Winter Model Discussion - Cold Hunting -23/12/12

[-uksnow-]

FANTASTIC. WAA into greenland, lets see where this goes.

Of note is also the lack of PV on this run, a trend im sure many would like to see continue, compaing the 06 again to the 12

06z

12z

P.s if anyone could tell me how to post smaller images i would be ever so greatful.

edit: woopsy maybe i got a bit over excited

Edited December 29, 2012 by -eded-

[LomondSnowstorm]

Well this run shows, if nothing else, just how quickly the PV can get shifted off Greenland:

A much better looking run which ties in very nicely with the MJO phase 6 anomaly:

Looks like the GFS has indeed woken up and smelled the coffee.

[Summer Sun]

Just when snow fans thought things couldn't get worse GFS 12z produces this.................

High pressure remains on course to build during next week gets to 1040mb by next Friday

Remains in place during the weekend

Even into FI and the high dominates with the surface temperature starting to fall as the high drifts west

Fine if you like it cold and dry but terrible if its snow you want / like

Edited December 29, 2012 by Gavin.

[PubliusEnigma]

The CET for december has been below the seasonal average, it's been rather cold at times with plenty of frosts in most of the uk during this month, the glaring item missing has been snow but hopefully we can put that right later next month and during february. At least the weather by the middle of next week will be turning more settled, so at last some welcome respite for the flooded areas and for everyone who would like to see some sunshine, your patience will soon be rewarded.

We have't reached the end of December yet. ? I very much doubt the South of England has been anywhere near below average. The wettest ever recorded in England IMO, would seldom coincide with below average temps. In fact the absence of frost for the last ten days or so has been notable. The only snow that has fallen in this neck of the woods was around 6am on 5th December which lasted about 30 minutes.

I think sunshine will be at a premium. over the next week / 10 days. The latest ECM output has the high never quite reaching the UK. Next Friday (4th) is the closet it gets to us, nosing into SW England and Wales,

By the following Sunday, its pushed away south again by a resurgent PV

And by Monday, a deep low over NW Parts sends Fronts across the country, and by Tuesday a developing low just south of Ireland

could deepen rapidly and bring some very wet and windy the UK from the SW.

More runs needed of course before we can be sure of the extent of the ridging from the Spanish High, however based on the available

output, apart from maybe next Friday/Saturday , we will continue to see yet more rain over the UK & Ireland, from time to time for the foreseeable.

Lets see what the 12z throws up, it may push the High closer to us, as the current 00z never gets the High over the UK, it keeps it

over France or Spain, before it moves away SW at the end of the run.

Edited December 29, 2012 by PubliusEnigma

[Summer Sun]

UKMO is now high pressure dominated about time we saw an end to the rain

[-uksnow-]

Just when cold fans thought things couldn't get worse GFS 12z produces this.................

High pressure remains on course to build during next week gets to 1040mb by next Friday

Remains in place during the weekend

Even into FI and the high dominates

With the high sticking around so long it could actually become quite colder under the surface of it, so perhaps not all that bad for cold, but bad for snow fans!

[Great Plum]

With the high sticking around so long it could actually become quite colder under the surface of it, so perhaps not all that bad for cold, but bad for snow fans!

Indeed, and if it was to drift to the west of the UK, then I believe it could be prime for an inversion which would at least make it more seasonal!

[Panayiotis]

What location is this graph for? Cardiff?

Yep Cardiff.

[Iceni]

With the high sticking around so long it could actually become quite colder under the surface of it, so perhaps not all that bad for cold, but bad for snow fans!

Just give me that still cold air. Just no more wet stuff falling from the sky. Faux cold or True cold, some clear skies would be wonderful.

[bluearmy]

The high hanging around is fine. There is no sign of any snow within the next fortnight (unless the jet relents to the north and allows the arctic high to nose through). Having the block in our latitude is better re retrogression or the scenario painted in parenthisis than if it sinks south or southeast. Given that everyone accepts the current position, not sure why the high hanging around could be seen as a bad thing by anyone. All in all an excellent gfs op run which begins to grasp the background teleconnections.

Lets see where the control goes if it has similar amplfication to your orth at the point of low res.

[mcweather]

all conjecture at this stage I know, but with that caveat in place the far end of FI to me looks like a high trying to retrogress to the mid atlantic and then possibly greenland. This is not a surprising development really the last couple of runs have shown a few colder outlooks on the FI ensembles. Tonights 12z ensembles will be interesting if they continue the trend of heading below average around the 13th again.

[cooling climate]

Sad I know but considering how poor the model output has been.

The 12z GFS t384 chart could be the first real sign of a major pattern

change. There is only one direction that high is going and that is north.

[Cheshire Freeze]

Evening all...

Starting to get the sense that we're approaching a watershed in the NWP; on the face of it it's looking like remaining poor for cold lovers but to me it's becoming pretty obvious we're approaching some kind of pattern change as we enter January.

