Model Output Discussion - cold spell to end Autumn

[bluearmy]

Funnily enough when I saw FIM 12z  undercutting with the slider I wondered if gfs would step back again. Also the eps spread shows a cluster on the undercut so it it's not something to be discounted as yet 

[Mokidugway]

Ice cold Bellini anyone ?

[winterof79]

Snow maker? incoming

[I remember Atlantic 252]

2nd slider, well in FI now though

[Ice Day]

2 minutes ago, Singularity said:

In truth, it's absolutely fascinating that such an extreme difference can be resurrected within the 5-day range and with the key sliding setup evolving late on day 4...!

Indeed so, but the next slider might deliver the goods?  It will be tight looking at the uppers though!

 

[andymusic]

4 minutes ago, radiohead said:

Indeed it is.

 

and the 12z was further north east on the slider - no model will be sure of the exact positioning until much closer to 0 hour

[karlos1983]

Still cold uppers across the land as the next slider takes aim.  Could do with it being less intense however 

 

Edited December 4, 2017 by karlos1983

[Eskimo]

[Day 10]

The second slider produces the goods, but will it last?

Seems so!

Edited December 4, 2017 by Day 10

[karlos1983]

Just now, Day 10 said:

The second slider produces the goods, but will it last?

Probably be about 300 Miles west of Ireland by the time we get there 

[I remember Atlantic 252]

3 minutes ago, winterof79 said:

Snow maker? incoming

ya certainly not wrong there, FI remember though folks

[bluearmy]

That's about the best track we've see thus far for widespread snow event at the shortest timescale 

Edited December 4, 2017 by bluearmy

[andymusic]

2nd slider BOOM!

[winterof79]

1 minute ago, I remember Atlantic 252 said:

ya certainly not wrong there, FI remember though folks

Not much difference from 12z

[tight isobar]

Anyone wanna see a great modeled slider-type there it is.

Impactual snowfall most england!!!

[Singularity]

Dare I say it, a strong scent of GEM 12z to this chart?

A brief note on the volatility of Channel Lows for you; in mid-Dec 2010 there was such an event which was predicted at +12 hours to run neatly along the Channel and deliver a lengthy period of mostly moderate snow rates in my locality with the snow-rain boundary a good way out at sea. What actually happened was a northward deviation large enough to bring the heavier snow (boy did that excite me at the time!) but also transition to rain (and boy did that disappoint me!) as far north as my location; a shift of around 25 miles. My nice deep snow turned into a layer of slush which then froze into a 4-inch thick layer of ice overnight (which admittedly was very interesting in itself).

Okay, brief deviation OT over; I promise not to make a habit of it!

Not far off the GEM run but still not merging the lows quite so dramatically. 'Warm' sector of the LP is barely above zero 850s. 

This is how disruption and sliding of lows is supposed to work; not the barging in as a full-fat storm that ECM shows - that model clearly isn't seeing sufficient forcing from ridging N of the UK, be that wrongly or rightly so.

[Allseasons-Si]

From 162 the 18z produces snow over the BI,but i will refrain from posting snow charts.....

 

 

 

bloody hell

Edited December 4, 2017 by Allseasons-si

[blizzard81]

1 minute ago, bluearmy said:

That's about the best track we've see thus far for widespread snow event at the shortest timescale 

Shame it's the 18z 

[SMU]

16 minutes ago, bluearmy said:

That's about the best track we've see thus far for widespread snow event 

Yes yes

shallow- tick

no onshore SW flow -tick

low heights - tick

cold uppers - tick

PPN - tick

The snow accum charts for Mon will look like some of those ECM ENS !! ( not the Op )

Anyway cold now hanging on well...

[Methuselah]

5 minutes ago, Day 10 said:

The second slider produces the goods, but will it last?

Seems so!

And there it is...the Triangle of Doom sticks out all on its lonesome!

[feb1991blizzard]

People can say what they like about positioning / boundaries between cold and mild changing / PPN type etc not been nailed until much nearer, I actually the first diving low will be where the GFS has it, either way though, the fact remains that a heck of a lot of model runs have given a dumping across large swathes of the country recently.

[comet]

39 minutes ago, bluearmy said:

You actually force me to check the archive charts for the past week. Not surprisingly ukmo has done best with the northerly as ecm and gfs had it before day 6 although gfs got the trigger low badly wrong for quite a few runs. As far as the diving trough thereafter, gfs and ecm have both been trailing it with ecm actually making a decent fist if it at day 10 (though it went arwy in its days 8/10 output for a coiled, runs thereafter). Gfs has made a poor call on the diving trough the past couple, days although we can't be sure that the 12z are right on this just yet. Ecm was right to call the accelerated  demise of the Atlantic ridging. 

No model is right but to say that gfs is the model to follow is just plain wrong ! 

In your opinion. Meanwhile lets hope the ecm gets its act together and manages to deliver an output that is somewhere near accurate tomorrow, Fingers crossed eh.

[Methuselah]

Now here's a nice little twist...

[blizzard81]

120hr fax agreeing with the ukmo raw. 

[Pembroke Dangler]

I think the 0oC isotherm will play a part on the second slider if the low elongates like it shows it will draw a continental feed lowering dew points so South of it will be rain north of it sleet and snow and lots of it too. Somewhere will get pasted I think.