Model Output Discussion - 7th-13th November

[Bale]

The 12z GFS has moved us nearer to a continental feed next week not further away. I really don't see what you see. you keep saying temps could reach 18c at the weekend but i do not see any evidence in any current model output that this will be the case.

17c max temp for London is forecast this saturday...itl probably change but not far off 64f

[Geordiesnow]

Now Ive got to say this is a remarkable turnaround now even I didn't expect this I expected this in the last week of November and stick by it however if things keep changing like they are then Matty may well be right and it could happen earlier im literally at loss for words

I wouldnt get too carried away but if the ECM and now the GFS is right about the link up and increased heights into Greenland then that of course is a step in the right direction. Conversely if the UKMO and previous GFS runs are right then we kinda back to square one again and never rule out the UKMO!

Of course people must note that even a Greenland high and blocking does not mean the fun and games will begin but at least it will give model watching a more interesting look to it.

[Isolated Frost]

Geordiesnow, yes I agree with your weekend summary there, but PL said next week had southerlies and if you are lucky the odd sse'ly, when in reality e'lies and se'lies ruled on the 12z of both outputs.

Snowstorm1, its very similar to some of yesterdays charts; the retrogression is un-noteworthy and as kw says the jet should let loose in fi, the simple change is orientation and duration, which has in turn provided a cool outlook for e europe and scandi. It's very unlikely for us to get any cold weather precipitation wise, but temperature wise, yes maybe if hp is nearby and inversions and clear skies come in to play.

[ITSY]

not exactly a dream run for coldies but what a change! shows how quickly things can develop! -5C at T+276 in West Midlands. I doubt this is how it will play out but very suprised at the sudden change - it certainly makes the likelihood of cold increase.

[Snowstorm1]

I wouldnt get too carried away but if the ECM and now the GFS is right about the link up and increased heights into Greenland then that of course is a step in the right direction. Conversely if the UKMO and previous GFS runs are right then we kinda back to square one again and never rule out the UKMO!

Of course people must note that even a Greenland high and blocking does not mean the fun and games will begin but at least it will give model watching a more interesting look to it.

I know but its just nice to see things improving for a change!

Snowstorm1, its very similar to some of yesterdays charts; the retrogression is un-noteworthy and as kw says the jet should let loose in fi, the simple change is orientation and duration, which has in turn provided a cool outlook for e europe and scandi. It's very unlikely for us to get any cold weather precipitation wise, but temperature wise, yes maybe if hp is nearby and inversions and clear skies come in to play.

I would be happy with a cool down and get some fog and frost then let the monster cold on the continent rip leash on the UK but as you say lets get the cool down in place first

[ITSY]

GFS FI is horrendous for coldies - ends up paralleling the 12Z ! Other thing to note is that both the 12 and the 18Z end FI with a strengthened Jet over the British Isles...hopefully not an emerging pattern out of todays up-down output

[ukpaul]

240h GFS looks relatively similar to ECM now but it's from that point and further into the wilds of FI it appears to want to go back to its earlier option of raging lows to our North. That's way too far in the future to be seen as probable but there appears to be some cross model agreement now for before that (I think BOM, GEM and JMA were tending to the ECM solution).

[Rocheydub]

For me, well it's an improvement. It's showing that after this week, we are out of this rut of euro-HP dominated blandness, so I'm happy. Even if the 12z GFS run is closer with the LP powering through, or tonights 18z is closer (and ECM's earlier run) I will be a happier bunny. In Summer, I want summer weather, In Autumn... etc. You get the picture!

[kold weather]

Well the good news is the 18z decides to move towardfs the 12z ECM solution which keeps the upper high quite close to the UK and helps to keep increasingly cooler air comingm in from Europe.

Nothing amazing, but a frosty looking 1z GFS in the main...better then raging SSW airflows!!

[nick sussex]

I think the GFS 18hrs run has decided to dangle that deep cold over eastern Europe as a way of getting some attention, it was beginning to feel a bit neglected with the ECM getting all the interest!

Unfortunately as we can see theres no trigger to pull the cold west due to a lack of low pressure over central/southern Europe. It is however a cooler run with the mild mush feed from the south cut off as we get that troughing into Iberia.

This is a good example however of how just some smaller changes earlier can really help, no change in pattern but these small details can make quite a difference.

Not to be too dramatic but I think we've reached a crunch point in terms of whether we can see some much colder conditions within the next few weeks, if you put aside the easterly tease how do we get from mild to cold.

If we accept the overall patterns not changing much then we need to see the models pick up the ECM baton, so we're looking to squeeze every last bit of amplification out of the current output within 168hrs, as we've seen from the GFS before it went into tease mode, also as much eastwards push of troughing into Iberia, it's likely that more deeper low pressure will try and move in towards the UK later and its whether some of this energy can get diverted under the ridge to the north.

Any real cold for the UK will not happen with the current type of pattern unless pressure falls substantially over central/southern Europe, when the next low approaches if the ridge is well supported by low heights to its south and the trough disrupts to the west then the outlook would be much more favourable.

It is interesting regardless of my reservations regarding both the ECM and GFS 18hrs run that they are playing with some different scenarios, I still think though that if swift cold redemption is going to happen then it's not going to be from FI, quick changes will occur within 168hrs.

As we've seen already a few small changes within 120hrs somehow led the GFS to the easterly tease, let's hope they continue with the surprises tomorrow!

