Model Output Discussion - 30th November onwards

[Mair Snaw]

This run shows pretty us much in no mans land whilst the PV gathers it energys for an eventual full on  Zonal onslaught, I could totally see this happening which would pretty much wipe out the rest of this month and Jan

Thats it winters over!!! so you are righting off all of December and Jan?? on what model output are you basing this on?? could you possibly back this up with charts etc?? its only 02/12/13 And already winters over....when oh when will people on this thread ever learn??

[Cheshire Freeze]

I just died a little inside. Could you explain how you can see this happening? This run has moved towards the Scandi scenario but just does not quite make it in FI, still dont see this "zonal onslaught to wipe out december and jan"?

 

The post wasn't worth replying to. Ignore.

 

Any post writing off the next 8 weeks based on one run of the 18z GFS needs to be deleted by the mods and treated as a wind up!

 

Nice to see the trend maintained today with height rises to the east of the UK. As others have pointed out, it's not a certainty and the extent to which any block would affect us is debatable. Looking forward to tomorrow's model runs.

Edited December 2, 2013 by CreweCold

[swfc]

I just died a little inside. Could you explain how you can see this happening? This run has moved towards the Scandi scenario but just does not quite make it in FI, still dont see this "zonal onslaught to wipe out december and jan"?

there is no sign of a zonal onslaught!!

[jam]

"This run shows pretty us much in no mans land whilst the PV gathers it energys for an eventual full on Zonal onslaught, I could totally see this happening which would pretty much wipe out the rest of this month and Jan"

Laughable! So many drama queens have joined the fold this yr.. Perhaps peoples age and the yr/month they joined should be added to post count so you can judge the maturity of the poster?

?

[Panayiotis]

The NASA model is on the 00z for 120hrs, its updating now

[Captain Shortwave]

People need to remember how important a Greenland high is. In my experience a greenland high is key to sustaining a significant cold outbreak.

And although there are positive signs this evening with increased amplification of the rossby waves and disruption of PV, there has been one constant and that is the positioning of a very low heights in and around Greenland. If this gets in cemented for the coming months, it will be very difficult to get a prolonged cold spell to affect B&I.

....Except for January and February this year 

[Airedalejoe]

Read through all the posts and although I'm a cold/snow fan, a couple of posts mentioning the possibility of record warmth next week caught my attention as mid to high teens would be canny at this time of year!

Just checked the GFS chart viewer and max temps here range from bitter on Friday to no higher than 4C for the next 2 weeks which in my book makes it cold to say the least. Am I missing something??

[johnholmes]

Evening All-

 

 

The model that's come out best again is the UKMO- resilient & Smooth, seemless & minimal fuss.

In this case it started at 144 with the 2 thirds house & has never changed since.

 

 

 

 

The Scandi High..........

 

I'm pleased that I presented this idea first ( even Mr Holmes questioned the 500 heights not following ANY ridging to Scandi)

 

Therefor the updated forecast based apon the model bias today is-

 

Northerly toppler, for 24 hours, high pressure ridging over the top but contrary to the GFS no WAA getting into the UK barring the extreme NW -

The SE staying cold-

day 8 -9 look for Energy dropping south into scandi in the form of a shallow low- with rapid pressure building NE, the UK sitting at the extreme western end of blocking for day 9/10.- light Southerly or SE tug.

Then energy getting underneath tugging the winds easterly & increasing day 12.

 

 

Look out for the Maps for 13/14 December.

 

best regards

Steve

I copy really just Steves' comment about the 500mb anomaly charts. True Steve, I post as it is along with a lot of experience at using them. When I asked the question they did not show any tendency to move +ve heights that way, in fact the reverse over several days. I accept your take on what the longer term synoptic models showed as I rarely if ever save them. What everyone has to remember though is that they are more volatile than the anomaly charts for obvious reasons. Yes a synoptic model can and will pick up a signal that is subsequently picked up by other models to a greater or lesser extent. Sometimes they are correct-not always by a long chalk. The anomaly charts over the last 2 days have begun to show +ve heights tracking first east now more generally NE(that is +ve height anomalies at 500mb for those not used to the terminology I use), and thus I am about 65% swayed to that idea but would prefer to see them get totally consistent before I show the same degree of enthusiasm as yourself for this development.

Turning to a general comment the post by Steve is a first class example of being able to watch, save and remember, how different models can behave in similar types of patterns. Yes I disagree with Steve at times and at times with his methods but that is part and parcel of two different views on model watching. As they say, nowt wrong with that, we can differ and discuss those differences without it resorting, I hope, to childish comments that one sometimes sees on here.

Finally it is the weather and none of us get it right anywhere near every time, like I regularly say, old man weather is brilliant at making us all look chumps at times.

Edited December 2, 2013 by johnholmes

[swfc]

The NASA model is on the 00z for 120hrs, its updating now

where can this be viewed?thanks

[Mair Snaw]

....Except for January and February this year 

And March dont forget Spring for a good Snowfall....

[Dancerwithwings]

where can this be viewed?thanks

http://www.meteociel.fr/modeles/geose_cartes.php

[bradymk]

there is no sign of a zonal onslaught!!

 

I know, think you misread my post, was just quoting someone above, no sign of it!!

ECM is not way, way too amplified cc - one 'way' will do. I think that in two weeks time, those of us in the se will feel like we've been in a sustained cold spell Matty. gloomy and cold would be my expectation.

