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Paul

Model output discussion - here comes the beast!

Paul

Please only post model discussion in this thread 

For more general chat and banter, or moans and ramps loosely around the models, please head to the banter thread:
https://www.netweather.tv/forum/topic/86721-model-moans-ramps-and-banter/

For general weather chat including about the snow/cold chances around the country, please go to the regional threads:
https://www.netweather.tv/forum/forum/142-regional-discussions/

We also have a special post SSW cold spell discussion open here:
https://www.netweather.tv/forum/topic/89358-ssw-related-cold-spell-will-it-wont-it/

Thank you!

Message added by Paul

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4 minutes ago, Quicksilver1989 said:

Yup I agree Iberia is unquestionably too far south but its something to be wary of. For reference here is the ECM clusters

image.thumb.png.9b8a2b3ca60bd577427c8d14c7061642.png

The northerly cluster 2 resembles this evolution. Remember the 00z yesterday. Aside from that the cold pool could still just be focused on the SE, one or two members show this.

Personally I think we would be really unlucky if things didn't materialise, especially given the size of the cold pool. The ensemble swing of February 2009 still lingers on my mind though.

But isn't that Northerly Cluster 192 hours away AKA after the Cold has already hit?

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1 minute ago, frosty ground said:

But isn't that Northerly Cluster 192 hours away AKA after the Cold has already hit?

Perhaps! I just don't want any hiccups to come along and I don't like the Finnish low, anyway I'm just a very cautious person lol. I think we are almost there and hopefully the 12z will eliminate any lingering fears.

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11 minutes ago, Catacol said:

I know this is the model thread - but have to challenge you on this: where in the MetO forecast does it suggest a move south? I cant see it. They have tweaked the text at lunchtime today to be a bit more region specific (the SW gets a mention!!) but nothing else.

In terms of model support for a move south - also don't really see it. This excellent chart for 100hpa winds from Hannah Attard shows very clearly the latitude of the block and the trough slamming through the UK.

100_nh_31.png

 

All good.

See my follow up- but briefly, yes I think most things are looking great, but I think the Met Office will be cautious until solutions such as those found in Cluster 2 disappear. So I think they are about as confident as the ECM ensembles are about the upcoming beasterly (so around 70%). I don't think you are challenging me though, since I almost wholly agree with your posts!! Just hope everything falls into place!

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21 minutes ago, Raythan said:

Has there been a comparable pattern like this current one where the output has just evaporated in the past ? Was ‘that ecm’ after a SSW ? 

The 2012 fiasco is the one that sticks in my mind, where if i recall correctly the switch around at t96 was just astonishing, especially the ECM which i believe had nearly full ens member support?  However, i don't think the MetO was fully on board in that instance (only goes t120) and on the previous thread some alluded to that change in output being due to significant solar weather impacts on the strat - NB i've no idea if that's true!  Don't believe a SSW was involved in that instance.

Edited by swebby

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Guest

Well it's a wonderful sunny day down here in Exmouth and 12c right now and set to continue (here) for 4-5 days with overnight frosts but gradually cooling off by day. The south-east will be the first to see the cold weather biting and some early snow flurries (perhaps by the weekend?).  Very few people will believe us or the MetO etc (and certainly not the Daily Express - crying wolf far too often) that we are heading into deep cold! 

This benign, sunny and mild weather reminds me of what proceeded many of our severe cold spells and I thought that it would be the perfect time to compare some of these to the current and predicted patterns. Before my time, it was very mild in mid-January going into the 1947 epic cold spell. At age 3 (before I can remember), it was very mild prior to the severe cold of early Feb '56. Then my actual experiences started with the '62/'63 winter. Some early cold and snow in November and early December. Then cold and foggy. Then mild and benign for a week and then from Dec 25th, sudden cold and snow and 11 weeks of winter wonderland. There are other and more recent examples, including February 1991 and March 2013 which some have already alluded to. What many of them have in common is the HP building into the country (either Azores HP ridging north-east, HP developing right over us or HP ridging down from the Arctic or Scandi). They all brought in winds from a southerly quarter with mild and benign conditions. Then the Siberian or Arctic (or in between) HP built and the wind backed into an easterly or north-easterly quarter. It actually all makes sense. Almost all of these spells started slowly and then the doors to the freezer were suddenly flung open.   

