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Model Output Discussion - 31/10/2014 and Beyond


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Can we keep any moans to the banter/moan thread please, As others have indicated, We are very early in the Season and Winter has not even started yet. There's plenty of time for Wintry weather in front of us, And maybe this will be a learning curb for some not to build to many hopes up from delicate but very interesting output.

 

Please let's continue to discuss what the Model Output's are showing.

 

Many Thanks, PM

Edited by Polar Maritime
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Would have thought a mid lat/ n of Scotland high has as much chance of verifying as an Atlantic onslaught.

At day 10 (and if the last week or two taught you anything it should be not to look at ten day ops) only the soon to be defunct GFS has the Atlantic steaming in with the parallel into low res following suit.

Add to that the more reliable gefs in fi range are still unable to indicate a reforming p/v to concern us and I can't see what all the fuss is about. It's only patience needed because it's only November (before the middle!)

Edited by bluearmy
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No surprises this morning. I think we are seeing that the models are reverting to the modus operandi as the PV gets better organised (though remaining far from normal). With the block to our east, timing issues remain, which on the surface may translate to intensity of the lower height flow from the NW. So at least some of the stored up energy from the upcoming US cold pool will likely spill into the Atlantic; ECM has on previous runs sent the majority of energy into the other PV lobe allowing heights to build over the UK. Today they are allowing a bit more, but are still behind the other models.

 

The next question is how long this westerly flow will last. Looking at the D16 GEFS its hard to be confident that we will escape its grip before December. The D16 mean is quite strong:

 

post-14819-0-28681000-1415779116_thumb.p

 

Only 4-5 members suggest some sort of blocking in our region. The MJO signal suggest heights building over the UK in around 3 weeks time so maybe that is the next change. With wave 1 warming in the background also hinting at maybe height rises early December then that date looks a good target. In the interim with the meridional flow easing (after D6-7) this should allow the uppers (850's) to become more mobile, so I suspect there will be a cooler more seasonal flow, especially for Northern regions:

 

London: post-14819-0-42407500-1415779513_thumb.g

 

Rain is the main concern and if we do get that chunk of the PV from the US like the GFS P has been suggesting for a couple of runs then flooding may be a concern (13 days away so low confidence):

 

post-14819-0-92598600-1415779925_thumb.p  About 33% support on the GEFS for this though in various states of warming out.

 

 

 

 

 

 

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General trend continues across the models this morning for mild wet weather to predominate with the ECM showing heights dropping over Greenland and rising to the south of us and most of Europe. Natural forcings very evident and the default early winter pattern setting up so nothiing unusual really.

ECM illustrates well

 

Recm1681.gifRecm1921.gifRecm2161.gifRecm2401.gif

Although there is still the 'marvelous' 'split vortex' picture the main lowering of heights is gathering pace over N Canada / Greenland

Recmnh2401.gif

 

 

OK - on the plus side there is some sign of 850hPa tenps trending down to average and there are a few more cooler / colder runs appearing at the latter end of the ENS runs.

MT8_London_ens.png

Still looking very wet though so the picture from the GEFS suites appears to be cooling somewhat but remaining very unsettled - in contrast to ECM which indicates a drying trend but with mild temps generally. So an uncertain outlook apart from no convincing signal for anything cold yet awhile. :)

Edited by Purga
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HERE IS MY LATEST ANALYSIS FROM THE OUTPUTS OF THE WEATHER COMPUTER PREDICTION MODELS FOR TWO WEEKS FROM 8AM TODAY WEDNESDAY NOVEMBER 12TH 2014.

 

NEXT UPDATE THURSDAY NOVEMBER 13TH 08:00

 

THE CURRENT GENERAL SITUATION Troughs will clear NE over the UK today with a showery SW flow following. Tomorrow sees a strong South flow ahead of a further Active trough arriving from the SW later.

 

MODELS-2 WEEK HEADLINE  Unsettled with rain at times across the British Isles especially over the South and West at first and the North and West later. Drier and slightly colder weather over the North and East for a time from this weekend.

