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Model output discussion - Post SSW - Will it turn cold?


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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/

Thank you!

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9 minutes ago, Catacol said:

Agreed. This is still a risk. I'm slightly concerned the models may not yet be seeing the full impact of the SSW... and if anything that storm track might drop further south. The wailing and gnashing of teeth that would follow if Paris was buried and it was sunny in Portsmouth would be hard to bear!

Ha ha! We're so used to missing out in Portsmouth that we're pretty hardened to it!!

A little look at 850s on EPS T300 - looks like ECM ensembles staying cold for the long haul this morning

ec-ens_millikort_mslpmean_t850mean_t850s

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Cold - Yes Instability - Yes Prolonged - Yes I just wet myself - Yes!

I quite often agree with your sort of sentiment, as I'm one who opts to look at the most likely solution to fit the signals rather than the preferred one But, equally impartially and with intended

Sorry, I just thought I’d walked into the moans threa.. oh wait. <passes around a big bag of grips> No sooner do we get a cold spell within sight it astonishes me that time and time again some p

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21 minutes ago, Retron said:

Hah, no - I'm Retron here as well, albeit I usually just lurk.

I guess there are quite a few of us who use both forums!

Mind you, both forums are absolutely buzzing today. As I said on TWO, it really does look like 2005 all over again... although to be fair the ensemble output from both GEFS and EPS is colder than it was then.

EDIT: And thank you, Chionomaniac - yes, maybe I will post a bit on here!

Darren, your posts on TWO are always worth a second read (and you're right, both forums buzzing today). Am sure your contribution would be most welcome on here by lots of us who are not so knowledgable but remain keen to learn.

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By a considerable margin the best set of ENS I ever remember seeing for the Eastern counties. Am gonna see if I can unearth the ensembles for 2009/10 when I get time later - be interested to compare - but honestly I'm not sure they were ever this good.

graphe3_1000_296_42___.thumb.gif.ae7b47b1277fb73fc8459f48a9753a8c.gif

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12 minutes ago, Retron said:

Ah, the reason I mentioned 2005 is because I live in Kent - that was the last time we saw syntopics similar to this, ie a long-lived easterly spell. I was lucky enough to see some snow out of that 2005 spell, but I know many areas missed out completely. At least if things pan out the way they're looking at the moment there would be more widespread snow and - with temperatures a degree or two down on 2005 - whatever falls would probably linger too.

 

That was day after day of falling snow in fits and starts but where there wasn’t enough volume to cover the ground effectively, it melted fairly quickly. Where you live, i suspect it covered to quite a depth so resisted the solar input when it occurred. 

A word of caution on the gefs - we are potentially at the mercy of shortwaves on this evolution - the GEFS will be worse than the ops and the eps picking these up. At least we have much of the action with the building blocks whilst the gefs are in their higher res so a decent comparison with the eps though still not going to be as good. 

 

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1 minute ago, Man With Beard said:

Biggest news of the day for me so far is that there are now NO mild EPS clusters at all between D6 and D14

The more progressive approach of the deep cold (ncep route)  is around 14%

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1 hour ago, Catacol said:

Morning all - are we all ready for a 2 week rollercoaster ride? Have to say I'm a bit surprised this morning - I had expected at least one of the models to jump ship a bit and put the block in a poor place.... but perhaps the signals now are so strong that NWP cannot ignore the likely evolution.

The mother of all undercuts is now in place. Timing uncertain - in my book I suspect things are going to be moved forward gently, rather than back, but let's go with the best performing model and plump for this as the start of the peak period of cold and snow

ECH1-216.GIF?18-12

Both UKMO and GFS show snow possibilities before this, but not of a severe nature to my eye - I'm past looking for fleeting snow showers and a 1 inch covering: what we can potentially gain from this upcoming spell is 15cm+ widely to all parts, and considerably more in lucky spots.

But we need to stay reflective. Charts at 216h rarely verify - even when all models seem to be pointing in the same direction there will be micro changes to the pattern. There are risks. The storm track could be forced so far south that all the snow ends up in France/Spain. This is a real risk. Less likely is that the undercut pushes further north as the block drifts towards the arctic... but for me that isnt going to happen. But it could. Atlantic barrels in - no chance. That risk was all but gone many days ago.

So.... first major frost on Wednesday morning, chances of snow flurries from Thursday onwards (it will certainly be cold enough in -4 uppers with a dry continental feed) and maybe some more sustained shower activity over the weekend... but all eyes looking for embedded troughs and possibly a major frontal system for the early part of the week after. By this stage the cold will have penetrated the ground a bit and provided an ideal surface for snow to fall (even given daytime frost melt under a warming sun....)

All good still. 1 in 10 to 1 in 20 year event on the horizon. I checked back through the archives for the "big" Februarys of recent decades: 2009, 1991, 1981 and 1978. The currently modelled synoptics surpass all of them... but just for fun I'll let you compare.

