Model Output Discussion 01/09/17

[Daniel*]

In the very near term for tonight, forecast minimums show a huge contrast between north and west and south and east. Scottish Highlands freezing while along the West Sussex coast a tropical 15C. 

[Derecho]

7 minutes ago, Ed Stone said:

But have you analysed the annual Yuletide shortage of balloon data, QS?

Not yet , that's for someone else I think thankfully .

For my research I look at how atmospheric circulation impacts regional climate, quite of bit of my earlier knowledge prior came from reading these forums over the years before I got deep into the studying .

[Frosty.]

From what I've seen on the models and read about (MO) the short / mid / longer range signal still has a wintry flavour to it with rain, sleet and snow, the snow especially on high ground and some clear / frosty nights..not bad at all for late autumn / early winter and there is always potential for significantly more wintry conditions to develop with a bit of fine tuning..not long before the colder air arrives!

Edited November 22, 2017 by Frosty.

[phil nw.]

The 06Z GFS  cuts a low across the Atlantic ridge at day 4 as do the other 2 but it still re-amplifies again next week also similar to the ECM and UKMO but not quite as much.

 

A look at the 06z graphs-C.England on the left- then C.Scotland

shows the Op is pretty much in the middle of the cluster with the usual up and downs as the colder/milder air masses pass through.

We do see GFS often correcting it's sometimes flat bias as we get closer but similarly the ECM can over amplify,especially past day7.The truth is we can't be sure for now which is nearer but they all show a similar theme of Atlantic ridging bringing polar air mainly from the north west over the top.

 

[winterof79]

Looking at the GEFS and the Atlantic high at 168Z ,the Control and quite a number of other perturbs have the high more robust and allowing nothing over the top

I have also included link for the 168 for the UKMO and if you click  on the other models at D7 they too say no to a sinking high scenario as only GFS has the milder air coming over the top.

https://ruc.noaa.gov/hfip/tcgen/

 

It will automatically take you to D2 on GFS ,then you can navigate to D7 and see the differences

 

 

Edited November 22, 2017 by winterof79

[Summer Sun]

Not a bad way to start winter for the Scottish Ski slopes

[swilliam]

15 minutes ago, winterof79 said:

Looking at the GEFS and the Atlantic high at 168Z ,the Control and quite a number of other perturbs have the high more robust and allowing nothing over the top

I have also included link for the 168 for the UKMO and if you click  on the other models at D7 they too say no to a sinking high scenario as only GFS has the milder air coming over the top.

https://ruc.noaa.gov/hfip/tcgen/

 

It will automatically take you to D2 on GFS ,then you can navigate to D7 and see the differences

 

 

Yes looking at those even the mean is better than the Op and all the spread is around the size of the ridge.

[phil nw.]

17 minutes ago, winterof79 said:

Looking at the GEFS and the Atlantic high at 168Z ,the Control and quite a number of other perturbs have the high more robust and allowing nothing over the top

I have also included link for the 168 for the UKMO and if you click  on the other models at D7 they too say no to a sinking high scenario

https://ruc.noaa.gov/hfip/tcgen/

 

 

The jet is actually running over the top-see the stamps-T168hrs same time. 

 

http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=3&ech=168

Bear in mind though that is a snapshot of just day 7 just about the peak of the second wave.If you look further on 24/48hrs in the gefs we can see the ridging toppling in various ways..

http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=1&ech=204

The main high cell drifting towards the Azores by then.Not to be taken as gospel by that stage of course but just to clarify what we are seeing.

Edited November 22, 2017 by phil nw.

[winterof79]

16 minutes ago, phil nw. said:

The jet is actually running over the top-see the stamps-T168hrs same time. 

 

http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=3&ech=168

Bear in mind though that is a snapshot of just day 7 just about the peak of the second wave.If you look further on 24/48hrs in the gefs we can see the ridging toppling in various ways..

http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=1&ech=204

The main high cell drifting towards the Azores by then.Not to be taken as gospel by that stage of course but just to clarify what we are seeing.