 

THE JET STREAM ENSEMBLE FORECAST The GFS Jet Stream Ensemble forecast shows little sign of any significant shift in the flow from it's 50-55 deg North location with a split flow for a time with a weak Northern arm travelling East over the Arctic Circle. The flow will blow with varying strengths and orientation this side of the Atlantic the only changes through the period.

 

GFS OPERATIONAL As of previous runs the run concentrates on two different elements of unsettled and wet weather over the two week period. The first week sees Low pressure on Southerly latitudes, mostly near Southern Britain with rain and showers for all as a result in generally mild conditions in a South or SE wind. Over week 2 more mobility is shown as Low pressire migrates towards the NW with SW and West gales featuring frequently in periods of rain and showers moving much more quickly East and average temperatures seeing all areas through to the end of the run and beyond.

 

THE GFS PARALLEL RUN The GFS Parallel run is broadly similar in trend but does indicate a drier and mild period over some Eastern and SE Britain for a time early next week as pressure builds over Europe before the very windy and wet conditions arriving in the NW then spreads to all areas by the end of the run.

 

THE GFS ENSEMBLES  The GFS Ensembles are much more akin to it's operational version with a very mobile and potentially stormy spell of weather likely over the UK in Week 2 with severe gales likely almost anywhere. All this of course following another 4-6 days of being under the influence of slower moving Low pressure as it drifts down towards Southern Britain over this period. Very late in the run pressure is shown to rise from the South over the South setting up drier and relatively mild weather then.

 

UKMO UKMO today shows Low pressure close to Southern Britain continuing to fill but remain influential enough to maintain rain at times over Southern Britain. A ridge of High pressure from an European Anticyclone lies West across Scotland early next week with dry and bright weather with some frost and fog possible up here.

 

THE FAX CHARTS  The Fax Charts maintain that the UK skies will be governed by Low pressure with concoction of troughs moving gently North and NE across the UK. Innitially there will be strong winds in places but later pressure becomes slacker as Low pressure is shown to fill near Southern England with rain at times still for all well into next week.

 

GEM  GEM shows Low pressure holding control over Southern England early next week as the current deep mid Atlantic Low drifts ESE slowly towards this position over the coming daysat the same tome as filling slowly. After a couple of days of ambling around over the South while the North gets breathing space from wind and rain under a ridge from the NE Low pressure gathers momentum again moving NE from the SW to return wind and rain to all areas again later next week. Temperatures though mild at first will probably fall back to more average levels later especially under the strong SE flow over the North late in the run.

 

NAVGEM NAVGEM keeps Low pressure domination across the South of the UK with a deep centre over the Atlantic drifting down over Southern England by early next week filling steadily. As with GEM rain for all at first will become more restricted towards the SW for a time before a renewed Atlantic attack returns NE across the UK later as High pressure to the NE declines slowly later at the same time as receding SE.

 

ECM  ECM this morning continues it's recnt run of different evolutions to the rest of the models, this morning showing a slow rise of pressure late in the run under complex synoptics which sees a cut off Low near the West of the UK at the end of next week with rain at times and a slack and benign look to the UK synoptics at the end of the run with a lot of dry if benign and cloudy type weather under pressure that has risen sufficiently to develop a High centre to the NW at the end of the run in average temperatures.

 

THE ECM ENSEMBLES   The Ensembles point to a SW flow of some sort the most likely outcome covering the UK in 10 Days time in association with Low pressure over the NW Atlantic and higher pressure over Europe. No doubt that troughs of Low pressure will lie somewhere close to the UK delivering rain at times in continuing mild conditions.

 

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The trend today generally focuses on maintained unsettled weather but with a change of emphasis of rain shifting from the West and South more towards the North and West as SW gales develop later.

