Jump to content
Snow?
Local
Radar
Cold?
IGNORED

Focussed Model Discussion


Paul
Message added by Paul

This is the focused model discussion - please only post about the model output. 

For a more laid back, bantery model discussion please use the Cold hunt - models and banter thread.

Recommended Posts

Posted
  • Location: STEVENAGE, HERTS (100M ASL)
  • Location: STEVENAGE, HERTS (100M ASL)

With zonal winds heading back to normal levels soon are we are likely to see the PV reform and get back to normal? If so let’s hooe it doesn’t take up shop over Greenland and scupper our chances of a cold Feb! 

 

251BD12E-4166-4418-AFA7-761C93B5CCF1.jpeg

Link to comment
Share on other sites

Posted
  • Location: st albans
  • Location: st albans
10 minutes ago, phil nw. said:

Just been going through those again Nick and it seems frome day 11 they reduce to only one cluster.Indicates that around this time the last ejection of low hts from the Canadian pv is cut off and the ridge heads north.Pattern adjustment to more of a north/north easterly?

Looks like a strong signal for day 11-15 to reduce a scenario to one cluster,unusual at that range for sure.

I know it’s one cluster Phil but that’s not feasible. The pressure and heights spread on the extended eps graphs clearly shows that. So there must be more than six clusters which is when, as far as I can tell, they reduce to one all encompassing cluster which may or may not be of any use !  (Likely not although it could be a ‘single’  pattern with different timings and transitions and therefore tough to pick up how the retroughing is achieved)

Link to comment
Share on other sites

Posted
  • Location: Nuneaton,Warks. 128m asl
  • Weather Preferences: Snow then clear and frosty.
  • Location: Nuneaton,Warks. 128m asl
7 minutes ago, Tim Bland said:

With zonal winds heading back to normal levels soon are we are likely to see the PV reform and get back to normal? If so let’s hooe it doesn’t take up shop over Greenland and scupper our chances of a cold Feb! 

 

251BD12E-4166-4418-AFA7-761C93B5CCF1.jpeg

The downwelling on any increase down to trop level will take some time Tim.

Latest forecast at all levels at 60N.

umedel60.thumb.png.76959e4a666a04608925d4ae549d80dc.png

 

  • Like 3
Link to comment
Share on other sites

Posted
  • Location: st albans
  • Location: st albans
11 minutes ago, Tim Bland said:

With zonal winds heading back to normal levels soon are we are likely to see the PV reform and get back to normal? If so let’s hooe it doesn’t take up shop over Greenland and scupper our chances of a cold Feb! 

 

251BD12E-4166-4418-AFA7-761C93B5CCF1.jpeg

That’s at 10hpa Tim .....it’s taken weeks to get the reversal wave down towards the trop .... would be an incredibly unlikely kick in the proverbials for the restrengthening to just propagate quickly and imprint onto the trop!  

  • Like 5
Link to comment
Share on other sites

Posted
  • Location: st albans
  • Location: st albans

ICON at day 4/5 already bringing the problem low onto a nw/se trajectory when only 12 hours  age it was building a ridge ne at this short timescale 

Edited by bluearmy
  • Like 2
Link to comment
Share on other sites

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

I know it’s one cluster Phil but that’s not feasible. The pressure and heights spread on the extended eps graphs clearly shows that. So there must be more than six clusters which is when, as far as I can tell, they reduce to one all encompassing cluster which may or may not be of any use !  (Likely not although it could be a ‘single’  pattern with different timings and transitions and therefore tough to pick up how the retroughing is achieved)

Yeah i get you Nick re.number of clusterings.

I tend to think the evolution day 11 onwards with extra atlantic ridging is a strong signal based on today's data and it seems likely as you suggest there are differences on timings and exact pathway to it in those spreads in the extended.

Unfortunately i haven't access to all the ext eps suite..

Link to comment
Share on other sites

Posted
  • Location: Essex Riviera aka Burnham
  • Weather Preferences: 30 Degrees of pure British Celsius
  • Location: Essex Riviera aka Burnham
13 minutes ago, phil nw. said:

The downwelling on any increase down to trop level will take some time Tim.

Latest forecast at all levels at 60N.

umedel60.thumb.png.76959e4a666a04608925d4ae549d80dc.png

 

Am I reading that right down welling at peak by 1st February?

Link to comment
Share on other sites

Posted
  • Location: Nuneaton,Warks. 128m asl
  • Weather Preferences: Snow then clear and frosty.
  • Location: Nuneaton,Warks. 128m asl
1 minute ago, Froze were the Days said:

Am I reading that right down welling at peak by 1st February?

