Model output discussion - 1st December onwards

[Cheshire Freeze]

5 minutes ago, bigsnow said:

Well it took until the 3rd week of January in 2013 and then most of us had a right good few months after that... defo a sniff of a change in the pattern from new year onward... its good to see but still does not guarantee the UK cold and snow.... but anything is better than what we have had so far..

What is remarkable is that, given some long range model ideas, we could end up with a weather contrast in the extreme between the end of this year and the start of next. There does seem to be somewhat of a parallel between now and '12/'13. It's a possibility we end up with a very late, lingering autumn and winter lasting well into spring. Pretty much every CFS 9 monther I've seen has shown March to feature HLB...in fact I've not seen one with HP to the south as a mean feature- not one.

Edited December 17, 2015 by CreweCold

[Mair Snaw]

Just now, CreweCold said:

What is remarkable is that, given some long range model ideas, we could end up with a weather contrast in the extreme between the end of this year and the start of next. There does seem to be somewhat of a parallel between now and '12/'13. It's a possibility we end up with a very late, lingering autumn and winter lasting well into spring.

if i remember back to 12/13 we had that ECM in December and a coldish week followed by a very mild Xmas and New year ( i remember not using my heating for 2 weeks over xmas and new year) then first half of Jan was still mild then the models did a sudden switch and then it was cold and snow Nirvana right up until end of March.... so if we see something similar to that then i wont be unhappy and if it is to be extreme contrast then it will be one for the record books...

[Weather-history]

Has anyone seen the charts for North America, Christmas Eve? 564 line as far north as Nova Scotia?! The charts look more like summer!  20C+ forecast for Washington DC on Christmas Eve.

[Mair Snaw]

5 minutes ago, Weather-history said:

Has anyone seen the charts for North America, Christmas Eve? 564 line as far north as Nova Scotia?! The charts look more like summer!  20C+ forecast for Washington DC on Christmas Eve.

Good them buggers over there have had far to much cold and snow the last 2 winters while we have had very little.... i remember looking at the cold and snow they got in 13/14 while we got nothing but wind and rain and mild....and again last winter they got some real brutal cold and lots of snow....they deserve a mild or mega mild winter....lol

[phil nw.]

Yes the northward extent of tropical air is quite remarkable for Europe and many parts of NA.

Just glancing at things leading up to Christmas and as the jet wavers back south east we see something of a cool down,especially further north.This means of course some more wet days especially towards north western districts where they have had more that their share recently.

Days 4 and 5 onwards sees wave depressions along the rippling polar front.

so looking more unsettled nationwide with temperatures closer to normal although still rather mild for many going into next week.

We then have to see how the expected build of heights to the east develop post Christmas,too far south then i fear a return of the balmy tm air,further north then maybe some surface cooling off the continent.What we can't be sure at this early stage is we will see a block or just a temporary high.

 

 

 

[chris55]

The weather will always balance out, it's a fact! In the simplest of terms, the replacement of Low pressure to High pressure is inevitable at some point. Even if that just means a cold inversion that's certainly a change id welcome, but of course we can do a lot better...... lol

[Methuselah]

6 minutes ago, chris55 said:

The weather will always balance out, it's a fact! In the simplest of terms, the replacement of Low pressure to High pressure is inevitable at some point. Even if that just means a cold inversion that's certainly a change id welcome, but of course we can do a lot better...... lol

I don't buy that, Chris. If that really were the case, the globe would not be warming???

Edited December 17, 2015 by Ed Stone
Speeling mistake!

[Dreamnine]

Nothing remotely cold showing in the models - question is: how long will the current warmth last?

I'd bet on March being the coldest 'Winter' month.

[Singularity]

For me, the ECM det. run is a much better fit than the GFS det. run in terms of the sort of pattern development in response to tropical kelvin wave activity that has been discussed in recent days. You've got the Atlantic trough digging well south, with warm air advection heading toward the UK that will help those height rises to the east to take off.

