Model Output Discussion 17th Dec.2013-12z onwards.

[johnholmes]

SW will hopefully be large enough over Greenland and Newfoundland to disrupt the polar vortex. If we are really lucky, it will split it, then we should prepare for a colder second half of January with the S word creeping into the forecast. Until then, the models will continue to churn out atlantic storms and mild weather. Poor wildlife, the animals and insects think it is spring.

SW please?

[IDO]

SW please?

Strat warming.

[johnholmes]

BOOM...

 

h500slp.png

 

 

....and mild as hell. 

 

Ian

 

and in another attempt to show what the actual model is showing here are the maximum temperatures, only the far south really mild although nowhere is cold by Met O definition away from the far north of Scotland?

http://www.wetterzentrale.de/topkarten/fsavneur.html

[Nick L]

SW please?

 

Stratospheric Warming maybe? I'm sure there are plenty of good posts in here, it's just that they are buried under acronyms and made up terms!

[johnholmes]

Strat warming.

thanks for that  mate

 

why the heck cannot the actual words be written in the first place please?

[bobbydog]

if you look at there monthly outlook it has updated which it does every Monday and it says those wanting cold and snowy conditions it doesn't look good

 

nope... i've read it several times and i can't see that line anywhere.....

[johnholmes]

nope... i've read it several times and i can't see that line anywhere.....

 

it is in the BBC monthly forecast and why that is different when both versions come from staff at Exeter is beyond me. If I had the patience I would send an e mail and ask.

Edited December 30, 2013 by johnholmes

[lassie23]

Sorry John, that's me being lazy. Indeed, stratospheric warming. Last year we had sudden stratospheric warming that brought us cold and snow, this years is slower, can it still produce the goods?

[bobbydog]

it is in the BBC monthly forecast and why that is different when both versions come from staff at Exeter is beyond me. If I had the patience I would send an e mail and ask.

 

thanks john. it somewhat contradicts what the Met Office website says-

 

"

UK Outlook for Tuesday 14 Jan 2014 to Tuesday 28 Jan 2014:

Current indications suggest the unsettled start to January is more likely than not to persist through the middle to latter part of the month. This would mean spells of dull, wet and windy weather alternating with brighter but colder and showery periods, including some wintry showers. Some signs are also emerging to suggest temperatures being less mild in general terms than during the first half of January, with the possibility of colder weather later in the month."

 

which is a good summary of the current model output, including the possibility (as discussed in detail on here) of a change to colder conditions by the end of the month

[bradymk]

it is in the BBC monthly forecast and why that is different when both versions come from staff at Exeter is beyond me. If I had the patience I would send an e mail and ask.

I'm not entirely sure but i believe the BBC Monthly Outlook uses just the ECM 32 Day whereas the MetOffice extended outlook uses the 32 day alongside some of there other models (MOGREPS-GEO4 etc) to get a more detailed picture? Im not sure though so hopefully Ian F is around to answer as it is a bit strange that the outlooks differ like that

Edited December 30, 2013 by bradythemole

[Summer Sun]

I'm not entirely sure but i believe the BBC Monthly Outlook uses just the ECM 32 Day whereas the MetOffice extended outlook doesnt always follow just the 32 day if some of there other models (MOGREPS-GEO4 etc) show something different? Im not sure though so hopefully Ian F is around to answer

 

This is taken from the beebs monthly outlook page right at the bottom

 

The weather beyond about a week ahead stretches even the most experienced weather forecaster. Complex numerical weather forecast models from the Met Office and the European Centre for Medium-Range Weather Forecasts (ECMWF) are run many times for the month (and season) ahead to build up a picture of the likelihood of different weather types affecting the UK.

 

Looking at the ensembles there are some promising signs from the 8th of Jan with rainfall finally easing giving places time to dry out after a very wet few weeks

 

 

Temperatures out to mid Jan never look too far away from average

[phil nw.]

The fax charts for the next few days sum up the outlook for this week and probably beyond as well.

 

A couple of images below show the persistence of low pressure in the eastern Atlantic feeding the south westerly winds across the UK with frontal bands of strong winds and rain moving through from time to time.

 

 

A very persistent setup so far this Winter and it looks likely to continue into the first week of January with mean outputs supporting continuing low pressure close to the UK feeding of the main core of the Greenland/Canada vortex.

 

 

Some mountain snow likely in Scotland where somewhat colder air mixes in at times outside any warm sectors but nothing out of the ordinary for a UK Winter.

I wish i could see signs of a change but nothing really new is promised by the looks of the current runs.

The main interest for weather watchers presently continues to be for any gales and heavy rain.

[forecaster]

Oh okay thenWrong! There are a lot of lurkers in this thread who will quite understandably take charts at face value. Unlike your rather rude and aggressive post I was at least discussing the model output. By all means disagree but its posts like yours that deter people from posting in here.

Yes, and referring to the original post, the model is not really an "algorithm".

[Summer Sun]

Latest NAO update continues to suggest it staying around neutral during the first part of January 

 

 

Latest AO update stays negative for the opening few days of January after this we have a lot of scatter

 

Edited December 30, 2013 by Summer Sun

[UV-RAY]

I'm not entirely sure but i believe the BBC Monthly Outlook uses just the ECM 32 Day whereas the MetOffice extended outlook uses the 32 day alongside some of there other models (MOGREPS-GEO4 etc) to get a more detailed picture? Im not sure though so hopefully Ian F is around to answer as it is a bit strange that the outlooks differ like that

Well that would explain why the discrepancy then, as the ECM32 are pointless after 15 days regardless of some defending them.

