Model Output Discussion - 16th Jan 12z onwards - Smile While You Post!

[Dancerwithwings]

Forget far reaches of FI, these are two charts I personally saviour for parts of the UK waiting for a long overdue snowfall and these both fall within the reliable on the 20th and 21st January respectively.

 

I know, judging one operational run is isolation is fraught with danger and that there are many parameters to consider when looking for those magic white crystals, however, these two charts look tasty to say the least. I ain't looking for a breakdown or considering deep FI when we have this showing up on our doorsteps in the meanwhile. Good luck for the longer-range weather hunt in the meanwhile.

 

t+72hrs

 

ECM 12z 170115 H500 UK t+72 hours 1300CET 200115.GIF

 

t+96hrs

 

ECM 12z 170115 H500 UK t+96 hours 1300CET 210115.GIF

Pretty much snow all the way looking at the ECM PPN.... 72h through to 96h.

 

[Ali1977]

Pretty much snow all the way looking at the ECM PPN.... 72h through to 96h.

 

I hope so but I'm sure METO would have released early warnings by now if it that was the case, unless they are waiting for slightly more clarity of where the slider "slides"

[MPG]

GFS 6h and 12h for Thurs 7am

 

 

Slightly strong heights over Greenland with westward correction of low to the south.

 

Scandi heights marginally stronger and slightly further NW. Low over southern UK slightly further north...

 

Wonder if the Scandi heights can find a way to link up with Greenland heights down the line with weaker LP putting up less of a fight against the heights to our N/E? If so we could end up with a slider?

There arn't any 'heights' over Greenland??

[Cheese Rice]

ECM PPN charts show a patchy decaying front on Tuesday followed by a secondary patchy and decaying front pivoting over central northern England.

ECM PPN type charts show patchy snow. Really snowfall further north.

Not sure what some are commenting on here.

[shuggee]

Below are some NW Extra GFS 12Z 850hpa temps + precipitation charts for next week.  Obviously 850s are but one indicator of the type of ppn that may or may not be falling from the sky....

 

Midnight Monday morning

 

Tues 9am

 

Midnight Weds morning

 

Weds Noon

 

Thurs Noon

[Sweatyman]

I hope so but I'm sure METO would have released early warnings by now if it that was the case, unless they are waiting for slightly more clarity of where the slider "slides"

way too early for warnings

[fergieweather]

ECM PPN charts show a patchy decaying front on Tuesday followed by a secondary patchy and decaying front pivoting over central northern England.

ECM PPN type charts show patchy snow. Really snowfall further north.

Not sure what some are commenting on here.

Yes. Greatest risk (of disruptive snow) NI and Scotland in MOGREPS too. That aside, UKMO lean towards broader snow risk essentially mid-Wales northwards. Some accumulations also likely S and E of here between Tues-Thurs. Anyway, all in line with previous assessment over past day or two, but devil still in detail. Confidence high now to mid-Tues but not thereafter. Edited January 17, 2015 by fergieweather

[snowray]

Not commented on this forum for some time, until today. But if I was a gambling man I'd say, keep an eye on midday Weds til the early hours of Thursday as the low sinks South/South East. That PPN could be quite heavy and of snow as a wave develops on the front. 

Of course nothing set in stone and only one run.

[Frosty.]

Tonight's Ecm 12z op shows another 168 hours of cold weather with rain, sleet & snow and lots of ice and frosts before eventually we see milder conditions arriving, whether it actually plays out like that is another matter entirely.

[KyleHenry]

You know looking at the ECM in the later stages with some reserve the beast is sitting waiting to move in if an opening occurs.

A 1045 mb High is a match for a weakened Greenland PV.

The Russians didn't cut gas supply to Eastern Europe if they didn't think it would hurt the most.

[Man With Beard]

OK looking ahead, it seems most accept a return of Atlantic dominance at T192-ish, and I accept that as the most likely outcome, but no winter is complete without the Scandi High that is more stubborn than the models expect - and it looks highly likely we will get a Scandi High now at T72:

So could this be the one? ECM mean at T168:

The High looks far away but the real point of interest is the thin blue line from Denmark down to Italy - that separates the cold to the east and the not-so-cold to the west. If the Scandi High is stronger than modelled (and often is once established), could that back west? A few GEFS ensembles think there's chance - here's the most extreme:

Maybe that's going too far, but I would put the chances of the cold divide being 500 miles further west than currently forecast at 25%. In other words, not a possibility to be discounted.

[Frosty.]

