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Model output discussion-mid Autumn and beyond


Paul
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Posted
  • Location: South ockendon essex
  • Weather Preferences: thunderstorms and HEAVY snow
  • Location: South ockendon essex
On 09/12/2018 at 19:19, knocker said:

God strewth another model thread to encourage the willie wagglers

And what model thread might this be please? I do hate to think im missing out on anything of importance!!

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Posted
  • Location: Nuneaton,Warks. 128m asl
  • Weather Preferences: Snow then clear and frosty.
  • Location: Nuneaton,Warks. 128m asl

The 12z GFS and ECM Operational charts at T144hrs 

ECH1-144.thumb.gif.4351bba6be2f0db943a347a5f9342b49.gifgfsnh-0-144.thumb.png.23586f508ec6e385926c7a4918918683.png

A large chunk of the vortex over the Pacific side but importantly for us a area of low heights draining south over Greenland resulting in return of a changeable period of westerlies with bands of rain or showers crossing the country.The Atlantic pattern re-established after the expected changeover at the weekend.

The mean path of the jet still further south so temperatures generally around average but with some polar air in the mix snowfall quite likely over the high ground in the north at times.

 

 

 

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Posted
  • Location: Windermere 120m asl
  • Location: Windermere 120m asl
1 hour ago, phil nw. said:

The 12z GFS and ECM Operational charts at T144hrs 

ECH1-144.thumb.gif.4351bba6be2f0db943a347a5f9342b49.gifgfsnh-0-144.thumb.png.23586f508ec6e385926c7a4918918683.png

A large chunk of the vortex over the Pacific side but importantly for us a area of low heights draining south over Greenland resulting in return of a changeable period of westerlies with bands of rain or showers crossing the country.The Atlantic pattern re-established after the expected changeover at the weekend.

The mean path of the jet still further south so temperatures generally around average but with some polar air in the mix snowfall quite likely over the high ground in the north at times.

 

 

 

Yes whilst we are going to see a more mobile atlantic flow, with the jet still just to our south, every chance of injection of polar maritime air at times, which would bring wintry conditions to higher ground in the north, something we have seen very little of so far this new season, and also a bit of frost in any clear skies more so in the north. Nothing especially exciting from all points of view, but could be worse if you like colder weather, we could have high pressure nosing in from the azores or a long drawn south westerly fetch, or indeed deep low pressure systems with marked warm sectors. Very typical December fayre, a month renowned for being predominantly westerly.

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Posted
  • Location: Nuneaton,Warks. 128m asl
  • Weather Preferences: Snow then clear and frosty.
  • Location: Nuneaton,Warks. 128m asl

Yes a more typical December outlook beyond the weekend.

Once established the Atlantic pattern looks like continuing for a little while- at least up to day 10 according to the 12z mean 500hPa charts anyway.

ecmwf-ens_z500aNorm_nhem_11.thumb.png.33c5b10478449b90f7039ec50f01ef8d.pnggfs-ens_z500aNorm_nhem_41.thumb.png.e6157a63ef200fe6fcac27e5463c1481.png

Both show a similar pattern with the 2 main vortex sectors linked between the Aleutians and Greenland with +ve hts to our south thus showing a fairly flat jet profile and a westerly flow across the Atlantic into the UK.

Temperatures for the period around or just above average,colder at times further north,rainfall looks slightly above.


gfs-ens_T2maMean_eu_6.thumb.png.d90f125961d50189da39b3eef433f767.pnggfs-ens_apcpna_eu_5.thumb.png.fcc8abc012fdc20ad42ebdb5476ad312.png

Similar conditions also extending into NW Europe.

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Posted
  • Location: Nuneaton,Warks. 128m asl
  • Weather Preferences: Snow then clear and frosty.
  • Location: Nuneaton,Warks. 128m asl

Pretty good agreement in the models now for a change showing by the beginning of next week as wet and windy weather sweeps across the UK.

A couple of charts from GFS and ECM showing quite a strong jet stream heading this way by Tuesday 00z pushing in the milder air from the west.

11.thumb.png.7fa1be802712274df79cc623d79b17f4.pngECM1-144.thumb.gif.efc69dfeb69a8661729bb6e72ea58db3.gif

so after a chilly and fairly quiet few days the blocking high over Scandinavia recedes as Atlantic weather takes over during the weekend.

Next week is looking changeable  with rain at times with temperatures varying around normal.

The London ens graphs

ensemble-rrrcum-london.thumb.gif.1fc14192982d61ccbe8978c68013e76f.gifensemble-tt6-london.thumb.gif.c2a6280e98fcbf343a0c65ae7f82ab10.gif

As usual in this pattern sometimes it will be wetter and colder further north with always the chance of snowfall over high ground when any polar air gets into the mix.

Edited by phil nw.
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Posted
  • Location: Nuneaton,Warks. 128m asl
  • Weather Preferences: Snow then clear and frosty.
  • Location: Nuneaton,Warks. 128m asl

The change to Atlantic weather looks well established by early next week.

