Model Output Discussion - 23rd Jan - 12z onwards

[sorepaw1]

On the current 18z at and beyond T+108 hrs what sort of wind speeds are we talking ,I would estimate 35mph,with gusts of 60mph which would cause significant drifting imo,is that a conservative reckoning .

Edited January 24, 2015 by sorepaw1

[Jason M]

4 AM

 

I'm not going to get involved but some odd comments re the output IMO. (not you)

 

 

I think were seeing some odd output tbh.

 

Charts like this http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=192&mode=0

 

wouldn't normally end up with 850s like this http://www.meteociel.fr/modeles/gfse_cartes.php?ech=192&code=0&mode=1

 

Especially in the last week of January!

 

Like others in here I've been looking at these charts for decades and I'm a bit baffled tbh. I'm seeing a poor 850 profile, but I've just watched a forecast warning of a screaming northerly!! The 850 profile isn't everything of course, but its also a maritime airmass with a fair amount of wind which rules out a surface cold pool. Even the theta values look iffy on most of the runs today, yet GFS keeps saying 'snow' with its precipitation charts. The thicknesses are low which clearly helps, but it just doesn't make sense to me.

 

If those 850s prove correct and we get any widespread lowland snow event from this, i'll be amazed.  ECM is better than GFS but even ECM isn't exactly what I'd describe as a 'screaming northerly'. I can only think that the screaming northerly is just about it 'feeling cold' rather than it actually being unusually cold. Maybe the MET office know something we don't (probably a given in fairness  ).

[Harsh Climate]

I'm just astounded by the negativity of some on here today and tonight!

What are people expecting from this setup? We are a tiny island surrounded by a relatively warm ocean.

-15 uppers and drifting snow from a deep sourced Northeasterly ain't gonna happen every winter! Would people prefer we are staring down the barrel of a long fetch Southwesterly Bartlett setup until May?!

I just wish some on here could accept that it is turning much colder and there is potential in the charts (even the 18z GFS 'rainfest') for for some falling and yes settling snow for a significant proportion of the UK population.

I would go as far as to say the upcoming cold spell looks more potent than anything we have seen for a couple of years, and in my opinion could develop into a significant pattern change.

I am very confident of seeing some snow over the next 7 days and who knows we may even (say it quietly) see some genuine northern blocking being modelled in the charts over the next couple of days.

Apologies for the rant but I just needed to get that off my chest!

 

 

The reality is though, there are no real signs of any major blocking developing any time soon and anyone who says otherwise without concrete proof/charts to back up what they are saying are just hope casting or guessing.

 

I think looking at how the gfs/ecm has hinted at possible height rises towards scandinavia/greenland over the last couple of days to finally offer a more watered down versions today just shows how difficult it is to get solid northern hemispheric blocking without the aid of a propper SSW event or MJO in phase 7. As some of the most experienced posters on here have alluded to, any northern blocking at the moment will most probably be transitory as the jet stream/zonal train is just too strong at the moment.

 

So until these upstream drivers/signals become more favourable at best we can hope for are some polar maritime shots, the odd northerly toppler or a rather brief atlantic ridge.

[TEITS]

Reading some of the posts this evening and I am somewhat inbetween the opinions of others. Whilst I am more upbeat compared to yesterday I still have my concerns. Here is what the models don't show.

 

1. Significant blocking over Greenland.

2. Upper temps below -10C.

3. No ice days except parts of Scotland and higher elevations in N England.

4  No obvious widespread snow events.

5  Finally contrary to some posts, nothing severe showing.

 

What the models do show.

 

1 +5 days of a N,ly flow.

2. upper temps ranging from -4c to -7C.

3. Snow showers and possible troughs bringing more prolonged snow showers.

4 Temps below average max temps around 2-4C although 5-6C  across far S.

5. Areas away from exposure to N,ly winds are more likely to see dry, cold weather.

 

So compared to this winter and last its looking promising. However compared to say Dec 2009, 2010 or even the cold winters I remember in the 80's, then this is looking tame in comparison.

[Geordiesnow]

There is even a -40c 850 temp just north of the Great Lakes area. They'll not need to quibble about thickness, dew points and marginality.

 

 

Yes but with the air that frigid and dry, you won't be getting much PPN with cold air such as that.(i believe most will probably evaporate before reaching the ground) The -40 hpa is becoming more rarer nowadays so it be interesting just how cold Canada and Northern US could actually get.

[Mucka]

I think were seeing some odd output tbh.

 

Charts like this http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=192&mode=0

 

wouldn't normally end up with 850s like this http://www.meteociel.fr/modeles/gfse_cartes.php?ech=192&code=0&mode=1

 

Especially in the last week of January!

