Model Output Discussions 12z 01/09/2016

[Eskimo]

Even the GFS is showing that big ol' high...just in the wrong place to really 'benefit' us. 

[Nick F]

Following temperatures in the high teens today and as high as 22C in north Wales, the forecast maximum temps of 9-10C in the south on Wednesday will surely be noticeable, even if they aren't exceptional for early November. Perhaps colder still on Sunday, GFS forecast maxes of 7-8C across the south. Not really any signal for snow away from the hills in the north, but it is only early November after all.

GFS/EC operationals and GEFS and EPS 500mb mean today still keen to bring a 500mb vortex east into Greenland later in the medium range, which would eventually cause the  mid-Atlantic/Greenland/Iceland ridge to collapse south and allow low pressure to drop SE from Greenland eventually feeding into the  Euro trough.

However, positive signs IMO for coldies longer term, with the latest ECMWF ensemble system MJO forecast moving through colder phases of 7 and 8 towards mid-November. Take in the lag, that would perhaps impact for the 2nd half of November:

Also strong indications of an early-season split in the stratospheric polar vortex over the coming weeks which, if it works its way down to the trop, will increase the likelihood of high latitude blocking as we head into early winter. Though whether these blocks, if they form, position favourably will be another hurdle to worry about nearer the time.

All to play for if you like your November and early winter average to cold and certainly no signs of mild zonality taking over anytime soon.

Edited October 31, 2016 by Nick F

[Frosty.]

The Gfs 18z hardly has anything you could call mild and plenty of below average to rather cold temps. I just get the feeling with the amount of attempted cold reloads from the northwest that upstream there could be a major cold blast with our name on it.

[legritter]

Yes this Fim weather model looks good ,i simply typed in fim weather model . Its been a very interesting day today ,some action hopefully coming our way cheers .

[weirpig]

Can't post charts. But if you want in my opinion to see the run of the day check out the control run  for this time of year it's great 

[Ravelin]

4 minutes ago, weirpig said:

Can't post charts. But if you want in my opinion to see the run of the day check out the control run  for this time of year it's great 

Some select charts from it's FI

    

[feb1991blizzard]

Any 46 action yet please anyone?

[Yarmy]

14 minutes ago, feb1991blizzard said:

Any 46 action yet please anyone?

UK around average, but the overall NH profile looks good to me for the start of winter. The positive anomaly around Alaska would suggest the deep Aleutian low is still extant and pumping warmth toward the pole.

[feb1991blizzard]

• 1 minute ago, Yarmy said:

  UK around average, but the overall NH profile looks good to me for the start of winter. The positive anomaly around Alaska would suggest the deep Aleutian low is still extant and pumping warmth toward the pole.

  looks mild to me though, as regards synoptics going into winter, I would like to see the H500 and surface level pressure in normal format not anomalies before celebrating anything.

[Nouska]

1 minute ago, feb1991blizzard said:

• looks mild to me though, as regards synoptics going into winter, I would like to see the H500 and surface level pressure in normal format not anomalies before celebrating anything.

Maybe get in trouble for posting in the model thread but Meteo France have just updated their three month outlook and that pattern seems indicated for the forecast period.

The translated text to go along with it.

The proposed circulations do not allow clear case except for the Mediterranean areas, which are expected to milder conditions than normal, the British Isles, where temperatures should be close to normal, and Central Europe (the Austria to Ukraine and south of the Baltic States) with conditions rather colder than normal.

 

 

[SMU]

Very clear -AO that-

The UK is always on the periphery of the continental cold so will never be part of a forecast cold anomaly on a negative AO.

looks good to me...

[bluearmy]

19 minutes ago, feb1991blizzard said:

Any 46 action yet please anyone?

Curates egg

the standard model relaxes any euro low heights second half Nov but then brings them back for December  (more marked through the med) with higher anomolys w scandi across towards Iceland. would have to be a cold outlook for us in that general setup and second half November could be surface cold anyway.

The parallel model keeps the whole of November lower than average T2 maxes for N Europe in a general continuation of the pattern but then loses any low euro anomoly for December  and the T2's recover to above normal

 

[feb1991blizzard]

3 minutes ago, bluearmy said:

Curates egg

the standard model relaxes any euro low heights second half Nov but then brings them back for December  (more marked through the med) with higher anomolys w scandi across towards Iceland. would have to be a cold outlook for us in that general setup and second half November could be surface cold anyway.

The parallel model keeps the whole of November lower than average T2 maxes for N Europe in a general continuation of the pattern but then loses any low euro anomoly for December  and the T2's recover to above normal

 

Thanks - lovely, especially like the bit about December!!!  (operational)   off to bed optimistic now.

 

THANKS ALL PEOPLE WHO UPDATED ME.

Edited November 1, 2016 by feb1991blizzard

[northwestsnow]

3 minutes ago, Steve Murr said:

Very clear -AO that-

The UK is always on the periphery of the continental cold so will never be part of a forecast cold anomaly on a negative AO.

looks good to me...

