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Model Output Discussion 18th Nov.2013-12z onwards.


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The Gfs 00z shows high pressure building in across the uk and intensifying early next week with temps below the seasonal average and frost overnight along with fog patches, later next week, pressure begins to leak away and the pattern gradually flattens out with atlantic weather sweeping in, however, high pressure has another go and gets a foothold across the southeast but the north and west generally unsettled..even a cold snap later on the 00z with frost and wintry showers into the north.

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The Ecm 00z ensemble mean shows a decent spell of anticyclonic weather with sunny spells and night frosts with fog becoming the main hazard, however, as time goes on, the anticyclone drifts away slowly southeastwards into mainland europe with pressure falling to the northwest of the BI heralding a more unsettled phase by the end of the month and into early Dec with temps returning closer to average, some milder wet and windy spells / some colder showery days.

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Total agreement across the board this morning for high pressure over the UK, no chance of this getting further north, too much energy running over the top and and the upstream pattern continues to flatten out.

Frost and fog possibilities but much depends on where the high eventually sets up, after that its looking underwhelming from a cold perspective, with the PV increasing to the north.

The models overall have not had their best day, especially the ECM which as last winter continues to overamplify the upstream pattern and develop phantom positive heights further north.

Indeed we saw across the board the models making a mess of the upstream pattern but the Chump award certainly goes to the ECM.

PS To the Mods now that the will it won't it easterly has imploded any chance we can get the names back at the bottom of the page as I doubt the server will be under too much stress for the next few weeks!

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Hmm was it ever on for widespread snow in any case?

 

Other than what some of the media over hyped no, the BBC weather videos from day one said Tuesday and Wednesday would see the peak of the cold

 

Latest from Gibby

 

All models show a deep Low pressure moving South down the North Sea on it's journey towards Southern Europe and the Mediteranean tomorrow. As a result today will be an unsettled and rather cold day with showers and outbreaks of rain, wintry on hills affecting many parts, some of it heavy and squally with hail a possibility. Later today, tonight and tomorrow improvements will sequentially move down from the NW as pressure builds strongly. By Friday the improvements to dry, cold and settled conditions look complete with a fine but chilly weekend with frost and freezing fog patches night and morning looking likely but with pleasant daytime weather where fog clears.

 

GFS keeps High pressure over the UK for much of next week with the continuing likelihood of overnight frost and freezing fog to keep temperatures rather lower than they otherwise would be. Some bright or sunny spells are expected though. Later in the period pressure falls as the Atlantic breaks through with wind and rain for a time before things become more settled again at the end of the run with Northerly winds and strong High pressure over the Eastern Atlantic.

UKMO closes it's run with High pressure over Ireland with fine and settled weather for all but with a lot of night frost and freezing fog in the very light winds. This would become hard to shift through the daytime's making it feel very cold where that occurs.

 

GEM keeps High pressure locked in over the UK with varying positions determining the amount of cloud gets carried within the flow. As a result frost and fog amounts would be tricky to predict but there most certainly would be some perhaps biased more towards the South without the Atlantic drift.

 

NAVGEM today has played catch up at last joining the other models in a Southern UK based High with cloud cover spilling across Northern areas and down over the South too later restricting the amounts of fog and frost late in the run with benign conditions developing and temperatures slowly recovering somewhat towards near average.

 

ECM shows High pressure in control over the UK but the position has slipped further west and SW this morning allowing the Atlantic to pull cloud cover around the top of the High and down over the UK gradually replacing the overnight fog and frosts with cloudy skies and lifting temperatures slowly towards the average. A little rain could move SE on a weak trough towards the end of the run followed by a pressure rebuild across the South.

 

The GFS Ensembles are not exciting for anyone with a long period of normality with regard to uppers and with little rain shown High pressure will remain close by. Frost and fog will be the main issues and this can make fundamental differences to temperatures experienced at the surface with the likelihood of conditions ending up rather cold especially at first before Atlantic cloud cover gradually erodes the risk of both of these perils to help aid temperatures back to average at the surface too.

