Model Output Discussion 01/09/17

[summer blizzard]

While the Euro is less gung ho about it i think that both models agree on a generally cool and unsettled outlook heading into the longer term (probably too early for snow for most but sub zero uppers will deliver for hills and ski resorts will love the west facing slopes getting a good whollop).

The pattern at the start is essentially driven by a two wave amplification in both the Pacific and Atlantic however over time the Azores heads home (quite weak) but the Pacific High actually cuts off on both models keeping pressure high near the central Arctic. 

This remains the case right out to day 10.

 

[knocker]

A quick look at the ecm this morning albeit there no  great changes from the previous run.

By 12 Friday the high cell is over Ireland with the cut off upper low to the south west in mid Atlantic beginning to stir. But the high quickly comes under pressure from a trough tracking east via Iceland which is north of Scotland which initiates a fresh north west flow across the UK by midday Saturday. The low then intensifies and tracks swiftly SE to be over the south Baltic by 06 on Sunday as high pressure once again surges north to the west of the UK. This will veer the wind over the UK northerly but more to point bring gales to the North Sea.

The aforementioned high pressure then ridges briefly over the UK but a combination of the troughs tracking E/SE to the north west and the upper low to the south have split the high pressure and the next frontal disturbances impact Ireland Monday evening and with much more affect on Tuesday bringing heavy rain and strong winds particularly in Scotland.

The main low then again tracks SE into the North Sea over the next couple of days which once again veers the wind northerly introducing a cooler showery airstream. All pretty predicable.

[Ice Day]

Well *IF* the GFS is to be believed, the 0c Isotherm will be draped across the UK for over a week starting on the 1 November, so we should see some chilly temperatures.  Whilst not cold enough for snow in low lying areas, the Scottish ski resorts should get off to a pretty decent start to their season.  

What's noticeable is that on the face of it the charts seem to to scream cold, such as this at 192

However, as it's so early in the season the uppers aren't as cold as you would imagine, we get -6 uppers over Scotland for a very short time but nothing colder.

There just isn't enough cold air around to bring deep cold to our shores......yet.  All in all though, good early signs and reasons to be cheerful for the coldies on here.

 

Edited October 25, 2017 by Ice Day

[Northern Sky]

For those that know and can remember these things, I just wondered how similar the current set up is to November last year? Particularly the background signals?

The reason I ask is that last November we saw snow here in Leeds and I thought this is a great set up for the Winter to come. Of course then we hardly saw another flake for the rest of winter and no more lying snow.

Is there anything in the models to suggest this cold/cool snap will be anything other than a little blip before the PV gets organised and we are back to business as usual?

[KDME]

8 minutes ago, Northern Sky said:

For those that know and can remember these things, I just wondered how similar the current set up is to November last year? Particularly the background signals?

The reason I ask is that last November we saw snow here in Leeds and I thought this is a great set up for the Winter to come. Of course then we hardly saw another flake for the rest of winter and no more lying snow.

Is there anything in the models to suggest this cold/cool snap will be anything other than a little blip before the PV gets organised and we are back to business as usual?

Is there much correlation between years?  The atmosphere is a turbulent thing and a whole multitude of small changes can affect the bigger picture.  Bring into that climate change as well!

As humans, we like to bring order to chaos but I am now a big sceptic on possible outcomes based on yesteryear.  Always will be a case of look at the models in the very reliable timeframe.

[Summer Sun]

The Inverness snow row shows around a 43% chance mid next week

[weirpig]

Vortex  sliced in two    Some beautiful looking charts on the 6z  Then we end up with  cold air very close by in Europe   not a bad way to start in November

Edited October 25, 2017 by weirpig

[tight isobar]

1 minute ago, weirpig said:

Vortex  sliced in two    Some beautiful looking charts on the 6z

Text book cross-pole split.

V-good/favourable wave activity.....

 

[LightningLover]

Just now, tight isobar said:

Text book cross-pole split.

V-good/favourable wave activity.....

 

Maybe, just maybe, we could get a decent winter! 2010, anyone?

[LightningLover]

Or am I just dreaming?

[Polar Maritime]

Just discussion on what the Model Outputs are showing in here please, There are the Model ramp and winter thoughts/hopes threads already open for anything other.

