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Model output discussion - into 2018


Paul

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Posted
  • Location: Dipton, Nr Consett, Co.Durham, 250m, 777ft asl
  • Weather Preferences: Anything but boringly hot
  • Location: Dipton, Nr Consett, Co.Durham, 250m, 777ft asl
4 minutes ago, Ali1977 said:

There are only around 4/5 GEFS ENS that follow something akin to the ECM - not bad but was hoping for a bigger switch to get some confidence. Not sure what will happen during the next few runs, I’d have to still side more GFS but only as that’s what the METO seem to be leaning to at the minute. By day 12 we only have 1 ENS showing something glaring the continent !!!

It really is a conundrum, personally I think the gfs is king at picking out cold trends in the winter but as soon as they come within the 5 day range it seems to go off on one until the very last minute. At day 5 point I seem to put my faith in the European models, but it's definitely an interesting watch for an event which is practically on our doorsteps and really only the longevity in question.

Hopefully the longer term outlook from gfs will again trump as it seems to have done for a good while now.

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Posted
  • Location: st albans
  • Location: st albans
8 minutes ago, Ali1977 said:

As blue mentions above, breakdown from west but unsure if timing - no breakdown on the ECM is there!! Updated METO may change 

Exeter will not be making a forecast for next week based on any op output

They will mainly use mogreps and eps 

the eps bring the Atlantic into the west as next week progresses - how Far East ? How quickly?  If the op is right then the eps will catch up and their forecast will evolve

i know we live in a ‘want it now’ society but not everything works like that !  Patience ....

gfs is right about something in its general evolution but try working out what it is and whether it’s going to scupper the other models current view. 

Edited by bluearmy
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Posted
  • Location: North West Leeds 124m
  • Location: North West Leeds 124m
26 minutes ago, Tim Bland said:

Metoffice long range reads more like the GFS than ECM or GEM unfortunately. If I was in Northern England, Scotland or on High ground I would be hoping GFS is right with its cold Zonality. Which output you want Depends if you are after Mainly dry but bitterly cold or Marginal heavy snow events. My money is on a middle ground between GFS and ECM where the easterly lasts until midweek and the Atlantic comes back in end of the week. I’m hopeful for some transient snow though before cold zonalty sets in

True cold zonality would be great but as I said earlier it always seems to be reserved for the low res latter part of the GFS. In reality those cold uppers are always watered down. Just an observation and I could be wrong but a true cold NWly seems much more likely when provided by a mid Atlantic block. The jet digging far south looks great but the uppers become too modified crossing the full expanse of the ocean  meaning charts like this 'probably' won't happen.

image.thumb.png.308789dbc1fff8a0209c60dea4534d78.png

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Posted
  • Location: Ski Amade / Pongau Region. Somtimes Skipton UK
  • Weather Preferences: Northeasterly Blizzard and sub zero temperatures.
  • Location: Ski Amade / Pongau Region. Somtimes Skipton UK
2 minutes ago, johnholmes said:

they tend to think GFSmodel picks up a trend better than most to end a certain weather pattern rather than evolve a pattern

the above from Carinthian (where did you get that name Paul?)

I would agree with that comment, pity I no longer have any lonks back into the Ops room at Exeter to see if they also think that, at least sometimes. Closer in and GFS quite often 'loses' it in my view, with ECMWF and UK Met better until all 3 models hone in around 48-72 hours, although not always. A fascinating science meteorology and forecasting in particular. Almsot wish I was back as an operational forecaster, times like this current period T+12 out 144 would be great on shift!

Sadly John, the days when Joe public could speak to a duty forecaster ,just like you when shift forecaster at MWC days long gone now. We have to pay or the tourist board do to speak with a forecaster. God, they sound young, clever things, speak multiple languages and high tech information. Sometimes , I have to rein them in to simplfy matters I can understand. However, Its great talking to fellow professionals although in my case now a distant memory. Still love it and I am sort of looked up to as the duty forecast for our ski village and sometimes get free beer as well. But stay low when it all goes wrong ! The buzz will never leave you JH... keep posting your valuable thoughts and knowledge for all to read..

PS Just laughed at the thought of Ross sat in the Weather Shop with fag in mouth and dealing with the great British Public  !

C  

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Posted
  • Location: st albans
  • Location: st albans
9 minutes ago, Steve Murr said:

Why are people worrying about the GEFS they are cannon fodder in easterlies...

At their low res post day 8 they certainly should be !

i do recall a few years ago that a 12z run of the gefs suddenly picked up Scandi highs from pretty well nowhere and all the nwp followed suit. One swallow ..........

