Another balls up on the model runs? 

For me it pretty much was snowmagedon, I got more days off school in 2005 than I did in 2010 although the snow was somewhat less deep coming out I think just under a foot. But this is low ground, and it stuck around for a week! 

It's been a saga of willow it or won't it, and most of the time yew couldn't make it up

18Z ensembles definitely showing the weakening of the polar vortex after 300hr, backing the OP up. Number of colder options there. 

Poor model runs for any cold this morning again - hate to say it but unless there is an extreme event like March 2013 in the wings Winter is looking pretty much over for the south on this mornings runs. Pressure is just too high to the south which is always a killer for any cold, must admit did enjoy yesterday's sunshine down here so looking for some spring warmth now - GEM by +240 looks quite pleasant:

http://www.meteociel.fr/modeles/geme_cartes.php?&ech=240&mode=0&carte=0

Agreed.  The clock is ticking louder on winter BUT as Gooner says there are several weeks of potential left after the arbitrary cut off point of February 28th.  In just the last 10 years, the following spells IMBY delivered the most severe snowy weather in "spring"

2005 - early March snow fest. 

2008 - early April day based snowfall

2013 - March - 3 events in one month

However, on a personal level I could do without a cold spring this year and would welcome some gentle warmth and bright sun that just gradually crept up on us.  No spring heat waves as we always seem to pay for them when we can least afford to!

Yes I agree, April warmth especially seems to somehow be linked with quite a poor Summer - not always but certainly recent years it seems to be the case. Either way you can bet we will have excellent winter charts sometime in late March or April with loads of northern blocking come June!

GFS control run is rather interesting and still no agreement over the sliding trough later in the week

HERE IS MY LATEST ANALYSIS USING DATA SUPPLIED BY THE NWP OUTPUT COVERING 5 OF THE WORLDS MOST POWERFUL WEATHER COMPUTERS

THE CURRENT GENERAL SITUATION High pressure lying across Southern Britain today will drift away slowly East tomorrow but maintaining a very light Southerly flow over the UK.

http://www.wetterzen...cs/Rtavn001.gif

MODELS-2 WEEK HEADLINE Dry at first and possibly again later with an unsettled period from late this week and into the beginning of next.

THE GFS JET STREAM ENSEMBLE FORECAST The Jet Stream Ensemble Forecast shows the flow blowing in an Eastward motion to the North of the UK. Later in the week it dips South across the UK in association with a trough and this may be repeated next week before it realigns back to the North of the UK late in the period.

http://www.netweathe...ction=jetstream

GFS OPERATIONAL The GFS operational today shows the current High pressure slipping away East at the end of this week with Low pressure troughs crossing East over the UK at the weekend and early next week with several spells of rain in a blustery breeze and average temperatures. then through the second half of the run High pressure rebuilds from the South to lie over or close to the UK later with mild west winds in the North with further rain in places there while at the very end of the run High pressure located in a colder pool of air could bring widespread frost and cool weather to the UK by Day 15.

http://www.wetterzen...s/Rtavn1441.gif

http://www.wetterzen...s/Rtavn3841.gif
 
THE GFS CONTROL The GFS control run shows a very similar sequence of events over the next week as the operational model with all areas seeing some rain for a time. The same build of pressure shown by the operational is shown by the control run too towards the South too late next week before weak troughs bring new interventions of High pressure behind them, positioned such that colder air moves into the UK and as High pressure then moves across to the NE a bitter easterly wind sets up over the South with the risk of snow showers.

THE GFS CLUSTERS The GFS Clusters today continue to indicate that High pressure is likely to be positioned somewhere close to the SW of the UK in two weeks time. There are variations within members that show a different positioning of the High but without too much fundamental difference in weather differences at the surface in what would likely be generally benign and non-descript conditions.

http://www.weatheron...=0&WMO=&PERIOD=

UKMO UKMO this morning shows Low pressure moving into the SW of the UK late this week with some rain there before the Low is shown to pull away South leaving the UK under 'Col' conditions over England and Wales with a milder SW flow over Scotland by next Monday.

http://www.wetterzen...cs/Rukm1441.gif

THE FAX CHARTS The Fax Charts this morning show High pressure declining away to the East through this week leaving slack winds behind until the end of the week which shows Low pressure and associated troughs edging into the South-West of the UK by the weekend.

http://www.weatherch...momslp.htm#t120.

