Some absolutely fascinating output in the 12z GEFS - something's definitely brewing, but whether it leads to cold weather for us is still very much up in the air.

A couple of the most noteworthy charts:

The highest pressure I've ever seen modelled over Scandinavia. It's worth mentioning that more than a few of the runs bring a 1050hPa isobar in the same general area:

and not far off a record for the UK on this one (the record is just under 1055hPa IIRC):

Retron, didn't you say something was brewing weeks ago only for nothing to change ?

You weren't paying attention.

I said something was brewing and indeed we had an attempt at a pattern change; in the end the amplitude of the Atlantic ridge wasn't enough to effect a permanent change, but it did at least give a few days' respite from wind and rain.

This one has stronger support in the models, take that as you will.

EDIT: And here's a reminder showing the attempted pattern change.

Certainly a bit more of a 'wobbling on the wall' feel to the 12z GFS and GEFS which makes the game more interesting again after the sense of unbeatable zonality that seemed to be brewing this morning.

JFF but the size of the block across Asia at the end of the GFS 12z op is something to behold:

Rawr!

Working in combination with blocking across the U.S. it does show the potential for a pincer move on the vortex. 

Generating a 1hpa level temperature map for the GFS 12z at +384 shows a messy picture but with the effects of that blocking across Asia very much apparent. Just needs a SSW to kick off! 

A calm response from yourself Darren

Yes your right , it did slow down the onslaught of the wet stuff. Hopefully we will get 'that' change that many of us crave

Looking much closer to now, I'm struck by how closely this:

http://www.instantweathermaps.com/GFS-php/showmap-strat.php?run=2015122112&var=TMP&lev=1mb&hour=048

represents what was being shown two weeks ago. My thoughts are that predictions regarding major changes in the stratosphere are much less susceptible to failure than the lower layers of the atmopshere - although as we still don't know the exact effects that warming will have it's hard to pin down effects lower in the atmosphere.

The12z's in the lead up to this exceptional mild spell have certainly verified excellently. 

Quick question for you Kieren: In you view, having followed the model output for quite a while I imagine, have the 12z runs from the models generally tended to prove more accurate that runs from other times of the day over a long period of time? It would be interesting to hear your views on that given what you have said about the 12z runs earlier on the month predicting the excpetional mildness of the second half of last week.

Lets hope the 12h GFS is the more accurate>the GEFS compared to the 06h a swings back to more blocked.

Meanwhile ECM stays resolutely mild -but haven't yet seen the ENS.

Good grief we dont need that and look at ecm 850 temp gradients that means one thing very unsettled for sure

Look at the power there just too much 

Brian will love some of these charts

http://www.meteociel.fr/modeles/geme_cartes.php?&ech=192&mode=0&carte=0

Latest from wpc for xmas period

MODELS AND ENSEMBLES STILL SHOW GOOD AGREEMENT ON THE FORECAST
THROUGH ABOUT FRI/SAT THIS WEEK BEFORE THINGS GET MORE
INTERESTING. STRONG RIDGING ALONG THE EAST COAST AND WESTERN
ATLANTIC WILL GET SQUASHED TO THE SOUTH AS AN UPPER LEVEL TROUGH
DIGS THROUGH THE INTERIOR WEST FRI-SAT. THEREAFTER, THE MODELS AND
ENSEMBLES SEEM TO HAVE FINALLY CONVERGED TOWARD FORMING A CLOSED
LOW BY SATURDAY NEAR THE FOUR CORNERS REGION AND SLIDE IT EASTWARD
AND NORTHEASTWARD THEREAFTER. PREVIOUS MODEL/ENSEMBLE RUNS SHOWED
ANYTHING FROM A COMPLETELY CUTOFF LOW GETTING STUCK IN NORTHERN
MEXICO SAT-MON TO A PROGRESSIVE TROUGH LIFTING INTO SOUTHEASTERN
CANADA. WITH SUCH MIXED SIGNALS, HAD TO RELY ON THE RATHER WASHED
OUT ENSEMBLE MEANS UNTIL THE 00Z GUIDANCE TILTED THE SCALE TOWARD
THIS MORE AMPLIFIED, BUT NOT COMPLETELY CUTOFF, SOLUTION. THIS
RESULTS IN MUCH MORE NORTHERN STREAM ENERGY TO PUSH INTO NEW
ENGLAND SUN/MON THAN PREVIOUSLY ADVERTISED.

A BLEND OF THE RECENT 00Z/06Z GUIDANCE THROUGH SAT STILL SEEMED
REASONABLE, WITH THE UKMET/CANADIAN ON THE SLOWEST SIDE WITH THE
CLOSING OFF UPPER LOW -- NOT IMPOSSIBLE, BUT AM NOT WILLING TO BE
THAT SLOW RIGHT NOW. FOR SUN/MON, THE ENSEMBLE MEANS EJECT THE
CLOSED LOW AT DIFFERENT SPEEDS, BUT PREFER TO BE SLOWER RATHER
THAN QUICKER. 00Z/06Z GFS RUNS WERE CLOSE ENOUGH TO THIS SLOWER
PREFERENCE SO THAT THEY WERE USED TO ADD SOME DETAIL TO THE
INITIAL BLEND. ECMWF WAS ON THE SOUTHERN SIDE OF THE SPREAD AND
QUITE A BIT DISPLACED FROM THE MAJORITY GEFS/ECENS ENSEMBLE
CLUSTERING.

Looks like its turning out  like a omega block in the wrong place if you ask me jet will just ride over the top

HI David.

I don't have verification stats to hand at the moment but can try and produce something...though not sure how.

I started looking solely at12z's at the beginning of November and my inference is that they appear to be verifying successfully a high percentage of the time.

How I would look at verification is general conditions and temperatures pronged vs Actual Conditions. 

I don't yet have enough stats to hand to say it's an exact science but based on what was progged on each specific day in November I would say verification is over 50% at a ten day range which is quite exceptional in my view.

I am off for a few days so will do some reanalysis of actual conditions v what models were showing at a 10 day range and try and come up with a more precise figure.

This could just be a quirk of fate with GFS due to the fact it was going for exceptional mildness for a number of weeks.

It would be more interesting to see how the current 12z charts verify 10 days hence. Sadly as you know I won't be in the country in January so could be difficult to carry on my experiment after 30th December.  But I will try.  ☺

Xmas Eve has looked potentially lively for some days now so no surprise if it actually turns out that way.

Cheers Kieren.

I've noticed that one or two GFS 12z op runs in the past few days have been tinkering with the idea of raising heights to our NE as we go into January; yesterday's 12z made a pretty good attempt at it. Even in the ECM op runs there has been a tendency of some kind to try and build heights over Europe further north towards Scandi, rather than having HP located right over central & southern Europe. It may mean nothing at the end of the day, but we can but hope that they build on this theme in the coming days in the same way as they did last month with the exceptional mild spell we've had in recent days.

Now http://www.meteociel.fr/modeles/ecmwf/runs/2015122112/ECM1-0.GIF?21-0 
10 days later http://www.meteociel.fr/modeles/ecmwf/runs/2015122112/ECM1-240.GIF?21-0 

I thought last Winter was bad but this top's it by far for the level of unrelenting borefest.

Might get a ground frost in the next few week's

http://modeles7.meteociel.fr/modeles/gens/runs/2015122112/graphe6_1000_275_97___.gif 

When will it end?

18z out to t+180 - looks odd:

http://modeles.meteociel.fr/modeles/gfs/runs/2015122118/gfsnh-0-180.png?18

But then that is the pub run.

Trying its best to give us a Beast:

http://modeles.meteociel.fr/modeles/gfs/runs/2015122118/gfsnh-0-216.png?18?18