Nothing to quicken the pulse on the 12Zs.

I think the Azores High looks particularly smug, fat and happy on ECM. At least GFS low-res knocks it about a bit.

Other than that it's a ridge, trough, ridge, trough ride into the middle of January 

At least it will be changeable 

Dreadful, massive downgrades in the last day or two.

too right! Some useable weather at times hopefully. Fairly typical westerly flow, nothing too cold or nothing overly mild. 

Good luck getting any HLB to affect us from this. ECM 12z mean at day 10

Looks like model watching will be fairly predictable for a while - I don't think a single GEFS perturbation the past few runs has shown a HLB in our locale out to +384. With such agreement now in the output Shannon entropy must be low with just the positions of the ridge, low, ridge, low etc to be sorted out.

All can change by the 3rd week of Jan at least so hopefully this isn't a prolonged zonal rut.

Yes I can't see anything to brighten the mood for the cold fraternity in tonight's output and while it is only one run there are few if any grains in the distance to pin hopes upon. All talk of SSW and what's going on over the other side of the globe is all very well but as long as that Azores High remains as strong as it is programmed to be and has been for a month or more now any changes in pattern are more likely to change the weather elsewhere rather than here in the UK as long as that remains as strong.

The Jet Stream is also a factor in this persistent repetitive pattern and even though we have broke out of it in recent days the power of the Jet flow and the Low pressure vortex to the NW fuelled by the Azores High continues to flatten any cold air sinking down over the UK and Europe. I've noticed too that the deep and colder zonality weather progged from recent output in the later part of the runs gets watered down with time as the High dominance to the South gets understated until we come into more reliable frameworks.

So what of the models. Well we all know how they all badly predicted the path and the eventual outcome of the depression which brought some parts their first snows of Winter over Christmas but on the whole I think they have performed quite well in the face of some occasionally dynamic situations. Of course their accuracy falls with time into the future but while some people particularly bate one models better handling over the other on forecasting the future with a sometimes seemingly bias against the merits of the ECM I can accurately say that this model outperforms all the other models on numerous occasions with that accuracy showing a wider margin in favour of it's verification over the rest even at Day 10, albeit at that range they can all be a bit of a loose cannon. For those interested here's the latest verification stats up to and including Boxing Day.

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day3_PMSL_MSL_G2NHX.png 3 Day

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day5_PMSL_MSL_G2NHX.png 5 Day

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day8_HGT_P500_G2NHX.png 8 Day

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day10_HGT_P500_G2NHX.png 10 Day

Though at Day 10 there is around a 1:2 chance of an accuracy in verification on any model being correct the important thing to believe is trends and the trends from all models tonight is that zonal Westerlies with a mix of cloudy rainy periods being interspersed by cooler and more showery winds with snow over the normal locations of the North and West is where we'll likely be over the next couple of weeks once this current interlude of winter cold abates midweek. See you for my report in the morning.

NWP output =

Good summary Martin.

Just for the record, 18Z GFS shows no change.

Quite an average looking set of charts on offer at the moment.  One chart that did grab my eye was this:

Looks very similar to the chart that hit us on Boxing day - from 6 days before the event.  Will be interesting to see if the GFS models it nore southerly as we get closer to T-0 generating northern edge snow threat interest

Weve had a number of winters recently of repetitive patterns.  Last year a prime example.  Could we be on the verge of a reload?

Combined with sustained amount of interest around the 5th jan - aswell as increased snow row interest on the 5th - would be a strong enough signal for now.

Whenever very intense storms turn up in a model run in the 6-10 day range, I'm inclined to view the output with more skepticism than usual, even if there's full agreement for it... what we saw in the run-up to this weekend being an excellent case for this.

ECM has no such monsters on it's 12z op run so it seems  a bit more sensible. It's important whether such a powerful storm system develops or not, as it's location allows it to drive a strong westerly flow across the UK to bombard the UK with a rapid train of secondary lows, at least one of these very nasty indeed on each and every one of the past few GFSP runs.

Very wet and windy with gales to severe gales, occasionally storm force winds. I can see why those who are taking GFSP in FI at all seriously are feeling negative tonight. If support for the super-storm grows tomorrow, I'll start to worry too (while also becoming a bit excited in my own slightly insane way).

My earlier point regarding new strat. warming in the model output remains valid though - in fact it's gaining strength in the output, with GFS and GFSP still favouring an origin in the Atlantic (GFS rather weak with it though - builds to end of high res then suddenly dissipates) while ECM and JMA are going for something more Greenland-based.

