The Hunt for Cold continues 02/01/19

[damianslaw]

Models are in the main pointing to a generally cold outlook - not significant cold, but with continued blasts of polar air, from the north west, with the jet aligned NW-SE thanks to deep trough formation to our NE, steering low pressure on such a path, with noses/ridges of high pressure behind. Temporary shortlived milder sectors will invade southern parts at times - however, for the north, it looks like next week will mark the start of winter proper, with much high-level snow, and possibly snow to lower levels at times - more so as we hit mid-month, when an expected deep low from the NW will pull down some very cold uppers behind.

As others have said, the trend towards buildings wedges of heights to our north and north east as the month wears on, will aid the development of more sustained colder spell, with low pressure then likely to disrupt - we are then in slider territory, what we saw at times Dec 2017, and as mentioned in Jan 2013 especially.

 

[Norrance]

No more bickering please. A number of posts have been hidden and it could have been more. 

[danm]

24 minutes ago, Singularity said:

 

As BA pointer out earlier, wedges can work very well for individual snow events. Mid-Jan 2013, central and in particular eastern parts were unlucky that a lot of dry air was piled in just before the front moved across from the southwest, causing it to fizzle out quite quickly.

Yes, remember that well. The front you mentioned fizzled out as it pushed east on I think it was the Friday the 18th. However, another area of snow moved into the SE/EA from the continent on Sunday the 20th which gave moderate to heavy falls all day with another 3/4 inches. 

Shows we don’t always need a strong HLB to deliver.

Edited January 5, 2019 by danm

[Ali1977]

17 minutes ago, BLAST FROM THE PAST said:

Having gone through the 06z suite, there is a general increasingly cold theme and I’d say 16 of them are pointing to 13-16th when main cold surges down when a PV displaces (a pretty good suite ratio going forward) .  I would take most of the runs as plenty of pretty snowy set ups.  None suggest real HLB to directly affect us (unlikely for most of this month) but that’s not needed as long as we get the deep troughing to our E/NE linked with further troughing over Italy with ridges nosing in.  Very cold air from the north over us and any LP that approaches forced to slip and slide on NW/SE axis.

 

BFTP

Sounds good, I’m not sure how much SSW accuracy is there within the models now (any ideas on this or is 10 days way too FI during these set ups??) but you’d think cold surges could gain some potency as the PV weakens as it comes into play more. We just need more -8c upper blasts rather than -5/6c , then the whole of the UK may get a chance before a “possible” main event later on. 

[Kirkcaldy Weather]

7 hours ago, TomSE12 said:

Having had a quick look at the early overnight runs, IMO it does look like the Models seem to be gearing themselves up for a mid-Jan, pattern change with something more favourable to deliver something much more wintry, to our shores.

As perhaps G.P, suggested we need to look towards the Arctic initially, rather than East, with Models suggesting the possibility of a couple of glancing, short duration wintry bursts, coming south around a mid-Atlantic ridge. Dare I say it, "A Dwarf From The North". Take note, Nathan Rao and the Daily Mail!!

Certainly patience being the "watchword", at the moment.

Regards,

Tom.  

Some from the 06z GEFS highlighting the blocking possibilities in the arctic / Greenland, I am expecting more blocking showing up in those kinds of areas in the coming days, could be beginning to tie in with MJO phase 7

      

NAVGEM 

 

a reminder of nino MJO phase 7 in January 

  

17 minutes ago, Singularity said:

Increasing indications for a 2013-like sequence with us first looking for ‘wedges’ of high heights to disrupt troughs on a sliding trajectory, and then for the major HLB episode (remember Mar 2013? Imagine that about a month sooner! Thats the most optimistic possibility but you get the idea), possibly with a less cold interlude in between as the tropical cycle makes its way back toward the cold-supportive phases.

 

 (snowy ramp?)  anything along those lines (Mar 2013) think the majority of us would happily  

https://www.metoffice.gov.uk/climate/uk/interesting/march2013-snow 

 

[Mike Poole]

This reversal of winds following the SSW shows no sign at all of relenting.  GEFS zonal wind 10 hPa, 60N plot today:

Breaches the -15 m/s mark at 10 Jan and not a single member back in westerly territory by the end of the run.