 

 

13 minutes ago, johnholmes said:

I would not totally accept that blu, they will use everything and I mean everything, their own and other centres and will almost certainly have a list of, what in the old days were called empirical pointers, now using the computer models with data continuously assimilated and this updated into their soft ware. This guidance will be used by the senior man and all other forecasters.

My ideas so not certain I am right but experience years ago suggests something along these lines.

I guess they may refer to the current direction of travel on the gfs/gefs and hold back a bit on a very cold forecast for later next week and beyond (if mogreps and eps are in agreement) but I’m pretty sure that Ian told us they will not use ncep as anything like their primary guidance.

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Posted
  • Location: Isle of Man
  • Weather Preferences: Cold, Snow, Blizzards, Storms, Hot, Foggy - Infact everything
  • Location: Isle of Man

I'm really happy with the way things are developing for our upcoming cold spell. I would always go with the ECM in such circumstances as we are about to have, and the fact that it is given support by UKMO and GEM further reinforces that fact. GEFS is poor at Easterlies. What will most likely happen is it will flip in the shorter range and go to the opposite extreme showing even better synoptics than the ECM.

  

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Posted
  • Location: Ski Amade / Pongau Region. Somtimes Skipton UK
  • Weather Preferences: Northeasterly Blizzard and sub zero temperatures.
  • Location: Ski Amade / Pongau Region. Somtimes Skipton UK
18 minutes ago, johnholmes said:

they tend to think GFSmodel picks up a trend better than most to end a certain weather pattern rather than evolve a pattern

the above from Carinthian (where did you get that name Paul?)

I would agree with that comment, pity I no longer have any lonks back into the Ops room at Exeter to see if they also think that, at least sometimes. Closer in and GFS quite often 'loses' it in my view, with ECMWF and UK Met better until all 3 models hone in around 48-72 hours, although not always. A fascinating science meteorology and forecasting in particular. Almsot wish I was back as an operational forecaster, times like this current period T+12 out 144 would be great on shift!

We live just on the border with Carinthia State ( Karten ) . Records most sunshine in Austria over here, so though Carinthian will do for me. My wife though from the Tirol so a bit of friction with this name !

 C

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Posted
  • Location: Thornbury, South Glos
  • Weather Preferences: Extremes
  • Location: Thornbury, South Glos
46 minutes ago, bluearmy said:

Can we just wait an hour for the updated meto to come out 

the forecast for next week said becoming milder in the west as the week progresses but uncertain as to timing  - would you predict anything different ???

That would suggest battleground scenarios are quite possible. 

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One comment only, in two halves.

When, as now, it's GFS vs the European models it's often the GFS which is right.

However, there's one notable exception to this general rule. An easterly set up. As now.

/—————————————————————/

Actually I have to disagree with the first statement. More often than not, European models tend to accurately forecast something before the GFS understands the pattern and joins in. GFS did very well (In My Opinion) in Autumn but has slid down the cliff edge since mid December, even when it’s  been consistent.

IMO, an accurate model predicting something beyond a week should explore with the possible scenarios before firming up on the general pattern. Even the Met Office is cautiously preparing to announce a brutal cold setup, I think the GFS will need reforming after this! ?

 

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Posted
  • Location: st albans
  • Location: st albans
11 minutes ago, Man With Beard said:

and the situation at T300 possibly even better for the NE block as all 4 clusters are evenly matched for population, and 3 of the 4 have a good NE height anomaly to them (a classic example of how reading the mean at face value does not tell you the whole story):

ec-ens_nat_z500scenarios_2018010200_300.

 

 

The conundrum at T300 is whether the bigger mobile cluster is more likely or the 75% more blocked clusters - very different surface conditions???

who’d be a forecaster !!

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Posted
  • Location: North East Cotswolds, 232m, 761feet ASL
  • Location: North East Cotswolds, 232m, 761feet ASL

Interesting charts showing last few runs of both ECM and GFS Ops and ENS.  GFS Ops definitely on their own !!

0589C1BD-2DC3-444F-9165-6CED0EF4AA01.png

Edited by Ali1977
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Posted
  • Location: Drayton, Portsmouth
  • Location: Drayton, Portsmouth
7 minutes ago, Catacol said:

So... as we approach the weekend where are we? 

