winter model output Winter Model Output Discussion -12Z 07/02/13 onwards

[Bristawl Si]

That's a very interesting update from Ian F and pretty much in line with the METOs latest FAX for t72.

FAX is further s/w than any other of the "big" models and slightly more shallow too, being a little weaker should keep the system further s/w as it enters the Channel and on into N.France. Will be very interesting to see the updated FAXES for t96/t120, later on tonight.

From a very IMBY perspective would hopefully like the low not to deepen and enter France around about the Cherbourg Pen.

Would expect a track like that to result in snow for many parts of southern England.

Regards,

Tom.

And checkout Ian's v latest posts in our regional thread - makes for v interesting reading!

Sorry i aint no good at posting posts from other threads!

[Long haul to mild]

Yes, important to note that it is not just the track of the low that is important, but its depth too. ECM showed earlier what could happen if the low deepens too much and becomes dartboard shaped; it would not be anywhere near as good for snow prospects.

However, Fergie's comments and the FAX charts suggest a slightly weaker feature (still plenty of ppn though!) and further south and west.

There are always winners and losers in these setups but judging who they are at the moment is a tough call, so keep following the FAX charts and then the NAE from tomorrow!

Edited February 7, 2013 by Chalk Serpent

[Severe Siberian icy blast]

ECM op to progressive with the Atlantic at days 9/10 as shown on the Deblit 10 day ens,

Interesting to see that the op also At the top end of the ensembles early on , with many runs going very cold, then more or less an outlier toward the end.

[Tamara]

ECM op to progressive with the Atlantic at days 9/10 as shown on the Deblit 10 day ens,

The ensemble maps at t168 show just over half with some quite good easterlies

http://www.ecmwf.int...t!2013020712!!/

Some that are progressive with the atlantic as well - but a greater number blocked than this morning overall

Edited February 7, 2013 by Tamara Road

[shotski]

EC Moyenne is good , Ec oper is false outlier at the end.

End Cma 12z als , look at that at 144 .

Hi Ryan

Have you got any data from the Dutch Met office ?

[Captain Shortwave]

ECM op to progressive with the Atlantic at days 9/10 as shown on the Deblit 10 day ens,

Interestingly there are a lot of high precipitation spikes (more than say mild members) towards the end of the run (216h-240h), would I be right to potentially call there are quite a few slider options in the ECM suite. I know that you are really suppose to take notice of the precipitation chart but that does stand out quite a bit.

[Long haul to mild]

The ensemble maps at t168 show just over half with some quite good easterlies

http://www.ecmwf.int/samples/d/inspect/catalog/samplers/banner/mean_sea_level_pressure_and_temperature_at_850hpa!168!pop!od!enfo!enplot!2013020712!!/

Good to see some of the ECM ensembles agreeing with the NOGAPS tonight, which had a great Easterly next week with no pesky shortwaves messing things up!

[Cheshire Freeze]

Good to see some of the ECM ensembles agreeing with the NOGAPS tonight, which had a great Easterly next week with no pesky shortwaves messing things up!

Write off ECM op at your peril. As Steve said a couple of days back, it's the highest resolution run in its suite and thus more likely to identify spoiler shortwaves!

[Grimsby Snow Lover]

And checkout Ian's v latest posts in our regional thread - makes for v interesting reading!

Sorry i aint no good at posting posts from other threads!

Ian's latest posts. Is this what you was refering to?

Key thing perhaps being overlooked in some MOD thread discussion is nocturnal chilling of boundary layer versus what 850's show per se. RegIonal modelling of lowest boundary layer currently beyond reliable scope of GM models for Sun night.

Latest modified GM for 12z Sun. Compare to FAX. Takes ensemble mean position. Note rain-snow discrimination thro Somerset etc is clearly clearly not to be taken literally at this range. Shorter sea track further E on S Coast enhances snow potential, as per event in Jan.

Edited February 7, 2013 by Grimsby Snow Lover

[Long haul to mild]

Write off ECM op at your peril. As Steve said a couple of days back, it's the highest resolution run in its suite and thus more likely to identify spoiler shortwaves!

Oh well I can dream! I'm getting quite fond of the NOGAPS nowadays and it would be great if this was one of its finest hours........

[Ryan Dutch Weatherman]

They put already Bilt eps here , every ok , en route.

