Model Output Discussion 29th December - Into mid-Winter.

[Nouska]

18 minutes ago, blizzard81 said:

Indeed. You wouldn't think it was the UK model would you? Seems more interested in the US. The UK hardly makes it into the map - ridiculous!

It is a tropical cyclone genesis view - NOAA and NHC don't focus on beasts from the east when hurricane forecasting, their interests are focused on ocean beasts.

Edited December 30, 2016 by Nouska

[Scandinavian High.]

Meto are saying north easterly is the most likely are they seeing something we can't maybe the gfs 18z will show what meto or seeing regarding a north easterly next weekend.

[LRD]

10 minutes ago, mountain shadow said:

Yes, it was posted a few pages back. Neg AO is irrelevant unless we get a neg NAO too.

Is that true?

A negative AO can lead to strong Scandinavian high pressure systems even with a positive NAO and lows over Greenland. It makes cold spells a little less likely without a negative NAO too, granted, but not impossible as long as the jet is pretty weak which (unless I've misunderstood things) it would be with a negative AO. Apologies if I have that wrong

Not sure if Feb 91 or Jan 87 had a neutral or positive NAO. Again, might be wrong

[bluearmy]

Going to make a brave call (not really) and say none of the models have the correct solution days 6-8. 

Ecm op is back to a hybrid version of what it showed between 36/48 hours ago. Gfs seems unsure of where it should be going. UKMO seems consistent but that's only to a degree. 

lets get the Azores low interaction with the northern arm modelled correctly (hopefully tomorrow) and then we will see if the northerly can still be backed far enough west to include the uk. Then it becomes Atlantic ridge, U.K. ridge, scandi ridge or sceuro ridge ??? 

[Rocheydub]

3 minutes ago, bluearmy said:

Going to make a brave call (not really) and say none of the models have the correct solution days 6-8. 

Ecm op is back to a hybrid version of what it showed between 36/48 hours ago. Gfs seems unsure of where it should be going. UKMO seems consistent but that's only to a degree. 

lets get the Azores low interaction with the northern arm modelled correctly (hopefully tomorrow) and then we will see if the northerly can still be backed far enough west to include the uk. Then it becomes Atlantic ridge, U.K. ridge, scandi ridge or sceuro ridge ??? 

Exactly what I was saying earlier. There is such a huge difference made by miniscule changes early on in the afternoon runs, that you'd feel that they are hardly nailed on, and this has a profound effect as the run progresses. I still doubt that we'll see the northerly that was predicted on the 7th, but I very much doubt that this pattern is set. The ECM is most likely outcome to my untrained eye, but just from experience watching charts roll out... Anything beyond 72/96 is FI until we see consistency in the major NWP's

[fromey]

NAO going neg but not as much as the AO

Edited December 30, 2016 by fromey

[MR EXTREMES]

31 minutes ago, Boro Snow said:

JMA still has a decent 2nd northerly around the 6/7th of January

Has it because I looked at the jma this morning and it was worse but that means 2 models have jumped ship that's the jma and gem just on this evenings run.

I think the ukmo is not dealing well with this situation remember it's very busy with vortex mostly on the eastern side of the Arctic.

The norm has been for more vortex over Greenland and western side of the Arctic.

[Ali1977]

ECM ENS at 120 looking a little iffy - I think

Wrong, looks great later on , better than GEFS

Edited December 30, 2016 by Ali1977

[Mark wheeler]

https://mobile.twitter.com/MattHugo81/status/814930508148834304?ref_src=twsrc^google|twcamp^serp|twgr^tweet

Some positive news I think .

Edited December 30, 2016 by Mark wheeler

[Iceberg]

Ecm mean at t240 is hardly warm. 

I have to say though that the models Do seem in a certain confusion ATM. 

[Ali1977]

Would love to see the control and look forward to seeing the extended looking at this .

Extended looking v good still

Edited December 30, 2016 by Ali1977

[Iceberg]

Unsurprisingly the largest spread in ens for the n.hemisphere is bang over us for the ecm ens. 

The 12 z has simply confirmed no answers are available 

[That ECM]

I get that it hasn't been as great today but it isn't this is it? Plenty of interest moving forward. 

Edited December 30, 2016 by That ECM

[mhielte]

4 minutes ago, Iceberg said:

Unsurprisingly the largest spread in ens for the n.hemisphere is bang over us for the ecm ens. 

The 12 z has simply confirmed no answers are available 

That isn't at all surprising. Our little island makes a big noise  

It's another reason why I'm staggered some can dismiss our cold prospects given the spread of options available. I'd love to be confident about our chances for sustained cold but it is impossible to be! Time to enjoy the New Year northerly and see what the models tease us with afterwards

[stewfox]

28 minutes ago, bluearmy said:

Going to make a brave call (not really) and say none of the models have the correct solution days 6-8. 

Ecm op is back to a hybrid version of what it showed between 36/48 hours ago. Gfs seems unsure of where it should be going. UKMO seems consistent but that's only to a degree. 

lets get the Azores low interaction with the northern arm modelled correctly (hopefully tomorrow) and then we will see if the northerly can still be backed far enough west to include the uk. Then it becomes Atlantic ridge, U.K. ridge, scandi ridge or sceuro ridge ??? 

Is this the low we need to watch ??

