Model Output Discussion 19th January 2014-18z onwards.

[Downpour]

GFS 00z is a colder run with out doubt as the 8 day temperature anomaly shows

 

Good to see that evil mildness going into SE Europe. Always a good sign.

[snowice]

Read in article the other week that the lag in temps for winter is the 21st Jan, from there on the Northern Hemisphere doesnt get any colder, know that wasnt your point about Feb Tim, just a little interest to add

 

 

The 19^th January is technically the coldest day in the Northern Hemisphere,

 

After that the solar power of the sun heats up the Atmosphere, but it takes up to 21 days before

 

We really notice it, so it’s not too late for a big Snow event.

 

GFS UKMO ECM get a move on the train is leaving the station.

[Blake]

Loving this! Will miss a couple of frames out but....

 

Westerly theme Saturday morning.

 

 

Secondary low forms about 400 miles west of Ireland...

 

 

Heads for the NW bringing W/SWerlies....

 

 

Slap bang over Scotland bringing NWerlies....

 

 

Slides SE bringing easterlies to northern areas and N/NWerlies to most of the rest of the UK with heights building again over all of the north and the original low flattening out....

 

 

Sinks further SE inviting colder air from the NE and hopefully more E on the next run as the low sinks south...

 

 

Also, Atlantic high extending further north meeting the Greenie high creating a block for anything heading out of Canada?

Edited January 20, 2014 by GUWeather

[terrier]

well lets see if the06z verifys for sat night. But with the wild swings in the output think we need to wait to see if this is still been shown on wed or thur eve.

[ghrud]

Loving this! Will miss a couple of frames out but....

 

Westerly theme Saturday morning.

 

 

Secondary low forms about 400 miles west of Ireland...

 

 

Heads for the NW bringing W/SWerlies....

 

 

Slap bang over Scotland bringing NWerlies....

 

 

Slides SE bringing easterlies to northern areas and N/NWerlies to most of the rest of the UK with heights building again over all of the north and the original low flattening out....

 

 

Sinks further SE inviting colder air from the NE and hopefully more E on the next run as the low sinks south...

 

 

Also, Atlantic high extending further north meeting the Greenie high creating a block for anything heading out of Canada?

 ... and then low leaving eastern seaboard USA on strong jet, flattens ridging high and we're back to square one.

 

[nick sussex]

The lull before tonights storm as we wait to see how two scenarios evolve, the first being the trough disruption  and possibility of some colder air in from the east meeting up with an Atlantic low pressure so this is the first chance for snow.

 

The next the more interesting and possible pattern changer with the Arctic high desperately trying to overcome the limpet PV to the nw.The mobility in the Atlantic is unlikely to disappear so its whether high pressure can extend far enough south and west to force low pressure to run se to the west of the UK.

 

There is of course the perfect scenario where the models continue to edge west with the pattern so you get the first outcome and then remain in the cold waiting for the next one but at present that looks an outsider.

 

There are quite a few variables to take into account with all the scenarios, shortwave activity near Svalbard, that stops the Arctic high from exerting more forcing on the next big low, the GFS 06hrs removed that shortwave before going to its normal zonal rinse and repeat in the lower resolution.

 

As soon as the Arctic high is allowed to ridge south between Greenland and Norway you effectively have two highs working against the low.the key thing though is that you don't get so much energy thrown eastwards in the earlier timeframe, the ECM already has you at a disadvantage because its got energy running over the top of the high to the east.

 

We need the ECM to pull back from its last few days trend and start correcting west with more energy going se, this gives you a more solid foundation going forward.

 

Overall there is a chance of a change but we need the upstream set up over the USA to play ball and need that Azores high to retrogress more to give some leeway to get the Arctic high over the top of the deep low.

 

If not that then a big westwards correction to lower the impact of upstream phasing.

