Model Output Discussions 06z 04/11/16

[Frosty.]

The GEFS 6z mean indicates an increasingly cold unsettled mid range into early December with polar / arctic sourced air so I would expect some snow, especially on hills and frosts/ice from this set up.

Edited November 23, 2016 by Frosty.

[bluearmy]

15 minutes ago, mountain shadow said:

The 6z is generally the least blockie of the GFS runs I always thought. I just find it hard to believe that both the op and control could be so wrong at such a timeframe.

The 6z has newer data too, hopefully they have picked up on a new signal.

 

Like at T96 for several runs last week re the Greenland ridge ??

 

[nick sussex]

10 minutes ago, mountain shadow said:

The 6z is generally the least blockie of the GFS runs I always thought. I just find it hard to believe that both the op and control could be so wrong at such a timeframe.

The 6z has newer data too, hopefully they have picked up on a new signal.

 

Well the NCEP state forecasts don't help with no preference for a certain model. In terms of the GFS I wouldn't bank on its run because the last time we had a disagreement it came down to a similar scenario. The ECM threw a shortwave east which stopped the stronger ridge near Greenland, the GFS was reluctant to do that and was even slower than the UKMO to backtrack.

I suppose a positive is that yesterday evenings UKMO phases the lows and now today doesn't but you can see how things are on a knife edge , even on the GFS 06hrs run the lows come very close together. What saves the GFS is as that amplification digs in over the central USA this also sharpens up the low near Newfoundland at the same time WAA builds a lobe of high pressure into Greenland however if you look closely it still ejects a weak shortwave into the high to the east.

We can just about get away with a weak shortwave being ejected se into the high but if the main low phases then its game over. And it will be very difficult to develop that colder set up.

[Connor Bailey Degnan]

Have to say, 6z was very exciting, however, I'm not getting carried away and until I say any back up from any other model, I'd say it's unlikely to verify that way.

Whatever happens regarding the early part of December, oh and btw, (I think you'd be very brave in giving a forecast for that time because it seems nearly impossible), I think we have plenty of cold opportunities throughout the month, particularly mid month onwards. 

Best I've felt about a December, since 2010, easily. 

[mountain shadow]

6 minutes ago, bluearmy said:

Like at T96 for several runs last week re the Greenland ridge ??

 

Can't say I recall that Blue.

[SteveB]

1 hour ago, karlos1983 said:

B-E-A-UTIFUL!! it's being modeled, so it most certainly IS possible.

What a run from the GFS. Likey likey, come to Blighty!!

No chance of uppers being mixed out there, wonder if this is what I.F is talking about when he's say's unsettled start to December, but not like last year.

This year = unsettled cold

Last year = unsettled mild

?

One thing that I've noticed being consistently modelled is a cold plunge around the 4th December......

Edited November 23, 2016 by SteveB

[Gael_Force]

5 minutes ago, nick sussex said:

I suppose a positive is that yesterday evenings UKMO phases the lows and now today doesn't but you can see how things are on a knife edge , even on the GFS 06hrs run the lows come very close together. What saves the GFS is as that amplification digs in over the central USA this also sharpens up the low near Newfoundland at the same time WAA builds a lobe of high pressure into Greenland however if you look closely it still ejects a weak shortwave into the high to the east.

Well, the UKMO has a full hurricane in the Atlantic by day 7 so we could end up with the kitchen sink, such is the volatility and vagaries in current output.

[mountain shadow]

10 minutes ago, nick sussex said:

I  What saves the GFS is as that amplification digs in over the central USA this also sharpens up the low near Newfoundland at the same time WAA builds a lobe of high pressure into Greenland however if you look closely it still ejects a weak shortwave into the high to the east.

 

On this latest GFS 6z the Newfoundland low is less developed and negatively tilted, this helps promote the blocking between it and the low over Greenland. On the 12z I wIll be watching for the Newfoundland low to hopefully be slower and sharper as you say.