Thanks please continue.

[Snowy Hibbo]

52 minutes ago, Northern Sky said:

Is there anything in the models to suggest this cold/cool snap will be anything other than a little blip before the PV gets organised and we are back to business as usual?

Very intriguing question.

Firstly I will show the modelling in a different light, compared to the determ models.

This is the NAEFS (North American Ensemble Forecast System) model, which is actually a combo between GEFS and GEPS. Comparing it to EPS, provides a very useful outlook IMO, especially for longer range modelling.

First the next 7 days worth of 500mb anomalies.

 Then the first 7 days of November.

Big contrast between the ridge influence in Wk 1 and then the cold snap/trough coming over in Wk 2. Lots of others have pointed this out, but just showing it a little differently.

 

Now for the question. 

The NAO is currently going into a negative phase. Beyond the 2-3rd Nov, it is expected to climb to positive neutral figures. I am not sure whether it is going to continue for a proper +NAO phase. 

 

The MJO is currently entering Phase 7. These phases (6+7) are deemed to the best for a -NAO(+10 days), which is occurring. The relationship with Scandi highs and Atlantic ridges and MJO is poor.

EPS and GEFS (Bias-Corrected) MJO RMM plots above. 

The EPS shows a rapid decline to neutral MJO during Phase 7. GEFS shows a slower decline, entering the neutral realm at Phase 1. POAMA and the Canuck models agree with EPS, JMA is in between the main models.

For longer range forecasts, the POAMA model provides a probabilistic (chance of MJO Phase) forecast for the MJO:

For 11-15 Nov, 50-70% Neutral, 10-30% Phase 3.

For 16-20 Nov, 50-70% Neutral, 10-30% Phase 1.

For 21-25 Nov, 50-70% Neutral.

For 26-30 Nov, 50-70% Neutral, 10-30% Phase 2.

Overall this means that MJO will likely remain neutral over November, and if it strengthens later in the month, it is likely to be in Phases 1-4. Which correlates with a +NAO(+10 days).

So in my opinion, we may see a +NAO setup come around in the 2nd or 3rd weeks of November (emphasis on the may). But I haven't looked at the PV, or any other climate driver, except for the MJO and NAO, in proper detail. It's kinda rushed, because it's getting late night here in Aus. I will have a proper longer range look tomorrow, provided the forum doesn't crash .

 

 

 

 

Edited October 25, 2017 by Snowy Hibbo

[captaincroc]

10 minutes ago, weirpig said:

Vortex  sliced in two    Some beautiful looking charts on the 6z  Then we end up with  cold air very close by in Europe   not a bad way to start in November

For me I just love the dark nights being cold and crisp, as the pas few years it's just been wet and mild.

I had a feeling this winter would start different, not that I'm predicting a 62-63 repeat, the feel of the charts looks far from normal which for me indicated there is more chance of the extreme happening one way or another. Yeah, not technical but with Ophelia etc the atmosphere seems from from it's normal state which is only a help rather than a hindrance.  Obviously it could, and probably will, be another mild, wet winter but as long as things seem volatile then that volatility could swing in our direction. Time will tell.  

Until then some nice seasonal weather to look forward too.

[Met4Cast]

I think the most important thing here is that whatever model you look at, Europe is about to turn decidedly cold. A problem we've had in the past few winters is that Europe (at least the West) has been rather mild, so whenever we did manage to scrape an Easterly it wasn't particularly cold. Thanks Euro High.

If we can get cold air into Europe and increase the snow cover, which it looks like we will, then we could be in a better position with heights being further North across Scandinavia this year. 

The continuous modelled splitting of the Vortex/Cross Polar flows is encouraging, but we did have the same kind of prospects this time last year and look how that turned out.

In the mean time - Turning cooler, perhaps colder into Early November with maybe some snow across higher ground in the North. It'll be nice to get some widespread frosts, though. There's a lot of spread on the ENS, but a small cluster getting close to that -10c isotherm which is interesting.. 

Edited October 25, 2017 by Daniel Smith

[Man With Beard]

After a day off, the ECM clusters are back online. No clusters suggesting anything exceptionally cold, TBH, but the Euro slug is definitely off the menu in the short-term.

