Model Output Discussions 06z 04/11/16

[karlos1983]

My my, what a run from the gfs 06z. Awesome stuff and entirely plausible which makes it even more fun.

Very big ECM update this evening, I'd be massively surprised if it goes against the tide after the brilliant updates from Ian, Tamara, GP and the mighty gfs 06z 

fun times ahead fellow coldies!! 

Gfs 06z looking at the ensembles is a bit of an outlier you could say, but it's not on its own and wasn't the coldest either. 

[nick sussex]

The good thing about the outputs is that mid Atlantic high pressure and troughing over Europe isn't built on dodgy foundations. By that I mean they've picked out solutions that aren't backed up by background data and of course GP has made a detailed post highlighting that our foundations at the moment don't look like crumbling.

Of course nothing is certain in weather and you need a bit of luck with where any blocking sets up. This is indeed a rare sight for November in terms of zonal winds, normally we see these accelerating but as you can see how weak these are :

If you look at the NCEP monthly forecast for the USA it does give support for downstream changes that are condusive for colder conditions in western Europe:

AN AMPLIFIED RIDGE IS FORECAST TO DOMINATE THE CIRCULATION OVER THE CONUS FOR
THE FIRST 7-10 DAYS OF THE MONTH, WITH MUCH ABOVE-NORMAL TEMPERATURES FORECAST
OVER NEARLY THE ENTIRE CONUS. OVER THIS PERIOD, POSITIVE TEMPERATURE ANOMALIES
COULD EXCEED 15 DEGREES F ACROSS PARTS OF THE NORTHERN PLAINS. THIS RIDGE IS
FORECAST TO RETROGRADE DOWNSTREAM OF AMPLIFIED TROUGHING NEAR THE ALEUTIANS
HEADING TOWARD MID-MONTH. THIS INTRODUCES MORE UNCERTAINTY IN THE TEMPERATURE
OUTLOOK OVER THE EASTERN CONUS, WHERE NEAR- TO BELOW-NORMAL TEMPERATURES ARE
POSSIBLE AT TIMES.

MORE INTERESTINGLY, AN AMPLIFIED MJO EVENT IS FORECAST BY DYNAMICAL GUIDANCE
OVER THE NEXT TWO WEEKS. WITH THE SUPPRESSED PHASE FORECAST OVER THE INDIAN
OCEAN, THIS INCREASES THE ODDS OF A COLDER SOLUTION ON SUBSEASONAL TIME SCALES
ACROSS THE CENTRAL AND EASTERN U.S.

That sort of pattern for the USA, so you have amplified troughing near the Aleutians, amplified high pressure central USA, amplified troughing in the east, this correlates with high pressure mid Atlantic. Its also good they talk about the MJO because that also supports the colder outlook for the UK.

 

 

Edited November 10, 2016 by nick sussex

[Nouska]

1 hour ago, BLAST FROM THE PAST said:

I storngly feel / believe that blocking will appear after this disruption by a displaced PV next week as we get to the last week of Nov and carrying through going into early Dec .  I have it to our NW too.  Be interesting to see where GLOSEA5 has it 

 

BFTP

This is where today's JMA sees it.

Still looking at 1976, putting some more flesh on the bones and taking MJO forecast into account.

The MJO phase December 1976 - the same as currently forecast - some cracking examples of Atlantic amplification in the archives to demonstrate the point GP was making. Also some indication of where the JMA 3-4 weekly might not be far off the money if all goes as currently proposed.

http://www.meteociel.fr/modeles/archives/archives.php?day=1&month=12&hour=0&year=1976&map=4&region=&mode=2&type=ncep

 

Edited November 10, 2016 by Nouska

[bluearmy]

The bias corrected gefs is continually building heights to our ne in comparison to the non BC mean later week 2

 

[nick sussex]

Just now, bluearmy said:

The bias corrected gefs is continually building heights to our ne in comparison to the non BC mean later week 2

 

Good news that should lock in the troughing over Europe. This looks great news for the ski resorts who could well have an early start to the season and should build up a good base compared to last season which had a terrible start.

[bluearmy]

3 minutes ago, nick sussex said:

Good news that should lock in the troughing over Europe. This looks great news for the ski resorts who could well have an early start to the season and should build up a good base compared to last season which had a terrible start.

If it's right nick ..........

[nick sussex]

3 minutes ago, bluearmy said:

If it's right nick ..........

Lol! yes of course. The outputs can find a way of striking back quickly to deflate the mood in here so best to be just cautiously optimistic rather than me ramping up things too much.

