Model Output Discussion; into 2015

[snowangel32]

Well, I will take this for the last op output chart of 2014 thank you very much...

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Much better run with an interesting ejection of energy SE on D8, better Arctic ridging throughout and eventual Greenland heights in FI land. A zonal outlook is soooooo 2014.

Happy New Years everybody!!!

Yh looks promising lets hope for a green and yellow new year for greenland and mild, so our little island will be white, Happy new year to all of you.

[geordiekev]

A Happy New Year to all on netweather.

Not long returned from sabbatical in Spain since April 2012 which was the 1st day of the terrible rain in UK, but have to say I sooo missed the UK weather.

The beauty of frosts, mist, dew, rainbows, storm clouds, amazing sunsets and even grey skies were such a miss. So I'm so glad to be back to WEATHER whatever it is, better than constant blue skies and heat.

We really are so lucky to have the widest range of weather on our small but beautiful island.

All the best, one and all!

[Mucka]

Happy 2015 all.

GFS Op fairly ordinary zonal until deepest FI where things get a little more interesting re cold chances.

It does show the strat warming well though, at least at the 10hPa level.

 

 

GFSp is better again in that it has deper troughing and so gives us more transient snow chances earlier.

It also gives us a Day After Tomorrow storm at day 10 with hurricane force winds and snow - that would be interesting.

 

 

Probably just as well it will never happen.

[Johnp]

New year.....same old dross from the models!

Looks like a stormy couple of weeks.

Happy new year, one and all!

[IDO]

GFS P quicker than I thought it would be to backtrack on it's height rises. The op and P at D8:

 

 

Still some fine tuning as to what latitude the jet fires through. ECM & GEM all have the same theme but variations of:

 

 

The GEFS and the mean from the last few days have picked this up well. A slight delay from a baby ridge in the flow from D3-5, that probably due to the changes in how the wedge of heights over the Pacific/Alaska interacted in the hi-lat; models now agree on that. That wedge created a brief respite from lower heights moving to the Canadian lobe and within that phasing two pushes of Atlantic WAA benefited our sector with transient heights.

 

The GEFS mean at D12 remains consistent with the zonal flow: 

 

Out to D16 (17th Jan) looking for any clusters that may suggest changes but they are as bad as they have been in the last 3/4 days. The Mean:

 

 

No surprise, looking at the charts, that the NAO remains stubbornly positive, with good agreement, right out till mid-jan:

 

The AO may be going negative mid-Jan?: 

 

I am not seeing on the ECM D10 chart any quick strat to trop coupling so it could be the case that there will the more usual delay? Then again with a PV that resilient the impact may just be inadequate. Further runs needed on that.

 

Happy New Year to all!

[fergieweather]

Shannon Entropy from end of next week falls to almost record-low levels, thereby exhibiting high confidence in the mostly westerly (and mostly cyclonic) story until end of 10-15d trend period, at least. More north of west bias by end, signalling drop in temperatures (unknown how pronounced).

[nick sussex]

Shannon Entropy from end of next week falls to almost record-low levels, thereby exhibiting high confidence in the mostly westerly (and mostly cyclonic) story until end of 10-15d trend period, at least. More north of west bias by end, signalling drop in temperatures (unknown how pronounced).

Hi Ian Happy New Year and Happy New Year to everyone here at NW.

 

Yes it looks like some very windy weather on the way and concerns IMO regarding any runner lows off the base of the troughing. I note looking at the ECM spreads that theres a wide spread in terms of where the Azores high might set up towards the end so this probably ties in with the more nw bias if the high displaces further to the west. That would of course bring temps on the colder side with wintry showers especially to the north and significant snowfall for the ski resorts in Scotland.

[Gibby]

HERE IS MY LATEST ANALYSIS FROM THE OUTPUTS OF THE WEATHER COMPUTER PREDICTION MODELS FOR TWO WEEKS FROM 8AM TODAY THURSDAY JANUARY 1ST 2015.

NEXT UPDATE FRIDAY JANUARY 2ND 2015 08:00

THE CURRENT GENERAL SITUATION A mild and moist SW flow covers the UK with a cold front moving SE across all areas todayand tonight leaving a ridge of High pressure crossing over from the West tomorrow.

MODELS-2 WEEK HEADLINE Rather changeable and sometimes mild with rain at times and strong winds too. Perhaps becoming quite stormy later and rather colder at times, especially in the North.

THE JET STREAM ENSEMBLE FORECAST(18z) The Jet Stream Forecast shows little change from that of recent output, remaining flowing in a relatively flat pattern West to East across the UK or close to the South between Low pressure to the North and NW and High pressure in a belt from Southern Europe and the Azores.

