something similar, I think the mods are getting a little out of whack with the upper air temps.  There's a lot of cold air that doesn't seem to do much at all on this run.

You have to remember it's still the beginning of October and a lot of energy goes into building that high, once the low gets cut off which is very quickly the cold pool will warm through quite a bit. In November beyond you probably wouldn't get this issue.

For cold to occur another route needs to be found fast, you absolutely have to stop the jet tilting SW/NE and pushing into northern France or the UK. The only way I could see this happening is some form of heights to our North east and try to undercut that. But in the end the polar profile is still good so there no harm in waiting. With heights over Greenland it's only a matter of when and not if (surely)

In other news the northerly today has now arrived, a bit wet and windy haha

Edited October 9, 2013 by Captain shortwave

[Gavin Hannah]

You have to remember it's still the beginning of October and a lot of energy goes into building that high, once the low gets cut off which is very quickly the cold pool will warm through quite a bit. In November beyond you probably wouldn't get this issue.

For cold to occur another route needs to be found fast, you absolutely have to stop the jet tilting SW/NE and pushing into northern France or the UK. The only way I could see this happening is some form of heights to our North east and try to undercut that. But in the end the polar profile is still good so there no harm in waiting. With heights over Greenland it's only a matter of when and not if (surely)

In other news the northerly today has now arrived, a bit wet and windy haha

 

You're right it is only October, but I still think the GFS is being a tad optimistic with the upper air temps.

Looking at the t 48-72, it does look as though the HP is pushing NE. It just seems to fizzle out come sunday..  

[East_England_Stormchaser91]

All i see is that Arctic high maintaining a split in the vortex. Very good signs indeed. this time last year, there was no Northern blocking to be seen whatsoever!

[Jonan92]

In my opinion there is a clear overpowering in GFS's run

[Captain Shortwave]

All i see is that Arctic high maintaining a split in the vortex. Very good signs indeed. this time last year, there was no Northern blocking to be seen whatsoever!

Precisely, patience grasshopper. The time will surely come and frankly the cold we will receive then will be much colder than what we probably would have got now 

Edited October 9, 2013 by Captain shortwave

[Isolated Frost]

All i see is that Arctic high maintaining a split in the vortex. Very good signs indeed. this time last year, there was no Northern blocking to be seen whatsoever!

That maybe because later on in that October, we had this?!

 

I think the balance between a E/NE flow w/ complete retrogression and a southerly Atlantic trough into the Bay of Biscay, and a SW/S flow w/ little retrogression as a more meridional Atlantic trough takes command will see plenty of solutions in the next few days; to stay away from the pain and anguish many get, try focusing on one model and a specific run (i.e. GFS 6z every day..), I'm looking at the EC 12z each day for trends; and keeping other NWP and t-connections in mind as well; but the EC for me performs the best, and the 12z is available each evening.

 

If we have anything remotely similar to this at 216, I'll be very pleased; a lot rests upon the NWP modelling of the retrogression around d6-d8 and how it copes with the Atlantic trough...

[Gavin Hannah]

I just don't want to see eastern Siberia melt out.  Much progress has been made and I'm happy for the cold to remain there. I'm not fussed what the weather does here so long as the Atlantic doesn't blow our winter hopes apart early in the season. I've always felt the GFS is Atlantic biased.

[Frosty.]

I just don't want to see eastern Siberia melt out.  Much progress has been made and I'm happy for the cold to remain there. I'm not fussed what the weather does here so long as the Atlantic doesn't blow our winter hopes apart early in the season. I've always felt the GFS is Atlantic biased.

It's the atlantic that's the problem, not the gfs :-)