[East_England_Stormchaser91]

Need to get rid of that azores high. I'm sorry, but that will always let the jet through over us no matter what. The absence of the high over the azores allows heights to build more thoroughly over N Atlantic, Iceland and Greenland etc. If you look at the notoriously cold winters and most notable spells, you will clearly see that low pressure systems are taking the path through the azores on into Iberia and into the Mediterranean, leaving us with raging NorthEasterlies or Easterlies. It certainly has been ruining this winter so far massively.

 

 

 

Edited January 20, 2014 by East_England_Stormchaser91

[Purga]

Still very uncertain how things will develop from now onwards with no clear signal.

Seems to look coldish for a while then a  lot of scatter again in FI land

 

 

With no sign of any SSW soon it looks like average conditions with colder shots possible mostly for northern areas I guess.

[Ali1977]

I wonder if the Meto have had any change with their thoughts on next weekend onwards, be nice to hear that a cold solution is looking more likely, rather than just hoping!!

[Frosty.]

Met office update indicates average weather unfortunately with a mix of mild and colder days, more gales and rain, snow on northern hills at times and frost / fog in the quieter interludes which is what we have now. Tonight looks very foggy in places so watch out for that..no pattern change on the way according to the experts but not constant mild mush either. There will be some wintry weather at times, just nothing sustained.

[EML Network]

February can be a lot colder than February in my opinion.  Yes technically the sun is higher than it was on 21st December and throughout January, but that doesn't mean that much especially when you consider that most years, December and January can be some of the mildest months of the winter.

 ha ha ha ha ha.

 

The building blocks are there and it's fiunely balanced as to whether or not some of us will actrually get a snowfall within the next 10 -1 5 days ....or not.

 

IF things go the way of the pear and the Atlantic wins out it's very plausable that we'd have to wait another couple of weeks before we get another bite at the cherry and by that time it would be Mid Feb.

 

So it's almost make or bust time but not quite, especially given what happened last March !!

[shedhead]

Still very uncertain how things will develop from now onwards with no clear signal.

Seems to look coldish for a while then a  lot of scatter again in FI land

 

 

With no sign of any SSW soon it looks like average conditions with colder shots possible mostly for northern areas I guess.

Indeed...the 06 ENS have the Op rather more in the middle of the solutions, rather than one of the coldest as it was on the 00. Still think we are a long way from seeing the post T+120hr evolution decided, but for now I think the milder Atlantic option is probably slight favourite to win out overall. However the farther northeast you are, the better your chances of seeing some of the white stuff, especially on high ground. 

 

EDIT: Pretty much in line with the MO's latest thoughts according to Frostys latest post....

 

Frosty

Posted 21 minutes ago

Met office update indicates average weather unfortunately with a mix of mild and colder days, more gales and rain, snow on northern hills at times and frost / fog in the quieter interludes which is what we have now. Tonight looks very foggy in places so watch out for that..no pattern change on the way according to the experts but not constant mild mush either. There will be some wintry weather at times, just nothing sustained.

Edited January 20, 2014 by shedhead

[IDO]

Met office update indicates average weather unfortunately with a mix of mild and colder days, more gales and rain, snow on northern hills at times and frost / fog in the quieter interludes which is what we have now. Tonight looks very foggy in places so watch out for that..no pattern change on the way according to the experts but not constant mild mush either. There will be some wintry weather at times, just nothing sustained.

 

In other words what GFS and ECM are currently showing.

 

ECM extended temps for London:  

 

Nothing to suggest a cold spell is creeping up on us. It also shows the GFS 0z was right at the bottom of the cooler solutions of the EC ens. Hence the downgrade in potential for snow Sat morning from the GEFS 06z: 

 

 

For London back to only 5%; on the 0z it was 30%. Better chance late Saturday as a cold front comes down from the NW; rain to snow rather than the other way round, so better in that respect.

 

FI in GFS for the last few days has then been a return to a zonal flow; some runs more progressive than other. This I believe is a pattern we have to go through, so the quicker we break the block to our east the better IMO. Never say never with weather but as others have said a stream of undercutters is difficult to sustain and we always risk, as we are now, having the pattern too far east.