[bradymk]

Well that would explain why the discrepancy then, as the ECM32 are pointless after 15 days regardless of some defending them.

Not backing the ECM 32 up, but to be fair, are there any reliable long forecasting models out there at the moment? The ECM32 is not great but is the probably the best available for the timeframe it covers. The problem is rather that forecasting accurately past 15 days is still no where near as accurate as everyone would like and the models (EC 32, CFS, JMA) all reflect this and take the stick. Modern day society needs and wants more accurate longer range weather forecasts and Improving longer range forecasts is probably the next biggest milestone to be achieved in weather forecasting.

Edited December 30, 2013 by bradythemole

[nick sussex]

Afternoon all

 

Just catching up with all the outputs, the ECM is a step up in terms of cold potential compared to last nights 12hrs run, the GFS still underwhelms me.

 

Earlier there is a marked difference with how the big 3 deal with that low in the NE USA, the UKMO looks very much an outlier solution with that although NOAA in their state forecasts suggest a high level of uncertainty.

 

NOAA also comment on another chunk of PV dropping into the US plains from NW Canada, and another possible ne USA storm for next week, this will be the one that develops around 168 to 192hrs, this really is the crucial system because its how this interacts with the PV that will effect the ridge thrown ahead of it that buys some time for western Europe.

 

 

Essentially here its a simple question of whether any phasing takes places between the PV to the west and that low near the UK, its really down to that, we don't want any phasing and must have enough ridging between the two to stop that.

 

 

There  isn't really a middle ground solution here either because if phasing takes place this will pull a bunch of low heights east with it and the window to escape this zonal stalemate closes.

 

So I'm afraid we have all our eggs in one basket here, if this opportunity implodes then we'll have to wait for another and I'm sure patience amongst coldies is wearing thin.

 

I should add the ECM and GFS deal with the crucial low very differently, the GFS has no interaction with the PV, the earlier timeframe here does have a big impact in terms of the chance of the ECM trend verifying, the further south low pressure is over the UK the higher chance of success so keep an eye on this around the 144 to 168hrs timeframe, also the shape of any troughing, the round one shown in the GFS is a big no no in terms of success, you want some elongation of this and it to be as shallow as possible.

Edited December 30, 2013 by nick sussex

[UV-RAY]

Not backing the ECM 32 up, but to be fair, are there any reliable long forecasting models out there at the moment? The ECM32 is not great but is the probably the best available for the timeframe it covers. The problem is rather that forecasting accurately past 15 days is still no where near as accurate as everyone would like and the models (EC 32, CFS, JMA) all reflect this and take the stick. Modern day society needs and wants more accurate longer range weather forecasts and Improving longer range forecasts is probably the next biggest milestone to be achieved in weather forecasting.

Agreed, it is the probably the best out there and the odd time it has picked up on a trend, but we've still a long way to go yet in producing accurate LFR. The Strat thread is like a breath of fresh air come the  winter, it's not infallible but it's certainly the future of making LRF during the winter months.

Edited December 30, 2013 by Sceptical Inquirer

[phil nw.]

Just a reminder to stay on topic please folks.

A few posts have been removed which didn't add anything.

 

Thank you everyone.

[phil nw.]

SI/Lassie23,

 

Noted but posts have been removed now.

[lassie23]

Weatherweb tv mentioned a cold snap in the middle of January. CFS is going for one too, but a brief one which may be extended due to the predicted Stratospheric Warming. As long as I get a fix of ice and snow, then I'm happy. Those snowless winters with 14 degrees in February in the 1990's were awful.

[Mucka]

GFS 12z continues to reverse yesterdays trend of flattening the Scandinavian ridge and pushing energy NE through the region -  96h 12z comparisons today/yesterday (Incidentally, yesterday's 18z was flatter still)

 

 

Let's hope for more amplification upstream than previous runs.

 

Edit. mid term 144

 

Jet bucking over Canada and much more amplified with better ridging ahead - this is a trend we need to see continued and improved upon.

 

Edited December 30, 2013 by Mucka

[mountain shadow]

Out to six days so far on the 12z GFS and its wet and windy.

 

Looking from the NH view, it looks promising for a colder spell with heights pushing towards the Pole,Northern Greenland and Scandi with the core PV shifting back to central Canada.

 

http://cdn.nwstatic.co.uk/gfsimages/gfs.20131230/12/144/npsh500.png

Edited December 30, 2013 by mountain shadow

[nick sussex]

The GFS 12hrs run is still blowing up that low over the UK, but its much better upstream with more amplification, and better to the ne.

 

A small step to the ECM upstream but we need to see a shallower low over the UK.

 

If that pesky low was shallower and more elongated running ne/sw then I would wager we'd see a good outcome, it will be a close run thing here.

 

We must not see phasing with that low over the UK, if only the damn thing would just fill more quickly!!!

Edited December 30, 2013 by nick sussex

[Mucka]

The GFS 12hrs run is still blowing up that low over the UK, but its much better upstream with more amplification, and better to the ne.

 

A small step to the ECM upstream but we need to see a shallower low over the UK.

 

That would be nice and the trough digging deeper would also help but I think we may be about to see the first decent FI on an operational run for quite a while nontheless - we shall see. Either way it is heading in the right direction.

 

UKMO looks pretty poor in comparison. Scrap that decent FI for GFS, Atlantic ridge not strong enough.

 

Edited December 30, 2013 by Mucka