GFS OPERATIONAL The GFS operational this morning shows a prolonged zonal spell of weather coming up with just brief chillier and drier spells in a NW flow alternating with much longer periods of relatively mild but very windy and potentially stormy weather at times later before the risk of something rather colder develops from the North as pressure builds North through the Atlantic turning winds towards the North winth wintry showers and night frosts for all likely by the end of the run.

THE GFS PARALLEL RUN The Parallel run is very similar to the operational this morning with the emphasis on the wettest and windiest conditions affecting the North primarily with some drier and mild interludes across the South before all areas come under attack from a full blooded and powerful Westerly flow later with gales and heavy rain frequently for all. The parallel run makes less of the risk of colder weather at the end of the run maintaining milder West or SW winds, not quite as strong with further rain at times for all.

THE GFS CONTROL The GFS control run maintains Westerly winds throughout it's duration this morning, often mild and sometimes strong with rain at times. Some drier weather is likely across the South as High pressure is never far away to the South early on. Later in the run little overall change is shown with strong Westerly winds with rain and showers the order of most days with some chillier weather in the North between rainbands offering showers a chance to turn wintry over the hills albeit briefly before the next rainband speeds in from the West.

THE GEFS ENSEMBLES The GFS Ensembles show strong support for a Westerly flow to dominate the UK through the period. With Low pressure biased to lie to the North and High near the Azores and Southern Europe 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 and later in the period while the heaviest rain occurs across the North and West also principally at first while all areas are at risk of this later.

UKMO UKMO shows a typical Westerly flow across the UK through the coming 6 days. Having said that the most influence from this will be felt across the North and West with some longer drier spells across the South and East close to High pressure to the South and SE. While temperatures hold up reasonably well in the cloudier wetter periods some colder phases with patchy frost and wintry showers over Northern hills remain feasible.

THE FAX CHARTS The Fax Charts show the current trough clearing SE tomorrow followed by a more active set of fronts and depression over Saturday and into Sunday move East over England before a ridge and subsequent broad mild sector brings a return to mild and damp weather across the UK early next week.

GEM GEM today shows a sustained period of strong Westerly winds with gales possible in all areas especially later. Through the first half of the run the most unsettled weather will be across the North and West with the South and East seeing less in the way of rain but later as winds tilt from SW to more of a NW component all areas are liable to gales and heavy rain at times mixed with colder and more showery periods when wintry showers will fall over Northern hills in particular.

NAVGEM NAVGEM also shows a Westerly flow dominant across the UK over the next week or so. Some rain at times is likely for all but with some reasonably long drier spells across the South when some frost could develop if skies clear at night. Howver, by next weekend wet and windy conditions in a strong Westerly flow for all look likely.

ECM ECM this morning continues to promote Westerly winds across the UK. In the South winds will often be slacker with benign conditions for periods while the North sees the windiest and wettest conditions. Later in the run this model too strengthens the Westerly gradient across the UK for all parts delivering spells of heavy rain and gales and also bringing interludes of colder, brighter weather with squally wintry showers to all areas at times late in the period.

ECM 10 DAY MEAN The ECM 10 Day Mean Chart shows Low pressure to the North and High to the South the most likely scenario at Day 10. However, there is a desire to shunt this further East bringing increased influences from colder polar maritime interventions across the UK under a WNW flow with wintry showers mixed in with rainbands.

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The trend this morning remains largely unchanged though a trend towards much deeper unsettled weather is likely with time with Westerly gales widely and some more pronounced colder interludes between the mild rainy ones for all areas by mid month.

MY THOUGHTS There remains little desire from the models this morning to break the UK out of a predominantly Westerly flow of winds over the next couple of weeks. There are slow trends which promote some small differences in distribution of weather types across the UK through the period. In the first instance pressure never falls that low across the South with slacker winds allowing less rainfall than further North and behind any cold fronts some colder nights could allow some night frosts briefly. Then as the run period elapses all models indicate the trend towards more deeply unsettled weather for all areas with potential gale or even storm force wind risk in places and spells of heavy rain rushing West to East across the UK in the flow. This also means that behind each cold front then deeper colder polar maritime air will sweep through at times and bring a heady mix of sunshine and heavy, squally wintry showers before the next milder surge pushes in. This fast paced pattern remains in place until mid month at least. If i was to be picky there are some signs of a desire to rise pressure towards the Atlantic and maybe Greenland around mid month lifting the peristent vortex out of there and as the pattern drifts East there is the potential for a chance of something more akin to the GFS operational developing towards mid month which could give the UK a renewed route to colder conditions later in the month. There is however, little concrete evidence that this will be a given yet and while possible in future runs there is no cross model support for this scenario to be anything other than a chance at the moment. However, we will break out of this pattern sooner or later and as for the period of Winter thus far I still feel that our best chance of snow and ice is from the North rather than East with a more pronounced risk of a Scandi High late in the Winter and towards Spring when the seasonal zonal flow from the West traditionally fades somewhat. I will conclude though this is not a forecast and just a gut feeling that is what is most likely and based upon past experiences of Winter in the UK of which I have had many I'm afraid.

