Model output discussion - 5th December 2016 - Into Winter we go

[radiohead]

Dear oh dear. A Christmas Day washout on the 18Z. Though it may start as snow before turning to rain for those in the north.

[Ali1977]

Now, this is looking much better, look at the heights building in across the NH splitting the PV. After Ian Fs comments I think we are about to start that roller coaster again!! 

[Frosty.]

At least it would feel like winter later next week and even Christmas day on the Gfs 18z with max temps in the low single digits celsius range..better than the very mild mush last Dec.

Edited December 16, 2016 by Frosty.

[nick sussex]

The set up shown by the GFS is very complex, it seems as if the outputs are determined to wring every last ounce of drama before Christmas.

There is an opportunity around T168hrs if there was a bit more amplitude upstream. This has been the problem for most of December and continues to haunt us.

The evolution from the GFS and ECM is complicated, so one of my paintjobs to explain this.

You'll see circled red this lobe of high pressure which has been pushed ne ahead of the advancing low, the key really is whether this can get further north and nw extending a ridge over the incoming low, so towards Iceland, southern Greenland, now when this happens it exerts some force on the incoming low to push more se and start disrupting. Now the issue is that low you can see leaving Newfoundland, both the GFS and ECM have a low there wants to run east and phase with the first low. If you had more amplitude upstream this would do two things, it would sharpen up the low near the UK and at the same time slow down the second low and you'll get that better ridge extension from the Azores high, if any phasing takes place then you'd be in a much better place because it would be later with the jet already more angled se'wards.

So as you can see by by mini novel of the evolution its complicated! lol Whether we get any mileage out of this we'll see in the morning.

 

 

[feb1991blizzard]

Just now, Ali1977 said:

Now, this is looking much better, look at the heights building in across the NH splitting the PV. After Ian Fs comments I think we are about to start that roller coaster again!! 

Yes - a cracker this, all started off by that Russian high staying in situ for that amount of time, if that pattern persists for any length of time its only a matter of time before we are in business.

[Cheshire Freeze]

Just now, feb1991blizzard said:

Yes - a cracker this, all started off by that Russian high staying in situ for that amount of time, if that pattern persists for any length of time its only a matter of time before we are in business.

Aye, something looks to be brewing back end

[Chris K]

6 minutes ago, Ali1977 said:

Now, this is looking much better, look at the heights building in across the NH splitting the PV. After Ian Fs comments I think we are about to start that roller coaster again!! 

Indeed and whilst Xmas is currently looking to be windy and wet (perhaps some hill snow depending on temps), what follows is a bit more interesting on the GFS 18z. However, the changes between 12z and 18z become apparent from about T+132, with the Low development in the western Atlantic.

Edited December 16, 2016 by Chris K

[feb1991blizzard]

Just now, CreweCold said:

Aye, something looks to be brewing back end

Yes, we will need strat feedback and that is hopefully the kick.

[nick sussex]

Everyone knows my thoughts about the GFS well into FI but really the T384hrs chart just sums up the UKs luck when it comes to cold, the PV disappeared from Greenland, a big Russian high and zip for the UK. God forbid if that chart verified after all coldies have been through but really that would be insulting even by recent standards!

Edited December 16, 2016 by nick sussex

[Frosty.]

Plenty of cold incursions with transient snow and wintry showers on the Gfs 18z which turns into a very unsettled run with bouts of wet and very windy weather..a big change from the boring, mild benign stagnation so far this winter!

[gottolovethisweather]

12 hours ago, gottolovethisweather said:

That's some serious depth of cold out towards Greenland but will it ever leave their shores. I cannot convince myself to look past the 21st/22nd December right now, but I have a feeling the period immediately around Christmas Day and towards the close of the year will be a memorable one. Everything but the kitchen sink springs to mind, so yes I favour an active period! Snow for some too with not everyone joining in the fun and a lot of transient stuff.

 

 

 

 

After tonight's cheerier updates (well, if you're active seasonal weather, they be cheery) I thought I'd BUMP my post from around midday. John Hammond's BBC long-ranger update was also an intriguing one. Slowly, Slowly, Catchy Monkey.

Edited December 16, 2016 by gottolovethisweather

[Cheshire Freeze]

2 minutes ago, nick sussex said:

Everyone knows my thoughts about the GFS well into FI but really the T384hrs chart just sums up the UKs luck when it comes to cold, the PV disappeared from Greenland, a big Russian high and zip for the UK. God forbid if that chart verified after all coldies have been through but really that would be insulting even by recent standards!

Run the progression Nick. Heights would link up either side with weakening trough sinking S. Should eventually open the door to a bit of CAA from Siberia. Though all complete conjecture

[Ali1977]

Now, this is looking much better, look at the heights building in across the NH splitting the PV. After Ian Fs comments I think we are about to start that roller coaster again!! 