 

MY THOUGHTS  The pattern of weather has shifted away from anything colder moving towards the UK in preference to a more mobile and potentially stormy spell of weather through the second half of this morning's output as Low pressure close to Southern Britain early in the period is absorbed by strong and deep Low pressure centred more towards the NW of Britain later which forces the High block to the NE to collapse SE and bring fast moving spells of heavy rain and strong winds East over all areas coupled with potentially stormy conditions. As always there are exceptions to this as there are some options that show High pressure possibly building from the South later and bringing drier and mild conditions into the South at times later. Also ECM continues to be different and brings a more universal rise of pressure over the UK late in it's operational run resulting in a slow dry out of current conditions into quiet and benign conditions in average temperatures if it verifies. It's Ensemble pack bases itself shows Low pressure being likely to be positioned to the NW in 10 Days time with a SW flow and troughs continuing to carry rain at times most prolific towards the North and West. So very little support there from it's operational again. In my opinion this morning the overlying support lies with Atlantic based weather continuing over the UK for the next two weeks with a shift in emphasis of the worst weather likely to shift to the North and West as the High pressure block to the NE largely collapses in the second week. The trend is also for more mobility to the sytems as they look to zip East quickly later on a strong Jet over the UK with severe gales at times offered from some output. The only grain of comfort for a pattern shift to something chilly is flown by the GEM operational today as it shows the cold block to the NE holding back the push from the Atlantic across the UK. However, without much support it really is a candle in the wind this morning.

 

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Alas, the blocking to the northeast of the Uk on this mornings runs show its not going to be anyones friend if you want early cold. It looks as though, if anything the Atlantic  going to step up a gear next week and give us some potent wet and windy weather at times. The saving grace for coldies is the gfs in picticular shows some cold air entrenched in the low pressure systems to give at least some limited wintry weather over high ground, but at the moment that's about as wintry as we are going to get. Once again ,high rainfall totals, and subsequent flooding may well be an issue in some places in the near future. :closedeyes:

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post-6830-0-15093700-1415784111_thumb.pn

post-6830-0-13045200-1415784150_thumb.pn

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Indeed, this mornings output in the troposphere, in our area, is poor enough from a cold lovers immediate expectations. But just to stop all the doom and gloom. The polar vortex (winter killer as I call it) is far from organised, and by the model output of the stratosphere with wave 1, and now wave 2 activity forecast, with potential mountain torque events, the PV will not be getting organised anytime soon. 

Now you may say, that these models could well be wrong too, and you'd be correct, but in general, the strat models are often more accurate with their predictions than the trop charts. I'd be pretty confident we will have a decent cold spell, but not within the next week or maybe 2, but hey, it's not even proper winter yet!

To get a proper insight to strat events, may I point people over to the strat thread here https://forum.netweather.tv/topic/81567-stratosphere-temperature-watch-20142015/ the incredible regular contributors share their wealth of vast strat knowledge, and dumb it down to understandable English, for the dummy like me! 

 

Keep the faith, cold lovers!

Edited by Rocheydub
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Looking at the ECM and GEFS anomalies this morning there is pretty noticeable change from yesterday which is not something straight off the stop press.

 

The evolution from T192 is very similar on both so following the GEFs will suffice.

 

At T192 the pattern is a blocking HP Alaska connecting to the HP Scandinavia but with a ridge connecting to the Bermuda high. Low Pacific, NE Canada (the key one) and a trough W/SW of the UK. Following the sequence sees the ridge vanishing from the Atlantic, slackening of the eastern block and eventual disappearance and increasing dominance of the Canadian trough in the Atlantic. From this scenario it's easy to understand why it seems very likely that the westerly unsettled weather could continue at least until the end of the month.

 

post-12275-0-52606600-1415785074_thumb.p

post-12275-0-50557600-1415785081_thumb.p

post-12275-0-72259100-1415785089_thumb.p

post-12275-0-80097300-1415785097_thumb.p

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Continues to be a very interesting variety of output with many possibilities and of course variables. As somebody else put it, "something for everyone" sums it up well as regards what may happen in the short to medium term. As for the main character in the drama itself, the weather, it's already been more interesting than it had been forecast a week or so ago, with some really heavy rain in parts, along with squally winds. (Some great sky-scapes too I might add, rarely typical dreary November).