                                                                    BEFORE                                                                                                                       AFTER 

1947  archives-1947-1-18-0-0.png  archives-1947-1-18-0-1.png  archives-1947-1-23-0-0.png  archives-1947-1-23-0-1.png 

 

1956 archives-1956-1-29-0-0.png  archives-1956-1-29-0-1.png  archives-1956-2-2-0-0.png  archives-1956-2-2-0-1.png

 

1962 archives-1962-12-20-0-0.png  archives-1962-12-20-0-1.png  archives-1962-12-30-0-0.png archives-1962-12-30-0-1.png 

 

1991 archives-1991-1-29-0-0.png  archives-1991-1-29-0-1.png  archives-1991-2-7-0-1.png  archives-1991-2-7-0-0.png  

 

2013 archives-2013-3-4-0-0.png  archives-2013-3-4-0-1.png  archives-2013-3-11-0-0.png  archives-2013-3-11-0-1.png

 

2018 ECM1-0.GIF  ECM0-0.GIF  ECM1-168.GIF  ECM0-168.GIF?20-12

 

I believe that we'll be referring back to the 2018 severe cold spell as an analogue for many years to come.

I'll be back with one of my Eurasia temperature and snow cover reports towards the end of this week. Everyone enjoy watching this all unfold. It's going to be something highly memorable. 

 

Edited by Guest
Correct typos and check charts

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34 minutes ago, kev238 said:

Well I must be missing something with all this talk of backtracks .

From what I can see the GFS 6z was one of coldest and snowiest I have ever seen . Yes the deep cold lands on our shores about 12-18 hrs later but that is hardly a backtrack

 

 

I think it is fair to say that this is indeed correct. 

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21 minutes ago, Catacol said:

I know this is the model thread - but have to challenge you on this: where in the MetO forecast does it suggest a move south? I cant see it. They have tweaked the text at lunchtime today to be a bit more region specific (the SW gets a mention!!) but nothing else.

In terms of model support for a move south - also don't really see it. This excellent chart for 100hpa winds from Hannah Attard shows very clearly the latitude of the block and the trough slamming through the UK.

100_nh_31.png

 

All good.

One question on this, I'm still trying to try to understand the reasons why this block sets up where it does - is the Hannah Attard plot that you quote not just itself an model output from a single GFS run?  So how does it give predictability for future runs, or are you saying that as this is at 100hPa the model will have a better handle on this at 7 days than it does for the surface weather?

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So the things to watch for as the 12’s start to roll out...

Short term: Continuity of the heights linking up and rising as per before. Pretty sure this is nailed at this stage!

No pesky short waves rearing their ugly faces!

And later when ECM comes out, that none of that cluster that appeared in the EPS ON THE 00z, appear in the op, and preferably in a perfect world, are all gone when the eps come out later!

Eyes down folks...

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3 minutes ago, Mike Poole said:

One question on this, I'm still trying to try to understand the reasons why this block sets up where it does - is the Hannah Attard plot that you quote not just itself an model output from a single GFS run?  So how does it give predictability for future runs, or are you saying that as this is at 100hPa the model will have a better handle on this at 7 days than it does for the surface weather?

It is a single run, but stratospheric modelling is more accurate... and so we can get a better handle on the upper pattern and the forcing on what happens below. Of course there are 2 types of forcing - one that upwells from below, and one that downwells from above. A point of debate sometimes as to whether the trop impacts the strat or the strat impacts the trop - it can work either way to be honest... but in this case what we have is a reversal in the strat that is downwelling to affect the trop (and has done so quickly) so strat forecasts provide guidance as to the impact lower down.

That one single run is no guarantee that the trop will follow suit as a perfect match... but it is one of a long line of signals all pointing in the same direction now.