I've noticed posts in here occasionally along the lines 'a SSW doesn't always lead to cold for the UK, you know'.  I know.  Pretty much everyone who posts here knows.  That's what makes watching this spell unfold in the model output so fascinating and exciting!  If cold were guaranteed in 2 weeks time, what would be the point?  

The position seems to be that the initial impacts of the SSW will not directly benefit the UK, the effects are evident in the model output only really in terms of the Arctic high, but this is not close enough to affect our weather now.  But the effects of such a prolonged wind reversal in the strat could have impacts for the next 6-8 weeks - people have mentioned 2013 when the strat caused not only the January 'wedge' but also was implicated in the very cold March.  The chance of a really great prolonged cold spell in mid to late winter have not been greater for years - but, yes, it is only a chance and it could go wrong.  My money's on it going right for once!

[BLAST FROM THE PAST]

17 minutes ago, Ali1977 said:

Sounds good, I’m not sure how much SSW accuracy is there within the models now (any ideas on this or is 10 days way too FI during these set ups??) but you’d think cold surges could gain some potency as the PV weakens as it comes into play more. We just need more -8c upper blasts rather than -5/6c , then the whole of the UK may get a chance before a “possible” main event later on. 

I think there’s every chance that more sub -8c air is likely to come down widely over us.  Re Model response on SSW, well its happened but I don’t know at what time the models do respond, there seems so variable responses to SSWs, none seem to be the same

 

BFTP

[bluearmy]

Looking at those MJO forecasts, I see it races through the favourable 7 into the much less favourable 8 where it looks to die a death (not a great place to stop re euro heights) .......phases 1 thru 3 are good for euro troughing ........ but it looks like it will miss those out ......so those pinning their hopes on the MJO better hope that the signal is being interfered with going forward 

[IDO]

2 minutes ago, bluearmy said:

Looking at those MJO forecasts, I see it races through the favourable 7 into the much less favourable 8 where it looks to die a death (not a great place to stop re euro heights) .......phases 1 thru 3 are good for euro troughing ........ but it looks like it will miss those out ......so those pinning their hopes on the MJO better hope that the signal is being interfered with going forward 

Yes, I remember lots of postings from mid-Dec suggesting the MJO would be a springboard to wave 2 actions, however, it never happened and we got stuck in the warm 4 & 5 phases, and there was very little forewarning of such a scenario.

Then ECM and GFS had us in phase 7, the latter at record levels. Now it looks like it flies quickly to the COD via 7 & 8.

In any case, the composite of phase 8 is exactly that, a mean of outcomes over 40 years. With so many variables this winter I would not be surprised if the composite and the outcome are at the extremes of that envelope. The SSW may trump other variables in any case.

 

[ICE COLD]

17 minutes ago, bluearmy said:

Looking at those MJO forecasts, I see it races through the favourable 7 into the much less favourable 8 where it looks to die a death (not a great place to stop re euro heights) .......phases 1 thru 3 are good for euro troughing ........ but it looks like it will miss those out ......so those pinning their hopes on the MJO better hope that the signal is being interfered with going forward 

But don’t them MJO plots change daily ? There always flipping and flopping .

[Mike Poole]

ICON much more amplified at T120, here with 0z T132 for comparison, 12z first

Well it's the 12s innit? Bound to be, happy days! 

[karyo]

1 minute ago, Mike Poole said:

ICON much more amplified at T120, here with 0z T132 for comparison, 12z first

Well it's the 12s innit? Bound to be, happy days! 

The 0z looked really good at 180 hours with a northerly developing. I don't think the 12z is anywhere near as good

[Ali1977]

11 minutes ago, Mike Poole said:

ICON much more amplified at T120, here with 0z T132 for comparison, 12z first

Well it's the 12s innit? Bound to be, happy days! 

Not much coming from the ICONs timeframe anyway, all about day 9-10 onwards and the potency of the NW/N flow for now.

