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Model Output Discussion - 16th Jan 12z onwards - Smile While You Post!

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Well a big step back on the 06 GEFS with just 3 members now supporting the Atlantic ridge around D10. On this run the trough is further east due to the Azores not being able to ridge towards Greenland. The UK remains in a zonal flow:

 

D10 mean: post-14819-0-28073500-1421840399_thumb.p  D12 mean: post-14819-0-38299400-1421840696_thumb.p

 

Clearly in this type of setup we are relying on many factors to be right to get that transient ridge in the right place for a brief UK cold spell. Obviously only one run but this shows how easy it is to go wrong. The synoptics remain the same but the UK is on the wrong side of the Euro trough, again! And of course we lose the colder mean uppers in this scenario.

 

 

 

 

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Going to post the ECM mean at +240 to show you what we need to see in future outputs. Forgive the rather crude drawings but you will get the gist.

Right so note the PV (B) & © we need to see this split with this highlighted by the arrows. This is turn will allow heights across the pole (A) to extend S. Now note (D) & (F) we need to see the trough extend as far S as possible whilst low pressure (D) tracks N towards the W side of Greenland. At the same time this will allow the Azores HP ridge N. All of this combined will allow a sustained flow from the N.

attachicon.gifECM N Hemisphere.jpg

In essence, all the cogs need to turn in the appropriate direction, pushing and pulling, pushing and pulling... Hard to see how any of that can click into gear with the progged Jet profile - and rightly or wrongly, that's where I always go first and if that looks unfavourable, tend not to look any further, which may well be very amateurish but, to paraphrase Kennedy, 'It's the jet, stupid,'

Nice post, TEITS.

Edited by pureasthedriven
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Fortunately don't think tides are predicted to be particularly high because there would be North Sea storm surge risk from the charts at the end of the month that have been appearing for a while -

 

gfs-0-192.png?6

The big spring tides are now till sunday then they start to drop off, by the end of next week they are neap tides.

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The ensemble for Manchester is keen on a steep temp gradient following the passage of the front Saturday after that there is solid agreement on there being some form of weather........seriously though the clustering offers cold zonality around the 29th for five days.

MT8_Manchester_ens.png

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There really is no chance of getting the 'right side' of the euro trough in the next couple weeks.

However, the amplification showing at day 10 was not really expected until four or five days later ( prior to yesterday's output) so to show week 2 ops as being evidence that x or y can't happen is unwise.

The theme remains the same - the nuances wide and varied.

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Well a big step back on the 06 GEFS with just 3 members now supporting the Atlantic ridge around D10. On this run the trough is further east due to the Azores not being able to ridge towards Greenland. The UK remains in a zonal flow:

 

D10 mean: attachicon.gifgensnh-21-1-240.png  D12 mean: attachicon.gifgensnh-21-1-288 (1).png

 

Clearly in this type of setup we are relying on many factors to be right to get that transient ridge in the right place for a brief UK cold spell. Obviously only one run but this shows how easy it is to go wrong. The synoptics remain the same but the UK is on the wrong side of the Euro trough, again! And of course we lose the colder mean uppers in this scenario.

Lets compare the 12z GEFS  IDO see if its a blip.They are pretty awful at 240z but hey ho.

Edited by winterof79

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Forgive me for saying but doesn't that contradict your previous post. Synoptically you are describing what we have seen already this winter i.e brief colder spells. The problem with this is that without HLB the N/NW,lys are not sustained enough to bring the very cold air S. What generally happens is upper temps of -5C arrive which generally only give snow showers to Scotland especially over higher ground. What this winter has taught us is we need to see HLB to bring severe wintry weather across the UK.

Not really Dave, the trough has been to our NW, main trough to be more over us or Scandi.  With AZH ridging in Atlantic or backing west it would allow for more N'ly flows or cold sub lows coming down western flank of trough....I've posted enough model images to illustrate the idea.  So no I'm not describing same synpotics.  How many times have you heard people mention the deep cold piling into Atlantic to our west but being modified?  Shift the pattern east.  It won't happen overnight but early Feb is target with the movement towards and descent into such a set up around end of month.

 

But on the post you responded to I can see the lack of clarity.

 

BFTP   

Edited by BLAST FROM THE PAST
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BA what do you make of the PV split? The GFS 06hrs run almost gets there and looks like its edged towards the ECM. I think most would be happy to just get a couple of days of non-marginal snow, which has been difficult so far this winter away from more elevated areas of the north.

 

nick, just been looking at the extended eps again and its noticeable that the really important part of the run re sthe split co incides with the drop in resolution of the ens at day 10.  given that andrew has shown on the strat thread that this upcoming euro trough is indeed strat driven (we did wonder yesterday when the trop modeliing began to reflect the strat profile at a similar time), i would be cautious about placing too much store in the extended ens until we begin to see the split from the pacific side relaxing pre T240.