This is very different to what we have been seeing these past couple of months, as those warmings have been on the other side of the hemisphere, always depositing the vortex somewhere not far from our shores (i.e. Canada/Greenland or Scandinavia/Siberia).

If this new one manages to be more Greenland based rather than Atlantic, it should at least help to shift the vortex further away from us, allowing high pressure to become more of a dominant force in the Atlantic/Europe sector.

Even if it is more like what the GFSP 18z shows (which has trended stronger than the 12z but no closer to Greenland), it will give the vortex a lot of trouble in the upper levels and could cause a lot of weakening:

That day 16 chart shows the sort of vortex state you'd usually expect to see during the winter to spring transition period. The associated late Feb-Early April period often sees a lot more high latitude blocking and that's because of this marked reduction in vortex strength. So it's a promising thing to see from what is one of the least effective solutions in terms of the position of the warming event.

We're basically in a situation where it has turned out that at least one more blow to the vortex is needed to take it down than was expected in the pre-season outlook. The timescales involved in wave breaking mean that this translates to a set back of some 10-14 days, maybe longer. So we're talking second half of January for any marked changes to occur in the troposphere.

To those who play down the strat. forecasting methods, so what if the strat. forecast didn't hit the bulls-eye with the number of warming events needed and hence the timing of events? That doesn't in the least bit make it obsolete, just another long-range forecasting tool that has the inevitable wide margins of error.

Obviously, if the vortex doesn't give way at any point in the next month then the worth of such an outlook even as a rough guide to what might happen (which is the intention) will be starting to look unreasonably poor and there will be some serious thinking to be done.

The main concern in the meantime is whether we see that super-intense low in the W. Atlantic which seems to be a matter of how much energy associated with the subtropical jet phases with that associated with the main Atlantic jet in that region. ECM avoids the phasing and that's why it's so different.

Finally, my favourite free-view chart of the evening:

Much stronger and earlier warming (compared to GFS/GFSP) on our side of the hemisphere from JMA and it's focused over Greenland!

This is actually quite close to what ECM shows, so we are seeing an unusually strong disagreement in the strat. for the 7-9 day range.

 Take today's GFS 12z and 18z model analysis wel for continued mixture of Neither that wintry or dry,but we would get some very cold nights and days but also the opportunity for som snow and slet is on the GFS and the UKMO agrees too.

Following on from that excellent update on the Strat temp profile, worth noting that the last 24-36hrs have seen an unusual shift and unusually strong disagreement at relatively short-medium range for developments over Greenland. The ECM and JMA offer massive warming, an entirely split strat vortex and the warming attacking both sides of the pole to put us dangerously close to the prospect of SSW. Navgem flirts with the idea and GFSP has progressed towards that scenario but with a watered down version. The other free-viewing models, including our old friend the GFS Op, reject it completely. Worth looking out for amidst the doom and gloom...

Wrg to the stratosphere; keep in mind that the models 'take it into account', some people seem to think that the models will be forced to obey the stratosphere which isn't true, all levels are modelled; the advantage, if any, of the stratosphere is that its probably easier to predict with greater accuracy. Unfortunately there is still no sign of a proper SSW like in 2010, these bubbles of warm air from siberia seem to be trivial.

Oh Dear.

00z GFS run keeps bringing Low Pressure On a Further South Track and this means it could get very windy, Stormy and Wet at Times plus mixes of Mild Short Spells and Slightly Longer Chilly Colder ish Airmass RPSTM to RPM swings.

May be need to watch out for alerts for Torrential Rains, with some Wintry weather for some spells that will be short lived but longer than mild sectors...

this Thursday mild windy and Very wet later... then Colder with wintry showers of rn/sly/hlsn.

Though GFS has the coming Weekend Cold Saturday with rain later, Then Sunday Fine and less Cold but eastern districts could see night frost again following clearance of next Saturday Low Pressure, wind and rain spell of midday aft/eve.

Then week after that Often heavy rain and strong West SW to WNW Flows.

Add on 00z UKMO - ahem...
It shows Low P and Showery NW flow this Friday, and that stays over UK Saturday 3rd, and we have Ridge of Large Azores High affect us PM Sarurday and all of the Sunday that follows.

Large PV Low's NW Atlantic is gearing up on ESE Journey to us by Monday plus I saw Deep Cold pool Polar Vortex Low dominate Northern and NE Europe less though over NE UK- Large Azores High ridges across Sunday but then Strong and Deep Polar Vortex Low from NW Atlantic Monday to be expected.

We see that west to ENE then SE Tracks of Active North NE Atlantic Through West Centrql Norwegian Sea PV Wednesday to Saturday that at 120 and 144 (2-3 Jan 2014- position Cold Windy Polar Vortex NE Europe as Cold Arctic NW flow for them.

