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Paul

Model output discussion - 7th January onwards

Paul

Please keep this thread solely to discussing the model output. The model banter thread is available for more loosely model related chat, ramps and moans.

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1 minute ago, Froze were the Days said:

Far more marginal towards the south...dolloping of the stuff to low levels further north, big totals in the hills in the north and Scotland (higher elevations).

What -8 uppers and thickness < 512 dam?

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1 minute ago, Froze were the Days said:

Far more marginal towards the south...dolloping of the stuff to low levels further north, big totals in the hills in the north and Scotland (higher elevations).

Of course, it's all academic at this range, but for what it's worth I think with uppers across the south at -6/-7, with embedded cold.  We should all be on the right side of marginal..... just!

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6 minutes ago, snowray said:

I think that the uncertainty is evident right now on the ensembles, the 12z after D7 show some members up around +6/7c, while the majority go a lot colder, -10c/13c in there, pretty big spread. What is clear is that there is a cooling trend, with the mean staying around -5c with snow symbols til the end of the run. This is good enough for me, much colder outlook starting from D5.

Ensembles for London.

graphe_ens3.gif

What I’m liking about that set of GEFS is we are starting to get a few dropping below -10 850s . Always a good sign . The meto update has now got cold to very cold in it , just saying 👍

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I've noticed that the GFSP shows snow accumulating even when its precipitation charts show a wintry mix/sleet, so the totals are way OTT. Not that those charts are worth anything at such range anyway.

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The para 12z has probably my favourite fantasy land I've ever seen at surface level. Deep freeze with constant snow showers nationwide : no one misses out. 

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12 minutes ago, Froze were the Days said:

Far more marginal towards the south...dolloping of the stuff to low levels further north, big totals in the hills in the north and Scotland (higher elevations).

Do i have to post the papers/states on both model exacts...

And thermo gradiants.

For even close prox-on uk-precip/upper values!!??.

I hope i dont p### u off but the elapse-of overheads in uk.. are virtualy non responsive..

Until 'nowcast-forecast'...

Or at least b4 any cold is established..

Then assumtions can be made.

It gets on my ####-..and 4 and ample-reason...

Edited by tight isobar

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just seen 12Z, 2 unreal sliders! huge snow potential, from 252! but always in blaady FI! but GFS conststent with it

gfs-0-264.png?12gfs-0-312.png?12

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850s required for snow vary a lot depending on the set up .

The 850 value alone can be misleading , then you have to factor in if it’s frontal snow or convective snow showers . The source of air etc .

Snow is one of the hardest things to predict at a long lead time for the UK.  PM flows are especially problematic because it’s often marginal away from higher elevations .

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Anyone not happy with this needs to Move Canada. Widespread snow cover with 50cm in places! 

60400CDA-49D8-4362-8084-3DB6C676D907.png

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10 minutes ago, Roger J Smith said:

Major cold outbreak in eastern North America seems to be a reliable feature, GFS currently has two strong lows around 19th and 23rd both moving north-northeast towards west Greenland. I'm not sure what forecasts were referenced earlier but the expectation over here in general (from extensive chat on similar weather forum to this) was that the cold would start pouring out of the arctic after the SSW and the El nino related Pacific warmth would try to amplify its push inland, reaching about the usual SK to OK boundary against the arctic regime. Some may have read that as warming into the Midwest but I don't think that was expected (it was up until about two days ago very mild across eastern and central regions). 

This cold outbreak will not necessarily reduce chances of simultaneous cold in Europe, by February the statistical analysis shows that simultaneous cold at 80W and 0W is a normal outcome (They tend to be out of phase more in early winter). I looked back to 1978 when there was a very strong northward moving low similar to what is shown on GFS for the 23rd (on the 26th in that case) and Feb 1978 produced about two weeks of very cold weather, not perhaps the most noteworthy cold spell ever, but several subzero days in a row. With the same lag this time, you'd be looking at perhaps 5 to 15 February being the coldest period. 

GEM was showing good potential for battleground scenario by Saturday 19th, if you can get some snow cover in parts of Britain from that, and higher pressure to follow, it might bring on some subzero days and slight improvements to the current outlook beyond that might then sustain a cold spell with the odd interruption. There are winters when cold dominates but mild intrudes every so often, look for example at January 1867. 

Doesnt read as bullish for UK as your post yday, Roger. I think you were expecting decent snowfall for UK around 19th-21st January. Do you see deeper cold maybe shunted back to February now, as opposed to late Jan? If so, seems to tie in with UK Meto - they seem to have shunted more extensive cold back to early Feb now.

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And just for fun, the GFSP ends up like this.. it's still snowing.

image.thumb.png.52e96a7a5b682aae2544188378484597.png    image.thumb.png.da515e4f4f49919a053d0ef5be21fc53.png

Froze Were the Days should be happy with the uppers!

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Too many over reactions - it is a theme to drop that chunk of the vortex on or near to the British Isles so a real possibility towards FI, the further north you are in that synoptic then quids in but it could be another M4 job! - a push a little further east would be an improvement🙂

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I really don’t understand all the negative posts in here when you have charts like this.

E82D786E-F47B-4E92-BCE3-B508151DB986.thumb.gif.79ac1473031dfd0bc36fbaeebda28e92.gif

49E45393-9921-4C1D-9A28-D4A8CB100EA8.thumb.gif.41c49518aebc959feca66e13ebb14446.gif

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Even by 96h the GFS 12z Op looks flat and progressive compared to the Euros

ECM/GFS

ECH1-96.GIF?12-0gfsnh-0-96.png

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49 minutes ago, blizzard81 said:

I would suggest that you ask yourselves just one question today. How confident do you feel today about a significant cold spell starting in about 10 days time compared to how confident you felt 24 to 48 hours ago? Be honest. 

No more and no less confident than yesterday. Nothing has changed for the medium to longer range outlook IMHO. A few operational runs do not alter the background pattern. I always thought 21st January was the turning point; anything before then was always going to be a bonus. We are still 9-10 days away from what I think will be a slide I to colder conditions. Not a sudden sharp flip to -15 uppers and heavy snow, but a change to increasingly colder conditions with increasing chances of snow.

Absolutely no reason to get depressed about flip-flops in deterministic NWP models that struggle post day 7 at the best of times, and even more so when there is an imminent pattern change.

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9 minutes ago, Tim Bland said:

Anyone not happy with this needs to Move Canada. Widespread snow cover with 50cm in places! 

60400CDA-49D8-4362-8084-3DB6C676D907.png

I'm not happy with that image......the shading is so passe, terrible use of colour and definitely won't match my wall paper and curtains.....lol

but gibberish aside, a remarkable image and just goes to show what potential is there.......Can you smell what the GFS(p) is cooking?!

 

download.jpg

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image.thumb.png.53ebda11bff66cc11d8873ab885640e1.png

EC looks good to me at 120..

 

Edited by northwestsnow

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