Model Output Discussion - 05/01/2016 18z onwards

[Hull snow]

18z charts going the right way early on thing could look even better by morning and there's still a long way to go in this yet but things on the up 

[MP-R]

7 minutes ago, Cheese Rice said:

Of course but the cold air doesn't look to get particularly entrenched in the south so an emphasis on marginal/wet snow if we see a favourable angle of attack. I think if we can get the cold air to really establish itself in the south then it's all to play for, but typically the south struggles in this regard unless it's cold air sourced from the east. 

... or proper cold air from the north. The problem shown by the models is that the flow is so slack so everything gets watered down too much. With a bitter flow from the north on a strong northerly wind, there would be no problem getting cold in and entrenched.

[damianslaw]

ECM evolution would maintain a cold theme across the country, a much drier one with a lot of surface cold and heights building into scandi which could easily pull in an easterly.

Its one option.

Is it a trend we shall see.

In the meantime it is a messy picture, the BBC have demonstrated this in recent long range forecasts, using the word 'hint' all the time, but nothing set in stone.

Its a tricky set up, prone to large margins of error - model performance at the moment has to be seen in this context - i.e. expect things to pan out differently as short term developments spring up out of nowhere making a mockery of longer range modelling - hence expect lots of swings in the 120 hr + range. Indeed best stopping looking any further than this range right now. I rarely ever look beyond 240 hours.

[Snowman.]

Just now, Hull snow said:

18z charts going the right way early on thing could look even better by morning and there's still a long way to go in this yet but things on the up 

They are on the up.

My memory is foggy but a cold spell in recent years also had a similar venture, all models on board for cold spell > nearly all models against cold spell > cold spell actually does happen. Not to say that this one will go the same way but as long as it's in FI and Op runs are still churning out different solutions there is still all to play for.

[Man With Beard]

17 minutes ago, Mucka said:

ECM London ensembles

Better than 00z off memory.

Mucka I don't think people have been  payimg enough attention to these. The main cluster has been cold for days, it was just above 0C this morning and it isn't far off zero again this evening. Interesting to see that the op run was very cold right to the end for London, too, not getting above 4C after D6. Not masses of scatter among that main cluster. 

The charts may not look so pretty now, but the cold is still there

[Weathizard]

After seeing those fax charts I'm even more confused now... I can only assume th MOGREPS and other restricted models we don't have access to are going against the messier evolution that has been predicted today by the GFS/ECM.

[Jason M]

Having looked through the GEFS out to day 9, my advice on this occasion is to completely ignore them. The mean charts are of zero value tonight. To sum the GEFS up I would simply describe them as chaotic.

Good luck to anyone making a forecast tonight!

 

[Yarmy]

4 minutes ago, Deep Snow please said:

To everyone saying it's only the GFS running towards mild - have a look at the ECMWF + 192 and + 216

 

Both those have entrenched cold 850s and would be cold down at sea level. They are also setting up a beast, but it's all moot anyhow as there's not a chance in hell of it looking like that tomorrow morning.

For all the uncertainty and messy synoptics, it's the gradual removal of HLB across much of the output that is of concern to me.  

[Nick F]

9 minutes ago, stodge said:

I'm not sure how "mild" these would be - going by 850s is a rookie mistake when considering winter anticyclonic features. Under clear skies, there would be sharp night frosts and the eventual re-location of the HP to Scandinavia at T+240 (not sure why you didn't post that chart as well) offers a tantalising chance at a continental drift which certainly wouldn't be "mild".

He posted the 500mb & mslp, the T850s still fairly cold with -5C line over UK, despite the yellows at 500mb. And agree sfc wouldn't be mild.

Edited January 8, 2016 by Nick F

[nick sussex]

4 minutes ago, karlos1983 said:

I'm amazed at those charts after today.

Sadly the second one is yesterdays! The first one isn't too bad but when the new T120hrs updates that will probably look more like the UKMO raw output. Anyway given the UKMO performance over the last few days the less said about it the better!

[Met4Cast]

3 minutes ago, Greenland1080 said:

The Indian model shows us all how NH Synoptics should look

Not too disimilar to tonights FAX charts actually. It's a shame Ian F isn't about, insight into where MOGREPS stands with this would be helpful 

[summer blizzard]

3 minutes ago, Nick F said:

He posted the 500mb & mslp, the T850s still fairly cold with -5C line over UK, despite the yellows at 500mb. And agree sfc wouldn't be mild.

Both 18z and Euro are likely still cold at the surface until at least next Sunday..

[weather eater]

Gosh it's been a while since I have posted in here, I've moved across the country from west to east, out of the rain, somewhat and what with one thing and another I haven't really had the time for NW. Obviously I keep up with the models and have a quick look at the thread if something interesting has been showing. So I've been following the thread for a few days now and I really cannot help noticing that the same mistakes are being made with this cold opportunity as with every other one over the last 10 or 11 years that I've been following the models and this thread. And it's this, synoptic projections evolve over time, each run has the latest data and every run is going diverge from the last, increasingly so from zero hour. There is no such concept of will this run verify, it's a meaningless idea. 144hr plus GHs or Scandia highs are just so much puff pastry, of little or no substance. A short wave here, a short wave there, features a 100 miles further north, south, east or West and what we get on our tiny spot on the edge of the Atlantic will change dramatically. It happens every run, every day of the week, all year round. But come a little offering of a bit of cold and snow and all too many people seem to expect it to just progress from 120 hrs plus to zero hour in a smooth and easy fashion like a boat on a mill pond. And when it doesn't  then they are disappointed and depressed, it never ceases to amaze me.   