 

Like others in here I've been looking at these charts for decades and I'm a bit baffled tbh. I'm seeing a poor 850 profile, but I've just watched a forecast warning of a screaming northerly!! The 850 profile isn't everything of course, but its also a maritime airmass with a fair amount of wind which rules out a surface cold pool. Even the theta values look iffy on most of the runs today, yet GFS keeps saying 'snow' with its precipitation charts. The thicknesses are low which clearly helps, but it just doesn't make sense to me.

 

If those 850s prove correct and we get any widespread lowland snow event from this, i'll be amazed.  ECM is better than GFS but even ECM isn't exactly what I'd describe as a 'screaming northerly'. I can only think that the screaming northerly is just about it 'feeling cold' rather than it actually being unusually cold. Maybe the MET office know something we don't (probably a given in fairness  ).

 

The 850's would usually be a fair bit lower, that is unfortunate and a consequence of two mild sectors being forced up toward Scandinavia before the sinking trough and then those modifying the flow that comes from the NE. At this range it is hard to know exactly how that will pan out but uppers of around -6c should be okay for most low lying areas to see snow given the low thickness values. Clearly it is minimum of a 6/7 day unsettled cold spell we are looking so comments suggesting something much shorter and much drier don't really describe the output IMO. 

As I say, I think it is because the upper air isn't really frigid and is predominantly coming from the North that maybe skewing opinions somewhat.

 

GFS short ensembles central England.

 

 

 

Cold/chilly with mean uppers of -5c or less from the 29th

 

 

I guess low expectations are better than over-hyping it but it doesn't look too shabby to me.

Edited January 24, 2015 by Mucka

[sorepaw1]

In most cases we need a stubbon 1050mb scandi high or a similar Greenland high for a traditional widespread snow event

,but there are exceptions to this rule,one been higher pressure near Canada,but years of chart watching this coming event seems quite unique to my study and I can't pin point a resolution to be honest to explain myself better

,maybe I should only post with a clearer picture for people but that's what makes this site friendly and useful to read and post,to be honest given the outlook for next Thursday on the 18z I've be very surprised not to be actively using my Subaru AWD,in deep snow given my geographical location ,

[blizzard81]

Quadraphonicics.MJO phasing /6/7 ..ample for mlb/hlb..synoptics will smile or cry..imo cold/ v.cold is incur...lets see what cross model suggest' on 00z suite.

Hard to understand your post! Are you saying there is growing consensus for MJO to head in to phase 6/7 ?

[summer blizzard]

Interesting that the GFS continues to suggest very strong pressure build over Europe day 10-15.

 

[Jason M]

The 850's would usually be a fair bit lower, that is unfortunate and a consequence of two mild sectors being forced up toward Scandinavia before the sinking trough and then those modifying the flow that comes from the NE. At this range it is hard to know exactly how that will pan out but uppers of around -6c should be okay for most lying areas see snow given the low thickness values. Clearly it is minimum of a 6/7 day unsettled cold spell we are looking so comments suggesting something much shorter and much dried don't really describe the output IMO. 

As I say, I think it is because the upper air isn't really frigid and is predominantly coming from the North that maybe skewing opinions somewhat.

 

GFS short ensembles central England.

 

 

 

Cold/chilly with mean uppers of -5c or less from the 29th

 

 

I guess low expectations are better than over-hyping it but it doesn't look too shabby to me.

 

If we can squeeze -6C at 850 that would probably just about be enough. Although maritime based the airmass is over relatively cold water. I'm def not of the view that its -10c or bust  ! Especially as its even rarer than turkey teeth for that to happen.

 

Wouldn't it be nice though, if just once this miserable excuse of a winter would give us something cold enough that there need be no debate on the subject!

Edited January 24, 2015 by Jason M

[sorepaw1]

Interesting that the GFS continues to suggest very strong pressure build over Europe day 10-15.

 

Interesting post that would be nice if it tracked North east,and with weaker low pressures to the north it carries potential to do so

[Argyle1980]

Interesting that the GFS continues to suggest very strong pressure build over Europe day 10-15.

The GFS had dropped this idea for the last 48hours or so but maybe it's bringing back the idea of future high lattatude blocking as Ian Fergusson had hinted to the possibility of blocking some where in the NH by or around week two.

One to keep a close eye on

Edited January 24, 2015 by Argyle1980

[blizzard81]

Interesting that the GFS continues to suggest very strong pressure build over Europe day 10-15.

 

Yes, I have noticed this trend today. What concerns me is that until today, the arctic high was modelled to ridge into Greenland at the end of Jan. There has been a big downgrade on that possibility across all models today. This has a decisive effect on the longevity of the proposed cold spell. If the trend for the arctic high to ridge towards Greenland does not make a comeback tomorrow then I fear this will be another mediocre event.

