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Model output discussion - into 2018


Paul

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Posted
  • Location: Lytchett Matravers - 301 ft ASL
  • Weather Preferences: Snowy Winters, Torrential Storm Summers
  • Location: Lytchett Matravers - 301 ft ASL
1 minute ago, Ice Day said:

Don't pack it in just yet, the 18z has, and will, never decided anything! The GFS inconsistency alone shows how complex this situation is.  I'm giving it one more day before throwing the towel in.

Im certainly not throwing the towel in lol. Was very tongue in cheek ! 

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Posted
  • Location: CARDIFF
  • Location: CARDIFF
1 hour ago, Catacol said:

So - here we go: starting tomorrow the height rises to the NE begin to fade away SE under the influence of falling AAM via low torques, unhelpful MJO phase and background Nina forcing. Ventrice posted this today - atmosphere clearly coupled to the oceanic nina signal.

DS8bUWnVMAAec0X.jpg

The logical progression of this is that there is insufficient forcing over the next 7 days to change very much, and let's remember that ECM has an over amplification bias in the extended range - I'm not buying a major block arriving in 7 - 10 days. A coldish pattern with plenty of polar maritime influence... but for lowland south of England we'd need to roll a double 6 to get something significant and even then it would probably be relatively transient. For high ground and the north - plenty more snow potential through this period: always worth acknowledging that not everyone on NW is a lowland southerner!!

But all is most definitely not lost. Taking apart the specific signals - as GP said a post or two ago - there is much for cold lovers to get excited about in the longer term.

Frictional torques have reached their approx cycle minimum

Frictional Torque

and shortly they will start to climb again. Relative AAM has gone through the floor, down to -3SD at the moment and probably bottoming out at that point

gltend_sig.90day3.thumb.gif.3c87f0e9682ffeaa6c13e705145d16c9.gif

With increases likely from this point as the atmospheric elastic band that constantly tries to keep momentum neutral at 0 kicks in. MJO currently in 2 but ready in around a week or so to move into 3 which has a much better composite for continental flow

ECMF_phase_MANOM_51m_small.gif

z500_p3_01_1mon.png

What does this all add up to? Chasing shadows for another week via NWP... but from around about this time next weekend we might start to see some very good looking charts hitting NWP output for Jan 20 onwards... maybe a few days later. Frictional torques will lead +MT and combine with MJO phase 3.. well supported by the atmospheric instinct to wipe away that very low relative tendency in AAM. This will encourage steeper incline of the Nina jet into Europe (that Nina forcing will remain so I dont see a Greeny high and -NAO from this) and the scandy high properly fighting back west. Undercut scenarios a-plenty.... and with Strat interest aptly timed to kick in later in the month we may see something of decent duration. It is too far out for me to speak about duration with any confidence... but I think lag effects of MT and the strength of the spring may well help establish a durable and strong scandy high which is then hard to shift... so a week of something cold seems a decent bet and if it went longer then it wouldnt be a surprise.

Eyes will be firmly looking for cold pooling over Eastern Europe in the meantime. Seeing -12 uppers heading for Greece in the modelling for next weekend could well end up being a rather good thing in the longer term...

Catacol 

I see MJO as now moving into phase 3 not in a weeks time but imminent. 

I also see Phase 3 as being the Catalyst for Increasing the NAO towards positive but around 14 days later so for me something rather more mobile around 23rd january

Here is what ECM say about it too

Time lag (days)

The probability of a positive phase of the NAO is significantly increased about ten days after the MJO is in phase 3 (phase 3+10 days), and significantly reduced about ten days after the MJO is in phase
6 (phase 6+10 days).

The probability of a negative phase of the NAO is reduced about ten days after the MJO is in phase 3 (phase 3+10 days), and increased about ten days after the MJO is in phase 6 (phase 6+10 days).

I disagree with the 10 day as my data shows few days longer but the rest seems fairly accurate. Obviously we have other drivers that can alter this but around 22nd i would expect very little blocking over Europe. Prior to this i would expect a period where systems move from our North West to South East as we move from the blocked pattern to a mobile pattern. At same time the AO may move into a negative.