Yes looks that way but negative anomalies look like continuing for some time beyond.As Blue said above we would be very unlucky to see a quick uptick to positive zw based on the time it has taken for the reversal to downwell. 

  • Thanks 1
Link to comment
Share on other sites

Posted
  • Location: Lincolnshire - 15m asl
  • Weather Preferences: Frost and snow. A quiet autumn day is also good.
  • Location: Lincolnshire - 15m asl
14 minutes ago, Froze were the Days said:

Am I reading that right down welling at peak by 1st February?

Roughly at the turn of the month - yes. Provided we can get a good long wave pattern in place for cold air supply from the continent at around this point and through the first week of Feb then the prospects for a cold to very cold month are good. We hoped the trigger was going to be in 72 hours.....but it might instead be in 144 hours as the surge of heights occurs behind the second trough event at the weekend. Not a big difference really in the grand scheme of things.

  • Like 4
  • Thanks 1
Link to comment
Share on other sites

Posted
  • Location: South Norfolk, 44 m ASL.
  • Weather Preferences: Varied and not extreme.
  • Location: South Norfolk, 44 m ASL.
2 hours ago, Catacol said:

JN192-21.thumb.gif.594da650ff7c76289eb9c9451482bde1.gif

Less strong block to the east from ECM but same basic setup

ECH1-168.thumb.gif.bf9fd24707c082690fe1ffcc08348be9.gif

And GEM (note - as good as ECM at 192 in Dec 2108 on verification stats) on the same page also though the trough is much less pronounced

gemnh-0-180.thumb.png.28f10a5c0fe23cd4f9f08a1a43be079b.png

Finally GFS - same again though heights over Russa are quite weak in comparson

gfsnh-0-192.thumb.png.0208e2749deeccde7af4e197800463d0.png

 

Interesting to note that, of these models, the ECM keeps the vortex more defined at this stage than the others; possibly underdoing the propagating effect of the SSW?  It's no surprise, given that this is the case, that the ECM is one of the less nthusiastic at allowing heights to extend northwards.

Link to comment
Share on other sites

Posted
  • Location: Longwell Green, near Bristol
  • Weather Preferences: Storms, Gales, frost, fog & snow
  • Location: Longwell Green, near Bristol

UKMO 12z T144;

13568982_UN144-21(1).thumb.gif.0d5745149d9c4dc66c5604ff5ed6950a.gif

Trough to the north of the UK may drop down into Europe giving a possible northerly down the line otherwise it's as you were, similar to its 0z output.

Edited by AWD
Add more info
Link to comment
Share on other sites

Posted
  • Location: Liphook
  • Location: Liphook

As BA has been saying the one really powerful trend is for the continuation of the cut-off low pattern. L:ooking through the ensembles though this will probably In combo with at least some strong midlatitude blocking , and possibly high latitude blocking around 240-300hrs. I think personally its still a little too soon for HLB to establish, my gut is telling me 5-10th and the vortex will hold a little longer over NW America than some of the models are expecting at the moment.

Biggest risk in this pattern is the trigger low that sinks south and is in combo with good blocking ends up sitting in a poor place and spreads in SW/S winds into the UK instead on feeding in colder air from the E/NE. Cold still, but with little chance of snow UNLESS we already have the cold surface established, preferably with snow.

 

Link to comment
Share on other sites

Posted
  • Location: st albans
  • Location: st albans
9 minutes ago, feb1991blizzard said:

Another rip-snorter from the GFS - good run to run consistency with the mid Atlantic / Greenland ridge.

Was just thinking how mobile the output continues to look .....without help from the polar field, I wonder how we get a ridge to stick for more than a day or so as it travels west to east ...

  • Like 1
Link to comment
Share on other sites

Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.
Just now, bluearmy said:

Was just thinking how mobile the output continues to look .....without help from the polar field, I wonder how we get a ridge to stick for more than a day or so as it travels west to east ...

Yes - sorry by the way - that was posted in the wrong thread, i am just thinking perhaps my worries about the strat split not being wide enough were founded after all, i thought we were going to get away with it until that ECM on friday!,  You are right that the persistent euro trough could be a snowfest - another one showing on the GFS 12z, but these wedges are frought with danger, even in this run a shortwave nearly scuppered the second attempt up into Greenland, only a slight difference in modelling would have been a failure which when its 210-240, you can't really put much faith in getting it to the reliable, given recent events.

