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Model output discussion - here comes the beast!

Paul

Please only post model discussion in this thread 

For more general chat and banter, or moans and ramps loosely around the models, please head to the banter thread:
https://www.netweather.tv/forum/topic/86721-model-moans-ramps-and-banter/

For general weather chat including about the snow/cold chances around the country, please go to the regional threads:
https://www.netweather.tv/forum/forum/142-regional-discussions/

We also have a special post SSW cold spell discussion open here:
https://www.netweather.tv/forum/topic/89358-ssw-related-cold-spell-will-it-wont-it/

Thank you!

Message added by Paul

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1 hour ago, Crashlanding said:

looks like the channel low will be too far south for snowmaggedon? 

 

viewimage.pbx?type=gfs;date=20180223;time=06;ext=174;file=tmp850;sess=2b2a285618d167f7248371844d7f2549;

I want it further south to keep cold holding on.

2009/2010 was classic for channel runners but the convection from the northeasterly was amazing.

Just a cm or 2 would make me smile.

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17 minutes ago, Man With Beard said:

One of the peculiarities of the models coming up may be snow where you don't normally expect it. Southern extremities such as IOW, S Devon and the tips of S Cornwall could see major disruptive snowfalls if the winds go direct E or ESE for a prolonged period, as a "channel streamer" may set up as shown in the fax charts. This is a big, big possibility. 

Yeah-id buy that devon-cornwall dorset-running along to coastal counties...and IOW..

may see best deposits in a very long period!!!

That not taking away preety much anywhere else running through nxt week!!

20180223_123458.png4

Edit; but highlighting marginality-as non problematic....

Situ given.

Screenshot_2018-02-23-12-32-19.png

Edited by tight isobar
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4 minutes ago, MR EXTREMES said:

I want it further south to keep cold holding on.

2009/2010 was classic for channel runners but the convection from the northeasterly was amazing.

Just a cm or 2 would make me smile.

i suppost in the long run yeah keep the cold at bay but id like to see 2 or 3 FEET!!!!

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The Irish Met service (Met.ie) has put out its 1st snow/ice warning:

National Weather Warnings

 

STATUS YELLOW

Weather Advisory for Ireland

Exceptionally cold weather is forecast for next week with significant wind chill and severe frosts. Disruptive snow showers are expected from Tuesday onwards, particularly in the east and southeast.

Issued:
Friday 23 February 2018 12:00
Valid:
Friday 23 February 2018 12:07 to Friday 02 March 2018 12:00
Edited by John Cox
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21 minutes ago, swebby said:

Only just glanced at the fax charts, not sure i've ever seen one with a convergence line set up over the channel, pembrokshire dangler yes but over the channel, no.  Would make for some interesting weather in the channel isles....

We always have ‘interesting’  weather, gales and fog.  Though rarely snow, 2013 was mega though,  got skis out for that occasion! 

662D9228-D05F-436A-93E2-5D3F7C589B9E.jpeg

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10 minutes ago, MR EXTREMES said:

I want it further south to keep cold holding on.

2009/2010 was classic for channel runners but the convection from the northeasterly was amazing.

Just a cm or 2 would make me smile.

There are a lot of people in the west and wales who want it a good deal further north as the 00z gfs....only chance of snow in these parts :( even if there is a thaw following.

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9 minutes ago, swebby said:

Quick Q - This is the result of generalised upper wind flows so may have a tendency to move in location? I.e it's not a fixed topographical feature as we see with the Pembrokeshire dangler that results from the Irish and Welsh mountains/hills during a northerly?

MWB - yes i was thinking IOW could well see some significant falls from the current set up but the channel isles is a surprise. Scilly Isles might also find this problematic, especially as they'd be well into the flower producing season which i believe is a large part of the economy.

I recall the Channel Islands doing very well from a similar setup in March 2013, where a low moved up from France, producing 50cm+ over the islands. The front never made it to the South Coast, but we did get some convective showers instead.

I still can't believe we are seeing such good outputs this close to the time frame, really is a 2010 and 2013 in the making this setup. Models have done a good job at this SSW induced cold spell thus far.

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16 minutes ago, swebby said:

Quick Q - This is the result of generalised upper wind flows so may have a tendency to move in location? I.e it's not a fixed topographical feature as we see with the Pembrokeshire dangler that results from the Irish and Welsh mountains/hills during a northerly?

MWB - yes i was thinking IOW could well see some significant falls from the current set up but the channel isles is a surprise. Scilly Isles might also find this problematic, especially as they'd be well into the flower producing season which i believe is a large part of the economy.

I think this GFS chart gives a nice example of where we might get to even without frontal activity (aside a band through N England/Ireland)

138-777UK.GIF?23-6

Those southern extremities shown up, and just a small change in windflow could elevate these figures massively - Channel Islands doing very well, and Isles of Scilly likely to go white. Bristol Channel streamer likely to affect N Devon (Cardiff seems a bit ambitious?). N coast of Wales also gets a good snowfall. Any any east coasts, and up to 100 miles inland would see moderate amounts I expect.