The pinks return after a short break:

http://wxmaps.org/pix/temp4.png

Nothing but zonal mush on offer on the various models and ensembles this morning. There remains a low chance of a colder plunge reaching the south in the wake of one of the many lows rushing eastwards over the Atlantic, but if you look at the ensembles for London, for example, they paint a generally mild picture:

http://www.meteociel.fr/cartes_obs/gens_display.php?x=306&y=141&run=0&ville=Londres&runpara=0&type=3&ext=1
http://www.weathercast.co.uk/services/ensemble-forecast.html?eps=london

To be fair, daytime highs look unlikely to be exceptionally warm, with a moderate chance of one or two coldish days in the next couple of weeks. It'll be the nights causing mean temperatures to be higher than normal over the first 10 days of January. Beyond that - too far out to tell, of course, but given the lack of cold ensemble members, the sort that show -5C 850s or colder for several days in a row, it's unlikely to change any time soon.

A pity, really, as all the action near Alaska seems to be doing is forcing the polar vortex to be exactly where it's not wanted (if you're a cold fan).

In the meantime, the hopes of cold fans will rest with ensemble member number 7 this morning!

http://www.meteociel.fr/modeles/gefs_cartes.php?code=7&ech=240&mode=0&carte=1

Indeed, the failure of the current high to hold at a more northerly latitude has opened our gates to Atlantic winds bringing their cloud and moisture.  In densely populated areas, frost will be rare, snow rarer.  I foresee this stable zonal pattern being maintained for up to 3 weeks, but who really knows how long it will last?  Perhaps the best answer is to refer to the Met O Men and their updates.

Thee is still considerable interest this morning in terms of the potential for deep lows in the flow. The Euros aren't too interested but GFS and GFSP quickly develop a deep low on Thursday affecting Scotland and then keep a train of lows into next week. Something to watch.

Howdy.

Brr. Okay What shall we say if I let you know that by 1900 Sunday yesterday it was -1 in East London Inner Suburb Wanstead Park Weather Station is 1 and half miles away from my home. and A -3 deg. C.

Certainly look as if was recorded I can see it outside, Frost On Cars and Roofs and Sheds, I'd expect Inner Greater London Suburbs to regularly see this -5 at 850 gaps Air to occur once and twice at times  every 3-4 days interspersed with 1-2 milder days.

Jack Frost according to this Nov- Dec. 2014 so far upto 8 day night a.m and p.m frosts recorded and I expect to see several more before the last week of January 2015 who says my area is urban... 

Agreed.  The main interest going forward will be just how powerful the storms are and exactly where they track.  Could start to get too close to comfort to 2013-14 if things to crank up to top gear though, definitely one to watch.

Looks like the worst sort of winter weather on the way (from the perspective of someone who commutes by bike) - wet and windy with below average temperatures. I don't mind cycling in the rain if it's mild, and I don't mind crisp frosty weather, but wet and cold, no thanks!

Still on the plus side this morning is beautiful, I'm currently on the train back to London through sparkling frosty Hampshire countryside, after a -5C start at 7.30am :)

We can only hope the models are underplaying the effects of the Arctic high but I think we have to take a break for a week. Looks like a very wet and disturbed period coming up

The models are even worse this morning as we lose the colder PM shots on the ECM with pressure higher over Iberia linked to a huge high pressure covering most of the Med and North Africa from +120.

It's not quite a Bartlett but getting close to a zonal Bartlett so no snow even in the North apart from Scottish mountains and even here you will need 2000feet.

For the start of the New Year it's difficult to see how it could be worse.

Andy

HERE IS MY LATEST ANALYSIS FROM THE OUTPUTS OF THE WEATHER COMPUTER PREDICTION MODELS FOR TWO WEEKS FROM 8AM TODAY MONDAY DECEMBER 29TH 2014.

NEXT UPDATE TUESDAY DECEMBER 30TH 08:00

THE CURRENT GENERAL SITUATION A large and intense Winter High pressure area will slip slowly SE over Southern Britain today with a slowly freshening SW flow developing over Northern Britain tonight and tomorrow.

MODELS-2 WEEK HEADLINE Becoming unsettled and windy later this week and onward with rain or showers at times and snow on Northern hills. Some drier periods likely in the South.