Link to comment
Share on other sites

Posted
  • Location: Camborne
  • Location: Camborne
19 minutes ago, chionomaniac said:

So the rinse and repeat pattern with the NW/SE seems to be the likely evolution. So what can this lead to?

Well looking at how the Eastern NA segment of vortex retreat to the Asian sector at 50hPa by day 10 then it is no wonder that there is only 1 Eps cluster. 

Today at 50hPa

44B883B9-FFEF-41BA-842B-A471D7937D12.thumb.jpeg.536f58f9c5bd841cc475ea0a010d6a8d.jpeg

And Day 10

657AE3DB-64C9-4A5F-A37C-2058CADDFF1E.thumb.jpeg.7b2c83222070257ec3125e08fc9d8474.jpeg

 

So with a little more amplification of the repeating pattern and the euro trough remaining then it won’t take much to get the mother of all northerlies  and a Greenland block to match

 

The latest GFS day 10 a good starting point

B34FAB76-CDC2-4C40-BA3B-D09B3A24B9B9.thumb.jpeg.c1077112590ae48c83e9337e04ef5122.jpeg

 

But I notice the gfs still has two centres

gfs_z50a_nh_41.thumb.png.004f2949a36677ce1227f8b37f8d48b6.png2019012012_f192_50.nonenonehghtnonebrbk_nhem.gfs003.thumb.gif.37218b9700ae5ce3f703abffe964772f.gif

Edited by knocker
  • Like 1
Link to comment
Share on other sites

Posted
  • Location: Hayward’s Heath - home, Brighton/East Grinstead - work.
  • Weather Preferences: Snow and storms
  • Location: Hayward’s Heath - home, Brighton/East Grinstead - work.
17 minutes ago, knocker said:

But I notice the gfs still has two centres

gfs_z50a_nh_41.thumb.png.004f2949a36677ce1227f8b37f8d48b6.png2019012012_f192_50.nonenonehghtnonebrbk_nhem.gfs003.thumb.gif.37218b9700ae5ce3f703abffe964772f.gif

Yep. But ECM has better Strat resolution.....

so gfs not surprisingly show no Greenland block

  • Like 2
Link to comment
Share on other sites

Posted
  • Location: st albans
  • Location: st albans

Extended eps still no appetite to hold a mean upper ridge in the greeny area .......there is one but it travels east - similarly the 46 doesn’t stick a sustained ridge up there either 

 

Edited by bluearmy
Link to comment
Share on other sites

Posted
  • Location: Camborne
  • Location: Camborne
3 minutes ago, bluearmy said:

Extended eps still no appetite to hold a mean upper ridge in the greeny area .......there is one but it travels east - similarly the 46 doesn’t stick a sustained ridge up there either 

 

I think care has to be taken how the Greenland ridge/block is defined. As you know you can have  a strong Atlantic ridge which effectively blocks eastward movement across the atlantic, or a compromise such as the ext EPS was indicating this morning with a partial Atlantic ridge and an associated one into east Greenland which acts as a partial block and splits the energy.energy flow.

  • Like 1
Link to comment
Share on other sites

Posted
  • Location: Liphook
  • Location: Liphook
18 minutes ago, bluearmy said:

Extended eps still no appetite to hold a mean upper ridge in the greeny area .......there is one but it travels east - similarly the 46 doesn’t stick a sustained ridge up there either 

 

Having just had a look through every 00z ECM ensemble at 500hpa thickness, I'd say the main theme is still definitely upper troughs spinning off SE. Some are a little too far west and introduce milder air, quite a few look ok, and some look amazing. But a fairly large majority are cold, some very.

There are plenty of good ridging attempts from the Azores though and so that's probably the other 'trend'.

PS, I think any decent northern blocking is still a fair bit away, though as n others have said repeating SE diving LPs followed by upper ridging in the Atlantic can provide a similar result.

Edited by kold weather
  • Like 1
Link to comment
Share on other sites

Posted
  • Location: Wyke regis overlooking Chesil beach.
  • Weather Preferences: Snowfall
  • Location: Wyke regis overlooking Chesil beach.
14 minutes ago, bluearmy said:

Extended eps still no appetite to hold a mean upper ridge in the greeny area .......there is one but it travels east - similarly the 46 doesn’t stick a sustained ridge up there either 

 

NOAA_2_1978021818_1.thumb.png.352c3e941580fe7a400a90453f7c1cfb.png

but I thought it was wedges what made sledges Blue

  • Like 1
Link to comment
Share on other sites

Guest
This topic is now closed to further replies.
×
×
  • Create New...