Knife edge stuff at only the 5/6 day mark too. Amazing how such a small difference in the shape and depth of a low pressure system can make such a massive change down the line. 

Edited November 23, 2016 by mountain shadow

[karlos1983]

24 minutes ago, Gael_Force said:

Well, the UKMO has a full hurricane in the Atlantic by day 7 so we could end up with the kitchen sink, such is the volatility and vagaries in current output.

Really? Not seeing that at 144, but I cant find a day 7 chart, please share

[Gael_Force]

3 minutes ago, karlos1983 said:

Really? Not seeing that at 144, but I cant find a day 7 chart, please share

http://ruc.noaa.gov/hfip/tcgen/

Edited November 23, 2016 by Gael_Force
forgot to put in link.

[marksiwnc]

10 minutes ago, Gael_Force said:

http://ruc.noaa.gov/hfip/tcgen/

I believe that's heading for the canaries.  

[karlos1983]

Just now, marksiwnc said:

I believe that's heading for the canaries.  

As long as it doesn't head North, I'm happy. That's a variable we could do without!!

[Frosty.]

Well I think we can safely put the very mild and very wet nightmare that was last December behind us as the models look much more seasonal with temperatures below average for much of the time and at least some wintry ppn in the mix. It looks like December will become blocked and predominantly settled after an unsettled start and unlike early last winter when there was a complete lack of wintry weather, this year it looks like frosts will feature a lot and all of us should have some snow at some point next month..The 6/15 day range has also perked up for coldies and now plays out similar to the Gfs 6z operational with a risk of snow as time goes on, and not just on hills!

Edited November 23, 2016 by Frosty.

[nick sussex]

Judging by that UKMO T168hrs output that looks pretty grim as the NF low heads ne and deepens. We really need the GFS to be right otherwise I fear this thread may resemble a wake this evening.

The ECMs output was a lesson in how everything that can go wrong does, the rest of the outputs bar the GFS look decidedly uninspiring so its going to be a nervous wait till this evening to find out which model is correct.

[Frosty.]

20 minutes ago, nick sussex said:

 the rest of the outputs bar the GFS look decidedly uninspiring so its going to be a nervous wait till this evening to find out which model is correct.

According to the way the latest MO update 6 / 15 day is worded, I think the peachy Gfs 6z operational looks similar  with our weather coming from the NW with windier conditions and rain turning to sleet or snow on hills, and a chance of snow on lower ground too..sounds wintry to me.

Edited November 23, 2016 by Frosty.

[Ali1977]

17 minutes ago, nick sussex said:

Judging by that UKMO T168hrs output that looks pretty grim as the NF low heads ne and deepens. We really need the GFS to be right otherwise I fear this thread may resemble a wake this evening.

The ECMs output was a lesson in how everything that can go wrong does, the rest of the outputs bar the GFS look decidedly uninspiring so its going to be a nervous wait till this evening to find out which model is correct.

I'm personally thinking the GFS is wrong and the 12z will say the Atlantic in some form is coming in. Whenever we have had a good coldie run it has never been followed by another so that is what I'll think for now.  To be honest though, it's not exactly late Feb so won't lose sleep over it.

"IF" we do see the 12z follow the 06z , then this evenings ECM do the same then I think we may have a rapid swing to Winter on our hands.  This is a possibility after all and the latest METO has taken away the talk of temporarily Milder weather, and introduced some more positive wording - this is good news.

Edited November 23, 2016 by Ali1977

[jvenge]

There used to be a chap who posted model verification stats every week or so. Where did he go to?