Just starting to line up at 180 on the ICON with HP building over Labrador/NFD

Edited January 5, 2019 by Ali1977

[Leo97t]

People have thrown Jan 2013 and Dec 2017 out as their maximum aspirations. If thats the best we can get then I would be disappointed. Honestly I'm expecting something more meaty. Perhaps a Jan 1881 style episode between 20 Jan to 20 feb

[Mike Poole]

5 minutes ago, karyo said:

The 0z looked really good at 180 hours with a northerly developing. I don't think the 12z is anywhere near as good

Fair comment, but obviously I was commenting on the run when it was out to just T120.  Let's see what the rest of the 12 suite bring us!

[Ventnor Viking]

Posted November 26, 2018 (edited)

GFS keeping things mild up to 144hrs

The pattern is unlikely to change until mid-late January in my opinion based on all of the long range models and the fact that we are continuously chasing FI 

November 26, 2018 by Shaftesbury Snow

----------------------------------------------------------------------

The post above is what I posted back 5-6 weeks ago and was based on many different models, solar activity, sea temps etc. and I got slated for it, even called vile names in a private message! However, I had 7 separate users message me to see they agreed but didn't want to post  because of the backlash they saw I had, even from forum hosts.

I don't feel smug, I just feel the regulars should give other people a chance to voice a realistic forecast not based on emotions, which many of you do!!! Its almost like being an out of towner going into a local pub and feeling uncomfortable in here, this is also back backed by others that messaged me.

I see many of the "respected forecasters" (you know who they all are) repeatedly get in wrong in here with only love shown to them.  I put a prediction which was well considered, but due to circumstances could not elaborate on at that time. I was planning later that evening to back it all up, instead I had to deal with playground intimidation. I have had training in meteorology and would have loved to have contributed to this local pub, I mean forum!!  

I couldn't care less if this gets taken down as I don't even bother here, but this is just some feedback in case anyone with a realistic forecast different to yours comes on here. Happy New Year all   

 

Edited January 5, 2019 by Shaftesbury Snow

[Methuselah]

The response to the early 1969 SSW was almost non-existent (at least as regards to UK snowfall) until Arctic northerlies swept in early in February; once it did set in, though, there was no turning back...I think we'll be performing Here We Go Round The Mulberry Bush a few more times, before the real change arrives...?

You ain't seen nothin' yet!

Edited January 5, 2019 by Ed Stone

[shaky]

13 minutes ago, Shaftesbury Snow said:

Posted November 26, 2018 (edited)

GFS keeping things mild up to 144hrs

The pattern is unlikely to change until mid-late January in my opinion based on all of the long range models and the fact that we are continuously chasing FI 

November 26, 2018 by Shaftesbury Snow

----------------------------------------------------------------------

The post above is what I posted back 5-6 weeks ago and was based on many different models, solar activity, sea temps etc. and I got slated for it, even called vile names in a private message! However, I had 7 separate users message me to see they agreed but didn't want to post  because of the backlash they saw I had, even from forum hosts.

I don't feel smug, I just feel the regulars should give other people a chance to voice a realistic forecast not based on emotions, which many of you do!!! Its almost like being an out of towner going into a local pub and feeling uncomfortable in here, this is also back backed by others that messaged me.

I see many of the "respected forecasters" (you know who they all are) repeatedly get in wrong in here with only love shown to them.  I put a prediction which was well considered, but due to circumstances could not elaborate on at that time. I was planning later that evening to back it all up, instead I had to deal with playground intimidation. I have had training in meteorology and would have loved to have contributed to this local pub, I mean forum!!  

I couldn't care less if this gets taken down as I don't even bother here, but this is just some feedback in case anyone with a realistic forecast different to yours comes on here. Happy New Year all   

 

Similar sort of thing happening/happened to me mate!!keep doing what your doing cos your just being a realist!!by the way you been pretty much spot on so far!!i see latest icon 12z is no where near as good as this mornings!!ah well standard stuff!!over to the gfs and ukmo!!

[Banbury]

14 minutes ago, Shaftesbury Snow said:

Posted November 26, 2018 (edited)

GFS keeping things mild up to 144hrs

The pattern is unlikely to change until mid-late January in my opinion based on all of the long range models and the fact that we are continuously chasing FI 

November 26, 2018 by Shaftesbury Snow

----------------------------------------------------------------------

The post above is what I posted back 5-6 weeks ago and was based on many different models, solar activity, sea temps etc. and I got slated for it, even called vile names in a private message! However, I had 7 separate users message me to see they agreed but didn't want to post  because of the backlash they saw I had, even from forum hosts.