[titchjuicy]

2 hours ago, Frosty. said:

Arctic incoming, Iceland taking a pounding from snow showers and northerly gales..come to the uk  meridional

Frosty, i've never hoped that you and the models are right more!  I'm off to Iceland on the 24th. I want two days of heavy snow followed by completely clear skies for the old Aurora Bozza-arlis

 

Sorry for going off topic mods.

[Jimmyh]

Welcome back Mr Sussex!!!!!!

[nick sussex]

1 minute ago, Jimmyh said:

Welcome back Mr Sussex!!!!!!

Thanks. I normally re-appear during November. Hopefully we can banish memories of last winters sad attempts at any cold and snow.

[Frosty.]

49 minutes ago, nick sussex said:

 Hopefully we can banish memories of last winters sad attempts at any cold and snow.

Yes Nick it was tragic and pathetic wasn't it..anyway, signs are good for plenty of cold air from the nw from later next week. And its not all doom and gloom before then either as we will see occasional frosts and even some freezing fog.

Edited November 10, 2016 by Frosty.

[nick sussex]

18 minutes ago, Frosty. said:

Yes Nick it was tragic and pathetic wasn't it..anyway, signs are good for plenty of cold air from the nw from later next week.

I think tragic and pathetic are perfect terms to describe last winters attempts at  anything remotely cold. In light of this it will be interesting to see what happens to ENSO,currently we're trending to a weak La Nina. The interest around this is the impact on the MJO, the MJO composites we see are often a little too blunt. The MJO is very much effected by what ENSO is doing, this was the subject of many of my posts last winter which I'm sure bored the pants off many, so I left behind my obsession with shortwaves and moved onto the MJO!

So by popular demand or not as the case maybe we're back to the MJO!

For people intererested or who need to get out more like myself I'll provide this link to some fascinating research on the MJO:

http://journals.ametsoc.org/doi/full/10.1175/2010JCLI3446.1

The research amongst other things concludes that the MJO effect on the NAO is greater during La Nina. At the moment we're not technically in La Nina but we're heading towards it but its expected to be a weak event. Indeed a La Nina developing this late in the season apparently hasn't been observed since 1980.

PS Section 4c is of particular interest as it discusses differences we might see compared to the normal composite in terms of especially the degree of amplitude in any troughs/ridges.

 

Edited November 10, 2016 by nick sussex

[Frank Trough]

17 minutes ago, Frosty. said:

Yes Nick it was tragic and pathetic wasn't it..anyway, signs are good for plenty of cold air from the nw from later next week. And its not all doom and gloom before then either as we will see occasional frosts and even some freezing fog.

It wasn't even a good winter in deep FI or deep among the 18z ensembles at t+384.

In the meantime, the colder flow is creeping nearer and nearer the "reliable timeframe" again.

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

 

Genuinely, quietly excited now.

 

 

[stodge]

A rare opportunity for me to offer my tuppence worth on the models and where we might be going in the next week to ten days and like everyone else the immediate thing to say is the vast difference in the hemispheric, stratospheric and tropospheric profiles between this year and the immediate two or three. My recollection of November 2015 was of a long period of HP dominated weather with the HP to the south or south west feeding in a long fetch SW or WSW'ly flow.

This was the 06Z OP from 10th November 2015 and that's about as zonal as it gets with the jet well to the north, the PV nicely set up above Greenland and Canada and the HP extending into Europe.

As the song says however "that was then but this is now".

I don't like looking too far into FI - my line is usually 168 and I'll kick off with the ECM 00Z OP for that time which is the early hours of next Thursday (the 17th):

The core of the PV appears to be over Scandinavia and while there's a residual secondary LP over Iceland, the flow is PM from the west. Pressure is high to the south but the Azores HP has retrogressed WNW leaving the obvious possibility of a connected mid-Atlantic ridge turning the airflow more north of west. The south still has some warmer air though the north is in a cooler regimen with showers already spreading west to east.

GEM at the same time:

Very similar and not much to add in all honesty.

GFS 00Z OP at the same time:

Something a little different and arguably less amplified. The Azores HP seems pretty well placed but there is a hint of ridging to the far west just off the coast of eastern Canada but one or two of those shortwaves which make the model forecaster's task so much more difficult. The incoming ridge might mean a fine day but the following trough promises wind and rain especially for the north the PV is yet to fully clear Greenland.

