WInter Model Output Discussion 12z- 28/01/2013

[mountain shadow]

Worst than the 6z so far will it be as bad as the 0z the other day?

Not much in it. The PV is definetely less intense than the 6z which I would have thought increases the chance of height rises to the North East, certainly trough disruption evident with no real toppler.

http://cdn.nwstatic.co.uk/gfsimages/gfs.20130131/12/150/h500slp.png

[Panayiotis]

Worst than the 6z so far will it be as bad as the 0z the other day?

One would say the 12z is bad compared to the 06z as the heights ridging north are not as extensive, but one would also say its better as the PV looks much weaker compared to the 06z, which will help more down the line?

[Nick F]

Bitterly cold day that I would think.

Gale force north westerlies with heavy squally rain/sleet/snow showers.

http://cdn.nwstatic....120/h500slp.png

The delivering low is further south and east than the 6z, will be interesting to see how this pans out. PV over Canada, a little less intense.

T850s and dew point charts for that same time certainly suggest squally sleet/snow showers blowing in across western areas Tuesday morning, even to lower levels. Though as others have mentioned, the 'warmer' core of the low moving down from the northwest will bring less cold air southeast - thus showers turning to rain afternoon/evening.

But once that low moves away into the North Sea on Wednesday, colder air and lower DPs return from the NW.

Thereafter, question marks over the track of further secondary lows moving down from Iceland area, ideally want the lows to track SE across Ireland or even further west than further east like the 12z GFS - to keep those warm sectors away!

Edited January 31, 2013 by Nick F

[Snowman.]

Not much in it. The PV is definetely less intense than the 6z which I would have thought increases the chance of height rises to the North East, certainly trough disruption evident with no real toppler.

http://cdn.nwstatic....150/h500slp.png

May be less energy but its moved back east which isn't ideal for Heights north.

[Beaufort12]

let it snow

Edited January 31, 2013 by Beaufort12

[Dibdabbers]

Not heard much regarding the SSW lately, are the charts beginning to show its effects, or could they still, or did it not have the impact we thought it would. Would be interesting to know your thoughts

[Snowman.]

Can that Dig south-east into france?

[Panayiotis]

Undercut commence?

[Snowman.]

She went under!! (sorta)

Still not the best run.

Edited January 31, 2013 by SN0WM4N

[bluearmy]

gfs fi still sniffing around a broadly reasonable solution - as eric morecambe once said - 'i'm playing all the right notes - just not necessarily in the right order!'. gfs op in low res could be said to be following the same line of thought. it has all the right features - just not necessarily in the right places!

[Nick F]

The models still seem to handle well north or northwesterly incursions, at t+144 - there's not a great deal of difference between 12z GFS and UKMO with the general flow, other than the positions of secondary lows on the western flank of the trough digging south over Europe.

[Severe Siberian icy blast]

gfs fi still sniffing around a broadly reasonable solution - as eric morecambe once said - 'i'm playing all the right notes - just not necessarily in the right order!'. gfs op in low res could be said to be following the same line of thought. it has all the right features - just not necessarily in the right places!

Agreed, the northern hemi make interesting viewing , a severely disturbed vortex, the trend has now been set , with northern blocking becoming a big player , over the coming runs we will see fi becoming very interesting , sometimes giving us freezing snowfests , and other times doing what it's done tonight, it will toy with the possible outcomes before settling down , so we may not actually see an end to the cold spell once it takes hold next week , if things into place that is, or we may me a rest bite , as the northern block takes its place.

Very interesting all of a sudden

Edited January 31, 2013 by Severe Siberian icy blast

[phil nw.]

The 12z GFS and UKMO showing good agreement with detail at T120hrs with that quite cold Arctic sourced North Westerly.

Should be fairly widespread snow showers from that next low-the one after the weekend.

Uppers widely around -6 to -8c for a short while next Tues with the cold air still in place at day 8 on the GFS run.

Quite a cold pattern developing now with that Atlantic high just far enough west to keep the UK out of the milder air next week.

Edited January 31, 2013 by phil nw.

[pipsta]

C'mon GP i can see you're viewing the model thread tell us your thoughts?

