Model Output Discussion 1200 hrs 15/11/14

[bobbydog]

Looking at the gfs 6z run looks like a mild weekend coming up then we trend colder early part of next week. Then it looks as though we will end up under a cloudy drizzley high. Nothing overly cold or mild out into fi. One thing I've noticed in the last few weeks is the Cfs is wanting to bring in some very stormy and wet conditions from 2nd week of December hope this doesn't verify as it seems to have been a trend over last few weeks.

 

do you mean this?-

 

 

i hope it does verify because that develops into this-

 

 

just 4 days later.

 

then on the 2nd Jan we get this-

 

 

 

 

if these are CFS "trends" then lets hope it DOES verify!

[carinthian]

The expected Med Low development , though not a classic Genoa Low, is likely to be centred in that location by Monday. A huge feed of warm African Sourced air on its SE flank pushing extra energy into the Alpine regions. Normally this low circulation is eventually deflected southwards into the Adriatic, this mainly occurs when high pressure is dominant over the Balkans. However, the dominant high pressure zone is further north this time and a general easterly circulation will be in place over much of mainland Europe by Monday. The question is : Will the ridge to the north collapse readily or hold to maintain a increasing colder flow over Europe ? The high pressure over Russia and Scandinavia has not been easy to remove so far this early in the season and is in affect shaping our current weather.

C

[mushymanrob]

While some look at deep FI as proof of a return to mild westerlys, I'm going to look at the reliable time frame.

 

 

Not a bad day 6 chart at all?

 

 

erm.... we dont have to wait for fi for milder weather barry... try a couple of days time fri/sat.

 

as for your day 6 ... average. 

the outlook is distinctly pretty normal, around average in the reliable. indications are that in fi it MIGHT get milder again, if that happens - it happens, if not, so what?

[Barry12]

erm.... we dont have to wait for fi for milder weather barry... try a couple of days time fri/sat.

 

Yep, I'd advise you to make the most of that. Looks average to below from then on...

[Frank Trough]

Yep, I'd advise you to make the most of that. Looks average to below from then on...

"from then on"?!

 

The METO clearly didn't get your memo this morning:

 

UK Outlook for Thursday 11 Dec 2014 to Thursday 25 Dec 2014: "Temperatures are generally expected to be around, or a little above, average for the time of year."

 

I'm looking forward to a bit of drier, colder, frosty weather next week (should it come to pass and not be cloudy and drizzly). It'll be cracking but I will make the most of it while/if it lasts. I don't like the GFS trend of sinking heights and the jet running north - let's hope it's wrong.

[Steve C]

While some look at deep FI as proof of a return to mild westerlys, I'm going to look at the reliable time frame.

 

 

Not a bad day 6 chart at all?

 

Yes, most of southern UK sat in a nice col. However days 7,8,9 and 10 evolve into an Azores ridge pushing in. I guess that doesn't matter though, as day 6 is bound to be 'reliable' and thereafter inevitably FI.

 

[Tamara]

Put into the mix the usual poor modelling of arctic high pressure systems within the day 10 period, and add to that the further difficulty in trying to model the transfer of upper vorticity energy across the pole from Canada to Siberia, the usual advice of sitting back and trying not to over- disentangle the mischiefs of each and every intra day face value model operational output suite becomes ever more pertinent. 

 

The pleasantly seasonal rather cold mid latitude high solution advertised in the shorter term looks to be well calculated by the models, but best be wary of reading too much into, and over anticipating, any lasting legacy (if it happens) from flattening out of the pattern to any long-lasting and meaningful extent thereafter with associated westerlies.

 

Whilst this is for sure a distinctly plausible (transitory) response to the energy transport across the pole, we should bear in mind that destination PV Siberia represents the next crucial step along the way with this winters pattern. This is said within the context of a very beaten up and weak polar vortex. It also represents a polar opposite to what happened last year in early December as Siberian energy transferred across to the Canadian sector as part of a centrally organising steroidal vortex that spat deep low after deep low across the atlantic towards us.....

 

Notwithstanding the uncertainties with regard to risks with over progressive model attempts to ditch the high to the east/north east in the short/medium term, the eventual outcome of energy balancing towards the Siberian sector will provide the fresh impetus anyway to the cold pooling SAI feedbacks which have been proven in recent weeks modelling to be in action.

 

We shouldn't fret too much over questioning timing when this next stage in the process is completed - even delayed by a short time. I stated in a previous post that this overall seasonal pattern process, once begun, was likely unstoppable and by the time the up-coming re-shuffling across the polar field has occurred, I would very much expect the next cycle of westward pattern backing to continue with vigour, whatever happens with regard to polar field modelling uncertainties in the shorter term.