My advice with this little cold spell is wait and see., it's certainly synoptically one of the most interesting evolving patterns I think I have seen for a good few years and it could go several ways, plenty to play for in my view and better than the dross of the last month. On the subject of the ECMs easterly, I've yet to see it spot one before the GFS does, still there is always a first time.

[Bristawl Si]

On 1/6/2016 at 6:05 PM, Greenland1080 said:

2 minutes ago, Daniel Smith said:

Not too disimilar to tonights FAX charts actually. It's a shame Ian F isn't about, insight into where MOGREPS stands with this would be helpful 

Into NEXT weekend and beyond nothing is certain - that's all i'm saying, having read Ian's latest post this evening.

 

[Nick F]

24 minutes ago, Earnest Easterly* said:

Fax charts

Day 4 -

Day 5 -

Battery about to die, looks good to me.

Looks like yesterday's 120 as should be Weds 12z  - today's updated 120 can be seen here

http://weather.noaa.gov/fax/otherfax.shtml

 

 

Edited January 8, 2016 by Nick F

[phil nw.]

You know in spite of the variations in every op.run today they all keep us cold to next weekend.

The ens. graphs have been rock solid for days in bringing the cold in by 12/13th and each op.run has shown this.

The pivotal time will be next weekend with the approach of that low from the sw.Depending on it.s track it could produce a snow event ,too far north will push the cold away.Further south we stay cold,hence the large spread in the ens.from day 7.

 

 

 

[Barry12]

Next Sunday looks very cold, maximum temps of 0-3C, northern England and Scotland not getting  above freezing...I wouldn't call that mild!

 

[Nick F]

8 minutes ago, Nick F said:

Looks like yesterday's 120 as should be Weds 12z  - today's updated 120 can be seen here

http://weather.noaa.gov/fax/otherfax.shtml

 

 

Here, similar to their UKMO global model, 528 dam across the south at least though

[Man With Beard]

The UKMO FAX chart doesn't look particularly west based -NAO to me. Greenland/Atlantic ridge appear to have some mileage? And a snowy low incoming for next Thursday

[Geordiesnow]

I think its looking more and more likely we will get a west based NAO now although detail wise its going to be sketchy over the UK thats for sure. 

I think it could be a case of trying to make the most of what we got and sometimes in these cases, snow potential could actually look better than perhaps the charts might suggest but I am disappointed at the way it turning out really, not in terms of how long it might last because that is still not certain nor has it ever been but I am dissapointen the short term that the trough over us just takes a age to move therefore delaying the cold air and modifying it as a result therefore making all the messy bit more marginal than it should be.

[Vince Coombes]

29 minutes ago, Weathizard said:

After seeing those fax charts I'm even more confused now... I can only assume th MOGREPS and other restricted models we don't have access to are going against the messier evolution that has been predicted today by the GFS/ECM.

They do my friend Tom C on TWO saying that 22 out of 23 mogreps runs continue the cold into next weekend .good to be back in the madhouse..lol.

[kumquat]

Interesting phenomenon that Azores Low. Courting both the build of HP into mid-Atlantic while dragging the flow of its predecessor parent low southeast like a magnet flipping poles, the two should be mutually exclusive yet are wholly entwined. I guess this is where energy splits and the reason why the vicinity houses one of the most pronounced features on the anomalies. Since it is happening now and enters the race at start data T=0, I’d suggest that we won’t get a grasp on it until transmissibility has completed. Somewhere mid-Atlantic, perhaps. The rest of the atmosphere can do as it wants, but in our neck of the woods, the outcome of this feature may well determine our fate.

[Daniel*]

24 minutes ago, Nick F said:

Here, similar to their UKMO global model, 528 dam across the south at least though

Cheers Nick for the direction, apologies for my error pity as that occlusion would have gave our region, London/SE a snowfall got me excited. Current T+120 looks quite a lot drier, a interesting day of model watching nonetheless. 

[Singularity]

14 minutes ago, Man With Beard said:

The UKMO FAX chart doesn't look particularly west based -NAO to me. Greenland/Atlantic ridge appear to have some mileage? And a snowy low incoming for next Thursday

There's a big difference to the raw model output (in general) that really gives me cause to wonder - there's no shortwave low south of Greenland. Given that it's evident at +96 is means they're seeing the shortwave moving south along the western flank of the trough rather than west under the high over Greenland.

It's almost as if the models are (in the  forecasters' belief) making a mistake in seeing a separate cell of high pressure over Greenland with the mid-Atlantic ridge detached. We know the high level of the Greenland ice sheet causes the models issues but could it lead to that sort of thing?

Imagine the mayhem on here if that turned out to be the case. Even if we did see that mysterious loss of negative AO we'd at least have a better outcome for next week in general. Speaking of which, I've been struggling to recall whether GP's 'torpedo' is expected to be the trigger for a neg. NAO to evolve with a neg AO already in place, or the trigger for the neg. AO with the neg. NAO following later? If it's the former then det. runs removing the neg. AO seem suspicious.

Here's hoping the weekend gives more than it takes in the world of model watching.

[Connor Bailey Degnan]

Looks like another night of waiting up to see if the gfs 00z delivers, got a good feeling about this one. ECMWF could be extremely interesting, will it continue the 12z run with bitter cold air close to us? Anything could happen after day 5. It's just a guessing game from there on tbh.