So on that note I wish all of you from my website and the forums to which I post a very happy and prosperous New Year for 2015 and thanks for all the support you give me with these reports through the year.

[KTtom]

Shannon Entropy from end of next week falls to almost record-low levels, thereby exhibiting high confidence in the mostly westerly (and mostly cyclonic) story until end of 10-15d trend period, at least. More north of west bias by end, signalling drop in temperatures (unknown how pronounced).

 

Just for once, couldn't you tell a whopping great lie.......something in the lines of.....

 

Shannon Entropy from end of next week falls to almost record-low levels, thereby exhibiting high confidence in a monster Greenland block  story until end of 2 month trend period, at least. More north of east bias by end, signalling massive drop in temperatures (unknown how pronounced).

 

If nothing else, the forum would be more entertaining than the dross on the TV! Happy New Year all.....what might of been

[Argyle1980]

Good morning and a Happy new year to one and all...

We start this year with a zonal flow but one thing I have been keeping my eye on is change around the middle of the month.

GFS and GFSp are showing this and the GFSP was on this yesterday and holds it this morning....

FI I know but it's trends wears looking for this far out.

Have a lovely day, GFS & GFSp .....

[bluearmy]

Ian and Nick have said the important stuff (and martins summary as level headed and informative as ever).

the trend to sink the pattern SSE so we take the Azores ridge and it's extensions into Iberia and the med and the trough drops slowly into our vicinity. Whether that establishes itself wth a mean just west, over or just east to be determined. Of course, the former will be less cold and the latter two offer some very wintry potential, especially with 'runners' guaranteed in the base of the trough. The gefs are broadly in line with this outlook which adds to Ian's assertion of low spread on the overall pattern though I'm sure there will be plenty of spread on when and where the small ridges and runners will ebb and flow. upland snowfall depth in northern Britain could be significant by mid month. those on low ground in the north can look forward to some events within this pattern and even in the snow starved south, opportunities would exist within this cold zonal trough.

The location of the mean troughing will also dictate where any Atlantic ridging may appear. Troughing close to our longitude or to our east will allow for it.

Still no sign of a desire for the extended modelling to want to move the vortex from west of Greenland. If it stays there (and there is an upper ridge forming just ne of svaalbard on the ECM suite which is a recent trend), then I don't see any reason why an established upper pattern will change markedly once we have it. That means the troughing could hang on for a while. getting into real conjecture land there, something which is very much at odds with low Shannon entropy.

the strat warmings continue but the general gfsp profile looks like being closer to reality than some of the exhuberant ECM ones we saw. Difficult to know what may follow up there as we are again without the Berlin wave charts this morning.

Edited January 1, 2015 by bluearmy

[Penrith Snow]

Shannon Entropy from end of next week falls to almost record-low levels, thereby exhibiting high confidence in the mostly westerly (and mostly cyclonic) story until end of 10-15d trend period, at least. More north of west bias by end, signalling drop in temperatures (unknown how pronounced).

Some of the charts this morning have a January 1984 look about them but tend to get downgraded as the time approaches which is a shame, we need to look NW for any cold as you can forget Scandy and Greenland Highs for a while yet.

Can I ask anyone what the Shannon Entropy is?

Andy

[Captain Shortwave]

It does look like the Azores high will lose some influence into week two as it shifts a little further away to the south west allowing a west or north westerly flow to dominate with spells of wet and windy weather interspersed by showers (wintry over the hills).

Mean 850s by day 10 look rather chilly for a westerly pattern suggesting a more polar maritime influence

So the first week of January looks like being a little above average temperature wise whilst week 2 looks nearer normal or even becoming slightly below normal. But no signs as of yet of a true cold spell emerging. Rainfall looks below normal away from northern areas this week whilst rising to around or above normal next week as low pressure becomes more dominant over the UK.

[KTtom]

Can I ask anyone what the Shannon Entropy is?

Andy

 

In one word....uncertainty.

[fergieweather]

The most striking thing in 00z EC-EPS clusters is how by T+360, all 51 members offer singular consensus on high pressure to our W, low to our NE; a broadly NW flow and apparent lessening of deeper cyclonicity from the NW. But a long way off for now.

[Frosty.]

I like this trend from ecm with the Azores high becoming less of a pain in the bum, becoming centred further sw enabling colder shots to swing SE, hopefully a more arctic spell will take over during second half of January.

[shaky]

The most striking thing in 00z EC-EPS clusters is how by T+360, all 51 members offer singular consensus on high pressure to our W, low to our NE; a broadly NW flow and apparent lessening of deeper cyclonicity from the NW. But a long way off for now.

fergie anything of interest in the short term! ! Regarding the shortwave gfs and gfs paralell have come in line with ecm and take it across the south midlands/m4!!