 

The Jet Stream is forced to High latitudes after this week and beyond as a UK or East Atlantic based high pressure area develops soon.

 

In Summary there is little to be said about the prospects from the models that hasn't been said on previous runs. In essence all areas look like becoming dry and settled soon with light winds. With clear skies frost and fog will make for difficult driving conditions at times and this may prove stubborn to shift through the mornings. However, as time progresses it looks like our High will infill with cloud cover from off the Atlantic to allow temperatures at the surface to modify to nearer the average with less in the way of frost and fog. As usual the further out one goes into the output the chances of a breakdown look feasible and on this morning's evidence it looks like any such breakdown would look to be likely from the NW as the High declines.

 

http://www.norton-radstockweather.co.uk/Model-Analysis%282859336%29.htm

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Whilst the GFS and ECM have provided contrasting model predictions for the past few days, the UKMO  has gone consistently along the lines of showing high pressure building over the UK and low pressure circulation maintained over the Northern Med regions. This situation is going to last up to 144 hours. So not all is lost for the UK cold lovers as most of the UK is going to be cold, especially the SE over the weekend. Beyond that period, still a lot can change. As long as the White Sea upper low circulation continues to feed Arctic air into Eastern and Southern Europe the longer term sinking of the high pressure zone over Britain will be slow and the tap of cold air never too far away. So do not give in cold lovers, not all is lost and just enjoy the next 6 days of cold weather, even if not snowy. 

 C

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The Ecm 00z op run shows a prolonged spell of rather chilly anticyclonic weather but the high eventually pulls back further into the atlantic to the west/sw of the uk with lowering heights to the nw/n and even before the end of the run, northern britain is turning windier and more unsettled as atlantic weather invades..the Ecm has been a disaster.

 

 

Lets get the high in place first ,it is just arriving at the party , bit rude telling it where to go before it gets here. They can be stubborn things.

 

In the semi reliable timeframe up to T168 we will have chilly days and chilly nights with the likelihood of persistence fog/frost becoming a problem depending or exactly where the high sets up and how much cloud cover we get.

 

Wide spread temps could max out at 3-5c across large areas of England and we could get persistence freezing fog in some places.

 

Hit -6.5c near where I live in Benson last night not mild for sure.

 

November 1984 I think we had a similar set up ?

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Full house, even a royal flush of HP dominated charts this morning, so for those who like dry, quiet, settled weather there is definately something to look forward to....for a change!  Thinking longer term it looks fairly reasonable to assume the HP will eventually sink into Europe, perhaps allowing that very unwelcome relative Uncle Barty to pay us a visit, but until then mostly dry and progressivly less cold pretty much sums it up for the next 7-10 days imo.

Edited by shedhead
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Total agreement across the board this morning for high pressure over the UK, no chance of this getting further north, too much energy running over the top and and the upstream pattern continues to flatten out.Frost and fog possibilities but much depends on where the high eventually sets up, after that its looking underwhelming from a cold perspective, with the PV increasing to the north.The models overall have not had their best day, especially the ECM which as last winter continues to overamplify the upstream pattern and develop phantom positive heights further north.Indeed we saw across the board the models making a mess of the upstream pattern but the Chump award certainly goes to the ECM.PS To the Mods now that the will it won't it easterly has imploded any chance we can get the names back at the bottom of the page as I doubt the server will be under too much stress for the next few weeks!

 

I had hoped with the new servers that this would be a thing of the past?

 

 

Looks like some weak height anomalies appearing in the mid-atlantic from day 10

onwards which would take us into a cool unsettled pattern for the start of Winter.

 

ECM240..  naefs360..

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Morning all :)

 

I realise some will be disppointed but it is still the last third of November and while it's entirely possible we will be in some form of Atlantic-driven weather for the next 4-6 weeks, nothing is certain.

