Model output discussion 25th Jan - The final third of winter beckons..

[feb1991blizzard]

10 minutes ago, snowbunting said:

Agreed. Was looking at the charts, I think a scandi high bringing a brief easterly then settling into high pressure centred over the North of the UK would not be unreasonable, if following the ECM. Repeat 2013?

The concerns are the BA one that the angle of the Jet is too SW to NE aligned and its linked with my concern to a certain extent, even if you get the  -10c isotherm in, it doesn't guarantee heavy snow showers, if the 500mb heights are too high then PPN will be limited, we really need that UKMO run to be repeated soon on other ops / suites in quantity within the next 24 hours, surface pressure can be as high as 1025 and still deliver big, but you need cold 850's with steep lapse rates up to 500mb as well, The most brutal dumpings from Easterlies will have occurred with heights at least below 530dam, I doubt many proper lake / sea effect snow events have occurred with 500mb heights near 540dam. The 'get the cold in first and then the snow will crop up' line doesn't always ring true, especially not with these setups (excluding any subsequent battleground events that is)

Edited February 2, 2017 by feb1991blizzard

[Severe Siberian icy blast]

3 minutes ago, Daniel* said:

Here is 192 from OP mirroring the mean really the bigger cluster is with ECM op it seems - the latter frames of ECM is bitterly cold it must be said although dry less so to the SE. 

Not an outlier^ 

It's got the pattern clock on. It's the 850's that's at the milder end of the ensembles 

[snowice]

37 minutes ago, Bring Back1962-63 said:

EDIT:  This post took me about an hour to prepare but I see that there are another 3 pages in that time!

 

I thought you were working on the posts since 1963 lol. Very informative post much appreciated by all

[mulzy]

5 minutes ago, Daniel* said:

Here is 192 from OP mirroring the mean really the bigger cluster is with ECM op it seems - the latter frames of ECM is bitterly cold it must be said although dry less so to the SE. 

Not an outlier^ 

Sadly, some people have no clue what the meaning of an outlier is.

https://en.wikipedia.org/wiki/Outlier

 

[Allseasons-Si]

These are not a bad set of ens from just across the channel are they,temps hovering or just above freezing and dew points getting toward the -20 mark

add to that,that is a good cluster of easterlies there,but uncertainty for first few days

full set

 

 

Edited February 2, 2017 by Allseasons-si

[booferking]

7 minutes ago, Severe Siberian icy blast said:

It's got the pattern clock on. It's the 850's that's at the milder end of the ensembles 

That post is spot on look a the rest of europe not just the uk. Onwards to 18z lets hope we see the deep cold grow.

Edited February 2, 2017 by booferking

[tight isobar]

Aldo sadly..

Is the geographical scale of being a polar maritime island. .defines' micro-scale observation of an outlier' and not..

Mirrored against the complete suite. ..

Its called exactions on micro-scale. 

And this is why its s##t or bust for our Islands. 

Details are of mass-implications. 

Edited February 2, 2017 by tight isobar

[Connor Bailey Degnan]

I was just trying to be positive. Perhaps I overhyped it, when I said "big outlier". It is a slight outlier, I apologise.  Remove my previous post please mod.

[Allseasons-Si]

56 minutes ago, Man With Beard said:

Ah yes ... the dream itself ... the mythical cut-off Scandi High in early February. A 1991 revival. Make the most of it chaps!

And goes on in the 8-14 dayer

[SMU]

16 minutes ago, Allseasons-si said:

These are not a bad set of ens from just across the channel are they,temps hovering or just above freezing and dew points getting toward the -20 mark

A nice post

ive left in the image that shows that whilst the Op is not an outlier in the clinical sense, it is a tad disjointed away from the pack at day 6 with the dewpoints, with the mean some 5 degrees colder - indicating much colder air @ 850 ( good correlation there )

What we are doing here is micro analizing & critiquing each run,- which is fine as theres enough data to spot the holes in the wallpaper so to speak  - thats if you look hard enough

The bigger picture has firmed up today on a decent beast from the east over & above yesterday which wasnt really getting much support other than UKMO & some rookie models- Also developments today have indicated that the odds have shortened on the uber rare king of the beast from the easts - Which is sub -14c air getting across the channel ( ~ 510 DAM ) -

For me sub -14c is the line in the sand where we go from a decent 80s standard fair easterly to the more infrequent ( more so these days ) 'Classic' / Historic easterlies that are the 'talk' of the forum in years to come-

Im not suggesting that this is the case or ramping -im just suggesting that with all things considered the best case scenario still on the table is that 'classic' outcome-

Lets hope we hit the jackpot- we will know the outcome of what the upper air will be by Sun 12z.... only 3 days to wait!!

eyes down for the pub run which is always a lottery !!