I know I shouldn't but as we have it here's the GFS 06Z OP for T+162:

Subtle changes as you might expect and perhaps a nod toward ECM/GEM in terms of the mid-Atlantic ridging but the main Azores HP remains oriented toward the British Isles and Europe. The lobe of PV energy moving from Greenland east is introducing colder air into the UK on a strengthening W or WNW flow.

The Control not too different:

Plenty of agreement across the Ensembles to my eye - here's one for you all to enjoy (P4):

A tad brisk as you might say. Plenty of interest in FI especially as both the OP and Control are well away from what you might expect from late November but that's a very long way off and I'll leave the commentary on that to others at this time.

My forecast for next week is broad terms is a gradual deterioration from a benign early part with some quite pleasant late autumn conditions in the south on Monday and Tuesday to a more Atlantic-influenced regimen by Thursday and Friday as the winds back more West and eventually North-West.

[Mucka]

Some brilliant technical posts in here today from the usual suspects (I won't name names for fear of leaving someone out) so forgive my layman speak.

Personally I still believe any milder weather over the next week will be a blip rather than a precursor to a fully mobile pattern change.

We have steadily seen the output firm up on moving a deep trough East that digs into NW Europe, though ECM was surprisingly flat through the mid term this morning with its demolishing of Scandi heights. That will probably be wound back somewhat this evening and anyway the more relevant piece of the puzzle, the jet digging SE in FI, was intact.

GFS ensembles appear to be firming up on a chilly NW flow becoming established around the 17th/18th so snow on hills again around this period. That takes us through to around the 20th where pressure patterns can be reasonable forecast in broad terms as they relate to local weather conditions on the ground. Probably a period of near normal temperatures thereafter as we hopefully start to see blocking develop with the reappearance of the Atlantic ridge the form horse. Other than another brief chilly snap just after mid month we could well see a cold spell proper before November is out but that is way beyond the shores of FI even, let's see if we can get this blocking consistently modeled first. 

 

Edited November 10, 2016 by Mucka

[Ali1977]

Nice UKMO at 144 with things going to plan and similar to the GFS 06z.  GFS seems to be stuck at 108 on meteociel.

[Ravelin]

2 minutes ago, Ali1977 said:

GFS seems to be stuck at 108 on meteociel.

Yeah, that's cos it's collapsed with shock at the later output, hopefully.

[gottolovethisweather]

6 minutes ago, Ali1977 said:

Nice UKMO at 144 with things going to plan and similar to the GFS 06z.  GFS seems to be stuck at 108 on meteociel.

 

Yep, echoed my thoughts as well, I was ahead of myself on last night's post as it is tomorrow's UKMO t+144 which is what I want to see but it's today's D7 (17th) on the ECM which will be equally important., Slowly does it, bound to get some backwards steps again soon but the overall picture for the 2nd half of November is setting up nicely for coldies if you ask me.

Edited November 10, 2016 by gottolovethisweather

[feb1991blizzard]

6 minutes ago, Ali1977 said:

Nice UKMO at 144 with things going to plan and similar to the GFS 06z.  GFS seems to be stuck at 108 on meteociel.

174

[Mucka]

GEM an improvement but still a toppler.

[Ravelin]

GFS blowing up one of it's trademark dartboard lows off the tip of Greenland starting at d7. Looks too extreme to be a probable evolution.

General theme seems to remain though, Azores high retreating at around d6, allowing heights to drop and a NW flow.

Edited November 10, 2016 by Ravelin

[Ali1977]

GFS quite different this run, some big hopefully unrealistic low pressures spinning up in Canada and Greenland and in turn powering up the Jet stream, not sure it looks right but you never know.  I imagine the ECM will be different again later. 

 And still we have no real idea what is happening in 10 days time.  

Personally I'll just be happy if these ECM monthlies follow the GLOSEA signal for blocking, then it's just a waiting game hopefully.

Edited November 10, 2016 by Ali1977

[marksiwnc]

1 minute ago, Ravelin said:

GFS blowing up one of it's trademark dartboard lows off the tip of Greenland starting at d7. Looks too extreme to be a probable evolution.

Ian f did say that there could be a few windy spells before the transition. this could be what he had in mind maybe?? 

[Mucka]

3 minutes ago, Ravelin said:

GFS blowing up one of it's trademark dartboard lows off the tip of Greenland starting at d7. Looks too extreme to be a probable evolution.

The general theme is okay though with the upstream pattern becoming increasingly amplified in line with some of our resident experts expectations.

Edited November 10, 2016 by Mucka

[Methuselah]

But should it swing SE, it might turn into a 'snow hurricane'? What's more it might end up in the North Sea...So, on balance, a good outlook still...