There's a gradual cooling trend and from the output in general I can see further cooling likely overall, with potential for some winteryness either through PM air wrapped up in one or two of the troughs coming very close to these shores, and/or through a cooler anticyclone that may develop or extend over us. Both of these scenarios at this stage of autumn would be very welcome to many I'm sure, representing something that we traditionally call 'seasonal' (has to be taken in the context of changing climate!) and possibly also a drying out opportunity for areas affected by/at risk from serious flooding.

 

Finally there is also the potential, narrowly missed so far this autumn, of some major stormyness to occur over these islands in the near future. November has been a month where in the past some of the most significant storms have occurred but if my memory doesn't desert me I can't recall many such events in the last 20-30 years or more. Alot of rain, alot of anticyclonic periods but not that many major storms.

Startling contrast between GFS & ECM outputs this morning too, one very disturbed even in the shorter term, the other very settled overall.

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Good Morning, I am not sure the main models show overly mild after next weekend. Drying up, particularly in the east and temperatures will be around normal and it may feel chilly in the E/SELY win flow. ECM still showing some high pressure resistance in the vicinity of the British Isles.  Beyond that the UKMO still expect a SWly to return, especially in the NW with GFS increasingly backing this thought. However, ECM still showing a difference line of thought and may prove to be a surprise winner !

 C

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Was trying to post a comparison but this completely rubbish and ancient computer system at work won't complete the task...so intended post removed.  Basically was trying to show that we are not 'as yet' headed same way as last winter.

 

BFTP

Edited by BLAST FROM THE PAST
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The GFS 0z ensembles look fairly interesting to me, there's a growing cluster of colder solutions in FI, when comparing to the 18z & 12z suite from yesterday, a muted signal at this stage but worth keeping an eye on.

I don't see the mild charts that some are mentioning, there's nothing 'mild' in a reliable timeframe.

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Yes agree with Steve here and also in not alienating others, I can also understand what some of our other experienced members are hinting at too. So if I were to do a brief summary of where things are heading, I would suggest the following attempt at a forecast.

 

Near-term up to the early part of the weekend.

 

Showery outbursts in most regions and perhaps more general rain (some heavy) towards the SW along with strong winds on Friday, Temps slightly above average at 13c or 14c in the larger cities.

 

Weekend into early part of week commencing 17th November

 

Nothing really changed here broadly speaking with the Easterly still forecast, for some 4-5 days it has been shown that North Eastern and Eastern parts look likely to endure the coolest and perhaps cloudiest of weather. Far from snow inducing synoptics at this range but a shock to the system for a few coastal residents for sure in the Easterly winds. NOT! a strong flow either though so certainly not beast.

 

From t+192 hours (next Thursday 20th November into the final third of November)

 

This time next week, the general synoptic situation over the UK remains very unclear. here are a few likely outcomes, or not as the case might be.

 

  • Will the Atlantic get reinvigorated by the shenanigans over the Eastern Pacific.
  •  
  • Will the HP towards the North of the UK strengthen further as indicated by certain model outputs and eventually hold some hope for drier weather for all.
  •  
  • Will the Greenland heights build stronger as again indicated by some outputs and at least halt or deflect any reintroduction of the Atlantic as we head deeper into late November.

 

Questions, questions, questions with no answers yet but before this week is out, we should at least know some answers. Let us not forget it is but only the 12th November.

