Model Output Discussions 06z 04/11/16

[knocker]

Today and the next couple of days. The low to the east of Iceland dominates affairs with the UK in a W/NW airstream bringing showers. wintry in the north with snow on the hills, and occasionally longer periods of rain. Today the milder weather hangs on in the south as the rain band edges slowly south with the cooler air behind so here cloudy with some sunny intervals.

The GFS this morning

Saturday sees the upper through firmly in position over the UK with the European HP surging NE. The main point of interest at this stage is the formation of the perturbation in the western flank of the trough and thus the development of the surface low that is SW of Ireland 977mb by 1800z on Saturday with the large rain belt approaching Cornwall

The low quickly tracks ENE and is in the North Sea by 00z Monday so a pretty damp, cool and quite windy in some areas, weekend.

Whilst all of this is going on amplification of the upper pattern continues apace and by 00z Thursday we have a somewhat distorted version of two Omega blocks with the main trough orientated to our SW  The actual position and orientation (negatively tilted) of this trough is quite important because on the eastern flank there is WAA flooding into Europe with the colder air  to the west and the UK is right in the boundary firing line.

Thereafter we arrive at the position that the anomalies have been hinting at with the area of low pressure to the south and HP to the north. So all in all a rather cool  unsettled outlook and remaining so in the south with perhaps, for a change, the north getting the better of the weather.

Edited November 16, 2016 by knocker

[Ali1977]

Differences at 144 are pretty big - ECM not keen with the idea of WAA heading North into Greenland. Quite a difference at relative short range.

[Polar Maritime]

Some choppy Channel Crossing to be had on Thursday.

 

[Mucka]

Aye, shortwave dramas what they good for?

 

One things for sure, we are in for the long haul on this one as far as finding a cold pattern goes.

Maybe once this Atlantic ridge drama has been sorted we might see something a little more conspicuous either way.

Edited November 16, 2016 by Mucka

[knocker]

Very briefly with the ECM this morning. The forming upper low in the main trough is further to the SW thus the surface depression tracks across northern France. The precipitation belt associated with this does not impact very far north over the UK but just how far might be interesting as it has some quite cold air in the UK over the weekend. It should be noted this evolution is a long way from the previous run which must be a concern given the relatively short forecast period.

It also is at odds with the GFS vis the amplification. It is certainly not as keen to strengthen the Atlantic ridge and keeps the Canada- UK  energy conduit open via Greenland next week. However it does eventually arrive at the Omega block position by Friday with the trough to the SSW

 

Edited November 16, 2016 by knocker

[Frosty.]

The GEFS 00z mean looks rather cold / wintry towards the end of November, especially further north with a scandi trough, height rises to the NW and the Atlantic looks blocked. The uk would be in a cold airmass with Nly / NEly winds.

[blizzard81]

What has struck me on the last few ecm runs is that none of them have a huge propensity towards a strong negative AO which makes it's runs way out of line with all the AO forecasts for late November. I really do think the ecm op runs have been struggling these last couple of days.

[fergieweather]

1 hour ago, Mucka said:

Aye, shortwave dramas what they good for?

 

One things for sure, we are in for the long haul on this one as far as finding a cold pattern goes.

Maybe once this Atlantic ridge drama has been sorted we might see something a little more conspicuous either way.

Indeed so. Mixed signals then emerging in latest output onward into 1st half of December, re anticyclonic v cyclonic and milder v colder phase balance. 

[bluearmy]

The output continued to play out different solutions but still heads in the same direction by days 9 and 10

gefs BC and ecm ops animolys

 

now looking for the eps extended to begin to hone in on the gefs mean as more eps runs cluster together (certainly the anomolys -  the mean days 10-15 is tough to get sharp)

[blizzard81]

5 minutes ago, fergieweather said:

Indeed so. Mixed signals then emerging in latest output onward into 1st half of December, re anticyclonic v cyclonic and milder v colder phase balance. 

Can I assume the milder cyclonic options have inceased in the last 24 hours?

[Frosty.]

As you would expect, with the GEFS 00z mean looking like this, there are some very chilly perturbations, some showing max temps around freezing and a little above. Hopefully we will have a noteworthy  cold spell late Nov and through Dec 

[northwestsnow]

9 minutes ago, fergieweather said:

Indeed so. Mixed signals then emerging in latest output onward into 1st half of December, re anticyclonic v cyclonic and milder v colder phase balance. 

That is most certainly not what many wanted to hear Ian! Although given the timescales it is perhaps understandable.The strat/Glosea/EC monthly ect were all pointing to cold and now we see increasingly dodgy ecm ops and mixed signals, oh well, strapped in for a bumpier ride than i anticipated..

Edited November 16, 2016 by northwestsnow

[Ali1977]

8 minutes ago, fergieweather said:

Indeed so. Mixed signals then emerging in latest output onward into 1st half of December, re anticyclonic v cyclonic and milder v colder phase balance. 

Sounds to me like we are losing some of signals of a blocked December, hopefully this trend doesn't keep going on for the sake of the coldies among us. The AO and NAO were forecast to go deeply negative last night so hopefully they have that correct then we stand half a chance of sending these highs to our North!! 

[January Snowstorm]

10 minutes ago, fergieweather said:

Indeed so. Mixed signals then emerging in latest output onward into 1st half of December, re anticyclonic v cyclonic and milder v colder phase balance. 