[Summer Sun]

0C isotherm and wind gusts are now available on GEFS through meteociel

http://www.meteociel.fr/cartes_obs/gens_display.php?x=&y=&run=6&ville=Londres&lat=51.5085&lon=-0.12574&runpara=0&type=8&ext=1

Edited October 25, 2017 by Summer Sun

[weirpig]

Short Gfs Ensembles   all show a drop in Temps as we enter a new month

[MR EXTREMES]

1 hour ago, Daniel Smith said:

I think the most important thing here is that whatever model you look at, Europe is about to turn decidedly cold. A problem we've had in the past few winters is that Europe (at least the West) has been rather mild, so whenever we did manage to scrape an Easterly it wasn't particularly cold. Thanks Euro High.

If we can get cold air into Europe and increase the snow cover, which it looks like we will, then we could be in a better position with heights being further North across Scandinavia this year. 

The continuous modelled splitting of the Vortex/Cross Polar flows is encouraging, but we did have the same kind of prospects this time last year and look how that turned out.

In the mean time - Turning cooler, perhaps colder into Early November with maybe some snow across higher ground in the North. It'll be nice to get some widespread frosts, though. There's a lot of spread on the ENS, but a small cluster getting close to that -10c isotherm which is interesting.. 

Spot on look at how many garden paths we been up over the last few years or more.

But I suppose it's very possible what with hurricanes galore and east QBO and declined solar cycle perhaps just perhaps we maybe lucky.

I won't hold my breath though.

Although there's no doubt the Atlantic is not full on so far we shall see as we enter November let's hope split vortex might benefit towards a decent stratospheric warming event.

Already you can see with in 2 days the deeper cold further east.

Although frost and fog will feature which I think is better than blow torch winter.

[booferking]

GFS up to its all tricks again backtrack city lol,  first Northerly clips Scotland which was modelled and now the second Northerly which modelled to hit for days goes pete tong another clipper for Scotland and east coast

Up the GARDEN PATH WE GO

Edited October 25, 2017 by booferking

[weirpig]

4 minutes ago, booferking said:

GFS up to its all tricks again backtrack city lol,  first Northerly clips Scotland which was modelled and now the second Northerly which modelled to hit for days goes pete tong another clipper for Scotland and east coast

Don't know if it's a backtrack just a variatllon of the theme  that far out still subject to change  but yes northerly not as potent  what is encouraging from my perspective is the theme for recurring height rises toward Greenland  and the stresses being put on the vortex   Hopefully allowing something more potent to happen when the uppers are that bit colder 

[northwestsnow]

And to confound the misery it now looks wet weather pushing in just in time for bonfire night weekend, oh joy.

[booferking]

2 minutes ago, weirpig said:

Don't know if it's a backtrack just a variatllon of the theme  that far out still subject to change  but yes northerly not as potent  what is encouraging from my perspective is the theme for recurring height rises toward Greenland  and the stresses being put on the vortex   Hopefully allowing something more potent to happen when the uppers are that bit colder 

Yep hopefully it reverts back to Mondays run but cant see but you never know,  would settle for some dry cool frosty Mornings all the same under a nice high.

[I remember Atlantic 252]

I prefer top one (todays run), looks a lot dryer, Mondays run screamed wet through Cheshire Gap

[bobbydog]

garden path? backtrack? misery?....

we have recurring modelling of wave 2 activity, throwing warm air into the arctic, battering the vortex at an important time in its development-

and people are worried about missing out on a couple of sleet flurries in the midst of autumn??

reality check - this is great stuff to see.

i like my snow in winter. 'deep and crisp and even' etc... and if these patterns keep showing up, we just might get some!

[booferking]

1 minute ago, bobbydog said:

garden path? backtrack? misery?....

we have recurring modelling of wave 2 activity, throwing warm air into the arctic, battering the vortex at an important time in its development-

and people are worried about missing out on a couple of sleet flurries in the midst of autumn??

reality check - this is great stuff to see.

i like my snow in winter. 'deep and crisp and even' etc... and if these patterns keep showing up, we just might get some!

Lol i was having bit of fun chill.