When this MJO (Madden-Julian Oscillation) 'flip' occurred, I was excited about it because this winter was going nowhere fast, and now we have at least a week of potentially exceptional wintry weather for some of us and although the models are indicating a gradual return to Normal UK winter fayre in around a week or so, give or take a day or two, I still think there could be a sting in the tail and perhaps this flip will turn out to be flipping marvellous for coldies after all, it's not a done deal that this cold spell will go out with a whimper as is currently being shown with the Azores high ridging in then sinking SE with a return of the atlantic.

Edited January 17, 2015 by Frosty.

[bluearmy]

extended ecm eps keep the nw/se jet into se europe with low anomolys over much of europe though the lowest concentrated generally just nw of the uk. tbh, i am taken by how low the mean thicknesses are under this zonal flow. actual thicknesses around the midlands coming out in the low thirties, occasionally lower. remembering that this is a mean i expect we will continue to stay colder than normal in the 10/15 day period. we're almost n of the mean jet as it travels very straight and strong from nova scotia to the central med. 

 

i assume this mean that cyclonic will be the story for the period although the pull back of the azores ridge either means continuing trough disruption into europe (which side are we on and if the thicknesses are that low, we arent far off not caring too much if its the western side. ) or runners into the base of a cold nw euro trough spinning off se as they pass the meridian. either way, it doesn't look like any return to mobility will make it much less wintry feeling although snow will be more likely the further north you are.

[Summer Sun]

Looking at the ECM ens the 850's for next weekend and into the final week of January they only rise slightly (don't go above 0) so I doubt daytime highs would rise much higher than average, certainly nothing what I'd class as mild on offer

 

 

Looks like a return to a westerly flow at this stage with a gradual return to breezier conditions

 

 

The question mark remains on whether a return to a westerly flow is proceeded but a snowy breakdown I wouldn't rule it out at this stage if we do see the above happen

Edited January 17, 2015 by Summer Sun

[bluearmy]

latest faxes are pretty well all ecm rather than ukmo in our vicinity.

[Jason M]

Stronger heights to our North on this run

http://www.meteociel.fr/modeles/gfse_cartes.php?ech=90&code=0&mode=0

More in line with the ensembles at last.

[warrenb]

GFS going ECM with second slider by the looks of it.

[Snowmadsam]

Models are still slipping I see. 

 

Tonights precipitation in the Wales and West, appears to be moving slower than forecast, sleet/snow also occurring in places according to radar  

[shaky]

Massive Scandinavian high on the 18z which has pushed west yet again!!! Chances of continues sliders out to 144 hours! !

[Met4Cast]

Massive Scandinavian high on the 18z which has pushed west yet again!!! Chances of continues sliders out to 144 hours! !

Yep - This is a trend I can get on board with!

[damianslaw]

BBC long range forecast update suggests any breakdown will be a slow protracted affair and still very uncertain how and when it occurs. Jetstream profile still suggesting a more NW-SE orientated flow with energy being sucked into Europe. A return to 'average' conditions at best I would say, certainly not the profile of early January.

[SnOwFeSt]

Looks like a classic battleground has been trending over recent runs. Much stronger scandi block, holding the atlantic further back, with what looks like another slider scenario setting up. Lets hope this trend continues.

 

From experience of these sorts of situations the trend will be for the block to continue to strengthen/ atlantic to be held further back as we approach T+0

[TEITS]

Well the shift W by the 18Z is why you cannot assume a return to W,lys is  guaranteed. Still scope for further shifts W of the output with LP slider SE next weekend rather than E.

[The Enforcer]

Yes. Greatest risk (of disruptive snow) NI and Scotland in MOGREPS too. That aside, UKMO lean towards broader snow risk essentially mid-Wales northwards. Some accumulations also likely S and E of here between Tues-Thurs. Anyway, all in line with previous assessment over past day or two, but devil still in detail. Confidence high now to mid-Tues but not thereafter.

Could anyone explain what is deficient in more southern areas to prevent snow falling at average elevations under the situation currently modeled for next Tues/Weds? Before the weekend, I was pointing out the mild sector on the 850's (which is still visible on current GFS and ECM charts), I was advised that this wouldn't be a problem. So what is the problem?

- 850's too high after all?

- dew points not low enough?

- lack of sufficient entrenched ground level cold air ahead of the front?

- precipitation not intense enough to generate adequate evaporative cooling?

- all of the above?

- none of the above - something else?

Edited January 17, 2015 by The Enforcer

[Mucka]

Op still cold out to the 24th this run which goes with the ensemble trend.

 

 

Get the pattern a few hundred miles NW and thing would be very interesting.

Edited January 17, 2015 by Mucka