[phil nw.]

We have a quite a fascinating period of model watching ahead with the Atlantic running up against the developing Scandi block.

As early as day 4 we see the cold air as far west as the north sea.

 

At this stage the battleground pitches up just to our east as we go into next week.Much of N.Europe going cold and as ever we are at the end of the line so we need another shift west of the battleground in the pattern to get the convective easterly rather than a drier continental south easterly.

The runs over the next few days should hold plenty of interest for cold lovers.

[SMU]

Yes the OP is higher res so should be accurate however the OP has been trending to Far East & as each passes all ECM 12z runs have corrected west the next day & so on- all towards the UKMO solution ...

18z is already better aligned out to 72 than the 12.. Could we scrape cycle 1 yet with a snow event.....

[bluearmy]

Not much changed from the 00z eps suite

the Azores upper ridge around the day 9/10 range should be drawn ne into the scandi feature (the 8/14 cpc chart illustrates that) 

the back end of the ec op isn't ridiculous in the context of where the modelling is going but I do think the ridge is too far south if that is indeed the route forward

the key (imo) remains the euro troughing and how strong it can be. Too far west and big risk that the scandi high will ridge south and bring too much of a southerly drift to cut off the cold.  Not strong enough and it's pretty obvious what will happen as the ridging will sink. at the moment, the euro troughing looks OK on the extended eps to support the ridge and keep the upper air cold enough to keep the majority on here on tenterhooks. 

And whilst the upper cold pool strike remains around a 30% chance, that should be enough to make sure your first action in the morning is to check the models! 

[Allseasons-Si]

The AO goes into neg territory with just the one straggler just above the neutral zone

as you can see from the bottom two charts(this is new to me so correct me if i am wrong),the one on the left is the warming at 1-10 hpa and the one on the right is the zonal wind speeds dropping off at the same height's,so looking good in that respect

the two charts below show the warming spikes at 10 and 30 hpa not bad looking are they but would prefer the warming a tad more but we are in a better position than the last few winters

 

[damianslaw]

Staying objective at the moment and not getting too drawn on the intra-run variability, as always to be expected especially when the atlantic looks like coming unstuck against blocking feature. The trend of the winter has been for too much energy to draw north and place forcing on height development to our east, sinking it southwards and sending coldest air to east/se europe, and this evening's ECM is showing such a scenario, with a NE-SW aligned jet, and no trough disruption, hence its no wonder we see the high sinking aided by the azores high nudging its way NE. UKMO and GFS showing trough action slightly further west and prone to trough disruption which helps to maintain more robust northern positioned heights.

The eventual theme is still a cold one, and a surface flow from off the continent would bring very low daytime temps, much like we had last Thursday when uppers were above 0 degrees, a cold surface flow from the SE in mid Feb can pack a very cold punch, ice days can easily be recorded. 

Longer term, every chance we will see a trigger low slide and disrupt from the atlantic with more robust heights building to our NE and north, a sinking trough scenario, indeed this weekend we have trough disruption, could take a couple of bites to get the proper sustained cold in. I'm reminded back to Feb 1994 when we had a shortlived easterly spell, scandi went in the freezer then a trough disruption scenario with copious snow here.

[SMU]

So 18z trending very well to the UKMO

The snowline exiting holland at just T114...

tasty !

[Allseasons-Si]

The 18z is a direct hit aproaching 138hrs

[snowray]

Lovely run, thanks 18z! Snow and freezing temps arrive early at D5.

[frosty ground]

Very cold charts.... think Steve called this right a few frames back

[Met4Cast]

-10c pushing into Eastern England at +132

 

[frosty ground]

For those worrying about the Azores high.... well it's pretty much a minor player in this setup the block to the north is the driver here and Ridge would be temporary 

[Wilxy]

Very Impressive Scandi High on this run!

 

 

[Man With Beard]

And here we go again, the twice weekly soap opera which is the EC Monthly. Remember those Atlantic dominated charts from last week? Yeah scrub that. Latest scribblings go cold much of February 

 

[Bartlett High]

2 minutes ago, snowray said:

Lovely run, thanks 18z! Snow and freezing temps arrive early at D5.

I'm sure you are far more knowledgeable  than me but according to the BBC forecast  next week is set to become colder from midweek and very dry and settled (BBC news channel 21:55)

[snowray]

That is a wicked chart, brrrrrrrrr Very cold, snow showers in the east.