Tuesday T120hrs sees a strong jet whipping across the Atlantic heading into the UK/NW Europe and down towards the Mediterranean.A large area of low pressure in the E.Atlantic pushing south westerly winds and bands of rain and showers into the UK.

jet.thumb.png.9d31240d7820d5aec71985a0f1762782.png

This pattern is modeled to the end of the week.The 2 mean charts for next Friday show a fairly typical westerly flow with low pressure continuing to swing this way off the Greenland vortex.

gensnh-21-1-204.thumb.png.59b79a77cb0efb743224176373d012a3.pngEDH1-192.thumb.gif.82f490849be7f44633bf54dc7858bf99.gif

So further rain or showers can be expected with temperatures generally not far from the average.

Edited by phil nw.
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Posted
  • Location: Nuneaton,Warks. 128m asl
  • Weather Preferences: Snow then clear and frosty.
  • Location: Nuneaton,Warks. 128m asl

A look at the overnight GFS/ECM day 10 ens mean hts.

EDH101-240.thumb.gif.07bf7d6fbfdf8727ef54ee10f19d4245.gifgensnh-21-5-240.thumb.png.44ff8527dd2b901c3123c0c0844733b1.png

so we see the Christmas eve. pattern with +ve ht anomalies across the Arctic with a continuing signal for Atlantic heights extending north towards Greenland.At the same time what looks like a cut off UK low  and a weak Atlantic jet flow.

The gefs graph for C.England(Warks.)

temp.thumb.png.02c4155a50ecf9909160719eae22b927.pngrain.thumb.png.9330d176aec3f3298bdf89b10a06ac0b.png

At that stage a north westerly setup looks likely with some rain at times temperatures still around or just below average.

 

 

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Posted
  • Location: Carryduff, County Down 420ft ASL
  • Location: Carryduff, County Down 420ft ASL
Just now, phil nw. said:

A look at the overnight GFS/ECM day 10 ens mean hts.

EDH101-240.thumb.gif.07bf7d6fbfdf8727ef54ee10f19d4245.gifgensnh-21-5-240.thumb.png.44ff8527dd2b901c3123c0c0844733b1.png

so we see the Christmas eve. pattern with +ve ht anomalies across the Arctic with a continuing signal for Atlantic heights extending north towards Greenland.At the same time what looks like a cut off UK low  and a weak Atlantic jet flow.

The gefs graph for C.England(Warks.)

temp.thumb.png.02c4155a50ecf9909160719eae22b927.pngrain.thumb.png.9330d176aec3f3298bdf89b10a06ac0b.png

At that stage a north westerly setup looks likely with some rain at times temperatures still around or just below average.

 

 

Cheers Phil. Those would indicate that the ECM Op was indeed an outlier, hopefully the 12z will be more seasonal.

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Posted
  • Location: Nuneaton,Warks. 128m asl
  • Weather Preferences: Snow then clear and frosty.
  • Location: Nuneaton,Warks. 128m asl
2 minutes ago, mountain shadow said:

Cheers Phil. Those would indicate that the ECM Op was indeed an outlier, hopefully the 12z will be more seasonal.

Here's the ECM 850's graph ms

1993413415_graphe_ens3(1).thumb.png.7e23b3ffce260ef6a8574e334c52de30.png

clearly the op was milder at day 8 generally ens looking in good agreement.

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Posted
  • Location: Camborne
  • Location: Camborne

The most noted aspect of the gfs this morning is we move through next weekend into the following week is the amplification of the subtropical high in the western Atlantic which drifts east and thus causes the trough over the UK to do the same. But not before more wet and windy weather on Friday and then a sunny intervals and squally showers weekend. Temps varying around the average

gfs_z500_vort_natl_22.thumb.png.bc23afc5c5bcace459d260b7541becf1.pnggfs_z500_vort_natl_31.thumb.png.64acd762ecfa0837b6a2e8d54e570d85.pnggfs_z500_vort_natl_36.thumb.png.8e017ea94e97fa2e4a0eff00f2335b94.png

 

 

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Posted
  • Location: Camborne
  • Location: Camborne

The ecm not dissimilar to the gfs. A frontal passage with wind and rain on Friday followed by an unstable showery weekend. But Monday sees the upper trough caught in a pincer movement as the subtropical high pressure zones amplify This does not stop a front tracking north east accompanied by more rain. Temps above average

t204.thumb.png.a7c207f852097113bd578b5c82f09598.pngindex.thumb.png.f653d91891c268f91db1f1591aec150f.png

Oh my......................

green-shoots.thumb.jpg.34b640d8d0d15375c8c5d30fa0fba019.jpg

Edited by knocker
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Posted
  • Location: Camborne
  • Location: Camborne

One has to say a pretty fair agreement between the GEFS and EPS ext anomalies this morning.

