Winter Model Discussion 18Z 13/1/13 onwards.

[bluearmy]

Would be nice to see the ecm ens suite swing behind the droppng out of the less cold runs in the extended. Certainly good continuity from the 00z suite re pattern.

[snowice]

Matt Hugo

Support for the block is there and the ensembles are quite cold overall into next week, away from Ireland.

https://twitter.com/MattHugo81

ECM 12z Full Ensemble

Away from Ireland can you please explain?

[dixonoid]

Please could you help me out here guys but what is a slider low? Thanks in advance

I think it is a low pressure system, that manages to slip past the block of high pressure, following the jet stream, and as it passes causes a snowy problem, if things are cold enough! Probably wrong lol, but this what my understanding is, please correct me if im wrong :-)

[bluearmy]

Away from Ireland can you please explain?

The atlantic gets into ireland. as the days progress, this may get pushed back further west keeping ireland cold aswell.

[GrangemouthBairn]

I think it is a low pressure system, that manages to slip past the block of high pressure, following the jet stream, and as it passes causes a snowy problem, if things are cold enough! Probably wrong lol, but this what my understanding is, please correct me if im wrong :-)

Yes, it slips underneath the block of high pressure and usually results in easterly winds.

[Methuselah]

Thanks for the explanations there, guys... Can we get back to the models now, please?

[phil nw.]

Please could you help me out here guys but what is a slider low? Thanks in advance

Here on the T120 UKMO chart see the low pressure sliding across the SW of England and into France- under the Scandinavian block.

You can see where the term slider comes from -sometimes called an undercut too.

It`s where the energy from the jet stream goes south east below high pressure to our north this generally keeps the UK on the cold side of things .

Edited January 13, 2013 by phil n.warks.

[snowice]

Thanks for the explanations there, guys... Can we get back to the models now, please?

I wonder will that low pressure south of Iceland at+96 that was on ecm, be there on 18z gfs?

[Severe Siberian icy blast]

Can I just say , Iv looked at the new nae , tomorrow now has a max temp for England of 1c , it has at its warmest -4 850's , and dew points at 1c , surely that will be snow in heavy ppn?? Definitely on any high ground I would of thought??

[Harsh Climate]

Big downgrade regarding tonights snowfall, at just 6h in

Edited January 13, 2013 by Harsh Climate

[IDO]

12z snow risk 6am tom: 18z:

[Frosty.]

Please could you help me out here guys but what is a slider low? Thanks in advance

This is what a slider low does, it undercuts the cold block and sucks even colder air from eastern europe across the uk, the ukmo 12z is a perfect example of what is still possible by the end of this week. It would bring widespread blizzards across the uk with severe drifting, it's something to think about as a probable outcome of the sudden stratospheric warming and could bring a severe spell of wintry weather to the uk in the coming weeks.

[Summer Sun]

Latest NAE for midnight

[Matty M]

Atlantic already further east in this run compared to the 12z, but lets see how it plays out.

[Severe Siberian icy blast]

Big downgrade regarding tonights snowfall, at just 6h in

Depends what your looking at

Snow risk further west, lower temps, lower dew points, very slight movement in temps makes the difference between sleet or snow , the 1800hrs tmoz is showing snow over the midlands widely.

[karlos1983]

Atlantic already further east in this run compared to the 12z, but lets see how it plays out.

Probably a little early to confirm IMO, and its extremely marginal

[Harsh Climate]

Got a feeling we could be getting a better under cut coming up, could be yet another upgrade regarding how prolonged this cold spell will be

[Summer Sun]

A decent snow event for many tomorrow especially for those along the east

And into Tuesday

[Harsh Climate]

Depends what your looking at

Snow risk further west, lower temps, lower dew points, very slight movement in temps makes the difference between sleet or snow , the 1800hrs tmoz is showing snow over the midlands widely.

What I meant is, the band currently over northern england on that chart is a lot smaller and decaying more rapidly than on the 12z run, therefore it is less good.

You say it's further west, but doesn't matter how far west it is if the precipitation amounts are going to be trivial..

Edited January 13, 2013 by Harsh Climate

[Snowman.]

Big downgrade regarding tonights snowfall, at just 6h in

I would take that any day.

Gives time for temps too drop as its west.

[Harsh Climate]

A risk of heavy snow in the south west wednesday if this chart is to be believed!

I would take that any day.

Gives time for temps too drop as its west.

Look at the next frame though, will it actually arrive..?

Edited January 13, 2013 by Harsh Climate

[Matty M]

Still the difference in jet and amplification as early as 60hrs between GFS 18z and UKM 12z.

[ChartViewer]

Need that energy going south pease...t72

Edited January 13, 2013 by ChartViewer

[picog]

Depends what your looking at

Snow risk further west, lower temps, lower dew points, very slight movement in temps makes the difference between sleet or snow , the 1800hrs tmoz is showing snow over the midlands widely.

That's right, it depends on your view. For us in the west, that's an upgrade - the snow has shifted west.

[Matty M]

Note the difference to our west at T66hrs GFS 18z

UKM 12z 72hrs

Massive repurcussions down the line.

Now the 18z GFS is not a model i pay too much heed to, but it would be nice to have it on board.

The 0z will be crucial lets hope UKM can hold steadfast.

18z would still give me a few inches by Wednesday morning.