The first signs of this (phase one) is now showing within medium range modelling and is seen nicely on the 12z GFS; this is the ridging north of the high that has been in evidence around Iberia.

The pattern may flatten out again temporarily after this initial ridging but I'd be wary of any NWP output which fires up the PV to robust levels again past this point. Another big point, touted by GP earlier, is the potential moving of the MJO towards a more favourable phase.

The crux of the situation, IMO, is what happens past phase one of the evolution as we enter January. There is a few options on the table at present, four major ones in fact.

1. UK high pressure scenario

2. Continuation of wet, mild conditions

3. Pressure rise to the E or NE

4. Pressure rise to the NW

Given stratospheric indicators and a general gut feeling, although scenarios 1&2 look more favourable given the recent NWP, I'd suggest that by the time we get to that 156 hrs chart above, the NWP outlook will have a completely different complexion, with outcomes 3&4 more favourable.

[snow1975]

Sad I know but considering how poor the model output has been.

The 12z GFS t384 chart could be the first real sign of a major pattern

change. There is only one direction that high is going and that is north.

Assuming that chart is correct, a northerly is in the pipeline. It ties in with the MetO forecast.

UK Outlook for Sunday 13 Jan 2013 to Sunday 27 Jan 2013:

There is greater than average uncertainty through this forecast period, though it looks likely to start with fairly average climatological conditions, meaning the south and and east of the UK will see the driest and brightest weather, while the north and west will tend to be more unsettled. However, there could be some rain at times anywhere across the UK. Temperatures will tend to be close to average for the time of year. Later, some marked changes of weather-type are possible, and the risk of spells of colder than average conditions increases.

Issued at: 1600 on Sat 29 Dec 2012

Edited December 29, 2012 by snow1975

[Grimsby Snow Lover]

And more importantly the Atlantic looks very quiet for a change which should help the high to regress up to a more favourable location

[Froze were the Days]

Jet stream running out of 'conk' on that run in the medium/FI term on the 12z run and as mentioned a possible Green land HP possibly becoming more prevalent on that run in the later stages? but that is only 1 run, but worth keeping a note.

[Cheshire Freeze]

And more importantly the Atlantic looks very quiet for a change which should help the high to regress up to a more favourable location

All will depend on the movement of that slice of PV & associated low heights around Greenland. If we can dislodge this to anyplace that's away from the Greenland locale I'd be quite bullish about the prospects of a Greenland height rise ETA 10th-14th Jan. If not, I suspect it will weaken favourably enough to allow heights to increase downflow around the Scandi area. I'm 50/50 on this particular aspect. Obviously I'd prefer a Greenland height rise over a Scandi one but, given the time of year, if everything fell into place then a Scandi high could really produce the goods if we can get the Greenland low heights to back off somewhat.

[IDO]

The GEFS mean not really supporting the High ridging as far north or staying close to the UK:

So we will have to see if GFS has spotted a trend. The ensembles suggest a split in synoptics:

Still the cooling down from the 850s back to average by T336: http://modeles.meteo...21-0-336.png?12

The control run has a failed first attempt at HP and as CreweCold suggested a further ridge tries again:

Interesting developments, at last.

Edited December 29, 2012 by i'm dreaming of...

[ChartViewer]

GFS possibly smelling the strat coffee...we hope....

Interesting to see ensembles over the next few days....

Edited December 29, 2012 by ChartViewer

[bobbydog]

has anyone noticed, over the last few frames of the GFS, the HP over us actually moves west. i'm no expert but thats not something i've noticed modelled often. is this the sign of the pattern change and the GFS starting to factor in the strat warming?

[bluearmy]

Assuming the gefs are following a trend, each gfs op run from now on could well throw up some v cold fi patterns. There seems to be a drift to somewhere more akin to winter by mid month. Given that the ecm op is noted for being rather progressive on occasion and rushing the likely pattern through, these may also throw up some fun runs over the next few days.

Thats retrogression bobbydog. Its normally the precursor to cold as heights build to the west and drop to the northeast.

Edited December 29, 2012 by bluearmy

[bobbydog]

Assuming the gefs are following a trend, each gfs op run from now on could well throw up some v cold fi patterns. There seems to be a drift to somewhere more akin to winter by mid month. Given that the ecm op is noted for being rather progressive on occasion and rushing the likely pattern through, these may also throw up some fun runs over the next few days.

Thats retrogression bobbydog. Its normally the precursor to cold as heights build to the west and drop to the northeast.

i thought it was, just wasn't sure. in which case, as you say, we should see some colder runs appearing as retrogression is a big step for the models to be showing, without good reason, is it not?

[Polar Maritime]

On the radio 4 weather forecast from the BBC early'er, they said January will get colder.

Things are starting to look good.

Edited December 29, 2012 by Polar Maritime

[Panayiotis]

Cooling trend on the 12z again, been a consistent trend in the past couple of days..

[Summer Sun]

Cooling trend on the 12z again, been a consistent trend in the past couple of days..

Maybe next weeks high pressure is whats needed to change the pattern