A brief history - pre xmas ongoing +AAM in the tropics sustaining a decent GWO 4 - 8  orbit was suggesting a scandy high in place about now. But the MJO progression collapsed... = sudden decrease in tropical momentum and consequent increase in westerlies at our latitudes. End result - the rain and wind we are seeing now.

But rather than fall into a low momentum 1,2 orbit GLAAM has rallied somewhat. The MJO did not languish and reemerged quickly and with some strength in the Indian Ocean giving us the current decent amplification phase 2 into 3

NCPE_BC_phase_21m_small.gif

and the actual orbit of the GWO has stayed on course for a move through 2 and into phase 3

Latest 90 Days GWO

To keep this clear for those learning - what this means is that there is resistance to a "typical" (whatever that means) low AAM Nina state which would see the canadian trough dominate our pattern. Pacific convection seems intent on doing us favours this winter.

However there is a crunch point coming: is there enough momentum at the pacific equator to maintain this progress, especially given the sudden collapse at Xmas. CPC MJO report yesterday was quite bullish again about the strength of the re-emerged IO progression, but then again several of us were becoming confident that there wouldnt be a collapse last time. 

We cant be sure... but we can try and make an educated extrapolation. Getting technical again - cyclical nature of torques would suggest rising frictional and then mountain torque once again before mid month. This will help support favourable momentum budgets and if the cpc are correct in their view of the current MJO situation I'm going to put a small pot of gold down on the idea that sufficient momentum will be retained at the tropics to allow successful resistance of the canadian trough and heights appearing once again.

Timescale? Well - I said I didnt think much would change until 7th Jan. I've been proven a bit conservative on that because we have NWP suggestions of height rises coming into the reliable for 6/7 Jan on the back of GWO phase 3 progression (see GWO phase 3 composite below for guidance)

hgt500_21.png

 

but I dont think this is quite the endgame. In the 10 day range I would expect torques to rise again, and as a result the blocking pattern to strengthen rather than fade.

Weather on the ground? Height rises this weekend, perhaps a slight relaxation in that pattern in the days afterward, and then a renewed push for stronger heights and chances for more sustained continental cold and undercut scenarios from mid month.

Final point - there is no guarantee of this. The flip side is that if momentum stalls again, as it did at Xmas, then the canadian trough will regain the upper hand mid month and then late Jan will be wet and stormy, much as the weather is now at the moment.

Interesting thoughts Catacol. Not totally unlike GP's (though sounding a tiny bit more positive for cold in the D7-D14 period). Will be interesting to see if you have nailed it, especially since I see the ECM maintaining the possibility of a cold period without any break :) 

 

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Posted
  • Location: Frome 330ft ASL
  • Weather Preferences: Most(see in interests section.)
  • Location: Frome 330ft ASL

Looks like decent two day cold snap across south with high wind chill. 

 

Looking for to snowfall that comes out of this before mild pushes in fro southeast south.

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Posted
  • Location: North East Cotswolds, 232m, 761feet ASL
  • Location: North East Cotswolds, 232m, 761feet ASL
Just now, offerman said:

Looks like decent two day cold snap across south with high wind chill. 

 

Looking for to snowfall that comes out of this before mild pushes in fro southeast south.

It’ll be longer than 2 days whichever way it pans out - more like 4/5

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Posted
  • Location: West Ipswich, Suffolk
  • Location: West Ipswich, Suffolk

A great analysis there Catacol, good read for those learning.

Unfortunately 2 posts later contradicts everything you wrote (to be ignored peeps)

As it stands i see a confidence in a 4/5 day cold spell with fairly good potential for extensions.

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Posted
  • Location: Solihull, WestMidlands, 121m asl -20 :-)
  • Weather Preferences: Cold and Snow -20 would be nice :)
  • Location: Solihull, WestMidlands, 121m asl -20 :-)
11 minutes ago, Ali1977 said:

It’ll be longer than 2 days whichever way it pans out - more like 4/5

Weeks :clap:

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Posted
  • Location: oldham
  • Location: oldham

The GFS 06z Run has moved towards the ECM, But i usually find that all models converge on the correct solution by moving towards each other.

Battleground synoptics on offer from the Met Office Update the phrase (moves erratically Eastward) is good for large snowfalls in this setup.

Edited by frosty ground
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Posted
  • Location: Frome 330ft ASL
  • Weather Preferences: Most(see in interests section.)
  • Location: Frome 330ft ASL
17 minutes ago, ribster said:

You more or less said that already 2 hours ago, or did no one bite first time?

Apologies for double posting just excitement overtaking me i guess as haven't had any proper settled snow yet.

Edited by offerman
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