[Severe Siberian icy blast]

The most striking thing in 00z EC-EPS clusters is how by T+360, all 51 members offer singular consensus on high pressure to our W, low to our NE; a broadly NW flow and apparent lessening of deeper cyclonicity from the NW. But a long way off for now.

All very interesting but like you say it's a long way off and we'v all saw how ens can bark up the wrong tree , iv saw lots of times almost an entire suit go for cold , only for it to back off on the next set. Sounds nice but it all depends on how much amplification we can get out of the high to our west , if it's true polar sourced air then cold and snowy from the northwest , if its cold zonal then don't expect snow in the South . All to play for at this range mind.

[Cloud 10]

The most striking thing in 00z EC-EPS clusters is how by T+360, all 51 members offer singular consensus on high pressure to our W, low to our NE; a broadly NW flow and apparent lessening of deeper cyclonicity from the NW. But a long way off for now.

 

Something along these lines perhaps?

 

 

 

Happy new year everyone.

[fergieweather]

All very interesting but like you say it's a long way off and we'v all saw how ens can bark up the wrong tree , iv saw lots of times almost an entire suit go for cold , only for it to back off on the next set. Sounds nice but it all depends on how much amplification we can get out of the high to our west , if it's true polar sourced air then cold and snowy from the northwest , if its cold zonal then don't expect snow in the South . All to play for at this range mind.

Yes... I should stress I'm not solely focused on reporting cold/snowy solutions anyway. Merely reflecting the output; whether cold/mild/somewhere in between.

[Frosty.]

I nearly forgot to say happy New year. Unlike yesterday's 00z which were abysmal, the current models are trending towards an increasingly wintry further outlook which means January could end up being a good month unlike last year.

[IDO]

The JMA update from yesterday has strong support for the current GEFS FI:

 

Week 1:   Week 2: 

 

The next 2 weeks a strong zonal signal and the second week having the negative anomaly to our north, so possibility of storms.

 

Week 3-4: 

 

No sign of a change; and the anomalous 850's average to above. Again any anomalous +'ive heights remains on the other side of the NH.

 

The GFS 06z, not much change by D7:  

 

Later a continued theme of alternating PM and TM flows, with the former on this run in ascendency as the run progresses. The op keeps the stormy conditions mainly to the north.

[mushymanrob]

 

 

Also pleased to say it appears to me the mild, zonal spell won't be as prolonged as we initially thought.

 

wont it?... this morning theres nothing but average on the cards for the next 10-14 days in any model run. the noaa 500bm are consistent in their expectation of a strong westerly upper flow. any ridges will be transitory. looking pretty wet and windy for the first half of jan.. with alternating mild/cold blasts between systems.

no sign of settled, no sign of fog (other then low cloud/hill fog), no sign of deep cold in fact after the various 'building blocks' over the last two months have failed to bring a decent widespread cold spell (note widespread - not everyone had the mini freeze i did!) the synoptic pattern this morning looks a million miles away from any cold evolution. 

 

yeah i know, this wont be popular, but as things stand its accurate?

[mushymanrob]

, the current models are trending towards an increasingly wintry further outlook which means January could end up being a good month unlike last year.

 

return of the great double act time... lol..

 

see i disagree with this.... why?... because the building blocks that first raised their heads in early november are gone, northern blocking - gone, eastern blocking - gone, western blocking (that was expected to produce a pre crimbo freeze, then a post crimbo freeze) - gone . (yes some of us got a cold snap)

as i see it theres no sign of any building blocks, the noaa charts have a strong westerly upper flow for the next two weeks, the signals for blocking from any quarter have decreased and are now practically zero. so surely the trend is away from any cold, not towards increasingly wintry?...

of course if you take the deepest fi charts as evidence, then ok... but until charts like the current gfs 00z predicts reach the reliable/ semi reliable timeframe then they cannot be taken seriously.

sorry, pc awaiting re-formatting  unable to download and post charts.

 

 

[Frosty.]

return of the great double act time... lol..

 

see i disagree with this.... why?... because the building blocks that first raised their heads in early november are gone, northern blocking - gone, eastern blocking - gone, western blocking (that was expected to produce a pre crimbo freeze, then a post crimbo freeze) - gone . (yes some of us got a cold snap)

as i see it theres no sign of any building blocks, the noaa charts have a strong westerly upper flow for the next two weeks, the signals for blocking from any quarter have decreased and are now practically zero. so surely the trend is away from any cold, not towards increasingly wintry?...

of course if you take the deepest fi charts as evidence, then ok... but until charts like the current gfs 00z predicts reach the reliable/ semi reliable timeframe then they cannot be taken seriously.

sorry, pc awaiting re-formatting  unable to download and post charts.

Update from Fergie was good though mushy, trend for more of a north west flow with high pressure further west