 

The upping of the ante in the wave breaking battle as a consequence of this takes us ever closer towards the very back-end of the year and the increasing likelihood of an SSW. Its worth riding a short troposphere/stratosphere bombardment pause while the pattern re-sets

 

@blizzard 81 - will send a pm message

Edited November 26, 2014 by Tamara תָּמָר

[Altohumorous]

Yes of course that's what it is showing - but I'm not talking about what the models show exactly, I'm talking about how they might evolve further. I'm suggesting that, given the experience of recent months, the block to the east might turn out to be a little bit stronger, and the easterly flow might hang on a little bit longer and it might even turn into a Scandi block. Might being the important word! I appreciate the models are on the whole suggesting this idea will be wrong. But my concept of a stronger Scandi High is not impossible either - especially when cross-referenced to the NOAA 8-14 day http://www.cpc.ncep.noaa.gov/products/predictions/814day/500mb.php ?

 

My personal feeling, having seen years of Scandi Highs on the models, is that, when models forecast its collapse beyond T144, they only get it right 50% of the time. Having said that, the ECM is usually the first to not collapse it, so I would lower the odds at the moment unless it "comes on board".

 

But how about these charts - ECM T192 two days ago compared to ECM T144 today - that low pressure system to the north of Scandi is already showing signs of being held back:

 

You would be right about 'certain types' of NE European anticyclonic set-ups. But those tend to be aligned and trending differently, and also to have very cold air entrenched. The current and projected situation shows alignment and trending that don't support a very cold and entrenched cold block of the type you suggest. There is a gradual build-up of something fairly cold but the trends otherwise tend to either not allow much if any cold to advect west or for the cold to pull away as milder air pushes in from the south and west.

 

If the current GFS P were to come off, it does at least bring a very cold pool of air into east Europe, but the alignment and trending are still not supporting it to advect or even to hold for very long. The overall alignment still needs to change. I think it's very gradually changing. Another 2 weeks at least before it might have changed enough to start trending cold our way, or setting up a block to our east/NE that could bring cold towards us/hold any real cold over us. IF it does at all.

 

My own feeling is that what will continue to happen is what the models overall are showing, that we are in the middle between the major players, and the result of these players is average (though very gradually cooling) temperatures, and overall relatively settled weather (average again I suppose! Slightly more settled than unsettled overall?). The models overall were correct about this over the last 3 weeks.

 

There is a very gradual shift in hemispheric patterns, perhaps. Is it going to continue or reverse or stay more or less as it is? Mid-lat blocking still looks the most likely overall outcome, if to say such a thing is relevant. The blocking may become more centred around these islands and west Europe, for a while. That in turn may gradually result in further change. Or the mid-Euro ridge may hold or rebuild. Nothing consistent suggests anything other than these type of outcomes in the next 2 weeks, to me.

Edited November 26, 2014 by Altohumorous

[blizzard81]

Put into the mix the usual poor modelling of arctic high pressure systems within the day 10 period, and add to that the further difficulty in trying to model the transfer of upper vorticity energy across the pole from Canada to Siberia, the usual advice of sitting back and trying not to over- disentangle the mischiefs of each and every intra day face value model operational output suite becomes ever more pertinent. 

 

The pleasantly seasonal rather cold mid latitude high solution advertised in the shorter term looks to be well calculated by the models, but best be wary of reading too much into, and over anticipating, any lasting legacy (if it happens) from flattening out of the pattern to any long-lasting and meaningful extent thereafter with associated westerlies.

 

Whilst this is for sure a distinctly plausible (transitory) response to the energy transport across the pole, we should bear in mind that destination PV Siberia represents the next crucial step along the way with this winters pattern. This is said within the context of a very beaten up and weak polar vortex. It also represents a polar opposite to what happened last year in early December as Siberian energy transferred across to the Canadian sector as part of a centrally organising steroidal vortex that spat deep low after deep low across the atlantic towards us.....

 

Notwithstanding the uncertainties with regard to risks with over progressive model attempts to ditch the high to the east/north east in the short/medium term, the eventual outcome of energy balancing towards the Siberian sector will provide the fresh impetus anyway to the cold pooling SAI feedbacks which have been proven in recent weeks modelling to be in action.

 

We shouldn't fret too much over questioning timing when this next stage in the process is completed - even delayed by a short time. I stated in a previous post that this overall seasonal pattern process, once begun, was likely unstoppable and by the time the up-coming re-shuffling across the polar field has occurred, I would very much expect the next cycle of westward pattern backing to continue with vigour, whatever happens with regard to polar field modelling uncertainties in the shorter term.

 

The upping of the ante in the wave breaking battle as a consequence of this takes us ever closer towards the very back-end of the year and the increasing likelihood of an SSW. Its worth riding a short troposphere/stratosphere bombardment pause while the pattern re-sets

What do think of the chances of a cold shot before Xmas Tamara ?

[Captain Shortwave]

The GFS ensembles do show a window of fine and potentially frosty weather during next week. 