I don't feel smug, I just feel the regulars should give other people a chance to voice a realistic forecast not based on emotions, which many of you do!!! Its almost like being an out of towner going into a local pub and feeling uncomfortable in here, this is also back backed by others that messaged me.

I see many of the "respected forecasters" (you know who they all are) repeatedly get in wrong in here with only love shown to them.  I put a prediction which was well considered, but due to circumstances could not elaborate on at that time. I was planning later that evening to back it all up, instead I had to deal with playground intimidation. I have had training in meteorology and would have loved to have contributed to this local pub, I mean forum!!  

I couldn't care less if this gets taken down as I don't even bother here, but this is just some feedback in case anyone with a realistic forecast different to yours comes on here. Happy New Year all   

 

Fair play to you , there should never be any backlash , say it as you see it . Its all opinions mate 

[Guest]

LOOKING FOR SSW SURFACE IMPACTS NEAR THE POLE IN THE MODEL OUTPUT - COMPARISONS TO EARLIER EVENTS - PART 2:  2013

I'm writing this post for two weather forums (US and UK) but most of it is relevant to both N America and UK/Europe. I will be mainly drawing on charts produced by Meteoceil and these + archived charts from the NCEP reanalysis show the Northern Hemisphere from the UK perspective. 

Abbreviations used in this post:

SSW - Sudden Stratospheric Warming

SPV - Stratospheric Polar Vortex

TPV  - Troposheric Polar Vortex

HLB - High Latitude Blocking

QBO - Quasi Biennial Oscillation

MJO - Madden-Julian Oscillation

COD - Circle Of Death

GSDM - Global Synoptic Dynamic Model 

GWO - Global Wind oscillation

GLAAM - Global Atmospheric Angular Momentum

FT - Frictional Torque

MT - Mountain Torque

EAMT - East Asian Mountain Torque

NAMT  - North American Mountain Torque

What I want to examine are the surface pressure patterns and charts in relation to previous SSWs and to show what to look out for in the current output.  My focus will be for signs of the reversal propagating down to the surface in the high Arctic and close to the North Pole.  I will look at charts around the time each main SSW event started, at the time of the specific types developed (ie: the displacement and/or the split), the time that surface impacts were beginning to show up and one or more later chart(s) to see how blocking patterns fell into place.  I am dividing this post into at least 3 parts over several days to cover separate SSW events.  In part 1, I looked at the current set up and then the February 2018 SSW (direct link to that post:  https://www.netweather.tv/forum/topic/91115-the-hunt-for-cold-continues-020119/?do=findComment&comment=3953148   

In this post (part 2) I'll focus on the 2013 SSW and in part 3, the 2009 SSW. Later on, I may move on to several earlier events - time permitting.  I've had several requests from members wrt to my covering other SSW events, such as for the 1984/5 SSW.  While there is no GLAAM, torque or MJO data available for back then, I can show the reanalysis charts for that "split" SPV event - I'll do a separate short post on it (later next week) once I've completed this today (and part 3 during the week) when I have more time.

2012/2013 SSW:  

SSW started in late December 2012; Rapid warming occurred between December 28th, 2012 and January 10th, 2013; 10hPa wind reversal on January 6th 2013; Type - Displaced SPV January 6th, 2013 and Split from January 8th; Ended February 8th, 2013; longest SSW on record (38 to 42 days depending on which analysis you read) in the modern "satellite" era (since 1979).  MJO - phases 4 and 5 at increasing amp at the time of SSW, then on to phases 6 and 7 at moderate to high amp later in January; ENSO - neutral with perhaps slightly La Nina like tendency (see table below);  wQBO (descending); solar cycle - closer to maximum (reached in April 2014 but the weakest since 1902) .