Upstream  shallow low pressure Siberia/Aleutians with the vortex N. Canada and reasonably flat across North America, Downstream a trough in the western Atlantic but quite substantial ridging from the subtropical high pressure in the vicinity of the UK. This would portend an upper flow a tad south of west and thus perhaps tending towards a N/S split vis unsettled weather with temps around average, perhaps a tad above.

gefs_z500a_5d_nh_61.thumb.png.dcb9e950a2b26ba5a8178e79fcca4c2c.pngindex.thumb.png.080b9bc5cc702b2848fcf4545c1b72cc.png

Last night's NOAA, although in the same ball park upstream, was not so bold regarding the subtropical high downstream.

814day_03.thumb.gif.961664a073a13146a7f7fd8bd3ec0b54.gif

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Posted
  • Location: Camborne
  • Location: Camborne

In the reasonable time frame not a huge difference with this evening's gfs output and the the midnight. Still looking at amplification early next week leading to trough disruption and the inhibiting of longitudinal movement. Thus the weather generally unsettled in the days up to, and including Xmas, with temps around average, tending colder later.

gfs_z500_vort_natl_27.thumb.png.0e07e6bc4c187c11f3c2fd8b326ceabf.pnggfs_z500_vort_natl_35.thumb.png.a6a896181b597d8d7526059127941525.pnggfs_uv250_nh_39.thumb.png.32328f00f27d49a94f48f901a8f87635.png

Edited by knocker
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Posted
  • Location: Camborne
  • Location: Camborne

The ecm has the amplification starting at t126 when an upper trough is dominating the Atlantic and a surface front is crossing the UK accompanied by rain.

t126.thumb.png.52f2d9500428b2ce2db884acbfd6cf8e.png

Fast forward to t168 and the upper trough starts to disrupt under the pressure from the amplification with one low center loitering to the west of the UK as a certain amount of pattern inertia sets in. But fronts and bands of rain do impact the UK, running around the eastern flank of the trough, at the beginning of next week as the aforementioned center drifts east. Temps varying around the average

t168.thumb.png.7b032ab01c2ca331b84f9e7dd2792c42.pngt192.thumb.png.9aeea82f2260fab7bf8feb89677bad54.png

Edited by knocker
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Posted
  • Location: Camborne
  • Location: Camborne

The GEFS and EPS mean anomalies again in the same ball park this evening with weak twin vortex lobes Franz Joseph and N. Canada and a very strong Pacific jet running south of low pressure Siberia/Aleutians.The end result of this is a strong westerly upper flow exiting the eastern seaboard across a quite amplified Atlantic with a trough in the west and ridging in the east adjacent to the UK. This still portending a quieter spell of weather over the latter, tending a N/S split with temps around average, perhaps a tad below..

gefs_z500a_5d_nh_61.thumb.png.a546cfe443807aa44f5abdeebc368685.pngindex.thumb.png.b64865895a15d0af954fa681950ec65f.png

And NOAA this evening has edge a tad closer t this

814day_03.thumb.gif.ee124e7c2a46bb503a6323755cb723e9.gif

Edited by knocker
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Posted
  • Location: Wantage, Oxon
  • Weather Preferences: Hot, cold!
  • Location: Wantage, Oxon
6 minutes ago, knocker said:

Oh and Happy New Year from the FV3

fv3p_z500a_nhem_65.thumb.png.0d93de0a607cbc64985c6c339156fc2a.png

In a state of flux though by that stage, the atmosphere, models and Netweather commentary, I would think.   It's post SSW, here be dragons!

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Posted
  • Location: Camborne
  • Location: Camborne

Moving on from the short range with the gfs. The rain quickly clears on Saturday but by Sunday more sustained amplification is taking place as the next trough brings more rain as it disrupts

gfs_z500_vort_natl_27.thumb.png.2311024ac44f504569f72d70bbb24f77.png

The rain clears on Monday and by Tuesday the ridge has moved east with a high cell to the south west of the UK which is in a north westerly flow with temps a tad above average. Perhaps some showery rain in the north west

gfs_z500_vort_natl_35.thumb.png.a2835734bb2ea6f707977297a4afd77e.png

 

 

Edited by knocker
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Posted
  • Location: Camborne
  • Location: Camborne

The overall evolution of the ecm post the short range is not dissimilar to the gfs albeit the detail different.

At 156 amplification and trough disruption underway with fronts bringing rain to the UK

t156.thumb.png.51b76d1ec18cf888d8f090751a591e2b.png

By t180 the rain has moved east as the amplifying subtropical high consolidates and the upper trough becomes cut off to the south west

t180.thumb.png.018fc34dc85abda7ab14f9048d3a2a3e.png

And by Wednesday lunchtime the ridge is over the UK spreading north west which relegates the trough to the south west and the energy leaving the eastern seaboard is much less than it has been, temps now a tad below average but weather quite benign and dry

t228.thumb.png.b06a55da876261ac38a54f9b73622d43.pngtemp.thumb.png.4ae7625f6e6c198f2ada7005fb50de27.png

 

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