EC 46 would suggest plenty of northern blocking highs to me steve.

[northwestsnow]

I assume the EC 46 will include strat data etc so perhaps we are indeed looking at a completely different ball game to last year, my hopes are on the rise !

And judging by Mr Fergies comments in the regional thread i'm thinking the pro's are not expecting any Atlantic dominance for a wee while

Edited November 1, 2016 by northwestsnow

[bluearmy]

9 minutes ago, northwestsnow said:

I assume the EC 46 will include strat data etc so perhaps we are indeed looking at a completely different ball game to last year, my hopes are on the rise !

All models (worth quoting) go to the top of the strat

i believe the parallel becomes operational 22 nov

With a difference evident between the op and para second half Nov I would be cautious until some consistency emerges

[northwestsnow]

1 minute ago, bluearmy said:

All models (worth quoting) go to the top of the strat

i believe the parallel becomes operational 22 nov

With a difference evident between the op and para second half Nov I would be cautious until some consistency emerges

Cautiously optimistic then Blue

 

[bluearmy]

Note the para ecm op 10 day 12z run slides the Atlantic trough to our sw against a developing scandi ridge with strong Euro trough. V Cold for us.

This is where I thought we might be headed but not as quickly as this! look out for this evolution in the upcoming normal runs but doesn't mean it isn't an over progressive solution 

 

[Geordiesnow]

This afternoon's operational runs do appear to sharpen up any ridging towards Greenland thus a more better alligned NE'ly flow as a result, the UKMO is most certainlt probably the pick of the bunch.

I think the general pattern is set and it will be the details that will determine what kind of weather we will get. Thankfully the models did not follow the GFS projections of having the trigger low stalling over the UK giving very wet and windy weather so the brighter showery NE'ly is more of a likely scnario. The question will be just how cold will that NE'ly flow gets, all depends on shortwave development just to the south of Norway, seen it before in the past how shortwaves can scuper the flow and start delaying and diluting the cold so that is something to keep an eye on in the coming days

Do also have to be wary of the thought of a lobe of PV heading into Greenland, the models do seem to keen to suggest this will happen and there is always that risk the Atlantic may come in sooner than we think but its by no means a certainty at this stage.

Either way, the chances of the coldest weather of the Autumn season so far will occur this weekend and whilst snowfall looks quite limited, air frosts should be quite widespread.

[knocker]

Today

A weakening cold front continues to travel south and eventually extending the colder air behind to all. Meanwhile south of that mainly cloudy with temps a little down on yesterday. North of the front more sunshine but obviously cooler.

.The GFS this morning

It continues to run the upper trough SE over Ireland on Friday and phasing it in with the trough to the east centred in western Russia. As the Irish trough swings SE it deconstructs from this scenario and phases with the cut off low to the south west and forms a new trough which by 00z Sunday is positively. tilted orientated Norway to Corunna. Regarding the surface evolution this translates to a depression and associated fronts tracking SE then east over the Friday and Saturday outbreaks of rain to most with temps below average. By Sunday 00z the complex low pressure area is to the east with the UK in the much cooler northerly airstream.

So what happens from here? the upper trough hangs around for a while whilst once again the Atlantic HP amplifies and ridges NE thus keeping the UK quite cool for the beginning of the week but slowly it drifts SE allowing the warmer air to encroach from the west.

One consequence of renewed amplification of the high pressure is it pushes the strong thermal gradient further north and thus the quite strong jet which means the troughs emanating from Canada are also further north and thus tend to descend further east. Keep still my beating heart. As with the ecm yesterday evening the evolution next week does rather depend on getting the amplification and orientation of the Atlantic high pressure correct

 

 

 

 

Edited November 1, 2016 by knocker

[feb1991blizzard]

Lovely cutback from 144-168.

[northwestsnow]

GFS looks cold in the reliable but goes horribly wrong thereafter with some pretty horrid looking charts in FI.

ECM looks better at 168 but the northern arm looks pretty potent ...

[knocker]

12 minutes ago, feb1991blizzard said:

Lovely cutback from 144-168.

I'm afraid I haven't come across the 'lovely cutback' terminology before but what does occur is a small feature develops in the Denmark Straight at T132 and nips SE to be N. Ireland by T150 and is absorbed in the main upper trough.

Edited November 1, 2016 by knocker

[feb1991blizzard]

Just now, knocker said:

I'm afraid I haven't come across the 'lovely cutback' terminology before but what does occur is a small feature develops in the Denmark Straight at T132 and nips SE to be N. Ireland by T150 and is absorbed in the main upper trough.

Its where you have a N or NE'ly clipping the SE and normally when the atlantic is strong, by the next frame the high would topple in but this time virtually the whole country is in an E'ly, in mid winter this would preserve bitterly cold conditions for a day longer, anyway its gone horribly wrong now!

[Ali1977]

GFS and ECM look similar everywhere apart from Scandy, which in turn makes quite a difference to our little island. Still not sure where this will lead us, ECM looking the better of the 2 for a prolonged colder spell - relative to early Nov that is.