Model Output Discussion 01/09/17

[draztik]

4 minutes ago, J-Man said:

Did it snow in London one late October in maybe 2009/2010....can anyone find the chart, if they can verify that it did snow, so we can compare that to this potential cold snap.

potential. I've missed this word. Come Late February, I'll be sick sore and tired of it. 

[knocker]

I think I would take this evening's ecm. The HP to the west ridging NE around the perennial upper low to the south west and connecting to the Euro HP at T120 is sufficiently well aligned to push the trough dipping south east just a tad further east. Thus although it does initiate a northerly over the UK at T144 (and gales in the North Sea) this  quickly gives way to the high cell moving in from the west as the trough continues on it's journey into eastern Europe. Of course this different again to the previous run

[ANYWEATHER]

10 minutes ago, J-Man said:

Did it snow in London one late October in maybe 2009/2010....can anyone find the chart, if they can verify that it did snow, so we can compare that to this potential cold snap.

Hi Probably end of October 2008 and here is the charts to verify......

[ANYWEATHER]

And the gfs and ecm are on some agreement of a cold spell next weekend , Take the Seaweed out and put it outside and we may see what is going to happen...

Edited October 22, 2017 by ANYWEATHER

[damianslaw]

An interesting synoptical set up this week, with the models showing a marked about turn in things come the weekend, a slow moving warm front pulling in milder and milder air behind it, but only to come unstuck by a u-turn in the jetstream which will send it crashing back down SE, allowing much cooler air to filter in from the NW. Not often this happens..especially in late October.

As we head into November, signal for mid atlantic ridging and a NW-SE aligned jet, the ridge may build into the country to produce some calm chilly conditions at times before the trough anchors down on it from the NW, the wettest weather reserved for the north and north east in such a set up. More importantly it will allow a significant colder pool of air to develop to the NE and I suspect a rapid advance of snow cover into NE Europe.

 

 

[knocker]

Not a bad fit with the MJO phase 6/7 and the anomaly at the moment

Edited October 22, 2017 by knocker

[northwestsnow]

GFS0Z is lovely for those wanting rid of this mild airmass!!

Nice Greeny block and cold air moving south to bring a cold start to November and a cold bonfire night for many, can we get a nice seasonal guy fawkes weekend where scarf and gloves take the place of rain coat and wellies!!

One has to say tis a shame its not 4 weeks down the line but even in early November i would suggest this setup could produce snow for higher parts of Scotland..

And sure enough.

Edited October 23, 2017 by northwestsnow

[knocker]

Following on from the post above last night's NOAA, GEFS and EPS anomalies are in pretty fair agreement. Alaska ridge and cold trough mid North America upstream  and in the Atlantic our faithful cut off upper low to the south west flanked by ridging either side and not the forget the important trough Scandinavia and eastern Europe. This portend a north westerly upper flow and cooler unsettled weather over the UK the detail of which, to be sorted by the det. runs, depending on the precise alignment of the Atlantic trough/HP.

A rough overview of today splits the UK down the middle longitudinally, dry in the east with cloud and rain in the west. This will slowly reverse as the fronts track east during the day although later more cloud and rain will move into the south west which will move a slowly east and north tomorrow. A fair range of temps but above average, particularly in England and Wales.

By 12 Wednesday the upper trough to the west has split and the beginning of what was mentioned above, the interplay and jockeying for position of energy emitted upstream and the Atlantic trough/HP, Thus on Wednesday there is a surface low  to the NW of Scotland, another to the south west of Cornwall and the high pressure pushing into England and Wales, Over the next 48 hours the the low to the NW clears out of the way, the mid Atlantic low develops whilst at the same time the high pressure to the west ridges NE around it ensuring quite calm and dry weather for all of the UK apart from the far north

This configuration forces the strong jet running east around the high pressure to turn south further east and thus the troughs follow a similar course will not impact the UK except perhaps Scotland and the north leaving the rest of the UK dry with not much wind with temps around average. But this is knife edge stuff and minor adjustments could still alter this and of course this is just one model

[bobbydog]

not too often you see a chart like this for the 2nd of November....

[knocker]

In general the ecm follows the gfs and the above anomalies becoming unsettled with temps dropping to average or below in the northwesterly upper flow towards the end of the ten day period.

 

[Singularity]

So the first northerly teaser of the season has been adjusted largely or entirely (depending on the model) east of the UK,  which I expect comes as little surprise to many who have battled through the last few winters. Good agreement in the EC ens. for settled conditions to predominate early next week, before much uncertainty arises over and a little east of the UK and the mean ridge shifts west, illustrating - as can be seen from other sources - the potential for a trough to drop down closer to our east in the 9-10 day range. Question is - will the same adjustments take place with time as seen with this weekend? This time we have the northerly signal coming forward from the long-range rather than appearing suddenly in the mid-range, so it's not the same situation as such... interesting times, although not very much so (at this stage at least) if you live way down south.

 

 

[Snowy Hibbo]

So a little update on the climate drivers.

This community should be aware of the Phase 6 MJO, occurring currently. This is a BOM RMM index.

As some may know, MJO Phase 6 + about 10 days, correlates with a -NAO. So the correlation would expect a -NAO around the 30th of October- 1st of November, based on current forecasts (referencing the EPS RMM forecast below).