 

GFS even less keen than yesterday for the ECM Arctic high, very few showing any of the strong upper variety,

 

mean at T216:

 

So no real change from yesterday if the GFS 06z is our guide:

 

1) Too far east for the warm front late Friday for most to get snow.

2) Uncertainty re the subsequent disruption of the trough

3) Inevitably (on all recent runs) such disruption simply delaying the return of the PV spawn.

4) After that zonality plenty of options remain (late Jan by then).

 

Always hope the weather models will have a eureka moment and we are plunged into cold, but at the moment that is not the showing on the charts. Possible transient snow for the lucky ones next weekend, and that is better than we have had for a long time.

[london-snow]

Met office update indicates average weather unfortunately with a mix of mild and colder days, more gales and rain, snow on northern hills at times and frost / fog in the quieter interludes which is what we have now. Tonight looks very foggy in places so watch out for that..no pattern change on the way according to the experts but not constant mild mush either. There will be some wintry weather at times, just nothing sustained.

To be honest i didn't expect nothing more or nothing less from the meto in their update. They won't call cold or mild when there is so much uncertainty (Rightly so). The thing is that atm their is no clear signal as per the amount of conflicting signals from the output over the past week. I just hope all those hours spent this winter having a look at various output is not in vain and we get rewarded for what has been a truly dreadful winter thus far. Let's hope this evening carries on some renewed hope picked up from this morning. Edited January 20, 2014 by london-snow

[Timmytour]

Yes I count 9 at 192 hours that look very good, it all looks down to how far North the Azores ridge can stretch and whether or not the Atlantic energy can become separated. 

 

heres one of the better peturbs :

 

but we could also end up with this :

Come in no.18 your time is up here......

[winterof79]

Let us balance things up regarding people posting nothing cold on the horizon.

Compared with winter so far the output is cold.

 

GFS

http://modeles.meteociel.fr/modeles/gfs/runs/2014012006/gfs-1-102.png?6

http://modeles.meteociel.fr/modeles/gfs/runs/2014012006/gfs-1-138.png?6

http://modeles.meteociel.fr/modeles/gfs/runs/2014012006/gfs-1-156.png?6

UKMO

http://www.meteociel.fr/ukmo/runs/2014012000/UW144-7.GIF?20-06

The Ensembles will not reflect an up an coming SSW or any warming that has not happened yet.However one could argue that the slight warmings that have already occurred have given rise to the changes in the arctic we see modelled right now.

GFS

http://modeles.meteociel.fr/modeles/gfs/runs/2014012006/gfsnh-10-180.png?6

 

ECM

The warm sector is being subjected to a lot of eastern influence and i expect that to continue,maybe to the point where the precipitation fizzles,much as i do not want that as regards seeing some snowfall,but better for longer term.

http://www.meteociel.fr/modeles/ecmwf/runs/2014012000/ECU0-96.GIF?20-12

http://www.meteociel.fr/modeles/ecmwf/runs/2014012000/ECU0-120.GIF?20-12

http://www.meteociel.fr/modeles/ecmwf/runs/2014012000/ECU0-144.GIF?20-12

http://www.meteociel.fr/modeles/ecmwf/runs/2014012000/ECU0-168.GIF?20-12

 

By all means quote the roaring jet etc etc, but the overall trend is for the models to bring more wintry conditions than we have seen so far this winter to our shores, even if they have their own differing routes on how to get there.

Edited January 20, 2014 by winterof79

[Gaz1985]

Up to 50% chance of snow for near this area. Overall a chilly set of ensembles.

 

Edited January 20, 2014 by Gaz1985

[winterof79]

In other words what GFS and ECM are currently showing.

 

ECM extended temps for London:  ensemble-tt6-london.gif

 

Nothing to suggest a cold spell is creeping up on us. It also shows the GFS 0z was right at the bottom of the cooler solutions of the EC ens. Hence the downgrade in potential for snow Sat morning from the GEFS 06z: 

 

graphe3_1000_306_141___Londres (1).gif

 

For London back to only 5%; on the 0z it was 30%. Better chance late Saturday as a cold front comes down from the NW; rain to snow rather than the other way round, so better in that respect.