[legritter]

Well the GFS run towards the end brought joy  but i,m going to have to see more runs yet and some back up from other models .great to see high pressure setting up further north and n west , looks like plenty of action weather even if this turns up as actual ,going to be a wild time on our forum ,a real roller coaster ,will be some troughs and highs ,emotional ones that is ,so on that note good night Gang ,

[Man With Beard]

35 minutes ago, CreweCold said:

Aye, something looks to be brewing back end

Interesting that the main vortex is entirely on the other side of the pole - rarely seen that modelled.

Hopefully it's one of those eureka moments from the GFS which it has from time to time.

[snowray]

Interesting controle run on the 18z too.

[Hotspur62]

8 minutes ago, snowray said:

Interesting controle run on the 18z too.

Yes it does look full of potential but i seem to remember we were at this stage at the turn of the month and it all went TU as December progressed!!.I would still like to see lowering of heights in the Med which i am not seeing atm although i appreciate the above maps are 14 days away and very unlikely to verify.The good thing is the rather benign pattern we have been in for the last 2/3 weeks looks to be changing and it is just the case if the dice go our way in terms of getting the cold in.I think today could be a turning point as the mood in here does seem a little more optimistic so lets hope a trend has started. It"s about time we had a little luck in the UK getting a bit of cold and snow!!

[Man With Beard]

The GEFS certainly joining in the theme of "the block fights back" for the new year. By D16, only 5 out of 22 members could even be remotely described as cyclonic for the UK. All the other members have some form of mid and northern latitude blocking near to us, though only a few shaped favourably for deep cold at that stage. Very much in tune with what we know of the ECM ensembles and the EC46 from yesterday. Now can they count down to a more reliable timeframe???

[snowray]

As others have mentioned already, if the partern remains out at day 10+ on the GFS, then it will likely be more pie in the sky stuff. For it to verify it should start moving forwards by a day or two over the course of the runs, I have seen this before where a feature that was out at day 11 or 12 suddenly popped up within the next 24hrs of output at around day 8 or 9 and so on down to the more reliable timeframe.

The pub run in particularly has picked up on new trends at times that have been proved to be pretty close to the mark. 

Edited December 17, 2016 by snowray

[karlos1983]

Well the ensembles certainly trended colder today. Much smaller grouping at the end going for mild. Not deep cold but certainly headed the right direction.

 

[Ice Day]

Well, I've been lurking around this thread for the last 10 days or so but with the moribund output I have not had anything remotely interesting to add.  However, there seems to be some momentum gathering behind a marked shift in NH weather patterns, so I'm very much in the camp of looking forward to some cold zonality.  Our learned friend Mr Ferguson's little titbits over the last couple of days have buoyed me still further.  We are heading towards an interesting period where we could start to see some top quality eye candy, with an increasing chance of north easterly, or dare I say easterly.  Time as always will tell, but this year just feels like severity is just around the corner.

 

 

[knocker]

Today

A fine clear day in N. Ireland, the far north of England and Scotland apart from the far north, Orkney and Shetland. England and Wales murky with fog patches with maybe some sunny interval later in the west,

 

The GFS this morning for the next ten days.

Little change with the long wave pattern with the lobe of the vortex over Greenland with associated trough running south to the west of the UK. And the large high pressure area centred over eastern Europe.  Ergo quite amplified with the upper westerly flow backing SW as it traverses the UK. So keeping that in mind how is the det, run coping with the fluidity within this framework this morning?

The high pressure ridges NE over the weekend and the beginning of next week but the large, complex, upper trough continues to progress east and by Wednesday midnight is dominating the Atlantic, suppressing the ridge, and surface fronts encroaching from the west

This trough quickly moves on but merely paves the way for the next one courtesy of the vortex and it is this one, and the next one, that will influence our Xmas weather. By 00z Saturday the main centres are around the Iceland area and the trough is partially deconstructing and phasing with the upper low to the south. On the surface this equates to a complex area of low pressure to the north west and fronts orientated Lerwick/Cornwall/Corunna so wet and windy for all particularly Scotland.

Again this quickly clears but the the next upper trough rapidly makes it's play and quickly deconstructs creating an intense upper low off the coast of North Africa but, and more to the point, spawning the next low which rushes NE to bring some decidedly nasty weather to Scotland. All of which is subject to adjustments in the next couple of days of course.

 

Edited December 17, 2016 by knocker

[knocker]

The ecm varying in detail but from midweek onwards we are looking at some decidedly grotty weather.

[Johnp]

17 minutes ago, northwestsnow said:

Grotty is one way to describe it knocker, i can think of a few others but they would most likely breach the swear filter.Its fast becoming another sorry excuse of a winter with no let up in the +NAO set up, i can honestly see absolutely nothing this morning to gove scope for optimism for coldies.Even at day 10 ecm is horrid with the strong PV STILL in place and the azores high preparing to ridge back to europe.GFS actually looks worse, if thats even possible with the PV in place out into lala land, is there any hope of a pattern change prior to the new year?

Definitely seems to have taken a step back this morning on all models.

Christmas not looking as cold + longer term promise seems to have vanished.

 

[karlos1983]

One thing I've noticed this morning is the distinct lack of deep cold modelled at D10. 

Wouldn't it be fitting if we were to get an easterly when the uppers aren't great. 

Edited December 17, 2016 by karlos1983