[Jason M]

GEFS out now beyond 300 hours and many of the runs are ramping up the vortex to our NW big time. Its certainly not a done deal that they will be right though and if they are wrong the evolution following this 'cold spell' may be very different to what we are seeing now.

In my view the opp is representative of its ensemble suite yet again. There are a couple of runs with colder 850s but nothing dramatically cold, which given the general pattern from day 5 to day 10 is a bit odd really as I'd expect a few cobra runs in amongst them.

Edit: This is a nice cold chart http://www.meteociel.fr/modeles/gefs_cartes.php?code=2&ech=384&mode=0&carte=0

Edited January 24, 2015 by Jason M

[igloo]

If we can squeeze -6C at 850 that would probably just about be enough. Although maritime based the airmass is over relatively cold water. I'm def not of the view that its -10c or bust  ! Especially as its even rarer than turkey teeth for that to happen.

 

Wouldn't it be nice though, if just once this miserable excuse of a winter would give us something cold enough that there need be no debate on the subject!

with a northerly the dew points should be a lot lower also the humidity levels than you would get from a westerly you could quite easily get snow with uppers at -4 inland i have seen it a number of times before

[Jason M]

with a northerly the dew points should be a lot lower also the humidity levels than you would get from a westerly you could quite easily get snow with uppers at -4 inland i have seen it a number of times before

Yes, its certainly not impossible. The criteria for snow can be very complex as we all know and this looks like being one of those times where its going to be tested to the max. This saga will have a way to run I suspect, but its easy to forget that three days ago everything just looked straight zonal. Despite the GEFS being not great past day 10 I do think there is room for change here (unlike this past week). Hopefully upgrades tomorrow!

[SE Blizzards]

Cracking set of ECM 12Z London ENS..

 

 

Not often you see that much agreement out to Days 9 - 10. Hardly any scatter.

 

So, starting from approximately Thursday it's looking like a week (at least) of cold weather to come. Finer details (like snow/ice etc) will no doubt be resolved over the next few days.

 

Not often i stick my neck out, but i do expect to see some upgrades with regards to 850's (especially from the GFS) over the next day or so.

 

All in all a good day of model watching, and IMO not much to be downhearted about tonight.

 

[ukpaul]

Weird set of ensembles, op and control clearly coming up with a different solution that the rest in far FI.

 

This for London -

 

[snowblizzard]

Surely, it needs to be much colder than this for a proper cold/snowy spell!

[tight isobar]

I' ll ATM refrain' from output synopsis.as the total matter of cross model support@gfs@ecm@ukmo@gem ...are as yet not comply; with determind...

[A.J]

That's a good idea.....get some rest, and don't forget to take some paracetamol for tomorrow morning's hangover 

Edited January 25, 2015 by ajpoolshark

[Ice Day]

That's a good idea.....get some rest, and don't forget to take some paracetamol for tomorrow morning's hangover 

 

In a day of so many highs, you sir, have stolen the show.  Brilliant post.  Please feel free to delete, but I had to say it!

[snowking]

Well while its late and a little quieter, may I just say how refreshing it is to come in to this thread after a good burns night celebration (should read - a few beers/wines/whiskeys later) to find such level headed, scientifically reasoned and very well humored posts.

I'm sure it is largely down to what is currently modelled but if I could urge everybody to remain this well natured during the good times and the bad this place will be even more successful than it already is. It has been a genuine pleasure to read the thread tonight.

SK

[kumquat]

A real slack period of low heights in and around Greenland between T96 and T168 across most models. The Azores high is looking to press and expand and it won't be able to do so to the East with the Euro trough. It's just gonna have to go North and give us what we all want.

 

ECM 12Z @ 120

 

18Z GFS @ 114

 

 

UKMO 12Z @ 120

 

 

Greenland is ripe for the taking. This spell is looking like amalgamating all the teleconnections together at last.

I'm also thinking the low(ish) looking uppers are far too watered down at present and expect these to significantly increase (downwards!).

I think this is a hangover from the fact that the initiation of the northerly is from the North West initially over the PM sea track but the uppers

in the Svalbard and further north Arctic Circle that will be tapped into as the Azores/Scandi trough dig in and SQUEEZE are not being properly represented due

to....wait for it.....poor data¬

[Mucka]

Good morning.

 

GFS being a bit of a pain with its warms sectors and modified polar air by making the trough as complex as possible 

 

 

It really does make sows ear out of a silk purse as far as coldies are concerned - this has to be close to the worse it could do with this synoptic.

 

UKMO much simpler, cleaner and no doubt colder thankfully.

 

 

Let's hope GFS has gone off on one.

 

It reamplifies the pattern and begins to draw colder air back in around 168h so not a total loss but give me UKMO instead. I don't want a messy, slushy, fits and starts, chilly spell followed by the promise of fI cold and even then the uppers aren't all that.

 

Edited January 25, 2015 by Mucka