GEM GEM shows a similar scenario to the majority of the output with an interruption in the fine weather by Low pressure troughs moving over from the West from Friday and into the start of next week. High pressure is then shown to slowly regain authority from the SW sending any rain bearing troughs away to the North where a stronger but mild SW flow will blow before veering towards a cooler WNW flow by 10 days time.

http://www.wetterzen...cs/Rgem2401.gif

NAVGEM NAVGEM shows a much more unsettled period developing in the wake of the trough on Friday as a period of sometimes wet and windy weather moves across all areas at the weekend followed by colder weather with wintry showers in the first half of next week in a strong and cold NW flow.

http://www.wetterzen...cs/Rnvg1681.gif.

ECM ECM shows the weather becoming much more changeable across the UK from Friday as the model shows the Low on Friday filling but leaving a trough near to the SW and linking to further instability moving in off the Atlantic from the West. This then leads on to a spell of much stronger winds and rain at times as various troughs pass over the UK in the strong flow followed by colder and blustery conditions in NW winds and showers, wintry over Northern hills.

http://www.wetterzen...cs/Recm2401.gif

ECM 10 DAY MEAN The 10 Day Mean this morning maintains the prospect that pressure is biased lower to the North of the UK and higher to the South and SW. The main belt of High pressure from the Azores will keep the UK in a generally Westerly flow with the biggest chance of the more unsettled and breezy weather likely to the North of the UK.

http://www.wetterzen...cs/Reem2401.gif

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The long term trend today has show a shift towards less High pressure domination as most output show High pressure held further to the South next week with more risk of a stronger Westerly flow spreading to many areas next week and rain affecting the North at times and possibly to the South too.

31 DAY HISTORICAL VERIFICATION STATS FOR GFS, UKM & ECM The current verification statistics for the past 31 days shows ECM leading the way at 3 days with 97.4 pts followed by UKM at 96.9 pts and GFS at 96.2. At 5 days ECM just about leads the field at 89.8 pts over UKMO at 89.2 pts and GFS at 86.9. At 8 days GFS takes over with 62.5 pts over ECM's 62.1 pts. Then at Day 10 ECM regains superiority at 46.3 pts over GFS at 44.5.

http://www.emc.ncep....L_MSL_G2NHX.png

http://www.emc.ncep....L_MSL_G2NHX.png

http://www.emc.ncep....L_MSL_G2NHX.png

http://www.emc.ncep...._MSL_G2NHX.prig
 

MY THOUGHTS Todays output has shown a small shift towards the chance of more changeable and breezy conditions to last rather longer than the models were originally programming earlier in the week. The introduction of this weather type is still likely on Friday as a trough moves into the UK from the West bringing some rain at least to the South and East. The models from the States indicate this as a trough crossing East over the UK while the models from this side of the Atlantic show a Low pressure cell close to Southern Britain slipping away South from the UK leading us into a slack no mans land area of atmosphere for a time with quiet and benign weather before all models then come together in bringing a spell of windy and changeable weather with rain at times to start next week. It's then all about how long this changeable theme lasts and how much High pressure still to the South and SW rebuilds sufficiently to shunt rain bearing fronts and Atlantic Westerlies back North to Scotland and return drier and more settled conditions from the South. Some output does indeed build High pressure over the UK later and the GFS Control run then migrates that North to Scandinavia later which would bring a draw of very cold wintry air with origins over Eastern Europe across the South for a time. This has little support though overall and the overwhelming factor is for the UK to lie somewhere between High pressure to the SW and Low pressure to the North with anything between mild SW'lies and colder NW'lies possible later a theme backed up from the ensembles. With regard to temperature there seems little evidence of any return to UK wide Winter anytime soon with temperatures often staying close to average with any wintry precipitation likely to be restricted to the hills of the North in any polar maritime NW'ly interventions of air later in the period.  