Very true, we could be on the brink of quite a sustained period of cold temperatures not long after this northerly "snap", especially further east you are in the UK. The potential SE/E feed looks like it could stick around for a while and with an inversion and dull overcast days, temperatures could really struggle, especially in the east. If we have a couple of weeks of that followed by westwards movement of the cold pool towards xmas, then December could become a very cold month. The high uppers on the ECM are deceiving 

Edited December 2, 2013 by bradythemole

[SMU]

Cheers John - Et al for the comments-

 

Finely poised tonight- fingers crossed for upgrades tomorrow- although probably a few pots of gold in the 18z runs-

 

Who wants to start ensemble watch for -5c from the east for London!!

 

Cheers

Steve

[johnholmes]

on a closer note the latest fax for 12z Thursday has deepened the low by about 4mb keeping its position about the same, so winds are going to be a fairly major issue in the far north especially and along parts of the eastern coast of Scotland, and probably extending into some eastern coastal areas of England. Tide surges are also likely to be an issue in places bordering the N Sea.

Obviously, assuming the precipitation forecasts at 24 hours are correct then the upper air temperatures and surface dewpoints are going to cause blizzard conditons over parts of Scotland, low and high ground.

 

Most aspects in the above paragraph look being at their worst for the Northern Isles. I remeber a strom looking not that different to how this is being painted on Fax charts when at Sullom Voe in 1984-5, gusts in excess of 85mph from SSW to NNE in the space of 10 minutes. Whether this will track the same way or be as severe is not certain but those responsible for shipping especially in the far north I am sure will already have recieved preliminary advice from whichever Met centre they take their weather from. That is over and above anything UK Met may have issued. No idea as I have not been in most of the day. Tomorrow morning will probably see warnings going out and updated with a comment from the senior man at Exeter.

[Captain Shortwave]

Cheers John - Et al for the comments-

 

Finely poised tonight- fingers crossed for upgrades tomorrow- although probably a few pots of gold in the 18z runs-

 

Who wants to start ensemble watch for -5c from the east for London!!

 

Cheers

Steve

I can try my best, though the need for sleep will probably prevent me getting the pub run ens

Btw the 12z showed 5 members from the Suffolk region which I think fits your description

[Mucka]

ECM ensembles

 

 

Certainly a stronger clustering going for turning colder again after mid month. Without seeing postage stamps, I think it reasonable to assume most of these are picking up some kind of Easterly flow. Just tentative signs but encouraging at least.

 

As for GFS 18z ensembles on the way out, they look like being a slight improvement on 12z with the Northerly a tad further West - well it all counts. 

[forecaster]

Read through all the posts and although I'm a cold/snow fan, a couple of posts mentioning the possibility of record warmth next week caught my attention as mid to high teens would be canny at this time of year!Just checked the GFS chart viewer and max temps here range from bitter on Friday to no higher than 4C for the next 2 weeks which in my book makes it cold to say the least. Am I missing something??

There is now little doubt that part of next week starts to see warming through much of the atmosphere but at this time of year and with light surface winds it may not be realised at the surface. At this stage hard to tell where is the boundary between cold continental drift and more maritime milder flow with possible downslope warming in the northeast. These fine details won't be resolved yet but likely the further se you go the lesser the impact of the warming airmass.

[NorthernRab]

...there has been one constant and that is the positioning of a very low heights in and around Greenland. If this gets in cemented for the coming months, it will be very difficult to get a prolonged cold spell to affect B&I.

 

I'm sorry Matt, but you know as well as I do that nothing is ever "cemented" when it comes to British weather, so there's absolutely no need to make such a bold suggestion for the entire winter period just because there's no strong Greenland blocking on the GFS this evening. 

 

Having lived through a number of severe cold spells in recent years (which I could only have dreamed of as a child in the 90s and 00s), how many of these spells were predicted consistently, other than a few whispers and trends, more than 2 weeks in advance?

 

Zero. 

[forecaster]

I know, think you misread my post, was just quoting someone above, no sign of it!!

Very true, we could be on the brink of quite a sustained period of cold temperatures not long after this northerly "snap", especially further east you are in the UK. The potential SE/E feed looks like it could stick around for a while and with an inversion and dull overcast days, temperatures could really struggle, especially in the east. If we have a couple of weeks of that followed by westwards movement of the cold pool towards xmas, then December could become a very cold month. The high uppers on the ECM are deceiving 

I would expect Pembrokeshire to push into low double figures for a time next week In a light s to sw flow if models hold.

[bradymk]

I would expect Pembrokeshire to push into low double figures for a time next week In a light s to sw flow if models hold.

Yes, quite possible for Pembrokeshire and other western areas for a time. But if the "potential" continental flow does materialise next week, then it would gradually turn a lot colder, especially in the east under dull conditions. ECM had 2c maxes for Central England middle of next week and if that flow holds, it will only get colder albeit mainly overcast and dry.

Edited December 2, 2013 by bradythemole

[johnholmes]

There is now little doubt that part of next week starts to see warming through much of the atmosphere but at this time of year and with light surface winds it may not be realised at the surface. At this stage hard to tell where is the boundary between cold continental drift and more maritime milder flow with possible downslope warming in the northeast. These fine details won't be resolved yet but likely the further se you go the lesser the impact of the warming airmass.

 

Yes would agree with those points

[Matty M]

One or two ensembles really want to take Scotland apart.

 

[bluearmy]

Those 12z London ECM ens do look to have some more average returns next week. lets see that repeat tomorrow. Note the strong clustering cold by mid month. Thats two weeks away!!

[Mucka]

GFS ensembles complete with our marginally improved Northerly (from GFS 12z set) Central UK.

 

http://www.meteociel.fr/cartes_obs/gens_display.php?x=249&y=89&run=18&runpara=0&type=0&ext=1

 

Now if only! (Warning: This is absolutely not representative of the 18z ensemble FI - take with a large dose)

 

[Matty M]

Number 19 please.

 

Only one that reallllly goes for easterly at day 10.