Feb 2nd 2009. Up to 50cm in places from this

archives-2009-2-2-0-0.png

 

Feb 7th 1991. 30cm widely from this.

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

 

Feb 22th 1981. 30cm from this, mainly for western parts

archives-1981-2-22-0-0.png

 

Feb 16th 1978. The famous "Great West Country Blizzard" showing that 30cm can fall widely (drifts of up to 24 feet!!) in marginal undercut scenarios

archives-1978-2-16-0-0.png

 

2018? Well - sod it - there's a wealth of heavy snow charts out there this morning... but this one from GFS would see all kinds of chaos...

gfs-0-240.png?6

 

Loving it. 

No Feb 1986 in there Cat?  Sub zero month.....

I too was surprised to see the lack of wobble, especially after that great post/update from Essexweather yesterday.

This incoming cold surge is much deeper tgan I anticipated should it remain.....but I suppose as I also believe we have a very delayed Spring (late April) I suppose we need extreme synoptics.

LIA footprint is upon us....I firmly believe

 

BFTP

 

 

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Been out this morning and once again it has been a beautiful day after a chilly start.  A real sense of spring in the air except.......

Can't help wondering if these few days are a bit reminiscent of the middle of January 1947 were like...the mild before the cold swarm.

Certainly to me the way the models are shaping up is to give is a little taste of what 1947 was like, albeit a month later down the line.  Do we know if 47 was the result of an SSW event? 

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4 minutes ago, supernova said:

By a considerable margin the best set of ENS I ever remember seeing for the Eastern counties. Am gonna see if I can unearth the ensembles for 2009/10 when I get time later - be interested to compare - but honestly I'm not sure they were ever this good.

graphe3_1000_296_42___.thumb.gif.ae7b47b1277fb73fc8459f48a9753a8c.gif

While you rummage around, here's the ensemble output just before the cold spell of 2010 started. They're for "London", from WZ, which is closer to the Isle of Wight than London IIRC!

FWIW, the mean eventually ended up at -10/-11 for 3 days by the 29th November.

 

ens.png

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31 minutes ago, Quicksilver1989 said:

Yup snow for the many and not the few hopefully! 

Still trying to keep myself grounded, I don't want a conservative cold spell under a strong and stable high....

I'm not going to call a snap easterly. 

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I remember 2012 (not the awful film, but February 2012).

If this does not go to plan it is going to be appalling in here :rofl:

icon-0-120.png?18-06

Caution is best policy.

Edited by The Eagle
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7 minutes ago, bluearmy said:

That was day after day of falling snow in fits and starts but where there wasn’t enough volume to cover the ground effectively, it melted fairly quickly. Where you live, i suspect it covered to quite a depth so resisted the solar input when it occurred.

Depth peaked at 15cm or so here, but it was a world of "drip drip drip" and the snow was melting even as it was falling... no ice days, you see, and the dew point kept going up to or just above zero. Great for forming big sticky flakes, but rubbish for forming a good base of snow.

What's interesting then is, like now, the models were showing negative double-digit dewpoints and next to no convection. What actually happened was plenty of convection, but with it came much higher dewpoints than modelled. Something to bear in mind should the current mega-cold charts come off!

The attached pic shows a few inches on the ground on March 2nd 2005. A couple of days later it had mostly gone, despite plenty more snow falling.

P3020060.JPG

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5 minutes ago, Timmytour said:

Been out this morning and once again it has been a beautiful day after a chilly start.  A real sense of spring in the air except.......

Can't help wondering if these few days are a bit reminiscent of the middle of January 1947 were like...the mild before the cold swarm.

Certainly to me the way the models are shaping up is to give is a little taste of what 1947 was like, albeit a month later down the line.  Do we know if 47 was the result of an SSW event? 

Yes, I must admit it's bizarre listen to the birds hailing the beginning of spring whilst looking at charts showing deep deep winter.

 

1 minute ago, The Eagle said:

I remember 2012 (not the awful film, but February 2012).

If this does not go to plan it is going to be appalling in here :rofl:

icon-0-120.png?18-06

It'll be horrendous if this doesn't come off now.

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11 minutes ago, BLAST FROM THE PAST said:

No Feb 1986 in there Cat?  Sub zero month.....

I too was surprised to see the lack of wobble, especially after that great post/update from Essexweather yesterday.

This incoming cold surge is much deeper tgan I anticipated should it remain.....but I suppose as I also believe we have a very delayed Spring (late April) I suppose we need extreme synoptics.

LIA footprint is upon us....I firmly believe

 

BFTP

 

 

Hehe - yes - 86 was very cold... but unless my memory is way off I dont think it snowed that much? Good grief - what am I saying.... a cold spell without snow. Gulp. We dont want that again.... :-(

Some snow fell on this day in the SE apparently - decent synoptics... but I think we will trump these :-)

 

archives-1986-2-5-0-0.png

 

Solar influence is a really interesting one. I'm not an expert.... but I can read the graphs well enough and see the theory of a grand minimum coming to crunch point in the next few years. I'm sure a lot of stratospheric analysis will be done on what has caused the current SSW. Will reduced solar = more chance of SSW? Something perhaps to read up on in the summer.