 

It's not unusual to have a mild or even very mild spell around the start of December - 2010 was extremely atypical - and I believe 18c has been recorded in favoured spots at the beginning of the month.

 

http://www.wetterzentrale.de/pics/Rtavn3241.png

 

Probably from a synoptic set up like that as an example though that's way out in FI. The concensus from looking at some of the Op output this morning is that the HP will decline westward and split with a second cell forming over Europe so that offers a more W'ly or even NW'ly incursion which wouldn't be very mild and something alluded to yesterday. Some FI output sees the HP try to re-establish to the SW while others doesn't so as always at this atge there's a lot of options still on the table but both long-fetch SW'lys and raging E'lies seem to be outsiders at a range which for many takes us only just over the cusp of winter.

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Don't see why people are writing of Christmas when it's a month away . I agree the next week looks settled and dry but after that who knows. The strat has cooled a bit so it's no coincidence that there is more of a PV shown in the models but what's to say that it can't warm up again. We jugs need to get this next week over with and then we will be in the start of winter which could give us something more seasonal

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Lets get the high in place first ,it is just arriving at the party , bit rude telling it where to go before it gets here. They can be stubborn things.

 

 

i'm only describing what the models are showing. : -) The anticyclone looks like it will sink away with the atlantic coming back in through early dec, hats off to the met office for being spot on again, hats off to mogreps, and hats off to the 500mb anomaly charts, all of these I have mentioned along with the gfs etc were never on board with the ecm fantasy.Posted Image

Edited by Frosty.
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Full house, even a royal flush of HP dominated charts this morning, so for those who like dry, quiet, settled weather there is definately something to look forward to....for a change!  Thinking longer term it looks fairly reasonable to assume the HP will eventually sink into Europe, perhaps allowing that very unwelcome relative Uncle Barty to pay us a visit, but until then mostly dry and progressivly less cold pretty much sums it up for the next 7-10 days imo.

Yes, certainly the US guys are seeing a very flat jet across their part of the World for December, so as the models indicate by day 9, we should see those low pressure anomalies begin to disappear over S Europe as the High sinks and we enter the next phase of zonality – the last one lasted exactly a month.

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On this run the high pressure over the UK is much more sturdy. This pleases me because it potentially extends the period of lovely cold sunny days and frosty/foggy nights, which, being a child of the 90s, is far more what I associate with seasonal weather before Christmas. Obviously there could well be a dramatic change in output at some point soon, but either way I like the theme presented for the next week or so in the models.

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The Gfs 06z op run so far shows a more powerful anticyclone than the 00z through the early to midweek period next week, crisp bright days if the fog clears, frosty nights, especially across the snow fields in the scottish hills / mountains.

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Yes as I feared, a dreadful outlook from the NWP especially the ECM having crushed all hope of any cold.

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A wretched pattern with low heights to the north and high to the south. To be fair there is a  huge amount of natural forcings at this time of the year leading to strong mild zonal set ups. A 2010 December was a one in a hundred year event for a reason and it's delusional to think it is likely to occur again so soon.

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Don't see why people are writing of Christmas when it's a month away . I agree the next week looks settled and dry but after that who knows. The strat has cooled a bit so it's no coincidence that there is more of a PV shown in the models but what's to say that it can't warm up again. We jugs need to get this next week over with and then we will be in the start of winter which could give us something more seasonal

With respect Cheese only one person has mentioned Xmas and even then they didn't write it off, just the lead up to it...Posted Image

 

06 GFS holds firm on HP domination across the weekend and deep into next week, but with the HP steadily sinking thereafter. Finally signs of increased amplification again in deep FI, but probably wise to remember that this time last week we were looking at a cold, northerly reload this weekend...which incidently had now been shoved 1500 miles east into Finland and the Baltic states.. Near miss or whatPosted Image

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