The fact that GFS blows down the building blocks with such a huge and intense storm system gives me cause to take an extra spoonful or two of salt with it's solution in the longer range.

Of course, this kelvin wave business is far from a done deal so a trend toward a trough that digs further south in the mid-Atlantic can't be expected without considerable uncertainty. Yet it remains the solution that I am most agreeable with for the time being, from a long-term perspective. It also offers the potential for a final wave of exceptional warmth to close the month and perhaps allow the December CET to challenge the November CET record, which would be really something.

[Hocus Pocus]

30 minutes ago, Ed Stone said:

I don't buy that, Chris. If that really were the case, the globe would not be warming???

It depends on what you class as short term timescales. In the grander scheme of things it's but a mere blip on mother natures thermometer.

As for the models well at long last we are seeing changes afoot to the long wave pattern by the end of the month, whether that's a change to anything colder who knows  but at least something drier looks on the cards, for how long who knows.

[Captain Shortwave]

ECM ens

The ECM also building that ridge like the GEFs from around the 26th/27th. Again this suggests a final blast of very mild air potentially at the end of the month.

 

regarding the GFS op, it does look like one of its more wild low resolution outputs, that said there are a few ensemble members putting heights in the Atlantic as there is a weakish anomaly on the GEFs at the very end.

Edited December 17, 2015 by Captain Shortwave

[knocker]

The ecm anomaly at T240 is a pattern I think we could all reproduce without looking. The vortex NW Greenland with associated trough digging along way south mid Atlantic and the European HP ridging from Italy to the southern Baltic. Ergo a SW flow bringing unsettled weather mainly confined to the north and temps above average.

In the ext period by T360 the vortex the same but both the trough and HP have weakened, albeit keeping the same orientation, thus veering the flow to WSW and perhaps introducing more unsettled conditions except perhaps to the south with temps a little above average. This is actually a little deceptive as during the ext period there is a brief amplification flourish that that could drag some warmer air up from the SW

So essentially pretty much more of the same with periods of unsettled weather more prevalent in the north before New Year the winds veering perhaps becoming more unsettled for all with temps much neared normal than of late.

Edited December 17, 2015 by knocker

[nick sussex]

The ECM ensembles are not really interested in anything significantly colder. I think the main issue is where any high sets up which makes a big difference to the temps.

There are some changes expected in the Pacific reported by WPC, perhaps as a response to the MJO.

BACK TO THE WEST, SQUEEZE PLAY BETWEEN RIDGING NORTHEAST OF HAWAI'I AND LOWER HEIGHTS OVER ALASKA MAKES FOR A TOUGH FORECAST ON SYSTEM DETAILS INTO THE PAC NW DUE TO THE FAST JET. TREND NEXT WEEK WILL BE TO AMPLIFY THE PATTERN OVER THE PACIFIC WHICH WILL PUSH RIDGING INTO THE EASTERN ALEUTIANS AND HELP DIG TROUGHING DOWN THROUGH THE INTERIOR WEST -- GREAT BASIN AND TOWARDS THE FOUR CORNERS.

This change does throw some variability into the NWP as to how this impacts Europe so we'll just have to see what happens over the next few days.

 

 

[knocker]

But they don't appear to be going for any major pattern change and have high confidence in this. You wouldn't bet the house on getting any cold weather out of that apart of course from Pm incursions

Edited December 17, 2015 by knocker

[Liam J]

Christmas day night looks pretty chilly on the ECM with minus 6 for parts of Scotland where it's also showing lying snow into Boxing Day with temps remaining sub zero, overnight into Boxing Day temps around 0c or just below for other northern areas and further south low single figures. A little festive cheer from the ECM although being a week away the detail will change again.... 

[nick sussex]

11 minutes ago, knocker said:

But they don't appear to be going for any major pattern change and have high confidence in this.