Issued at 08:30 Tuesday February 10th 2015

Looks like increasingly unsettled and chilly towards the weekend with rain at times.

With a changeable week to come thereafter.

Another very frustrating run from GFS in its 6z, at least for those keen in a cold, snowy spell from the East.

At t132 the Scandi High is ridging NW, there is an Easterly component over the UK and there is cold pooling to the East of Scandi. However, as has been the general pattern this Winter, there is insufficient energy heading South and the Azores High exerts it's influence by nosing in from the SW and the Easterly collapses.

A familiar story, with the dominance of the Azores High making it impossible for any sustained heights to our N/NE. The Azores must be a dry place this Winter

It actually occurs twice - once in the Hi Res section and again later. Both times, the Azores High spoils the party.

tamara post from NW --- which needs translating  ??????????????

It was expected to be a struggle anyway, but a traditional cold late winter European weak El Nino pattern is not materialising. However, the atmospheric state after mid January showed some reasonable signs this might happen to sustain the increasing interest that had been developing from this time and took us into the opening days of February.

Some sceptics on this thread clearly remain about the influences that the large scale atmospheric state has on the NH pattern, but the GWO has sketched out this -AAM pattern very clearly in the last few months with its repeated low angular phase states - punctuated in the second half of winter with brief incursions to more Nino like amplitude phases.

Whether one likes it or not, or whether one agrees with it (or me) or not, the patterns this winter across the NH have replicated this atmospheric state exactly to what is said on the tin. It just happens to be the case that this type of tropical Pacific led pattern is not favourable for the development of cold blocking our side of the NH, beyond periodic Atlantic amplifications during the winter months. But then this has been repeated more than a few times for quite some time now.

A West Pacific Tropical Cyclone helping to further pump up NH mid latitude anticyclones downstream from the sub tropics and current low amplitude and incoherent extra tropical (GWO) and tropical (MJO) signals are, in the very short term, masking those continuing trends of the whole winter.

However, the eventual destination is the same one as posted last week - with troughing on a NW/SE axis ahead of further amplification in the extended period. The question, as posed towards the end of last week, is when this occurs and not if it will occur

GWO orbit suggestions have remained steadfast on this, only simply delayed by upstream developments. Twin Mountain torques are in the process of occurring (EAMT already has occurred) which are set to provide vertical wave activity both sides of the pole and will serve in the extended period to pinch the vortex, much as they did in late January.

This process will serve to send vorticity energy across the pole and the weather become increasingly more mobile into the medium term. Timing is hard to be precise, but towards the 15 day period we are looking towards a next incoming amplification phase feeding downstream from the Pacific - and whilst it is difficult to know the extent of any possible colder conditions this might provide, it fits precisely with the cyclical pattern seen this winter.

GWO set to increase amplitude into Phase 1/2 in the extended period. This is only forecasted at this stage, but it is logically underpinned as twin torques re-initiate low AAM tendency - which subsequently drives the GWO orbit on to these phases.

Much as it has done at least three or four times since December

Phase 1/2 signals that next Pacific retrogression - which will serve to draw the Azores High further west much as it has done periodically during this winter to give the colder spells we have seen. These low AAM phases in (probably) late February teleconnect well to a NW European trough and NE Atlantic ridge.

The trend as we head to winters end and into March is to see the retrogressive signal increase - the shortening wave lengths under this -AAM regime (the reasonable assumption here is this entrenched atmospheric state will continue for a while yet) are supportive of a below average start to Spring as cold air expelled from the Arctic becomes more and more likely.

That might not fit with the changing wave lengths of the audience in this thread, with increasing numbers wanting to put on their sunshades instead of snow goggles - but again, whether one likes it or not a typical amplified change of season mix seems in line with prospects - as I see things anyway at this stage.