 

if the ops are showing the same broad solution at day 8/9, they may prove to be a more useful tool than would normally be the case at this timeframe when viewed in conjunction with the ens.  it may well be that the split will close up and the canadian continue to be the major player but i'm hesitant to say so based on the above musings.

 

what is clear from andrew's posting is the close coupling between the upper strat and trop as has seemed to be the case for a while now. only a few days delay for parts of the pattern to show although its not a clean reproduction down below.

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The GFS looks Wintry to me.. By Saturday we see a cold Pm N/Wly bringing a Snow risk for Wales and the Midlands North.

 

uksnowrisk.pngh850t850eu.pngukmintemp.png

 

 

Monday also see's a Snow risk for N/Midlands & Scotland. Out in the run towards the end of the Month the GFS & ECMWF both show a cold Northerly flow over the UK .

 

uksnowrisk.pngh850t850eu.pnguksnowrisk.png

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Thanks Tamara , another great post and very in depth. Who needs Glacier point. So basically you see another MLB to our west with a possible ridging north as it evolves ? Or have I read it wrong.

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I see the omnipresent February signal for blocking prevails in recent CFSv2 output :D

 

CFSv2 always appears to favour this type of broad synoptic for the latter end of winter, for whatever reason - seldom verifies, I hasten to add.  There has been some real Steve Murr eye-candy over the last few days.

 

Alas, none is currently supported by GS5 outputs; advertisement of average to very slightly below, is a broad theme; perhaps drier than average too.  Not a great deal of confidence though, so not worthy of any wrist-slitting.

 

ECM is a bit of a turn-up.  If that has legs...

Nice to see some more more Informed opinion SB.

Did GS5 see this upcoming displacement ? If so, does it also see a quick down welling into the euro trough as per the current trop nwp?

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Not much discussion about the 12z GFS well I will give you all a reason why http://www.wetterzentrale.de/pics/Rtavn1441.gif!!! If this verifies its game over until at least the start of the second week in feb. Its like a well oiled machine azores high and low pressure around greenland leading to a raging jet and zonality over us!!! Not even the cold type either. 

 

Dont buy anything after 144 either people mid range modeling has been very poor this season. 

Edited by Continental Climate
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Not much discussion about the 12z GFS well I will give you all a reason why http://www.wetterzentrale.de/pics/Rtavn1441.gif!!! If this verifies its game over until at least the start of the second week in feb. Its like a well oiled machine azores high and low pressure around greenland leading to a raging jet and zonality over us!!! Not even the cold type either. 

 

Dont buy anything after 144 either people mid range modeling has been very poor this season. 

Indeed that chart shows that it's all over until the 2nd week of February..... any charts that follow this and don't show that should be ignored.

Confirmation bias......  :rofl:

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The GFS op moving towards the GEFS 06z mean now, so at D8: post-14819-0-61438700-1421857986_thumb.p

 

The Euro trough has been pushed east and the UK ends up zonal. The second wave of heights from the US were blocked off by short waves running on the jet. These small features in FI dont show up but once we enter the more reliable timeframe they act as spoilers.

Edited by i'm dreaming of...
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Not much discussion about the 12z GFS well I will give you all a reason why http://www.wetterzentrale.de/pics/Rtavn1441.gif!!! If this verifies its game over until at least the start of the second week in feb. Its like a well oiled machine azores high and low pressure around greenland leading to a raging jet and zonality over us!!! Not even the cold type either. 

 

Dont buy anything after 144 either people mid range modeling has been very poor this season. 

The chart is dated 27th Jan, whats that got to do with the second week of Feb.

Sorry confused, as tomorrow it might be showing a northerly deep freeze.

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The GFS op moving towards the GEFS mean now so at D8: attachicon.gifgfsnh-0-192.png

 

The Euro trough has been pushed east and the UK ends up zonal. The second wave of heights from the US were blocked off by short waves running on the jet. These small features in FI dont show up but once we enter the more reliable timeframe they act as spoilers.

Yes IDO, i mentioned that a couple of days ago. Any ridging into Greeland should be taken with a large pinch of salt whilst a PV segment remains in that local, as invariably a bit of short wave energy spits of the vortex and cuts off the Northerly flow.

 

The only time I ever believe a proper Northerly is on the cards is when proper upper heights are modelled over the Greenland plateux and the PV has retreated NW away from Greenland.

 

The projected possible lower heights into Europe will not therefore bring any sustained cold as the Azores ridge will continue to be pushed East by the shortwave energy.

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UKMO shows high pressure building in over the weekend and into early next week if it did build in it frost and fog could return

 

Rukm961.gifRukm1201.gifRukm1441.gif

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The GFS op moving towards the GEFS 06z mean now, so at D8: attachicon.gifgfsnh-0-192.png

 

The Euro trough has been pushed east and the UK ends up zonal. The second wave of heights from the US were blocked off by short waves running on the jet. These small features in FI dont show up but once we enter the more reliable timeframe they act as spoilers.

The GFS op at 240z  compared to the 06z mean

gfsnh-0-240.png?12

 

gensnh-21-1-240.png

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