The MJO Looks likely to move towards phase 5 by 21st - 24th January  which brings opportunities for European blocking around 1st / 2nd week of February

 

Hope you do not mind me saying this and having a open discussion on thoughts on MJO, as i feel best progression is when members discuss these things and learn from each others data and experience - so its possible i am wrong but this is where we learn

 

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Posted
  • Location: Nr Chelmsford, Essex
  • Weather Preferences: Hurricanes, Thunderstorms and blizzards please!
  • Location: Nr Chelmsford, Essex
Just now, karlos1983 said:

Im certainly not throwing the towel in lol. Was very tongue in cheek ! 

Top man.....maybe we need to start looking north?

gfsnh-0-198.png?18

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Posted
  • Location: Tyrone
  • Location: Tyrone

Nice run 18z the pv that has been sitting for eternity over Canada is eroding &  shifting east some nice cold zonal getting more into reliable time frame.

All starts at day 6 cold zonal 

Screenshot_20180107-223052.png

Screenshot_20180107-223250.png

Screenshot_20180107-223800.png

Screenshot_20180107-223747.png

Edited by booferking
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Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.
3 minutes ago, Ice Day said:

Top man.....maybe we need to start looking north?

gfsnh-0-198.png?18

Problem is look at the 850's its not even a slushfest - its a rain showers fest, less the further SE you go.

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Posted
  • Location: Horsham, West sussex, 52m asl
  • Location: Horsham, West sussex, 52m asl
7 minutes ago, karlos1983 said:

Easterly not on, never has been, we should all pack up and go to sleep. Silly bunch aren’t we. ?

ECM, UKMO and even the gfs show that there is just a chance we might get an easterly in the 6-10 day period, not a high chance ill admit, but it’s on the table 

heres the big 3 at 120

4675B5FB-D5EC-40A1-9419-FF908BA21757.thumb.png.4c8b562da926d2eca5e9a1585e730f58.pngD5611317-8EF4-4BE0-A9BE-A5C5FBF28AAE.thumb.gif.13d817dc9720b84564102d27d8a8c2b3.gif6412752F-B46D-4376-BF52-A92B2FB1FE29.thumb.png.2c76510ae4d2ef5f01a66b1e1c93f823.png

 

 

giphy.thumb.gif.c607f5e491fc9d658f45024282ffabac.gif

GFS is sticking to the script. very cold polar maritime air incoming with snow for most of us :)

gfsnh-0-192.thumb.png.7df9fa699b2d047596b38fcfd7ae32ee.png

all bets now on the apparition of the SSW to bring us an epic february....

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Posted
  • Location: Nr Chelmsford, Essex
  • Weather Preferences: Hurricanes, Thunderstorms and blizzards please!
  • Location: Nr Chelmsford, Essex
3 minutes ago, feb1991blizzard said:

Problem is look at the 850's its not even a slushfest - its a rain showers fest, less the further SE you go.

Thankfully it's at day 8/9 so will be completely different in 6 hours!

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Posted
  • Location: Heckmondwike, West Yorkshire
  • Location: Heckmondwike, West Yorkshire

Bad trends in the modelling today. The easterly is as dead as a dodo. To add insult to injury, there is zilch amplification in the north Atlantic so we will be stuck in cold rain for the foreseeable after the next few days. It is probably yet another january down the pan.

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Posted
  • Location: Sowerby Bridge, West Yorkshire
  • Weather Preferences: Click on my name - sorry, it was too long to fit here......
  • Location: Sowerby Bridge, West Yorkshire

More marginal uppers than the 12z, which didn't have the spoiler low. -5 instead of -6 could make all the difference.

Still showing plenty of snow opportunities through Monday and Tuesday (even to the south in the strong flow) but a much more ragged system. Dew points good, temperatures fine the further north and elevated you are.

 

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Posted
  • Location: Lincolnshire - 15m asl
  • Weather Preferences: Frost and snow. A quiet autumn day is also good.
  • Location: Lincolnshire - 15m asl
2 minutes ago, pyrotech said:

Catacol 

I see MJO as now moving into phase 3 not in a weeks time but imminent. 