The 2012/13 SSW was an unusual and fascinating SSW with both displaced and split SPVs.  This is probably only the third (possibly fourth) time that this has occurred since at least 1978 (in the modern satellite era).  Depending on which reports one reads the previous years were 1985/86 (some contention on the displacement but ended up as a split event), 1987/88 (split, then displaced with a further warming and another split two months later) and  2001/02 (displaced and perhaps a split later on).  the 2012/13 event with combined wave 1 and wave 2 attacks leading to the displaced then split SPV events was the longest since at least 1978 lasting 38 to 42 days.  With such a long event, the impacts lasted at intervals right through to mid April with repeated bouts of HLB and cold spilling out of the Arctic.

You can see that ENSO was slightly on the -ve side of neutral throughout the period but not strong enough to be defined as a La Nina episode.

This table (up to 2013) shows the phase state of the MJO at the time of the "start" of major SSW events. Although the MJO can have an influence at that stage, we also need to see to what extent it might have assisted during the impact period. 

From the archives, we can see that the MJO was actually still in phase 4 at the time of the initial SSW event and then progressed through the phases from 5 to 8 at moderate to quite high amp.  ignore the green "forecast" period.

I pick it up from mid February.  Although the amp was much lower in phase 1 it never entered the COD and then managed another complete orbit at low to moderate amp. it reached phases 6, 7, 8 and 1 at slower reducing amp between Feb 25th and March 21st. The briefly slightly stronger amp in phases 6 and 7 (allowing for the time lagged impacts) was probably at least partly assisting renewed blocking through mid to late match (see model charts- further below).

It's a difficult exercise obtaining GLAAM and torque data from the archives. NOAA closed their map room in 2015/6 for this when Dr Klauis Weickmann and Ed Berry (who developed the GSDM and GWO) left. Ed berry (whom I'm in touch with by email) says that it's a time consuming (and therefore costly) exercise to reprocess the raw data (which is still available) to reproduce the archive charts again. I've been through countless papers, presentations and archived forum posts to find some earlier charts and have been building up a store of some of the key data.  Unfortunately many charts no longer show in early posts and many charts that do show up were copied across with the (copy image address option" and these charts "auto update.  I found a 2009 post with a current GLAAM chart showing! I save all of these type of charts to a file which freezes the image and date. if anyone has access to a good range of archived AAM and torque charts (and also GWD - gravity wave drag charts for my 2019 focus research project) from 2005 to 2016, please let me know.  I (and the specialists in this field) would really appreciate having a permanent and complete record of all archived charts.  Unfortunately, I could not find any torque charts for January to April 2013 but I do have enough useful data in my store to piece the GLAAM and torque position together.

This MT chart is up to Dec 24th 2012 and shows a huge spike in global MT (black line) to an extremely +ve position and still rising at the end.  NAMT (blue) was +ve but falling back and EAMT (red) is rising strongly and looking set to go into a strongly +ve phase.  Given the 10 to 14 days (or so) time lag, it would look that once again, EAMT played a significant role in helping to trigger the SSW.  As usual and fully consistent with the latest research (and the papers that I've read) the deeper red blobs in the upper part of the chart are between 35N and 50N and show us that the strongest MT was around the Tibetan Plateau and particularly the Mongolian Mountains. The area which generates the greatest uplift in the world with vertically propagating planetary waves and (gravity waves too through gravity wave drag).  Remember that we should consider that this is still "theory" but I've been gathering more and more evidence to support that theory.  

We can see that relative AAM spiked just after mid January and that "may" well have led to another spike in the torques later in January and into early February.

This table shows GLAAM averaged out for each calendar month from 1958 to 2014. December 2012 was +ve, January 2013 was neutral (as we can see the mid month spike was cancelled out but -ve momentum earlier and later), then Febraury to April 2013 all averaged out broadly +ve but not particularly strongly. That's confirmed by the chart above. That longer period of +ve GLAAM would have been strongly supportive of the repeated HLB patterns and may well have been the main factor in keeping the troposphere in its generally -ve AO and -ve NAO state for many weeks beyond the end of the SSW itself. 