 

FI in GFS for the last few days has then been a return to a zonal flow; some runs more progressive than other. This I believe is a pattern we have to go through, so the quicker we break the block to our east the better IMO. Never say never with weather but as others have said a stream of undercutters is difficult to sustain and we always risk, as we are now, having the pattern too far east.

 

GFS even less keen than yesterday for the ECM Arctic high, very few showing any of the strong upper variety,

 

mean at T216: gensnh-21-1-216.png

 

So no real change from yesterday if the GFS 06z is our guide:

 

1) Too far east for the warm front late Friday for most to get snow.

2) Uncertainty re the subsequent disruption of the trough

3) Inevitably (on all recent runs) such disruption simply delaying the return of the PV spawn.

4) After that zonality plenty of options remain (late Jan by then).

 

Always hope the weather models will have a eureka moment and we are plunged into cold, but at the moment that is not the showing on the charts. Possible transient snow for the lucky ones next weekend, and that is better than we have had for a long time.

Could you please explain the transient snowfall, as you are referring to the GFS output in your post.I take transient to mean that the snow would be short lived.

A good few may see snow this weekend

http://modeles.meteociel.fr/modeles/gfs/runs/2014012006/gfs-2-120.png?6

http://modeles.meteociel.fr/modeles/gfs/runs/2014012006/gfs-1-120.png?6

Mild air in the mix but not for long before its back

http://modeles.meteociel.fr/modeles/gfs/runs/2014012006/gfs-2-132.png?6

http://modeles.meteociel.fr/modeles/gfs/runs/2014012006/gfs-1-132.png?6

Thereafter the output remains cool/cold

http://modeles.meteociel.fr/modeles/gfs/runs/2014012006/gfsnh-1-168.png?6

 

The PV maybe constantly showing but so is the Scandi high and while ever it is our chances of a colder continuation improve.

http://modeles.meteociel.fr/modeles/gfs/runs/2014012006/gfsnh-0-180.png?6

http://modeles.meteociel.fr/modeles/gfs/runs/2014012006/gfsnh-1-180.png?6 There is no typical zonality on the 06z GFS to my eye only colder type with low 850s. according to GFS i may add

 

 

 

 

Edited January 20, 2014 by winterof79

[Timmytour]

i know the Daily Express is no barometer of the weather, far from it.  But in its desperation to get something weather related on the front page today, and in the absence of anything sign even it can interpret to mean four foot of snow is coming....it's gone with storms battering us all this week.Very strange because, from what i can see via the GFs this looks like being one of the quieter weeks, wind and rain wise, that we've had for some time (which is not to say we won't have at least some)Mind you, come next sunday there's a huge low pressure system just to the south of Iceland in situ.....so, if we are going to get some undercutting and that heads further south east.....next week could start with a very interesting picture!

[R.P. McMurphy]

Could you please explain the transient snowfall as you are referring to the GFS in your post.

A good few may see snow this weekend

http://modeles.meteociel.fr/modeles/gfs/runs/2014012006/gfs-2-120.png?6

http://modeles.meteociel.fr/modeles/gfs/runs/2014012006/gfs-1-120.png?6

Mild air in the mix but not for long...

http://modeles.meteociel.fr/modeles/gfs/runs/2014012006/gfs-2-132.png?6

http://modeles.meteociel.fr/modeles/gfs/runs/2014012006/gfs-1-132.png?6

 

The PV maybe constantly showing but so is the Scandi high

http://modeles.meteociel.fr/modeles/gfs/runs/2014012006/gfsnh-0-180.png?6

http://modeles.meteociel.fr/modeles/gfs/runs/2014012006/gfsnh-1-180.png?6 There is no typical zonality on the 06z GFS to my eye.