[Matty M]

Well the good news is the 18z decides to move towardfs the 12z ECM solution which keeps the upper high quite close to the UK and helps to keep increasingly cooler air comingm in from Europe.

Nothing amazing, but a frosty looking 1z GFS in the main...better then raging SSW airflows!!

Is there any jet signal precluding the possibility of the Greenland high sticking around for a bit longer around T72hrs?

[nick sussex]

Is there any jet signal precluding the possibility of the Greenland high sticking around for a bit longer around T72hrs?

The problem is the track of that deep low, it needed to run ne to the west of Greenland with better WAA the down stream amplification would have been more favourable and of course higher pressure over Greenland.

The models are though in good agreement upto that point, though any more northerly track we can squeeze out would help of course.

Edited November 9, 2011 by nick sussex

[summer blizzard]

Another good run for frosts/inversions..

[BLAST FROM THE PAST]

Hmmm...tentative signs again of a change to cold synoptics. Solar adnd lunar signalks have pointed to this and still do for colder weather/synoptics to arrive for late Nov, never before. Now lets see if this continues, Timing last week of Nov. If it happens....external forces driving the pattern????

BFT;P

Edited November 10, 2011 by BLAST FROM THE PAST

[ZONE 51]

Here is GFS 18z for today, for the learning zone i have indicated arrows, these are the directional air flows, i will be doing this when i can and upload one chart. this is to make it easier for those that are learning the charts and dont know what way the airflows go, always anti-clockwise for low pressure and clockwise for high pressure

Edited November 10, 2011 by ElectricSnowStorm

[yido]

There will be plenty who can articulate far better than me the 0z GFS run but it certainly looks like the sudden turn around of synoptics shown on the 18z have continued and if anything seem more set on retrogression of the high with a more easterly flow. I'd say positive signs?

[bluearmy]

Unconvincing would be my current take on the ops. Whilst this continues, stick with the ens output beyond a week whilst they remain fairly consistent. Ecm's latest trend is to ramp up a shortwave south of greeny around T168. If it becomes the trend, where will it go?

EDIT: the end of ecm shows the trough disrupting - again!! that does fit in with the ens which have little appetite to change the general current meridional pattern and more importantly, our position within it.

Edited November 10, 2011 by bluearmy

[kold weather]

Yeah there is a change on the models again being suggested in the Atlantic which allows the high to spread westwards and really influence our weather. Some ensemble members still go then full hog and develop a full blown Greenland high at some point in late November, but I personally think we'll have a colder spell of weather through surface cold rather than deep cold.

Pattern could eventually develop into a very good one but its going to take time.

[chionomaniac]

Unconvincing would be my current take on the ops. Whilst this continues, stick with the ens output beyond a week whilst they remain fairly consistent. Ecm's latest trend is to ramp up a shortwave south of greeny around T168. If it becomes the trend, where will it go?

EDIT: the end of ecm shows the trough disrupting - again!! that does fit in with the ens which have little appetite to change the general current meridional pattern and more importantly, our position within it.

I'm convinced Nick, that the current pattern will change to something flatter before a repositioning of the meridional pattern come December. Reasons? Well - shift of MJO wavelength setting due to seasonal changes and possible repositioning of stratospheric vortex come December. The flatter pattern will be transitional.

Presently the signals for change are being overridden for the signal for the current pattern but at some point this will be reversed. I know there has been a lot of clamour that this change would happen mid November, then late November, but December is more likely. I can't remember but does any know what pattern GP suggested for December - was it a continuence of the Scandi ridge?

[mountain shadow]

Have to agree with Kold. I think high pressure will settle around our shores which is never a bad thing if recent winters are something to go. Once it settles over us we may see a retrogression towards scandinavia or Greenland to give us a cold shot.

It does look like we will see the end of this euro high soon though.

[Frosty.]

The 00z models show the very mild spell continuing for another 7-10 days at least with winds from a S'ly to SE'ly direction in general although some brief disruption to this on saturday due to an atlantic depression with winds from a SW'ly point but the very mild SSE'ly back with a vengeance on sunday with quite a strong flow for a time, temps around 16c in the days ahead but a little higher than that where clouds break to allow some decent sunny spells but there will also be some rain around, especially in the north & west. Into next week it remains mild or very mild with pressure remaining high to the east and low to the west. In just over a week, the models show a vigorous depression will exit canada and hurtle across the atlantic but then as it approaches the block it will slow down and at the same time, a strong anticyclone will be building across scandinavia, the gfs 00z brings us the closest yet to a cold spell but there is no snow indicated and then it all breaks down from the west with milder unsettled weather returning but there is at least some interest for coldies on the gfs 00z.

[snowfall09]

Can anyone tell when this mornings run starts to roll out please ??

[Stuart]

GFS 6z run start to come out 9.30 to 10.45am

[snowfall09]

GFS 6z run start to come out 9.30 to 10.45am

Ok thank you

[wolvesfan]

I'm convinced Nick, that the current pattern will change to something flatter before a repositioning of the meridional pattern come December. Reasons? Well - shift of MJO wavelength setting due to seasonal changes and possible repositioning of stratospheric vortex come December. The flatter pattern will be transitional.

Presently the signals for change are being overridden for the signal for the current pattern but at some point this will be reversed. I know there has been a lot of clamour that this change would happen mid November, then late November, but December is more likely. I can't remember but does any know what pattern GP suggested for December - was it a continuence of the Scandi ridge?

Hello Chiono,appologies if this sounds stupid but do you mean a N to S meridional or S to N,thanks.