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JFF  :rofl: seriously you have no idea how long it took to find a mild solution in any model

gens-7-0-348.png

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4 minutes ago, winterof79 said:

JFF  :rofl: seriously you have no idea how long it took to find a mild solution in any model

gens-7-0-348.png

Bit odd if u ask me why u would look for a rogue mild chart tbh

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Can we have a new thread please, this ones far too negative. All models on board, SSW isn't going to suddenly dissapear oh and then we have these 😅

Snow depth at t384

S80220-15220740.jpg

Snow depth at t240

S80220-15311018.jpg

Snow depth in Newcastle at t?

S80220-14421292.jpg

Edited by geordiekev

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Just now, markw2680 said:

Bit odd if u ask me why u would look for a rogue mild chart tbh

Pretty sure he was posting it as a joke to reiterate how hard it is to find a mild chart at the moment.

The anticipation is building for the 12z's, let's hope for no hiccups. (I personally can't see any forthcoming)

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30 minutes ago, Nick F said:

I think some are worrying about small features that pop up in the models, which, physically won’t have much effect on the general well documented/agreed on momentum westwards of the deep cold as @Catacol has already highlighted. A small surface feature cannot alter the upper pattern and the jet, it’s normally the upper pattern and associated jet that dictates the movement of surface features.

 The movement westwards of the deep cold is being driven partly/mostly by the remnants of the daughter vortex that formed from the split of the SPV by the SSW beginning of last week, which dropped into NE Europe / NW Russia and will now move west over Europe and is coupled with deep cold pool moving west in the troposphere.

This weakening strat vortex can be seen on the 2PVU loop below (in blue) on GFS tropopause (where trop meets strat) pressure charts, dropping south over NE Europe then moving west. This is in turn causing the jet stream to push SW across Europe – helping pull the cold air west and southwest. A small surface low or ‘shortwave’ as some like to call it won’t stop this momentum.

5a8c3910bec6a_2PVUloop.thumb.gif.fa6c9eba76ad0aa78aaccd225d28e569.gif <--- click to animate

Talking of the JET :hi:

tempresultnur8_mini.png

Edited by winterof79

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4 minutes ago, Weathizard said:

Pretty sure he was posting it as a joke to reiterate how hard it is to find a mild chart at the moment.

The anticipation is building for the 12z's, let's hope for no hiccups. (I personally can't see any forthcoming)

Lol fair enough I misread it 😭

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15 minutes ago, winterof79 said:

JFF  :rofl: seriously you have no idea how long it took to find a mild solution in any model

gens-7-0-348.png

Why would you do that :nonono: that’s not funny sir, don’t give up your Day job :acute:

ICON steady!

D7CC3F9B-3BB7-4A5A-AECD-A73AB7538F8F.thumb.png.04ed1ac1fe89f3b15bc2b760e2462a3c.pngD5CF9A0C-8236-460C-9A4B-B45197CD99E0.thumb.png.d85000d49c1a617b5b0f2742a88b6a8b.png

Incoming 

D569700F-6262-4DC3-9C5C-F01A68B7036E.thumb.png.76302122a415a23a151e01b26e60a70b.png

Edited by karlos1983

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Amazing to think the building blocks for this (the high and cold pool being in place) are only some 36 hours away.

Edited by Duncan McAlister

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Minor feature develops..

Are a sure cause for a major inflow..

As exactions of flow are aligned..

Its like farting in the bath..

Smells at first...but then the bubbles clear..

Horrid way 2 relay it... but simple-..and honest!!!!!

Screenshot_2018-02-20-15-38-31.png

Edited by tight isobar

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12 minutes ago, markw2680 said:

Bit odd if u ask me why u would look for a rogue mild chart tbh

JFF (Just for fun)charts are normally looked at when very unlikely......... eh  :) #Banbury

and looking for deep cold when there is no chance.......the moments gone now

Edited by winterof79

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Well 120 on the ICON  quicker evolution  compared to the 6z

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2 minutes ago, weirpig said:

Well 120 on the ICON  quicker evolution  compared to the 6z

You could see that was gonna happen as there was more of a developed kick in the isobars near eastern europe and looked like it would push the cold air more directly towards the uk!!

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