Which begs the question why we bother to look beyond 10 days? I mean if everything is for cold 24hours ago and then gets watered down a day later (despite all signals pointing cold).

[blizzard81]

4 minutes ago, northwestsnow said:

That is most certainly not what many wanted to hear Ian! Although given the timescales it is perhaps understandable.The strat/Glosea/EC monthly ect were all pointing to cold and now we see increasingly dodgy ecm ops and mixed signals, oh well, strapped in for a bumpier ride than i anticipated..

Yep, a familiar tale unfortunately. Very sobering news for us coldies.

[mb018538]

This is exactly what I was saying yesterday - all the nice blocked charts have stayed at D10 for a few days now, and as we get nearer the time, they start to somewhat fade away. Nothing too overwhelming to see as far as I'm concerned.

[jvenge]

Maybe I don't read enough into what Ian says, or maybe others read way too much into it. To me he hasn't said anything other than pointing out that the models are still showing an uncertain situation, which is pretty much the same as yesterday....

[Frosty.]

1 minute ago, January Snowstorm said:

Which begs the question why we bother to look beyond 10 days? I mean if everything is for cold 24hours ago and then gets watered down a day later (despite all signals pointing cold).

This is the uk though so you should expect at least some Atlantic influence, I would be happy with a mix of cold and mild which would be a lot better than last December which was all mild. Anyway, the models show a cold, showery spell on the way with snow for some of us..let's enjoy that first!

[northwestsnow]

Evidently a fly of some sort has got into the ointment! wonder what the fly is  this time lol, anyway, dramatics aside its mid November, so i guess its very early days.Model watching is really intriguing at the moment, truely delightful if a tad agonizing at the same time...

[Seasonality]

No need for wrist slashing! We all know models have elements of uncertainty at longer ranges, indeed climate/weather itself is an inherently chaotic system, and it is often the case that when unusual weather types for the UK are predicted that the model uncertainty will increase. 

[terrier]

A very sobering update from Ian this morning. I'm wondering if the models behind closed doors are seeing something we are not in the models. Hopefully we aren't gonna see the dreaded west based nao setting up. But as we know things can change rapidly for our tiny island. Hopefully the gfs ecm ukmo gem will move us closer to the eye candy charts at some point and not at the 10 day range as seems to be the case at the moment. 

[Decemberof2010]

It does seem that whenever we have uncertainty regarding mild v cold emerging, that slowly but surely the mild signals then strengthen. It never seems to be the other way around. Hope that can change this time though. 

Such high spirits on here yesterday morning as well. Shows what difference a day can make. 

Keep your chins up fellow coldies and keep the faith we are well overdue some luck!

 

[Terminal Moraine]

1 hour ago, knocker said:

Very briefly with the ECM this morning. The forming upper low in the main trough is further to the SW thus the surface depression tracks across northern France. The precipitation belt associated with this does not impact very far north over the UK but just how far might be interesting as it has some quite cold air in the UK over the weekend. It should be noted this evolution is a long way from the previous run which must be a concern given the relatively short forecast period.

 

 

Not so sure about that, Knocker. Although the low approaches from the south west it then swings north/north east across the Midlands and exits over the North Sea somewhere near the Wash. That would take its area of precipitation north across the whole of southern England, the Midlands and into the southern half of northern England, probably with some temporary sleet and snow on its northern edge and particularly over any high ground.

[Geordiesnow]

3 minutes ago, January Snowstorm said:

Which begs the question why we bother to look beyond 10 days? I mean if everything is for cold 24hours ago and then gets watered down a day later (despite all signals pointing cold).

Which is why as old fashioned as it sounds, instead of focusing constantly on all these fancy background signals malarkey, lets focus what the models are saying in the short-medium term as that will be as true of a picture as you will get, I think some just get too hung up, drawn and quarted on what these longer range models are saying when such variability in the longer term will always exist. December might be blocked but it might not be either, traditionally its not usually a month which herealds lots of blocking anyway but lets just see if the models show that as we approach and head through December itself.

ECM still looks flatter too me but too me, I would probably take the risk of perhaps getting those blocked charts once Scandi gets cold again, the pesky Russian high looks like its going to be a stubborn beast and aslong as its there in that orientation, Scandinavia will stay above average.

Would not mind seeing the AO go a bit positive, lets get the Arctic cold and see if we can tap into any proper cold air at a later date because in terms of cold air at the moment, the UK will only be feeding on scraps at best really.

The low for Sunday is much shallower on this mornings runs bar the GFS, suspect this will be closer to reality but still can't rule out it could be a deeper depression, its still very much in the air that one.

[nick sussex]

So no agreement this morning between the outputs. Last nights GFS 18 hrs run did look like a move to the ECM but the 00hrs has moved back to the original view at least in terms of the more amplified Atlantic high. 

Although the outputs end up converging towards day 10 the ECM needs a lot more to go right because of its very messy earlier picture. For that reason if you're a coldie you certainly want the ECM to be wrong here.

Unfortunately US forecasters aren't sure which model is correct but given the amplified pattern the ECM seems to be very progressive within that and for the timbeing is the less likely solution. Doesn't mean it's completely wrong but the GFS and UKMO seem more likely given the upstream pattern.

We should get agreement today although I'm sure I said the same thing yesterday evening!

Edited November 16, 2016 by nick sussex