I must admit longer term, I'm struggling to spot any trend over the pole, each run seems to throw deep low heights all over the place without much consistency.

I really can't see a cold easterly from day 5, we could hold onto a rather cloudy and cool easterly from the low over central Europe, but we would be waiting days for cold to drain round the Scandi high with immense pressure from the west to split the ridge which ends that chance straight away. That ridge from here

This would still require a few days to drag the cold air round, re-invigorate the low over Italy and drag the cold to the UK. I would put this at less that 5% chance to be honest.

[shaky]

Better 12z run so far!! Stronger scandi high and arctic high also once again everything slightly further west!! Ukmo 96 hour much further west compared to 120 hours from yesterday! ! Especially across iceland area!!

[warrenb]

By 174 on the GFS the pattern is flattening out, with jet roaring to the north of us, quite a turn round from 2 days ago.

[shaky]

By 174 on the GFS the pattern is flattening out, with jet roaring to the north of us, quite a turn round from 2 days ago.

i guess at the moment we will have to live with cold and frosty mornings with high pressure on top off us!! Take that any day over the rainfest that we endured last year!!

[Barry12]

Within the reliable time frame the block has become stronger compared with the 6z:

 

Day 4:

 

 

Day 5:

 

 

Day 6:

 

 

Lets hope this trend continues...

 

Edited November 26, 2014 by Barry95

[blizzard81]

Better 12z run so far!! Stronger scandi high and arctic high also once again everything slightly further west!! Ukmo 96 hour much further west compared to 120 hours from yesterday! ! Especially across iceland area!!

 

Yes matey, at this rate we will be in the middle of an easterly this time next week

[Barry12]

"from then on"?!

 

The METO clearly didn't get your memo this morning:

 

UK Outlook for Thursday 11 Dec 2014 to Thursday 25 Dec 2014: "Temperatures are generally expected to be around, or a little above, average for the time of year."

 

I'm looking forward to a bit of drier, colder, frosty weather next week (should it come to pass and not be cloudy and drizzly). It'll be cracking but I will make the most of it while/if it lasts. I don't like the GFS trend of sinking heights and the jet running north - let's hope it's wrong.

 

I'm commenting on what I am seeing from the models, given this is the 'Model Output Discussion', not the 'Met Office outlook' thread.

[ItNeverSnowsInWindsor]

Look at the differences between GFS and GFS-P at T96. GFS-P has the Scandi High and the Low over S Europe further westwards. I wouldn't bother with the GFS any more!

 

GFS -

 

 

GFS - P

 

Edited November 26, 2014 by prolongedSnowLover

[knocker]

Yes matey, at this rate we will be in the middle of an easterly this time next week

 

Well...............................nearly

Charts courtesy weatherbell

[Captain Shortwave]

Day 6 charts

GFS

GFS (P)

UKMO

GEM

To be honest it's the American model which is holding most hope on the Svarlbard ridge which is really holding out much hope. The UKMO and GEM are more progressive with the eastward movement of low heights from Greenland, the GEM holds onto an easterly in the south via a much deeper low over southern Europe. The GFS parallel just about re-establishes an easterly, again due to low enough heights to the south.

Settled weather still favoured in week 2, maybe the chance of some wintry showers early next week, particularly over higher ground.

Edited November 26, 2014 by Captain shortwave

[Winter Cold]

Noticed on tonights GFS, GFS(P) and GEM that they all want to give Reykjavic and Iceland a wild Sunday night:

 

 

Looks settled for us in the UK though

[blizzard81]

Well...............................nearly

Charts courtesy weatherbell

 

Well...............................nearly

Charts courtesy weatherbell

Try the upgraded GFS Parallel run

[IDO]

Nice run from the GFS op with 4 Atlantic HP systems moving in over the UK in the next 16 days:

 

 

 Ending: 

 

GEM at D10:  GFS P at D10: 

 

Seasonal stuff, frost, cool at times, sunny and cloudy all possible, with a cool PM flow, but no trigger for cold in FI. If we do get a PV sending the Atlantic to our north for the foreseeable, I will not complain about that.

Edited November 26, 2014 by i'm dreaming of...

[mushymanrob]

Yep, I'd advise you to make the most of that. Looks average to below from then on...

 

i dont care! ill take what we get, whether i like it or not. its only weather. just as well really IF the gfs 12z varifies!

 

 

[MR EXTREMES]

may i ask am i reading this right from the models but is that the pv filtering across the arctic from the west?

[Polar Maritime]

Yes ido, Some pretty sharp N/W shots continue to be shown on this evenings GFSP, With -6/7 850's over the Northern half of the UK. The first snow of the Winter possible in places especially over higher elevation. The blob of hight's trapped over the poles is also nice to see. 

 

Edited November 26, 2014 by Polar Maritime