Edited January 31, 2013 by pipsta

[Richie V]

What my eyes see based on the 12 z.

If you ignore the western atlantic and eastern euro it is basically a very flat w to nw pattern, then a bit of a northerly attempt, then broadly flat again.

From a cold prespective... This does'nt fill me with hope or excitement although a big bonus for me is, it will often be very windy!

[-uksnow-]

What my eyes see based on the 12 z.

If you ignore the western atlantic and eastern euro it is basically a very flat w to nw pattern, then a bit of a northerly attempt, then broadly flat again.

From a cold prespective... This does'nt fill me with hope or excitement although a big bonus for me is, it will often be very windy!

Perhaps im just mis-interpreting this but, whats the point in assessing models and saying 'if you ignore x and y it looks rubbish' when x and y are the things that make it somewhat better from a coldies point of view!?

[legritter]

Wont be able to post this evening ,so just had a very quick look at charts and moddels , we should all be looking foreward to next week as im sure plenty of features popping up all over the place . met office faxes will be interesting day by day . any new posters and beginners take a look at NET/WEATHER Learning area its a good place to look ,and remember take time to read the posts from regular posters . and if we do get some good cold arctic air plenty of troughs and potent showers can turn up out of the blue .heres hoping for a good ECM Run ,cheers

[jules216]

the ensembles look great up to 240hrs me thinks

[SMU]

All comments on the GFS & not one on the UKMO>..

me thinks people are looking at the wrong model!

[chris55]

UKMO looking interesting at 144, hopefully ECM will be similar at this time-frame so we can see how the pattern may evolve. Overall, once we get the strong northwesterly followed by the northerly, we seem to have a window of opportunity to get a more sustained cold pattern in place.

GEFS still all over the place beyond 192 but plenty of good runs in there.

[nick sussex]

If the ECM follows the UKMO then they'll be a lot of happy people in here as that looks very good at 144hrs.

We've had the SM sausage high now its the SM wedge!!! The GFS still looks a bit lost in the lower resolution although that's hardly news given its recent trials and tribulations.

[bluearmy]

despite the general mess of the gefs suite, the mean manages to begin to retrogress the siberian ridge in week 2 as a mean feature. just about making its presence felt as far west as norway and the uk look to be setting up as the battleground. that fits in with the general expected solution though it doesnt get there in a clean fashion. hopefully ecm will continue to make the running in this regard.

[Captain Shortwave]

hmm that wedge is interesting. ECM planted that at t192 a couple of days back but dropped the idea since then. Not to say it couldn't come back though (fingers crossed)

[chris55]

I'm getting a sneaky feeling with the output at the moment, battleground scenarios don't need huge Greenland or Scandi highs, and the recent spell was in this vein and was pretty good for many, deep cold is wonderful but snow from the margins is also great.

Can we get two seperate snowy spells in one winter?? Haven't seen that often in the last 20 years! (long way to go either way yet though)

Edited January 31, 2013 by chris55

[nick sussex]

NOAA prefer the more amplified solutions from their earlier update, the GFS 00hrs was seen as too flat and too quick and this was also seen across some of the ensemble suite so perhaps we should take this into account with the 12hrs GEFS as that might also have the same bias.

...MODEL PREFERENCES...

IN THE EAST... THE 00Z ECMWF IS GENERALLY MORE AMPLIFIED AND

SLOWER THAN THE 00Z GFS ESPECIALLY BY THU/D7... AND THIS IS

MIMICKED IN THE ECMWF ENSEMBLES VERSUS THE GEFS ENSEMBLES AS WELL.

THE OVERLAP BETWEEN THE TWO ENSEMBLE SYSTEMS GENERALLY PROVES TO

BE A GOOD COMFORT ZONE FOR THE FORECAST AND THIS FITS THE BLEND OF

THE 00Z/31 AND 12Z/30 ECMWF WITH THE 00Z ECMWF ENSEMBLE MEAN.

SINCE THE GFS TENDS TO BE TOO WEAK/QUICK... HPC HEDGED ON THE MORE

AMPLIFIED SIDE OF THE ENSEMBLE SPREAD.