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Model Output Discussion - 23rd Jan - 12z onwards


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Short answer   The short answer to your question is yes, the presence of low pressure (at higher altitudes, being coincident with very cold upper air), makes the air more unstable, as the gradient i

Welcome to "Celebrity Model Discussion". Let's go out to our reporter, who has managed to corner the miracle man himself, Jesus Christ, for his thoughts: Reporter : Thanks for joining us Jesus, first

If people will insist on analysing the 850mb temperatures every single run here's something to bear in mind when viewing the output for the upcoming period - -6c is a baseline figure to put snow/rain

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That was exciting wasn't it?

Though I really wouldn't take this ECM run in isolation and jump on the deep freeze bandwagon just yet.

What the models do show this evening though, is that they are all sniffing a change in the 7 day range where the demise of the Atlantic ridge is set occur (or not) but they are all toying with different upstream patterns so tomorrow is going to be a very interesting day MO wise.

 

Here are the 168 charts ECM, JMA, GFS for comparison. 

 

ECH1-168.GIF?27-0JN168-21.GIFgfsnh-0-168.png

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Could someone please explain to me what I should be looking at on the charts when people say the energy goes under all I see is a flat picture really sorry if I sound stupid

Thankyou

Emma

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Could someone please explain to me what I should be looking at on the charts when people say the energy goes under all I see is a flat picture really sorry if I sound stupid

Thankyou

Emma

 

You don't have a 3D TV?  :p

 

I assume they are referring to the disrupting low SW of Greenland where energy is split with some going South and some NE.

 

ECH1-216.GIF?27-0

 

It is not a true "undercut" but with the trough to the SE the ridge will extend NE rather than topple and so low pressure would hopefully be forced under later.

Small changes in the distribution of energy can make the difference between a cut off high to our NE and a UK high.

Edited by Mucka
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Can we order the ECM control run for this evening:

 

attachicon.gifeps_pluim_tt_06260.png

 

The control run looking at the wind directions brings in an easterly for Holland and more than likely the UK also:

 

http://www.weerplaza.nl/15daagseverwachting/?r=midden&type=eps_pluim

Well well,you keep wishing Nick because lately your wishes have been the models command.

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Some  really cold synoptics on offer , the weekend really caught my attention with some bitterly cold air filtering down from the north during early weekend.  Usually a straight cold Northerly airmass will produce for my location inland nothing but winter sunshine, it wont take a lot to move some very wintry conditions further inland. Best winter charts Ive seen for a while.... :D  :cold:  :cold:

post-6830-0-99551400-1422387228_thumb.pn

post-6830-0-79696600-1422387285_thumb.pn

post-6830-0-71710600-1422387320_thumb.pn

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Well that is certainly a teasing chart Steve, for those of the younger generation, what followed was a winter that went down in the history books. The 1947 winter was late starting but became snowiest of the 20th century, not thawing until around the middle of March. The 12z ECM projection does show a similar set-up to that which set the 1947 winter in motion, all be it a few hundred miles to far west. 

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Hi Emma, basically when people talk about "energy going under" they are referring to the the fact that when Low pressure in the Atlantic (energy) "undercuts " or "goes under" (to the south) of a blocking high pressure situated in or around our vicinity then this is likely to draw colder winds in from the east.

Here's an extreme example of an undercut:

 

post-992-0-32065500-1422388917_thumb.gif

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For Sunday?

 

15020118_2712.gif

Thanks. Now that's more like it. Is it too much to ask for some precipitation at that time?

Edited by The Enforcer
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Back to trend for the 12z. A week of northerlies then high pressure. Could well be a very dry period for some places.

 

Rtavn2523.gif

Just what I was thinking from this weekend onwards, I think too many are relying on troughs and polar lows but the reality is that not many Northerlies bring these sort of features on a nationwide scale. To me it's looking a very dry spell from Sunday onwards for most of the UK, if the models verify that is.

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Hi Emma, basically when people talk about "energy going under" they are referring to the the fact that when Low pressure in the Atlantic (energy) "undercuts " or "goes under" (to the south) of a blocking high pressure situated in or around our vicinity then this is likely to draw colder winds in from the east. If the energy or low pressure goes over the top (to the north) of the blocking high pressure then this will draw in warmer westerly winds ( the normal situation).

 

Here is a very basic paint pic to give an example

 

66_zps4609372c.jpg

 

 

Thanks Chris (and The Enforcer Later) I am pretty new on here and that graphic illustration helps us newbies a lot.

 

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Just what I was thinking from this weekend onwards, I think too many are relying on troughs and polar lows but the reality is that not many Northerlies bring these sort of features on a nationwide scale. To me it's looking a very dry spell from Sunday onwards for most of the UK, if the models verify that is.

Got to disagree,mainly this being a more unstable airstream than a regular northerly.And also when the coldest winds set in,sunday onwards,kinks in the isobars show bands of showers spreading south.

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Just what I was thinking from this weekend onwards, I think too many are relying on troughs and polar lows but the reality is that not many Northerlies bring these sort of features on a nationwide scale. To me it's looking a very dry spell from Sunday onwards for most of the UK, if the models verify that

is.

Yes but how many times have we seen a true northerly flow and these troughs don't usually appear till 12 hours out!!!

Edited by snowice
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Time for a splash of colour which coldies love, the type of which is normally at T+240 range but is now within the semi reliable timeframe on tonight's Ecm 12z op run, we have excellent output tonight, ukmo 12z another cracker and the ecm is no slouch either. Best cold spell for a good few years on the door step and we should treasure every minute of it.

where's weds and thurs charts.??

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So, with some lovely NH amplification from the 12z UKMO which suggests some quite alluring cross polar ridging might follow, and (putting aside the precise synoptic face value details) hints also appearing in second half of the ECM operational output this evening - there is some tentative evidence advertised this evening of those possible trends as described above :)

 

The attempts to flatten the pattern after the displacement induced northerly remain susceptible to increasing meridionality of the pattern as suggested in the last week or two as we progress through February.

 

The ECM control this morning suggested a very cold easterly outlier.

 

However, speaking as cautiously as ever, could it just be those colder extended ensemble solutions from the north east start increasing in number?

Yes Tamara :) great ECM and nice trends today with GFS hints of trough disruption in the atlantic. Your forecast is coming together very nicely :)
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Got to disagree,mainly this being a more unstable airstream than a regular northerly.And also when the coldest winds set in,sunday onwards,kinks in the isobars show bands of showers spreading south.

We'll see but I'm in the over 50s bracket and I can tell you now these are as rare as hens teeth and apart from coastal districts and down the Eastern side of the country this will be a dry but very cold spell of weather from Sunday onwards, I hope I'm wrong I really do.

Edited by Hocus Pocus
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We'll see but I'm in the over 50s bracket and I can tell you now these are as rare as hens teeth and apart from coastal districts and down the Eastern side of the country this will be a dry but very cold spell of weather from Sunday onwards, I hope I'm wrong I really do.

 

Fully agree, Sun to Tues has wishbone written all over it, showers down coasts, dry inland

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