I also see Phase 3 as being the Catalyst for Increasing the NAO towards positive but around 14 days later so for me something rather more mobile around 23rd january

Here is what ECM say about it too

Time lag (days)

The probability of a positive phase of the NAO is significantly increased about ten days after the MJO is in phase 3 (phase 3+10 days), and significantly reduced about ten days after the MJO is in phase
6 (phase 6+10 days).

The probability of a negative phase of the NAO is reduced about ten days after the MJO is in phase 3 (phase 3+10 days), and increased about ten days after the MJO is in phase 6 (phase 6+10 days).

I disagree with the 10 day as my data shows few days longer but the rest seems fairly accurate. Obviously we have other drivers that can alter this but around 22nd i would expect very little blocking over Europe. Prior to this i would expect a period where systems move from our North West to South East as we move from the blocked pattern to a mobile pattern. At same time the AO may move into a negative.

The MJO Looks likely to move towards phase 5 by 21st - 24th January  which brings opportunities for European blocking around 1st / 2nd week of February

 

Hope you do not mind me saying this and having a open discussion on thoughts on MJO, as i feel best progression is when members discuss these things and learn from each others data and experience - so its possible i am wrong but this is where we learn

 

Hi Pyro

Dont disagree about NAO signature - I dont think we are about to get any Greeny block in place anytime soon - Nina trough is in place. It's all about the angle of that trough as poleward waves cause a more meridional pattern allowing a scandy high to develop. We will wait and see - but a building scandy high pushing west is possible in a +NAO setup. 

Speed of MJO progress to me is swift if it hits 3 now - filtered V200 forecast that I have come to use suggests not quite yet

twc_globe_mjo_vp200.png

but a week ago the RH plots were suggesting phase 3 about now - so you could be right. My most recent cpc Wheeler Hendon plot still reads 1st January which is a bit frustrating... but the filtered view above is today.

All interesting stuff. If the MJO progresses into phase 3 in the next few days then given lag effect it might bring more influence on jet angle a few days earlier than my post suggested. Timings are never easy - in or around 20th January give or take for me for the stronger scandy signal. If it comes a bit earlier I wont complain.

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Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.

This run is going to deliver a significant strat warming - notable because everytime so far the 12z (most progressive lately with these - used to be the 6z last season) has showed one of the more aggressive warmings, its either been toned down or practically gone on the 18z.

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Posted
  • Location: Heckmondwike, West Yorkshire
  • Location: Heckmondwike, West Yorkshire
4 minutes ago, Catacol said:

Hi Pyro

Dont disagree about NAO signature - I dont think we are about to get any Greeny block in place anytime soon - Nina trough is in place. It's all about the angle of that trough as poleward waves cause a more meridional pattern allowing a scandy high to develop. We will wait and see - but a building scandy high pushing west is possible in a +NAO setup. 

Speed of MJO progress to me is swift if it hits 3 now - filtered V200 forecast that I have come to use suggests not quite yet

twc_globe_mjo_vp200.png

but a week ago the RH plots were suggesting phase 3 about now - so you could be right. My most recent cpc Wheeler Hendon plot still reads 1st January which is a bit frustrating... but the filtered view above is today.

All interesting stuff. If the MJO progresses into phase 3 in the next few days then given lag effect it might bring more influence on jet angle a few days earlier than my post suggested. Timings are never easy - in or around 20th January give or take for me for the stronger scandy signal. If it comes a bit earlier I wont complain.

The word 'frustrating' keeps cropping up this winter lol. You can say that again :)

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Posted
  • Location: Sowerby Bridge, West Yorkshire
  • Weather Preferences: Click on my name - sorry, it was too long to fit here......
  • Location: Sowerby Bridge, West Yorkshire

Strat on the go by 288h, reaching this by  the end. May just be the real deal this time.

gfsnh-10-384_zwt1.png

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Posted
  • Location: Clayton-le-Woods, Chorley, Lancs
  • Weather Preferences: Snow
  • Location: Clayton-le-Woods, Chorley, Lancs
3 minutes ago, feb1991blizzard said:

This run is going to deliver a significant strat warming - notable because everytime so far the 12z (most progressive lately with these - used to be the 6z last season) has showed one of the more aggressive warmings, its either been toned down or practically gone on the 18z.