Dont worry.

Only the snow forecast for sunday/monday is difficult .

But you see agian , yet in my country lof of snow showers , the office didnt predict it .

At this moment wile i man writing to you.

Only the Hirlam had it good for Holland today.

But the people were sceptic , like here , wel let them look outside now.

[Bristawl Si]

Ian's latest posts. Is this what you was refering to?

Key thing perhaps being overlooked in some MOD thread discussion is nocturnal chilling of boundary layer versus what 850's show per se. RegIonal modelling of lowest boundary layer currently beyond reliable scope of GM models for Sun night.

Latest modified GM for 12z Sun. Compare to FAX. Takes ensemble mean position. Note rain-snow discrimination thro Somerset etc is clearly clearly not to be taken literally at this range. Shorter sea track further E on S Coast enhances snow potential, as per event in Jan.

Yes.

[Cecil Hogmanay Melchett]

stunning ecm ensmbles

[Chris K]

Ian's latest posts. Is this what you was refering to?

Key thing perhaps being overlooked in some MOD thread discussion is nocturnal chilling of boundary layer versus what 850's show per se. RegIonal modelling of lowest boundary layer currently beyond reliable scope of GM models for Sun night.

Latest modified GM for 12z Sun. Compare to FAX. Takes ensemble mean position. Note rain-snow discrimination thro Somerset etc is clearly clearly not to be taken literally at this range. Shorter sea track further E on S Coast enhances snow potential, as per event in Jan.

Emphasis on 'clearly clearly not to be taken literally at this range'. Interesting though and something to look out for in the models as we approach the days in question.

We are privileged to receive this insight into a modified output by the professionals

[Ryan Dutch Weatherman]

Pluim Holland oost.

Edited February 7, 2013 by Ryan Dutch Weatherman

[Captain Shortwave]

Indeed. Something to bear in mind nontheless.

I would say that the shortwave in question has been hovering around in most runs since the 12z runs yesterday. GFS had it on this afternoons run in a worse position and the outcome was not too bad for how far out the runs goes and what changes can be made. Just saying I'm pretty sure that the shortwave would have been shown in the ensembles to but modelled differently (track and sticking point).

Note, of course this post isn't directly aimed at you but in general consensus of what other people think of the ensembles

Edited February 7, 2013 by Captain shortwave

[Ryan Dutch Weatherman]

Pluim Holland oost.

Sorry NO Holland 15 daagse EPS.

[Tamara]

Pluim Holland oost.

Hm - spot the operational at the 15th...

[Ian Brown]

stunning ecm ensmbles

I'm not surprised they have shown what they have as the Atlantic breakthru on the OP is unconvincing and could easily go the other way.

[Ryan Dutch Weatherman]

But look even in the false oper 12z EC , you see something very interesting.

Look around the east side by 216 en 240 , just look.

Even if the oper is outlier.

Its just hinting something to me.

I come back later.

[fergieweather]

Would suggest the Met think the low maybe further South and West. Quite possible.

Further south. ARPEGE agrees. For now. More analysis awaited before midnight. Deputy Chief tells us there will be 'changes' in previous snow distribution forecast. Haven't seen these yet.

[Long haul to mild]

Normally I am not that bothered about the GFS 18z run but with the track and depth of the weekend's low still very much up for grabs, it will be very interesting to watch developments over the next hour.

I don't for one minute think that whatever the 18z shows will be the final nailed track but as we get closer to the event, the differences should be small (but potentially crucial!)

[Ryan Dutch Weatherman]

But look even in the false oper 12z EC , you see something very interesting.

Look around the east side by 216 en 240 , just look.

Even if the oper is outlier.

Its just hinting something to me.

I come back later.

East from Iceland /around Spitsbergen , Jan Mayen.

[Pixel]

Key thing perhaps being overlooked in some MOD thread discussion is nocturnal chilling of boundary layer versus what 850's show per se. RegIonal modelling of lowest boundary layer currently beyond reliable scope of GM models for Sun night.

not sure if this is the right info but was intrigued by the nocturnal chilling.. anyone with better insight?

https://courseware.e-education.psu.edu/courses/meteo101/Section4p05.html

[Ryan Dutch Weatherman]

CMA just a Easterly flow , simple as it it. Until 168 hours.

The run is not finished yet.