 

 

and while ever it is

 

Just to back you up on that re most not getting snow:

 

 

Edited January 20, 2014 by Glenn W

[IDO]

Could you please explain the transient snowfall as you are referring to the GFS in your post.

A good few may see snow this weekend

http://modeles.meteociel.fr/modeles/gfs/runs/2014012006/gfs-2-120.png?6

http://modeles.meteociel.fr/modeles/gfs/runs/2014012006/gfs-1-120.png?6

Mild air in the mix but not for long...

http://modeles.meteociel.fr/modeles/gfs/runs/2014012006/gfs-2-132.png?6

http://modeles.meteociel.fr/modeles/gfs/runs/2014012006/gfs-1-132.png?6

 

The PV maybe constantly showing but so is the Scandi high

http://modeles.meteociel.fr/modeles/gfs/runs/2014012006/gfsnh-0-180.png?6

http://modeles.meteociel.fr/modeles/gfs/runs/2014012006/gfsnh-1-180.png?6 There is no typical zonality on the 06z GFS to my eye.

 

 

and while ever it is

 

Hi

 

No probs.

 

The GEFS mean.

 

T180:   T240:  T300: 

 

The way I read those mean charts are that they are showing a cool zonality. There is no mean Scandi high; an euro/Russian one maybe.

 

With regard to transient snow, the GFS charts suggest maybe 2-3 short spells of snow for certain areas; too early to be conclusive as small changes can make a big difference but I don't see large scale snow downfalls though where you are, up north with height you will be in the luckier category, but us southerners, not so.

[winterof79]

Just to back you up on that re most not getting snow:

 

 

 

 

Thanks,i have to say  very rarely look at snowfall predictions, as i posted above,so far in advance of a forecast but i was responding to" Im dreaming of..".

Many things have to fall into place...... i will get that in before JH gets in to my ribs.

[shedhead]

Hi

 

No probs.

 

The GEFS mean.

 

T180: gens-21-1-180 (2).png  T240: gens-21-1-240 (4).png T300: gens-21-1-300 (1).png

 

The way I read those mean charts are that they are showing a cool zonality. There is no mean Scandi high; an euro/Russian one maybe.

 

With regard to transient snow, the GFS charts suggest maybe 2-3 short spells of snow for certain areas; too early to be conclusive as small changes can make a big difference but I don't see large scale snow downfalls though where you are, up north with height you will be in the luckier category, but us southerners, not so.

Yes, the kind of charts posted to suggest widespread snow on Saturday can be notoriously inaccurate/misleading at T+48hrs, let alone T+132hrs. As you suggest transient, localised falls currently look about the best on offer based on those charts, with ground above about 200-300m standing the best chance of picking up a temporary covering.  Considering the complexities of the overall pattern however, I'd be extremely surprised to see what is being progged post T+72hrs getting delivered, plenty more chopping and changing to come even in the relatively short term imo. 

Edited January 20, 2014 by shedhead

[Bobby]

Little change in the ensemble means at 10 days out, cyclonic westerlies over UK. Seems to back up the Met Office outlook, signs of perhaps something stirring but this is a good best guess at the moment I think looking ahead until we see something more concrete showing with regards to a cold spell

 

NAEFS   ECM

GEFS GEM

 

 

 

[winterof79]

Hi

 

No probs.

 

The GEFS mean.

 

T180: gens-21-1-180 (2).png  T240: gens-21-1-240 (4).png T300: gens-21-1-300 (1).png

 

The way I read those mean charts are that they are showing a cool zonality. There is no mean Scandi high; an euro/Russian one maybe.

 

With regard to transient snow, the GFS charts suggest maybe 2-3 short spells of snow for certain areas; too early to be conclusive as small changes can make a big difference but I don't see large scale snow downfalls though where you are, up north with height you will be in the luckier category, but us southerners, not so.

Thanks for the reply.

Yes the charts you show from T180 onward show cool zonality but thats way too far ahead for me.This weekend is a stretch.