Looking at NAO forecasts, GEFS shows the NAO diving, along with the EPO, towards a negative phase in the next day or so. During the MJO analog driven -NAO forecast period (30/10-1/11) occurs, the GEFS NAO forecast shows the negative NAO weakening to neutral, rather than the peak of a -NAO, as the MJO analogs would suggest. Anyway food for thought.....

 

I tried to get some of my contacts to give me the EPS NAO data, but I couldn't get it unfortunately.

However I do have the CFS long range 90 day forecast for the NAO.

It shows the negative peak of the NAO during the next negative phase to around the 30th of October, in contrast to GEFS which shows it to be the 26th of October. After the negative phase ends, CFS suggests a neutral NAO for the rest of November.

In summary, the NAO is forecast to go negative in the next few days. The peak of the -NAO is forecast to be the 26th of Oct by GEFS and the 30th of Oct by CFS. The MJO favours a -NAO peak between the 29th of October and the 2nd of November. But it looks like the MJO for the most part helps support the incoming -NAO IMO. 

 

A look at the latest EPS Control. A handy reference below.

The EPS Control 5-10 day outlook. Some of the jetstream makes a weird deviation down to that lower height anom, but the main portion of the jetstream comes right over the UK, brings a good first proper 'winter storm' and quite cold weather. You can see a fairly large Atlantic influence, but also an Arctic influence IMO, as the jetstream streams across Greenland and Iceland.

Then you have what looks a bit like a Atlantic Ridge pattern, but what could also be interpreted IMO as a +NAO pattern, with a fairly strong jet. I will have to double check the EPS jetstream zonal wind anomalies tomorrow to confirm that strong jet. Anyway the ridge is over the UK and you can also see Scandinavia troughing. Could be an interesting situation.....

Anyway, hope that was somewhat interesting. Thanks. I will post the EC Weeklies run tomorrow if there is interest.

[Man With Beard]

It's hard work getting a North-Atlantic ridge / Scandi trough from a standing start. Consider the progression of the two ECM clusters from T192 to T240. Not enough amplification between Greenland and Canada and it's back to a Euro High. However, 31 out of 51 members go for the northerly.

  

[karlos1983]

28 minutes ago, Man With Beard said:

It's hard work getting a North-Atlantic ridge / Scandi trough from a standing start. Consider the progression of the two ECM clusters from T192 to T240. Not enough amplification between Greenland and Canada and it's back to a Euro High. However, 31 out of 51 members go for the northerly.

  

It will be interesting to see what happens. Really need to see that dirty euro high disappear, but does have the feeling of Déjà vu about it 2016/17 kept promising height rises to the North that never materialised.  

[geordiekev]

8 hours ago, bobbydog said:

not too often you see a chart like this for the 2nd of November....

 

On 11/9/2016 at 08:05, geordiekev said:

Just wow,  I'm so excited this year I have to say...

No but we had this November 9th last year so not that improbable. 

Edited October 23, 2017 by geordiekev

[SMU]

A classic block in exactly the right place for early November

The 552 Line wayyyy up over western Greenland - allowing for a surge south of the early season polar air- all in time for November 1st...

Great to see however at 192 its outside of any total reliable frame- although consistency is generally good from the GFS

awaits weds for UKMO to start to come on board...

[mountain shadow]

1 minute ago, Steve Murr said:

A classic block in exactly the right place for early November

The 552 Line wayyyy up over western Greenland - allowing for a surge south of the early season polar air- all in time for November 1st...

Great to see however at 192 its outside of any total reliable frame- although consistency is generally good from the GFS

awaits weds for UKMO to start to come on board...

Shades of late October 09 which delivered early season snow  here, and we know what followed after!

[booferking]

Pretty tasty Northerly if the GFS is to be believed .  Hopefully we can get these chart in the more reliable frame 

[feb1991blizzard]

Beaten to it so wont post charts, I was just about to say ' hello 17th Dec 2010 in early Nov 2017'!

[tight isobar]

Setting up-first notable arctic outbreak...

Decent synoptics...

And early in too....

Northern hemisphericaly' looks like a decent chance of pressure on the vortex....

A good start !!!

Further down the line.

Eye catching waa at russian quarter! 'Teased'last season perhaps a real game player 'this time'.....goi g forwards?!

Edited October 23, 2017 by tight isobar

[Allseasons-Si]

The GEM smelling the coffee too,aaah!!

so some consistancy creeping in

so is the gfs following the 06z control

Edited October 23, 2017 by Allseasons-si

[Allseasons-Si]

37 minutes ago, mountain shadow said:

Shades of late October 09 which delivered early season snow  here, and we know what followed after!

Wasn't it October 2008 MS?

Edited October 23, 2017 by Allseasons-si

[Polar Maritime]

Stronger High Pressure pushing up into Greenland on this evening GFS leading to a stronger Northerly flow into Wk2, The PV continues to look disturbed into the run with more warmth being pumped into the Arctic.

[Allseasons-Si]

31 minutes ago, feb1991blizzard said:

Beaten to it so wont post charts, I was just about to say ' hello 17th Dec 2010 in early Nov 2017'!

I couldn't find the analysis chart but found the earliest one for that day,that will take some beating

 

Edited October 23, 2017 by Allseasons-si

[Allseasons-Si]

12 minutes ago, Polar Maritime said:

Stronger High Pressure pushing up into Greenland on this evening GFS leading to a stronger Northerly flow into Wk2, The PV continues to look disturbed into the run with more warmth being pumped into the Arctic.

What ever is happening,somethings got to give,latest control run