I suppose the stamps was not a great analogy of what I was trying to get over.

The D7 charts on my link ,however, I feel do show a resistance to the Atlantic and would allow a more Northerly/north Easterly flow which the METO may be leaning toward on their extended.

"Further showers or longer spells of rain, with some hill snow likely on Tuesday. By midweek, some organised rain is likely in the north and southwest at first, with possibly some hill snow. Elsewhere, a continuing mixture of sunshine and wintry showers, with some snow reaching lower levels later" 

Nice to be able to discuss the prospect so early.

[stewfox]

4 hours ago, Devonshire said:

ILast winter I discovered the 'ignore user' function (hover over a poster's info) - I soon moved up to 9 pages of ignored users!! It makes for a much less frustrating read - and much more informative when something is 'on the cards' and the forum comes alight.  (I also wonder if mods might consider adding a metric to posters' info-panels beside their posts, indicating how many members ignore them! - maybe a step too far?! - please feel free to 'ignore' me!)

 

9 pages on the ignore list..

I personally don’t like coming home to read one post in eight hours that would be depressing. I would assume a raging Bartlett High,  Ian Brown back to good form and no sub 10c CET any more in winter

Happy to read all levels of the debate

The GFS 6z is clearly a back track with 12z GFS awaited. As we don’t have cross level model agreement 12z GFS will either continue with the new trend and gain support from ECM UKMO or not , fairly straight forward.

Will have a better idea by the end of the pub run lets hope its not

 

Edited November 22, 2017 by stewfox

[karlos1983]

Whilst we wait for the 12z to show their hand, the Aperge has some wintry interest over the Downs in the early hours of Saturday morning.

Edited November 22, 2017 by karlos1983

[Met4Cast]

4 minutes ago, karlos1983 said:

Whilst we wait for the 12z to show their hand, the Aperge has some wintry interest over the Downs in the early hours of Saturday morning.

First time the APERGE has really shown snowfall potential for the South aside from the "wobble" it had a few days ago

[coldwinter]

3 minutes ago, Daniel Smith said:

First time the APERGE has really shown snowfall potential for the South aside from the "wobble" it had a few days ago

Isnt that the GFS from last night?

[booferking]

GFS upgrades cold early on in quicker and colder 850s.

Edited November 22, 2017 by booferking

[frosty ground]

Plenty of showers for NW England on this run...... 

 

[Allseasons-Si]

As some have alluded to above,some back edge snowfall for the home counties sat morning

dew points for the same timeframes

so an upgrade on the 06z in that respect

[Mucka]

3 minutes ago, frosty ground said:

Plenty of showers for NW England on this run...... 

 

Yes better run in the short term with more of a polar feed so colder uppers, plus the dreaded warm sectors are kept largely to the NE so should get some decent Cheshire gap showers that are wintry in nature if it comes off.

But while it looks marginally better upstream it is making a real meal of pushing shortwave energy through and leaving it around SW Greenland so a plus and minus for longer term prospects.

[feb1991blizzard]

Here we go again, gap even more closed now, no clean ejection of shortwave, saw this coming a mile off.

[frosty ground]

Big change at only 108 hours.

[Allseasons-Si]

Shouldn't jump the gun here,starting to eject now but it did take a bit longer,will it be a good thing?

[frosty ground]

Just now, Allseasons-si said:

Shouldn't jump the gun here,starting to eject now but it did take a bit longer,will it be a good thing?

Number one rule of this thread is people will always jump the gun.....

Less energy going East so a slower evolution

[booferking]

Ukmo & GFS @96hr..

[karlos1983]

UKMO looks good to me

[feb1991blizzard]

1 minute ago, Allseasons-si said:

Shouldn't jump the gun here,starting to eject now but it did take a bit longer,will it be a good thing?

It might well be aa good run still but the fact that complications are starting to occur at such short timeframes........

[weirpig]

stick with the UKMO