Yes no major NH pattern change but within that overall pattern the amplitude of troughing to the west of the UK isn't nailed on. And therefore where any Euro high goes is subject to revision. The anomalies do not pick up trough disruption at this range. You'll see  by the GFS 00hrs and 06hrs runs especially that within the overall similar NH pattern you can end up with different conditions for the UK.

This type of set up with high to the east and low to the west in winter  is difficult because for the UK theres a marked difference in temp from a south/sw flow compared to a se and this doesn't need a big pattern change but a shift in the Euro high.

Edited December 17, 2015 by nick sussex

[knocker]

Oh I wouldn't dispute that and I normally point that out. I assumed people took it as read. Agreed the troughing isn't nailed on and possibly the HP could move a tad west but I wouldn't have thought that was the percentage play at the moment.

[mountain shadow]

3 hours ago, January Snowstorm said:

Am liking the ecm @ 192 hrs.

Certainly different with deep cold not a million miles away esp for Northwestern parts. As I said a couple of days ago pattern changes can spring up out of the blue!! (Pardon the pun) ☺

I read your post before looking at the ecm and was excited that a change was on the way and well ermm i have no idea what you are talking about. There is no change of pattern advertised in its ops run.

Both the t+24 and t+240 have a deep low mid Atlantic and high pressure over central Europe. Bern has a surface pressure of approximately 1028mb in both charts.

The t+192 may show a brief Polar maritime incursion into the UK but it is in no way a pattern change.

[ukpaul]

Is there a day 12-14 anomaly chart or something similar?

Not that such a chart range would ordinarily ever show anything apart from 'average' but compounding the problem by averaging over seven days isn't exactly using a finely tuned instrument.

[Nouska]

10 hours ago, mountain shadow said:

I read your post before looking at the ecm and was excited that a change was on the way and well ermm i have no idea what you are talking about. There is no change of pattern advertised in its ops run.

Both the t+24 and t+240 have a deep low mid Atlantic and high pressure over central Europe. Bern has a surface pressure of approximately 1028mb in both charts.

The t+192 may show a brief Polar maritime incursion into the UK but it is in no way a pattern change.

There is quite a change of emphasis on the ECM at T+240 ish  - for days on end the deterministic has been right at the top of the ensemble spread - tonight it swings to being a massive cold outlier. To be looked at with suspicion until more support appears.

AM 18th  edit - the embedded link automatically updates and now has the latest run. Saved image for last night here...

http://i.imgur.com/TPRpHR6.png

Edited December 18, 2015 by Nouska

[mountain shadow]

1 minute ago, Nouska said:

There is quite a change of emphasis on the ECM at T+240 ish  - for days on end the deterministic has been right at the top of the ensemble spread - tonight it swings to being a massive cold outlier. To be looked at with suspicion until more support appears.

Indeed Nouska, and even the colder polar maritime shown on the set. is very brief and without any support.

[feb1991blizzard]

The EC32 control run should just be starting to trickle out now, it will be interesting to see what it comes up with, FWIW I think we will need a few attempts at a pattern change and it will take until the last 3rd of Jan to really start to establish.

[Fozfoster]

1 hour ago, Ed Stone said:

I don't buy that, Chris. If that really were the case, the globe would not be warming???

Sorry Ed but things have been much colder too!! But I don't buy that balancing out thing either. Not in one season or for that matter year. 

[Frosty.]

20 minutes ago, knocker said:

You wouldn't bet the house on getting any cold weather out of that apart of course from Pm incursions

 

 

 

Right now, Pm incursions would be a welcome change from this vile mild mush! : )

I bet your woodshed that coldies (the majority on here) will not be denied spells of significant wintry weather through jan/feb and March. 

 

 

 

[Ruben Amsterdam]

12 minutes ago, Fozfoster said:

Sorry Ed but things have been much colder too!! But I don't buy that balancing out thing either. Not in one season or for that matter year. 

It's funny how some interpret the fact that averages result from high and low values as an almost supernatural "power of compensation".