I'm actually quite comfortable calling this as far ahead as D6 because there isn't a great pattern change on the horizon between D3 and D6, and that's when higher uncertainty would kick in. Not this time though - the block looks quite well set for a few days. For me, Thursday or Friday are the days where something different might materialise, but once the cold is in there's only one way to get it out and that will involve snow. I think!!

(EDIT: I think Nick F's post above demonstrates this well - I'm guessing the huge difference in snowfall occurs on Thursday/Friday next week?)

 

Edited by Man With Beard
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Let's get this into perspective...

I've doctored the 06z ens below, which is for my tropical area of the UK.

t850Dorset.thumb.png.85e9f1c5bc073abb14c4027d95422fd1.png

Looks very decent still doesn't it!? And then... then you realise how bonkers the original, un modified, chart actually is.

 

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2 minutes ago, Paul said:

Just wanted to follow up, as the 6z run is much snowier!

snow-totals-again.png

Still the same caveats though....

....and the same gaps over western parts :nonono:Can someone find a model with no gaps please! 

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3 minutes ago, Luke Best said:

Here's an interesting excerpt:

"We have not seen such an absence of deep cold pool events since the 1970s, and therefore, in spite of global warming, who is to say that, following 1956 and 1987, the next extremely deep cold pool event will not visit us in January or February 2018?"

Considering that was written in Jan 2011, that's not a bad call!

Excellent, so a thirty one year repeating pattern.  So for the next one that'd make me - hmmm best not to think about that......

Edited by swebby
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1 minute ago, KTtom said:

....and the same gaps over western parts :nonono:Can someone find a model with no gaps please! 

Yeah, odd one that as 2010/11 easterly we got plenty of snow...but then again these are modelled, they aren't hindcasting so guess patience is a virtue...

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3 minutes ago, Man With Beard said:

I think this GFS chart gives a nice example of where we might get to even without frontal activity (aside a band through N England/Ireland)

138-777UK.GIF?23-6

Those southern extremities shown up, and just a small change in windflow could elevate these figures massively - Channel Islands doing very well, and Isles of Scilly likely to go white. Bristol Channel streamer likely to affect N Devon (Cardiff seems a bit ambitious?). N coast of Wales also gets a good snowfall. Any any east coasts, and up to 100 miles inland would see moderate amounts I expect.

I'm actually quite comfortable calling this as far ahead as D6 because there isn't a great pattern change on the horizon between D3 and D6, and that's when higher uncertainty would kick in. Not this time though - the block looks quite well set for a few days. For me, Thursday or Friday are the days where something different might materialise, but once the cold is in there's only one way to get it out and that will involve snow. I think!!

 

All good via your interp's...

Although north-sea convection and wider-spread inland shower activity...still being very much underplayed here.

As have backing of possible deeper feature influence @continent.

Some eye bulging (potential) via possible accumulates from above mentioned mon- weds....

Then after perhaps a more organised event.....OR THREE!!!

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11 minutes ago, Paul said:

Just wanted to follow up, as the 6z run is much snowier!

snow-totals-again.png

Must admit I’m slightly concerned given I’m in the red zone ( Newcastle upon Tyne ) yikes 

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1 minute ago, Raythan said:

Must admit I’m slightly concerned given I’m in the red zone ( Newcastle upon Tyne ) yikes 

'Again'..

All very speculative atm..

But firmly expect-quite notable upgrades via ppn charts by sunday.

And certainly more extensive!!!

Prime conditions @convective influence.

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1 hour ago, karlos1983 said:

ECM ens still corkers!!!! All the way out!

we’ve hit the jackpot guys n gals! Be sure to enjoy it!!! Especially you lucky bunch down the eastern side of the UK! I don’t envy you, I’m happy for you! Going to be memorable for many!

28495B17-65D4-41F8-A7F0-B698ACC556DD.thumb.gif.ad5c5daea7ea13722098a13e39265b9a.gif

 

 

Look at some of those runs, -15*C in London almost on one in FI. :O

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22 minutes ago, s4lancia said:

Let's get this into perspective...

I've doctored the 06z ens below, which is for my tropical area of the UK.

t850Dorset.thumb.png.85e9f1c5bc073abb14c4027d95422fd1.png

Looks very decent still doesn't it!? And then... then you realise how bonkers the original, un modified, chart actually is.

 

Yep, ensembles tend to be the first thing i check.  Glanced at the 850's/ppt 0z's for devon (although not much different from most of southern/central England) and thought the control would deliver snow, with the Op a milder/marginal solution for the 2nd/3rd of March. The 6z has dropped the Op now to where the control was on the 0z in terms of 850 temps but has again kept the control lower than the op.  Is this indicative of a trend or just an shows that the track of the low south of the uk is still guesswork. I'd say the latter.

Edited by swebby
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I still cannot believe what I'm seeing for now just a few days out. No doubt about it, this is going to have many people gobsmacked, especially those who pay no attention to forecasts etc. A lot of the new younger generation are going to find out what a proper dumping of snow looks like that's for sure. 

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14 hours ago, CameronWS said:

Would that head north into Scotland?

Cameron, you should go and look in the Scotland regional thread - I started in there when I lived up in Scotland and imo the Kilted Thread has the most accurate regional people going.

You'll get a really good answer in there, specific for your region of Scotland too. 

Tell 'em I sent you and they might even buy you a pint :)
 

 

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