7C8AA94D-6D37-4CEA-8B36-6A4543E2272A.thumb.png.8290ce29dbac2190106aefc376c87a0d.png

yep

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Posted
  • Location: Heckmondwike, West Yorkshire
  • Location: Heckmondwike, West Yorkshire
7 minutes ago, feb1991blizzard said:

This run is going to deliver a significant strat warming - notable because everytime so far the 12z (most progressive lately with these - used to be the 6z last season) has showed one of the more aggressive warmings, its either been toned down or practically gone on the 18z.

Well, if this year is a 1947 redux, I will forgive all  the frustration thus far :)Where is SM by the way? ;)

Edited by blizzard81
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Posted
  • Location: Chepstow Wales
  • Location: Chepstow Wales
20 minutes ago, abbie123 said:

Well now the door is shut to east where do go  from here.:)

Here i suppose ' only cold we are going to tap into , Failed easterlie , what else could happen :cc_confused:

iceland grocery.jpg

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Posted
  • Location: Nutley, East Sussex 120m ASL
  • Location: Nutley, East Sussex 120m ASL

I’m putting this up as I do not understand why people are exspecting an cold zonal to deliver snow for everyone!!! When has it ever happened?? I don’t know as normally when this cold zonal gets down to t0 the uppers are completely underestimated and too mixed out, all we get in the end is then freezing rain which is all the south east has had this winter. I believe the models are underestimating the block so I’m sure allot of people will be surprised by what the models show in a weeks time. But if you think cold zonal is going to deliver the snowfest people want it will not happen all it will bring is cold rain. 

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Posted
  • Location: Orpington Kent
  • Weather Preferences: Snow freezing rain heat waves
  • Location: Orpington Kent
6 minutes ago, A Frayed Knot said:

Here i suppose ' only cold we are going to tap into , Failed easterlie , what else could happen :cc_confused:

iceland grocery.jpg

Maybe a short wave will scupper it next time...:rofl:

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Posted
  • Location: West London
  • Weather Preferences: Snow
  • Location: West London
1 minute ago, Tom Jarvis said:

I’m putting this up as I do not understand why people are exspecting an cold zonal to deliver snow for everyone!!! When has it ever happened?? I don’t know as normally when this cold zonal gets down to t0 the uppers are completely underestimated and too mixed out, all we get in the end is then freezing rain which is all the south east has had this winter. I believe the models are underestimating the block so I’m sure allot of people will be surprised by what the models show in a weeks time. But if you think cold zonal is going to deliver the snowfest people want it will not happen all it will bring is cold rain. 

Speak for yourself! I live in an unfavourable place in the Southeast yet I’ve had two snow events this winter so far, Cold zonality looks likely in the near future and can deliver, I think we should appreciate what some northern areas may get and leave the IMBYism out of this thread :) 

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Just now, OfficialKevWX said:

Speak for yourself! I live in an unfavourable place in the Southeast yet I’ve had two snow events this winter so far, Cold zonality looks likely in the near future and can deliver, I think we should appreciate what some northern areas may get and leave the IMBYism out of this thread :) 

Here here. 1984 I think delivered cold Westerly winds which packed plenty of snow into North West. Way too much emphasis on the easterly

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Posted
  • Location: Tamworth, Staffordshire (83m ASL)
  • Weather Preferences: Heat, Thunderstorms, Snow
  • Location: Tamworth, Staffordshire (83m ASL)

So any modelled Pm blast shows -4 /5c 850s! No snow in that for the vast majority of the population. Waste of anticipation unless you are on a hill north of Manchester. Waste of time and certainly miserable days ahead. Watch the postive teleconnection musings become watered down as we close in on end of Jan. We really need to see a SSW so that we are not chasing the pot of gold until March.

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Posted
  • Location: NR Worthing SE Coast
  • Location: NR Worthing SE Coast

At least the Scottish ski  industry will be happy with the current outlook,cold zonality is perfect for them.If the rest of the month turns out like 1984 then many places will also see snow especially in The NW and Scotland.

However maybe we  need to see where we are tomorrow before we completely write off this Easterly yet.The end of the week is a long time in the weather model world ,look at the changes in the output over the last few days.

Edited by SLEETY
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