Winter Model Discussion - Cold Hunting -12Z 06/01/13

[Panayiotis]

Lovely GFS at 240hrs with Greenland/Iceland heights and and a cold pool heading our way from the east, it is Fi but at 240hrs the ECM has a cold pool heading our way but via a different route (Scandi high). I am very pleased with what the models are currently showing for the short and medium term. Also the CFS is looking superb, for the medium term too (00z)!

PS It seems to get better and better everyday for our chances for cold!

Edited January 7, 2013 by Panayiotis

[Southender]

Nowt wrong with this run. Snow risk for Eastern areas this weekend. Before a proper "potential" hit of cold and snow for all as we head into next week and beyond.

[Glacier Point]

Yes, for sure - but the broadscale (let alone mesoscale) set-up is a right mess in the ENS still, with some EC EPS members out past T+260 onwards showing a very wintry set-up; others a mild SW (!!) and this is symptomatic of the unreliability of where we are heading in terms of FI. The crucial point being stressed by Exeter is for folk (and newspapers!!) not to confuse the hear-and-now MR set-up and chilling-off story with the (potentially far more profound) SSW impacts further into the month. This is a story yet to unfold.

Indeed, this cannot be stated enough. The strongest tropospheric impacts will likely be felt 20-30 days following the initial warming. Current MJO forecasts are really gunning for a big amplication in the western Pacific which is going to off-load a lot of westerly inertia into the tropics and which will spike the pattern of mid / high latitude blocking structures around the end of the month which will add extra spice to an already persuasive stratospheric signal.

[MR EXTREMES]

jetstream onside to a t144

[Wilxy]

I think we can almost be certain that the weather will feel much more seasonal at best

Still some good signs at the moment im still trying to learn and found this thread very intresting thanks all for your input.

[Stu_London]

GFS fires up the northern jet post +300.

Given events further up - even less likely to verify than normal +300 output I would say

[AWD]

FWIW, the NOGAPS is very similiar to the UKMO at T120/144, bringing a easterly flow over the UK & possibly a little snow;

Then settling pressure over the UK bringing cool, anticyclonic conditions to us;

[Harsh Climate]

Ukmo at 144h is alright. looks like the high on this run is trying to retrogress towards greenland

[Dexter29]

If at 240hrs it were showing raging SWesterly's then I'm sure we would ignore them.

So ignore +240 on the 12z Today as well, it will change again come tonight's 18z or tomorrow's models.

I think we should concentrate on this weekend first. Good agreement of some kind of easterly flow affecting us with -8 uppers affecting some come Sunday. Possible snow event for Midlands/SE. The models can't even get to grips with the weekend let alone a +240 chart.

[MR EXTREMES]

gfs at t96

and gem at t96

[tight isobar]

A good run 12z. Will we soon get cross model agree?.my thoughts are yes...

[Coast]

Please allow me to be selfish, way out at +168?

[MR EXTREMES]

GFS fires up the northern jet post +300.

Given events further up - even less likely to verify than normal +300 output I would say

t300 dont really matter because i would hope greenland block would aid southerly tracking jet or the jet running northeast over the top of the block and thats just so far out its impossible to predict jet output.

[Sunny Kent]

A newbie question. With current uncertainty and Ian stressing an SSW event effect (if any) not being digested by the models what is the realistic FI? Namely how far are the models reliable?

[Iceberg]

Ukmo at 144h is alright. looks like the high on this run is trying to retrogress towards greenland

Yep Meto T144 is a classic chart, initial easterly due to the NW/SE tracking low, then instead of sinking into europe the high retrogresses, only one realistic outcome from that which is blocked atlantic and cold from either a North or NE direction. Hope the guys and girls who were saying this was all over yesterday evening are paying attention....

[BLAST FROM THE PAST]

As can be seen with some posts. Some are expecting the cold [that is real cold] too soon. Indeed the more I look into this and had some discussions with RJS, the more potentially intense and prolonged the cold could become during Feb. This could all be a decent taster/apparetif!

What we see now fits in with an old 'necessity' of mine for decent deep/prolonged winter cold. We need to see cold and northern blocking apparent or in place by last 3rd of Jan 'at least' or it just doesn't really happen.

IMO any deep FI that collapses the Greenland block is off the mark....anyway there is a lot to get through before then.

BFTP

[Wilxy]

A newbie question. With current uncertainty and Ian stressing an SSW event effect (if any) not being digested by the models what is the realistic FI? Namely how far are the models reliable?

Usally anything past 72h or 96h.

[phil nw.]

UkmoT120hrs going the same route as GFS

so a brief easterly before pressure rises but enough to bring the cold in from the continent - some sharp frosts to come.

[MR EXTREMES]

ensembles GEFS

is coming out now jma looks ok cold uppers sinking south under uk block but cold surface temps again.

[AWD]

ensembles GEFS

is coming out now jma looks ok cold uppers sinking south under uk block but cold surface temps again.

Today's JMA isn't out yet.

[Summer Sun]

The higher ground of Scotland and northern England could see some snow on Saturday morning

By Saturday evening lower parts could see snow with wintry showers heading further south

By Saturday night you can see all the cold air waiting to move in

Snow risk moves further south

During Sunday eastern coastal ares from the humber south could see frequent snow showers

The first story in the media regarding the cold spell has appeared this afternoon more will follow thats for sure - http://forum.netweat...80#entry2468212

Edited January 7, 2013 by Gavin.

[Iceberg]

Gem is nice at T114 and shows now the situation might change for the better for this weekend, it stalls the low in the irish sea for a wee bit, which allows much more under cutting of the colder air into its northern flank, as well as preping up the precip it will mean any precip to the north of the centre will be snow as well as the wrap around cut.

[Bobby]

A newbie question. With current uncertainty and Ian stressing an SSW event effect (if any) not being digested by the models what is the realistic FI? Namely how far are the models reliable?

I'd take anything beyond say day 5 / +120 with several helpings of salt. Beyond that best to look at the ensemble means / anomalies for trends to see where things might go. Lot of uncertainty in the models at the moment so anything could happen.

[Iceaxecrampon]

Beautiful run into FI. Would bank this all day long.

EDIT: high sinks eventually but a great run upto that point.

Refuse to do FI....

Stopped looking - T+132 this weekend will do thanks very much!

Ian

(assuming where FI is - anyones guess)

Edited January 7, 2013 by Iceaxecrampon

[Timmytour]

A good run 12z. Will we soon get cross model agree?.my thoughts are yes...

But will this be enough to get the strangely reluctant Daily Express on board????