Edited by gottolovethisweather
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Although a follower rather than a poster the last 4 years I feel compelled to post as some of the posts have been a bit OTT in last day or so. Yes, if you are a follower of the GFS it seems the prospect of a potential cold spell seems to diminish but there is so much volatility atm things could and probably will swing one way and the other much like a Nadal v Federer tennis match !!.As a previous poster stated just look at how models swung in November 2010.I love the cold and snow as much as I like warm sunny summers but we just have to be patient if cold is what you want. Personally I think that the Atlantic will have upper hand(not scientific, just a gut feeling and in my 43 years on this planet and having a huge enthusiasm on the weather, history will tell me this).However, we are in a totally different place to last year with split Vortex, Higher heights to NE and NW than last year, negative OPI etc etc so I don't expect a winter this year like last year.I have big respect for the likes of SM,JH,BFTP etc who have increased my knowledge and understanding of the models and I think this winter will have something for everyone although it would be nice to have a 2 week epic spell like they are experiencing in the likes of Minneapolis atm lol.

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Hi Steve^^^ The 06z is notorious for slowing down the Atlantic. Its runs yesterday were completely off kilter with the 12z runs:

 

post-14819-0-95751400-1415788169_thumb.p  post-14819-0-00553300-1415788180_thumb.p

 

Parallel and op building UK heights on yesterdays run.

 

Though I do agree there are strong ScEuro heights with energy splitting from the US cold pool to our NW and the Azores also in play trying to build in. However I do not see where the cold is coming from. e.g.  the GFS op 06z has indeed again greater heights and we enter in a mild southerly flow:

 

post-14819-0-70263500-1415788465_thumb.p  In FI its zonal but more N/S split: post-14819-0-86005000-1415788936_thumb.p

 

The Parallel looks like it will again bring in a warming cold pool from the Atlantic for a washout: post-14819-0-40710200-1415788579_thumb.p

 

It comes down to whether you believe the ECM is not leading you up the garden path again, it has dumped the idea of heights over Greenland from a few days ago, now it goes for heights elsewhere. The latest UKMO for the next 15 days suggests average temps: http://www.metoffice.gov.uk/public/weather/forecast/gcpvj0v07. They are going with the return of SW winds, not unlike the D10 P 06z:

 

post-14819-0-33663400-1415789177_thumb.p  D13 GFS P: post-14819-0-86280600-1415789570_thumb.p

 

 

Edited by i'm dreaming of...
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Yes currently looking at all current charts and Data it does look like a couple of weeks of Atlantic dominated weather .but things can change on that horizon of ours which seems to be around six days plus .Some very interesting weather going on in the northern hemisphere at present which gives me personally great encouragement on the coming winter ,.Its going to be a case of sitting back and learning as much as we can from eachother over coming months .This forum of ours i,m sure his the best ,Certainly beats just looking at charts out to t120 hrs which some of us only had 30 years ago , and boy did they change by fairly big margins everyday .And here we are Free charts great forum ,we are all on a winner ,Bring the winter on . :cold:  :drinks:

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Hi Steve

I thought you said to disregard the 06z run as it was the most unreliable.

From my not very experienced view point the charts are looking like last year where the Atlantic came in late November and never left !

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IDO

 

there is likely to be a 'push' east of the deep cold out of the states at day 7-9, a phasing of the subtropical & polar jet could well see a deep low somewhere close to the NE corner delivering a winter storm-

 

At that point the storm track is critical - if its an inland runner upwards & comes up through Winnipeg slightly shallow then like the GEM says the blocking could hold & split with the cold separating- 1 lobe will do an orbit of the US heading back into Canada & the other angled SE across the atlantic-

 

post-1235-0-44556500-1415789879_thumb.pn

 

Now look at the GFS phasing-

 

post-1235-0-80122900-1415790033_thumb.pn

 

The GFS has the system more positively tilted so it slides off fast - the 00z was even faster with more positive tilt.

 

 

it all boils down to storm track & speed + Phasing. If the pacific jet is slower & more amplified the jet will dig further into the US, then the track will be more inland, faster & flatter & the GFS will be there.

 

I suggest the GEM is overdoing it & the GFs under doing the amplification-  so a meeting point somewhere in the middle is likely which is difficult to portray on the charts as there doesn't seem to be much scope for halfway house- it seems all or nothing.....

 

S

 

 

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