[Thermohaline Conveyor]

It is very much a battle between the ECM and GFS tonight.  ECM is pumping much more energy into the higher latitudes beyond T+144 whereas GFS resists the higher energy and favours stronger height builds in crucial areas in and around Greenland.  The Greenland to Newfoundland region is the area that holds the key.  To be honest the differences are minimal and only very slight changes will alter the outcome thus slight sensitivities to the starting data in each model may be the cause for discrepancies between ECM and GFS at lead times beyond T+144.  ECM has been more consistent and bullish in building the extended ridging into the UK around the 1st week of December whereas the GFS has had a tendency to add increased incidences of  jumpiness in the possible outcomes.  Despite one models apparent consistency on modelling a particular synoptic over another it remains impossible to favour one solution over the other at this stage.

[Ravelin]

43 minutes ago, nick sussex said:

its going to be a nervous wait till this evening to find out which model is correct

If only it were ever that simple. Even if all of the models roughly back the same solution this evening I'm not sure I'll be 100% convinced. Too much scatter from all of them recently so it'll take more than one set of matching runs before I'm convinced.

Hell of an interesting model watching period though.

Edited November 23, 2016 by Ravelin

[Geordiesnow]

Think the ECM last night had amplification in the newfoundland area but never quite showed the northerly so the GFS cant be discounted.

I think the GFS is better at handling low pressure systems in normal circumstances, take storm Angus for example. At times the UKMO/ECM was going for a shallow feature whlist the GFS went for a deeper low and that turned out to be the case despite my thought it won't end up as a deep low. However in blocking set ups, it tend to vary a lot and I never take much notice of FI.

Who knows though but after its disaster of going for a Greenland high when other models never really did, I'll be surprised if the GFS is even close to being right.

[Summer Sun]

20 minutes ago, jvenge said:

There used to be a chap who posted model verification stats every week or so. Where did he go to?

@Gibby posted them more or less daily

You can see his model analysis below but he doesn't post the verification stats now from what I can see

http://www.norton-radstockweather.co.uk/latest-model-analysis

Edited November 23, 2016 by Summer Sun

[snowice]

15 minutes ago, Geordiesnow said:

Think the ECM last night had amplification in the newfoundland area but never quite showed the northerly so the GFS cant be discounted.

I think the GFS is better at handling low pressure systems in normal circumstances, take storm Angus for example. At times the UKMO/ECM was going for a shallow feature whlist the GFS went for a deeper low and that turned out to be the case despite my thought it won't end up as a deep low. However in blocking set ups, it tend to vary a lot and I never take much notice of FI.

Who knows though but after its disaster of going for a Greenland high when other models never really did, I'll be surprised if the GFS is even close to being right.

I find  ECM after 144 is more on the money,but i have to say there is an element of excitement  about tonight's outputs!

[tight isobar]

A few things to pick up on before 12zsuites.

Obviously' there are mass miss model agrre atm to which given current statistics/state are understanding. Hp cell in situ will have large implementation for our neck of woods and is atm static looking short/mid term . However upstream and Russian areas are obviously massively important of waa' incrochment' and will have outcomes for ourselves. Whats differing this season is mass mother 'lobe' situated on eastern pole.

That in itself is imo a major + for uk.. twitching and tweaking via suites is inevitable beyond even 96  hrs......atm.w

However the point of post is Gfs6z' is in evolution very feasible given flux/state..and although cannot post' outcome statistical atm..its the form model for smelling new trends!!!!..

Happy viewing! !!

Edited November 23, 2016 by tight isobar

[Iceaxecrampon]

I should know better but just had a look at T+186 (1 Dec) - interesting to say the least as does the whole week of the beginning of the month.

One to watch and hopefully wont collapse into abject disappointment.

[IDO]

I would normally say that the 06z is an outlier (it is); and its the 06z, so pretty rubbish after D6, but there is so little instruction as to what happens with the N Pacific Ridge from D6 and the knock on effect to the downstream Atlantic Ridge that it is difficult to rule it out. It could well be the Eureka moment that the models start veering towards, or not?

As always, more runs needed and we require these to be pumped out inter and cross model before we can tell our families and friends to baton down the hatches: