Model Output Discussion - 1st - 7th January

[Tom Montalbano]

Post t192 quite a few members showing a NW/SE tilted jet with a trough digging SE into Europe, with also some showing height rises over Scandinavia and even a few brief easterlys and a a few northerlys................Actually with a bit of everything really!

Would expect this run to be one of the coldest set of Ensemble members of the Winter so far. Mind you, that wouldnt take much!

Regards,

Tom

Edited January 7, 2012 by TomSE20

[SP1986]

Tom, the last three ensemble sets have been much colder than the 18z (well not much colder), there was many member straddling around or below -5C (850hPa) in the past few runs, so it'a actually a little milder than those (unless you're referring solely to the 18z run?)

[Tom Montalbano]

Tom, the last three ensemble sets have been much colder than the 18z (well not much colder), there was many member straddling around or below -5C (850hPa) in the past few runs, so it'a actually a little milder than those (unless you're referring solely to the 18z run?)

Hi Sp,

I'll take your word for that but I'm surprised, at face value they look a bit colder.

Mind you I hurriedly deleted my first sentence which stated "Yet again the 18z Op is one of the milder members!"

So what do I know!

Regards,

Tom

[Liam J]

I've never seen such stormy GEFS ensemble runs, loads to choose from, all fantasy land I know but this would bring the UK to a stand still, 925mb!!!

[Cheshire Freeze]

With something like that thundery showers, 'mini'- tornadoes, hailstorms looking at the potential temperature of the upper atmosphere. We can but dream, I suppose.

It's a very real possibility Stephen IF the pressure rises concentrate on the wrong side of the pole.

[DAVID SNOW]

With something like that thundery showers, 'mini'- tornadoes, hailstorms looking at the potential temperature of the upper atmosphere. We can but dream, I suppose.

Could be rather stormy ahead re models, just one thing, there is no such thing as a mini tornadoe

[La Bise]

Pattern change he said....more like Pattern destruction with chars like the one Liam posted!!!

[kumquat]

Indeed, the pattern change could bring total carnage and not just the fluffy white stuff that everybody seeks, but certainly a pattern change has been begrudgingly hinted at by all models for the past week. Can we imagine a pattern change that makes the storms of the past couple of weeks look tame? I think we'll either get carnarge storms (not necessarily cold) out of this or some nice wintry weather - depending on what the PV lobes decide to throw at us down the line through amplification off the American/Canadian east coast.

It will go one way or the other but plain average zonal does not look likely after 10 days hence.

[Jackd]

Could what these models suggest bring very heavy snowstorms?

[Cheshire Freeze]

Remember, if the PV was to set up shop over our shores, it would bring some very low thickness values so where you see the very darkest purple on the Meteociel maps, snow could/would fall even with marginal uppers such as -5

[SnowObsessor90]

The last time we saw anything like the setup depicted within those ensemble members back in December it was downgraded and we ended up with a decent toppler of sorts with lying snow even near coastal areas.

Could we see something similar again perhaps with it being a little less marginal this time? Well as people keep saying all we can do is wait and see how things develop as we near ever so closer to crunch time so to speak.,

Edited January 7, 2012 by Anonymous21

[Brum Watcher]

GFS 00z the most yellow run i have seen so far this winter, totally knocking the 18z ensembles on the head all the way till the end...whats happening???

[Snowmad79]

GFS 00z the most yellow run i have seen so far this winter, totally knocking the 18z ensembles on the head all the way till the end...whats happening???

The gfs 00z doesnt look good to me however I will say this. The ensembles show the operational back to being a wild outlier, on its own for large part of FI, being the mildest output run of the suite and the means for both Edinburgh and London still riding parallel to the -5 850 hpa mark and quite a few members below.

http://hw.nwstatic.c...erdeenshire.png

http://hw.nwstatic.c.../t850London.png

Ecm looks to have dropped the idea of mid atlantic ridging towards iceland and the cut off low, and looks typically like another dire "reset" and milder than yesterdays runs. However, the GFS FI does look more like yesterdays ECM 12z. Not sure who is more confused me or the three models.

Wonder if anyone can pull any straws out of the hat today then ?

Edited January 7, 2012 by Snow Time 79

[ICETAB]

The 240 chart on the 0z GEM model is the chart of the day for me. Shame it's cannon fodder!

Edit: I think it's actually the best chart of the season

Edited January 7, 2012 by ICETAB

[Duane S.]