THE JET STREAM ENSEMBLE FORECAST The Jet Stream Forecast shows the flow ridging North over the UK currently. It then becomes strong and flows from West to East across a point close to 50deg North for the remainder of the period

GFS OPERATIONAL The GFS operational this morning shows High pressure collapsing SE into NW Europe over the next day or two with a freshening and less cold Westerly flow developing across the UK. Within this flow is shown various periods of wind and rain from troughs crossing East in the flow attached to Low pressure persistently to the North and these then alternate with somewhat colder and more showery weather with some wintry showers over the North. Overall temperatures are shown close to average with some brief somewhat colder interludes with strong winds in places at times.

THE GFS PARALLEL RUN The Parallel run is very similar to the operational this morning in overall pattern with differences in specifics from day to day especially later when a period of very volatile weather is shown with severe gales and heavy rain as deep Low pressure areas crash into the UK from the Atlantic.

THE GFS CONTROL The GFS control run also shows a strongly zonal pattern under Westerly winds developing for the North by midweek and to all areas by next weekend with strong winds and rain at times for all through the second half of the period in average temperatures or a little above at times apart from brief colder interludes at times in the North and some drier periods across the South as High pressure over France remains close by at times.

THE GEFS ENSEMBLES The GFS Ensembles show strong support for a Westerly flow to dominate the UK from later this week. With Low pressure biased to lie to the North and High near the Azores Westerly winds, strong at times will follow their normal characteristics of spells of wind and rain for all with slightly colder and more showery interludes in between, these most prolific across the North.

UKMO UKMO shows the High pressure and attendant cold weather receding away from the SE through the New Year period replacing it with stronger but milder SW winds and a spell of rain as a cold front is shown to move SE followed by another strong rise of pressure from the SW with frost returning as colder conditions develop later at least for next weekend away from the far SW where cloud may be more prolific and a few showers affect North Sea coasts in a NW flow.

THE FAX CHARTS The Fax Charts follow the raw data quite well today with a milder SW flow replacing the cold High across Southern Britain over the New Year. A cold front in the stronger SW flow will clear SE by the weekend with a strong rise of pressure moving back in from the West with frost at night developing again over the weekend at least for a time.

GEM GEM today also shows High pressure moving away SE with milder SW winds ahead of a cold front taking hold over the festive celebration period. Into the New Year a ridge of High pressure returns a few nights when frost is likely before the pattern flattens under Westerly winds and rain at times in generally milder conditions as we move into next week.

NAVGEM NAVGEM also shows the well worn track between the models recently of replacing High pressure with a milder Westerly flow between High pressure to the South and Low to the North with rain at times with some brief drier and chillier days in between.

ECM ECM this morning shows the current High pressure moving away to the South with a freshening SW flow ahead of a cold front later in the week bringing some rain. A cooler spell is possible again at the weekend in a rather complex pressure pattern across the UK with slacker winds and variable conditions as troughs get hung up across the South. Then through next week the pattern simplifies into a relatively mildish and windy period with rain at times especially in the North and West.

ECM 10 DAY MEAN The ECM 10 Day Mean Chart shows Low pressure to the North and High well to the South the most likely scenario at Day 10. This would indicate a strong Westerly flow veering WNW at times with spells of rain mixed in with colder and more showery conditions.

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The trend this morning remains strongly in flavour of Westerly winds over the period with spells of wind and rain alternating with colder periods. A few models have leaned to another brief but strong ridge of High pressure for a time this coming weekend.

MY THOUGHTS The models continue to hold resolute in maintaining a general Westerly pattern of winds across the UK blowing between deep Low pressure to the North and High pressure to the South. The details of day to day conditions are hard to distinguish this morning with some output indicating some deeply unsettled weather later with svere gales and heavy showers plus colder wintry showery periods while others hold or bring High pressure closer towards Southern Britain at times sending the worst of the wind and rain towards the North and West while allowing some rather milder conditions into the South at times. However, these are just small nuances in an overall flat pattern of weather which sees the UK saved from any major cold incursions over the next few weeks at least. There is a hint that this weekend will bring a window of chilly and perhaps frosty weather for a day or two as another strong ridge attached to High pressure to the South and SW moves through but with a weak trough close to the South cloud could restrict night time frosts to more Northern and Eastern areas before all parts fall back into the Westerly regime soon afterwards and through next week. The Azores High remains the nemesis for our failure to lock into any lengthy and meaningful cold across the UK both in the past and the near future. The Jet flow riding across the Atlantic on the Northern flank of this High remains poorly aligned to play ball for cold weather to be other than passing shots as ridges between the Lows to the North pass by. There is still little evidence that there is a quick end to this pattern through January from the model output today though being the time of year it is things can and have changed quite quickly in the past but like waiting for a bus we are going to have to continue to be patient.