[EML Network]

I do love this forum, it amazes me that so many of us get caught up in the eye candy that charts POST +144 can sometimes churn out, for me the writing for a decent cold attempt was etched on the wall several days ago and when you  find that the charts that are showing a decent cold evolution always move  a day further away each day, then you find your always looking at charts between 168-268 (or further out), for a cold evolution. 

 

It's clear (at least to me) that after this weekend things are going to warm up slightly as we progress through next week. 

 

Then to me it looks like rinse and repeat again, I keep saying that were stuck in this pattern of MLB highs moving South East across the UK at a crawl and heading off into central Europe

since just before Christmas the models keep suggesting that one of these highs either links up with Greenland to form some sort of Omega block...Or moves North East into Scandinavia to for a Scandi High. 

 

But when it gets to within +168 on the charts we find that the highs simply continue their journey into central Europe and the pattern repeats

 

In fact RIGHT NOW, we're on the back end of one of these scenario's which has played out 4 or 5 times since the beginning of December

GOODBYE MLB High...ohh look there's the next one waiting in the wings !!

And where does THAT MLB High go ??

UKMO +120 has it to our South, 

I don't really tend to look into charts at +240 very much these days, but I know many of us do...so lets' look at the GFS Control at +240...

GFS CONTROL +240 ..doesn't that look familiar ???

 

Until I see this pattern disappear completely from the charts I'm not buying into an Easterly or North Easterly. 

 

Something will eventually give, but the longer this pattern repeats without being broken up by ridging to the North in some shape or form then it could be the job of the Atlantic...and then we'd likely be back to square one. 

 

Sorry...I know it's a bit of a doom and gloom post at a time where the charts are showing promise, but IMO that a chart full of promise is a far cry from a chart that I'm looking at to see WHERE the snow is going to be. 

 

Until I get to that point I find it hard to get excited about eye candy ...but it is nice to look at :-)

 

Happy 2017 to you all, let's hope I'm wrong and i'd be only too happy to eat humble pie whilst rolling in a 6 foot snow drift :-)

 

 

[Summer Sun]

 

[Glacier Point]

Well this is going to be an interesting standoff.

ops jumping around, but we have cmc, gefs and eps means all showing very coherent and cold solutions day 10 onwards, +ve height anomaly centred Iceland, becoming more Greenland over time as the North Pacific ridge retrogressive and pulls the core vortex with it. Cmc until now has been unconvincing on this.

It's worth noting that evolutions to cold patterns have not been straightforward, witness last November. Also problematic is the strong emphasis on the southern arm of the jet and rather diffuse northern arm (as has been the case all winter). Still not totally convinced by the Greenland bit, and would favour Scandinavia as the destination for ridge development. Interesting times, particularly coming against the wQBO / solar backdrop. 

[FetchCB]

1 hour ago, mountain shadow said:

Old data, before tonights runs. Will be gone by next update replaced by UK high cold.

Not so sure about that. Met Office use the models for guidance and the narrative that they publish is a consideration of the forecast team. If they believe that the models have issues then they use experience to guide their forecasting. What they do not do is jump around from run to run. You may be right in that the narrative will change but it is not a given thing just because the models are now saying something different. 

With the PV lobe over northern Canada it was always a big ask for the HP to reach up to Greenland but I believe someone said that the Iceland /Scandinavia area was a more natural home. The met office talk 9f North easterly which fit with this and the models may just be overreacting to the signals from the strat in sinking it southwards

Edited December 30, 2016 by FetchCB
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[bluearmy]

The eps post day 8 are pretty well back to where they were yesterday evening. 

A bit colder as the ridge is held a little further nw than 24 hours ago but not as far as the 00z run. So a middle ground found between the last two eps runs.

the control look ablot like the UKMO to our west day 5/6 and goes onto build a strong block to our wnw which goes up to Iceland (note the low temps into de bilt) and then sinks across nw Europe 

the background pattern remains the same, despite the melodrama with the Azores low in the short term - the casualty of those shenanigans likely to be a strong northerly or nor'easter for next weekend.

of course, another set of ops due within 12 hours !

[radiohead]

12Z GFS (P) is out. Weak ridging that is broken down by Atlantic lows bursting through.

[Ali1977]

1 minute ago, radiohead said:

12Z GFS (P) is out. Weak ridging that is broken down by Atlantic lows bursting through.

Chocolate fireguard ( must be) ha.

[snowking]

0z (Blue) vs 12z (Red) EPS (Note this is T2M max rather than average):

As Matt says, warmer in the mid range but pretty identical beyond that average wise, but notice the larger spread of the dataset on the 12z highlighting increased uncertainty

[snowbunting]

29 minutes ago, fromey said:

NAO going neg but not as much as the AO

Slightly negative NAO can still correlate to wintry outbreaks. I was having a look at NAO archives for some key snowy events. Some were even slightly positive. JAN 84 Was very cold and snowy with an NAO of +1.66, Jan 93 +1.6 Nly gales and blizzard conditions. +0.77 and +0.29 for Jan and Feb 1999 again some stonking cold outbreaks. So not bad news if it is slightly positive

[snowbunting]

2 minutes ago, snowking said:

0z (Blue) vs 12z (Red) EPS (Note this is T2M max rather than average):

As Matt says, warmer in the mid range but pretty identical beyond that average wise, but notice the larger spread of the dataset on the 12z highlighting increased uncertainty

Is it just my imagination or are the error bars much wider for the 6th than another other date?