As one who prefers deep winter cold, but still receptive to late wintry surprises (and likes to continue to watch weather patterns unfold throughout the year anyway) I am looking forward to seeing how things progress as always

http://www.atmos.alb...wo/gfsgwo_1.png
          

I think it translates as "we might get a cold snap in March but probably not"

None of this bodes well for the OPI.

Anyway the 6z seems to again illustrate the trend for a transition to perhaps colder weather in the >300hr period. High pressure reestablished across the UK combined with a weakening polar vortex does make the situation more favorable. 

But it will be the last week of February, any cold shot before is highly unlikely.

And do not get your hopes up about the 'snow event' this weekend, while evaporational cooling under light winds can do wonders, when there is no cold air at all I really think it will struggle, a cold frosty night could make all the difference imo.

What's this got to do with inflation?

Perturbation 6 on the GFS is the sort of thing that could happen. Be thankful this possibility is being shown at all.

Actually I'm surprised how many of the 6Z ensembles are pretty damn good. There is some real support for a wintry blast to end the month, will be watching this very closely.

My personal favorite:

But it is by no means alone, by 300hr support for a strong cell of HP to the west, south or over the UK is basically unanimous. The interaction of this high down the line is very classical with a trough attacking the main high, only to pump up a secondary ridge to the west, and the cycle continuous with the high favoring a more northern/western position. 

Full ensembles; a mean of -3 at 384hr is pretty impressive, note that the control and OP are mild outliers in this case.

Perhaps more importantly, this.

Note the peak around the 21st? That is roughly the 300hr mark I keep referring to and with a mean of 1030mb you can't really get much more confident at that range! The quick decline after 300hr, is due to the HP being kicked by troughs from the NW, thereby promoting pulses of HP to come up again from the south but this time to be much further to the west. Most seem to attempt this, with the ones suceeding usually resulting in brief cold spells, the very cold runs are due to the classical case of this being taken right to the endgame with HP ridges shifted further and further west until they naturally move to greenland.

Incidentally this is one of the two most common methods to promote a greenland high from my experience. The other involves setting up a scandanavian high and then using a 'slicer low' to force it to relocate to greenland. I prefer this method imo, because scandi highs are unstable and unreliable, and this one puts you in the freezer quite quickly without an annoying faux cold period.

Hi all,

Here's today's video update;

Extreme Cold In America + Let Battle Commence Here;

http://www.gavsweathervids.com/ 

Thanks Gavin, very interesting vid. Looks like my relations on the Cape (Massachusetts) are going to stay very cold and snowy.

But not much of a battle though. At least the weak scandi block may come about but it gets blown away in every ens member

Honestly that scandi thing doesn't interest me in the slightest, it won't produce anything of note away from the hills unless a warm front stalls and even then its unlikely. Anyway 12z is pretty awesome for the longer range. Look at this:

HP established across the UK; excellent  Notice the secondary ridge south of Newfoundland.

Attack by trough to the north, Primary high declines to the SE

First pulse from the secondary high, notice how the centre is now further to the west and the north than the original primary. This is now the new primary, with the secondary forming once again south of newfoundland.

2nd attack causes primary to decline to the SE, notice this time we almost get a northerly.

Secondary high pulses from the south, notice the centre is once again even further west.

By this iterative procedure, the HP will move further and further west and north, it is something I have observed countless times, eventually it gets to a stable location in greenland provided there is no pattern change. Also this is another reason why I do not want this bloody scandi high, this is a great situation to be in, it doesn't always get to greenland but it has a decent chance, I want to at least attempt this journey, not have a bloody scandi high preventing it before it has even begun. 

All I can say is...

Q, I have chosen this paragraph to comment. You have selected a chart for +384 and then said it might happen so long as there is no pattern change.

It is surely the model output equivalent of tipping a cup of water into a river and then expecting to recover the same water five miles downstream.

It is an interesting explanation of what might happen, but has very little chance of actually occurring like that. Time will of course tell.