Now on to what some of you have been waiting for - the archived model charts.  I will not comment on these other than to say that you'll see repeated periods of HLB with some lulls.  Here's the link so that you can go through the whole period: http://www.meteociel.fr/modeles/archives/archives.php?day=1&month=1&hour=0&year=2013&map=4&region=&mode=2&type=ncep

Finally a word of caution wrt to the current event.  No two SSWs are the same and even similar type of events can have very different impacts.  There remains uncertainty on the timing issues but it seems that we can all take comfort in a long SSW event which may, like 2013 (which has both similarities but many difference too) see several GLAAM, torque and MJO cycles creating repeated opportunities.  I do not know how patient we'll need to be but perhaps you can see why the models always struggle with these episodes - there is such a complex interaction of the strat, the trop. and all the teleconnections.  I remain very confident of some prolonged cold or very cold weather but no one right now can nail down the timing of the impacts. GLMT and EAMT are still +ve but less so and their time lagged benefits (+ the MJO still in phase 7 and on to 8 for a while longer)  should last through to around Jan 20th or longer.

Part 3 on the 2009 SSW (which has rather more similarities to the current event but also some significant differences) will follow later on during the week  - I'm unlikely to have more time before then.  David  

Edited January 5, 2019 by Guest
check charts, links and correct typos

[northwestsnow]

UKMO 144-

Can see the high over the Pole and an excellent profile to the SE - as ever, need something better to our west/north west.

[Mike Poole]

UKMO 12z might on first inspection look a bit of a mess, but I think it has good potential, here T96, T120 and T144:

The interest here is not the UK per se, but what happens to the purple vortex over Greenland, I think this is what some have referred to as the 'lobe of death'.  Anyway, it's on the move, and if we end up with all the purples on the eastern side, and the Arctic high links with the embryonic ridge at Iceland, we're possibly looking at a memorable spell, still well down the line and hurdles to vault!

[Chesil View]

37 minutes ago, Shaftesbury Snow said:

Posted November 26, 2018 (edited)

GFS keeping things mild up to 144hrs

The pattern is unlikely to change until mid-late January in my opinion based on all of the long range models and the fact that we are continuously chasing FI 

November 26, 2018 by Shaftesbury Snow

----------------------------------------------------------------------

The post above is what I posted back 5-6 weeks ago and was based on many different models, solar activity, sea temps etc. and I got slated for it, even called vile names in a private message! However, I had 7 separate users message me to see they agreed but didn't want to post  because of the backlash they saw I had, even from forum hosts.

I don't feel smug, I just feel the regulars should give other people a chance to voice a realistic forecast not based on emotions, which many of you do!!! Its almost like being an out of towner going into a local pub and feeling uncomfortable in here, this is also back backed by others that messaged me.

I see many of the "respected forecasters" (you know who they all are) repeatedly get in wrong in here with only love shown to them.  I put a prediction which was well considered, but due to circumstances could not elaborate on at that time. I was planning later that evening to back it all up, instead I had to deal with playground intimidation. I have had training in meteorology and would have loved to have contributed to this local pub, I mean forum!!  

I couldn't care less if this gets taken down as I don't even bother here, but this is just some feedback in case anyone with a realistic forecast different to yours comes on here. Happy New Year all   

 

Actually Shaftesbury it's mainly the respected forecasters that have been reiterating the mid Jan scenario and other more impatient members that have been wanting to see things sooner.. 

Looks like you made a good call back in November so well done you buy there were other factors that suggested the possibility of something sooner which even the Met office alluded to for a while.

Edited January 5, 2019 by Broadmayne blizzard

[snowangel32]

10 minutes ago, Mike Poole said:

UKMO 12z might on first inspection look a bit of a mess, but I think it has good potential, here T96, T120 and T144:

The interest here is not the UK per se, but what happens to the purple vortex over Greenland, I think this is what some have referred to as the 'lobe of death'.  Anyway, it's on the move, and if we end up with all the purples on the eastern side, and the Arctic high links with the embryonic ridge at Iceland, we're possibly looking at a memorable spell, still well down the line and hurdles to vault!

Yh that looks like a huge Atlantic ridge is developing. Great to see hieghts showing around the pole and hinting at a split. Just wish the initial ridge was more of a North West axis. Patience is the key.

[SMU]

UKMO has worked it out now - 168 would be great

GFS will be a day or 2 behind

 

Notice the Arctic high as well developing in Situ...