 

 

 

 

Edited by Catacol
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From looking at the models I would say we have a decent chance of seeing something very cold! The positioning of the HP very important.I am remaining cautious for the moment though as all the best charts seem to be 8-10 days away and I've seen it go wrong so many times at this range!so I would say that if the charts are still there in couple days we have great chance of bitter cold air from the east.consistency is the key here in the models.

Edited by Lukesluckybunch100
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4 minutes ago, Catacol said:

Hehe - yes - 86 was very cold... but unless my memory is way off I dont think it snowed that much? Good grief - what am I saying.... a cold spell without snow. Gulp. We dont want that again.... :-(

Some snow fell on this day in the SE apparently - decent synoptics... but I think we will trump these :-)

As ever down here, Feb 86 brought plenty of snow. My grandpa had died and for whatever reason the funeral went from our house... my dad and other mourners had to clear the road of snow so that the hearse could leave, as it got stuck in the snow. I was 6 at the time and didn't really know what it was all about, but I enjoyed the snow even if everyone else was down in the dumps!

This part of the world used to be amazing in easterlies. I suspect it still would be, if we ever got them.... which is why the potential of a deep cold easterly in a week's time is exciting!

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What we seem to be looking at predates the internet era, a classic easterly has been in deep hibernation like a dormant volcano. I won’t mention Feb 2009 that was very fleeting, it goes to show how rare synoptics like this are, when in Greater London we had the most disruptive snowfall since 1991 - 18 years.

And 2005 not really memorable not on level with may come. Last reference points has to be 1991 and this looks ruddy good if better, mean drops to -10C in London at day 8 looks like beast wants to pay a visit I think it’s coming... been a long time since. Exciting! 

B9492140-CE86-4B07-97A5-A7DFD0D45DC4.thumb.gif.bafce07b96f7c03462802bcb8a58d578.gif

Edited by Daniel*
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The cold trend will be locking in from tuesday onwards as winds switch to an easterly point, temps dropping a little each day and overnight frosts followed by mainly dry bright or sunny days..then from next weekend it should get more interesting with snow flurries / showers spreading in across eastern areas from the North sea..then from early week 2 our weather could become more severe with snow for many, severe wind-chill, ice days and penetrating frosts as easterly winds become numbingly cold..that is what the Ecm 00z ens mean / op and Gfs / Gefs 6z is showing..confidence appears to be sky high even though the really fun stuff is just over a week away!..hope the upgrades keep coming.:D:cold:

ECMAVGEU00_168_2.png

ECMAVGEU00_192_2.png

ECMAVGEU00_216_2.png

ECMAVGEU00_240_2.png

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22 minutes ago, Catacol said:

Hehe - yes - 86 was very cold... but unless my memory is way off I dont think it snowed that much? Good grief - what am I saying.... a cold spell without snow. Gulp. We dont want that again.... :-(

Some snow fell on this day in the SE apparently - decent synoptics... but I think we will trump these :-)

 

archives-1986-2-5-0-0.png

 

Solar influence is a really interesting one. I'm not an expert.... but I can read the graphs well enough and see the theory of a grand minimum coming to crunch point in the next few years. I'm sure a lot of stratospheric analysis will be done on what has caused the current SSW. Will reduced solar = more chance of SSW? Something perhaps to read up on in the summer.

 

 

 

 

We were lucky in Swansea because as the cold set up and the LP dropped directly n to s we had heavy snow at the beginning.  

Deep Snow laid, even on the roads for the whole month.

Incoming spell if verifying is looking incredible. 

I remember the confidence of Michael Fish and Bill Giles of it coming, so on the weekend before it ushered in I started to build a sledge, using the ladder of our bunk beds (we were to big to beed the ladder so was ok and  no rollicking).  I was making a hash of the nailing so my dad came down (worked the tools) and built it for me.  What a month  and amazing memories, it was with the fastest sledge around.  I hope many get similar over next few weeks

 

BFTP

Edited by BLAST FROM THE PAST
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gfs-0-234.png?6

Looking forward to 28.02.2018 there is an interesting feature of the Scandy stretching over as far as Greenland. 

gfs-1-240.png?6

With quite respectable uppers as well.

gfs-5-240.png?6

Something which I think is a relatively rare, a contraflow jet stream over the UK with SSE over Scotland

gfs-9-204.png?6

Though not exceptionally cold considering the chart - we would have done with a similar set up a couple of months ago. 

gfs-7-240.png?6

Yet it appears that snow is forecast - still another 10 days to go and many a slip twixt cup and lip! 

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