Indeed. the 00z (GFS) is an outlier. From about the 16th onwards it's off on its own.

ECM not as easy on the eye as the 12z, flatter and pretty messy. interesting to see where this sits in the ens.

Nice FI at the end of the GEM run though!

[SLEETY]

Another huge mild outlier from gfs once it hits low -res again. .Ecm looks like its trying to buil a scandi high in fl and gem is excellent.So who knows where we are?

[nick sussex]

If this doesn't shake up the NH pattern then nothing will!

http://wekuw.met.fu-...cmwf1/temps.gif

The warming at the 10HPa level of the stratosphere is off the chart.

We'll have to wait and see what Chiono has to say about this in the strat thread later on.

In terms of the overall output the GFS goes to its default zonal setting in the lower resolution and the ECM although not as good as yesterday evening shows a more plausible scenario of heights dropping in Europe with a nw/se tilt jet which could eventually lead on to much more interest.

Edited January 7, 2012 by nick sussex

[mountain shadow]

Still nothing in the ops runs of either GFS or ECM to indicate any proper cold within the next fourteen days, certainly any mid month change now looks unlikely.

The GFS ensembles aren't bad, but this have been the same for weeks yet the Ops run has proven right.

Still there are upstream changes which provide hope towards the end of the month to kick the PV away from Greenland.

In the meantime after a quiet few days the atlantic depressions will return.

[Duane S.]

If this doesn't shake up the NH pattern then nothing will!

http://wekuw.met.fu-...cmwf1/temps.gif

The warming at the 10HPa level of the stratosphere is off the chart.

We'll have to wait and see what Chiono has to say about this in the strat thread later on.

In terms of the overall output the GFS goes to its default zonal setting in the lower resolution and the ECM although not as good as yesterday evening shows a more plausible scenario of heights dropping in Europe with a nw/se tilt jet which could eventually lead on to much more interest.

Good grief, that's going to rock the stratosphere a bit! Also good to see 30 hPa temps responding mid month.

[winterof79]

http://www.wetterzentrale.de/pics/MT8_Manchester_ens.png A definate cluster of very cold members around the14th now which is approaching the reliable.That warming at 90N is incredible and will have an impact later this month and possibly for the remainder of the winter.Wild swings from the models but very interesting to see how they handle what is coming.

[Great Plum]

Have to agree with others re the ensembles... The 14 / 15 Jan is coming towards 'the reliable' now and there has been for days a downward shift in the ensembles at this point. Fingers crossed for coldies that the GFS ensembles don't start following the op!

[mountain shadow]

If this doesn't shake up the NH pattern then nothing will!

http://wekuw.met.fu-...cmwf1/temps.gif

The warming at the 10HPa level of the stratosphere is off the chart.

I would have thought that it was simple Physics that the greater the warming the higher the probability of penetration to other levels, the fact it is off the scale indicates that temperatures like this have never been recorded at that level. The conclusion might also be that SSW have also occurred with temps at the 10hpa level greater than this and that an SSW event is more likely now.

[IDO]

The GFS four daily runs reflect the current nature of our weather pattern; a change is in the offering but until the variables are more stable the models are just guessing in FI. One run is the Azores High, then cold zonal, then ridging, then heights. Either or all could be correct for the rest of the winter in one way or another. Once we get the next 7-10 days of above average temps, settled weather over, we will have a greater understanding. My opinion was that the HP would sustain till early Feb, then we would get a taste of winter; but I am less sure now and it looks like it could be more mixed as attempts are made to bring the cold weather to our shores from around the 20th onwards.

[nick sussex]

I would have thought that it was simple Physics that the greater the warming the higher the probability of penetration to other levels, the fact it is off the scale indicates that temperatures like this have never been recorded at that level. The conclusion might also be that SSW have also occurred with temps at the 10hpa level greater than this and that an SSW event is more likely now.

It's all very complicated! I think it's of course more likely that we will see a SSW but it whether we get zonal winds reversal thats still probably uncertain, if you get that the impact on the models can be very quick.

Thats what differentiates between a minor and major warming, also what happens to the PV, if you get that major warming you'll either see the displacement of the PV or its splits into little PVs.

[mountain shadow]

It's all very complicated! I think it's of course more likely that we will see a SSW but it whether we get zonal winds reversal thats still probably uncertain, if you get that the impact on the models can be very quick.

Agreed Nick, never any guarantee of an SSW event but the probability of it happening must have increased with unprecedented warming in the upper layers.