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Model Output Discussion; into 2015


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Can't post a chart, but the polar vortex is very weak come the later stages of the Gfs run. When viewing the height anomaly charts it was a pleasing sight to see the red colours over Greenland too. Quiet a change from the previous run. Let's hope that this is only the start of the trop response to the strat warming.

Edited by Grimsby Snow Lover
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12z clusters are offering glimpses of a different story after mid-month with markedly more meridional pattern(s), but of course it's just not worth detailing all that stuff showing out post-15 Jan unt

Some very poor quality posts have been creeping into the discussion which really don't add anything to the thread apart from raising the ire of many who view this thread....Even a simpleton (in meteor

Nice tease from the ECM, no surprise looking at the strat charts, shame it can't happen though because apparently cold is not possible before Mid Jan!?!   Rule nothing out folks, as I posted yeste

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Thought I would post this here as I have the highest regard for the Accu Weather forecasters.

 

"However, long range forecast model guidance is trending toward a possible split of the 10mb polar vortex and a possible significant, stratospheric warming event around the 5th, which in turn could translate to a very cold period late in January across parts of southern Canada and the U.S."

 

http://www.accuweather.com/en/weather-blogs/anderson/my-weather-pattern-thoughts-for-canada/39796333

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GFS Pub run is regrettably zonal right throughout with the odd Polar maritime air mass providing a little wintriness to Northern areas.No sign of any HLB.

Perhaps not but the polar vortex is a hell of a lot weaker towards the end compared with the previous run. Baby steps perhaps?

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GFS Pub run is regrettably zonal right throughout with the odd Polar maritime air mass providing a little wintriness to Northern areas.

No sign of any HLB.

I am no expert like others on here with regards to the Stratosphere. However I feel some are expecting HLB too soon. It appears to me that towards mid Jan we are going to see the PV split and weaken with one lobe vacating Greenland and backing W whilst pressure builds across Greenland. As a result we shall finally see a negative NAO develop. Hopefully this might be shown over the coming days in the F.I charts. You can even see the beginnings of this on the N Hemisphere 18Z GFS run.

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The gfs op doesn't split the vortex or have the same type of warming as ECM so no reason to expect it to show a response trop by the end of week 2

The gfsp also not generating the same signature at 10hpa

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The gfs op doesn't split the vortex or have the same type of warming as ECM so no reason to expect it to show a response trop by the end of week 2

The gfsp also not generating the same signature at 10hpa

 

The strength of the zonal signal is actually remarkable. Taking into account opp runs and GEFS and GEM ensembles, plus the ECM data, over recent days that is quite literally several hundred permutations and I've seen one cold run (ptrb 7 this morning). Even last year we had some deep FI teasers.

Edited by Jason M
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The strength of the zonal signal is actually remarkable. Taking into account opp runs and GEFS and GEM ensembles, plus the ECM data, over recent days that is quite literally several hundred permutations and I've seen one cold run (ptrb 7 this morning). Even last year we had some deep FI teasers.

 

Yup the models, GFS in particular painting a picture of zonal hell out to eternity it seems. 

But there will be a signal for a pattern change come along sooner or later and then they will change.

Easy this model lark. :)

Edited by Mucka
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Sometimes its worth taking a break from model watching particularly if you are looking for a change in synoptics, especially under a fluid mobile pattern as is being projected for the start of January. On this note I'll be doing this just like I did over Christmas, back this weekend.

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Yup the models, GFS in particular painting a picture of zonal hell out to eternity it seems. 

But there will be a signal for a pattern change come along sooner or later and then they will change.

Easy this model lark. :)

 

Yes, I've no doubt something will give eventually. Going to be very interesting couple of weeks given the position with the strat at present. Either something big will occur or there is going to be one hell of an inquest :ninja:

 

That's not to criticise anyone on either side of the debate. I think the strat angle is an interesting one and not something to be ignored.

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I see nothing which suggests a mild outlook in the slightest, temperatures generally are either average or colder, this is pretty clear from the Ecm 12z ensemble mean, a strong and broadly westerly airflow veering from oceanic to polar Maritimes, indeed, the flow eventually looks like swinging more towards the north just beyond T+240.

post-4783-0-10296200-1419896667_thumb.gi

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the GFS is a horror show for those with an irrational fear of computer generated weather models.

 

I've seen worse (mostly over the last few days) :rofl:

 

Looking through the ensembles tonight they are not quite as bleak, so something to carry through to tomorrow. Mind you 'not quite as bleak' is hardly a great selling pitch is it :p

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I am no expert like others on here with regards to the Stratosphere. However I feel some are expecting HLB too soon. It appears to me that towards mid Jan we are going to see the PV split and weaken with one lobe vacating Greenland and backing W whilst pressure builds across Greenland. As a result we shall finally see a negative NAO develop. Hopefully this might be shown over the coming days in the F.I charts. You can even see the beginnings of this on the N Hemisphere 18Z GFS run.

That is precisely what we should be looking for TEITS and nicely summed up

Western Greenland vortice to back westwards

Siberian/Scandi vortice to strengthen

Potential ridging somewhere in between

We see that almost instantly on the 12z ECM, though perhaps this is a little too quick with the modelled response right now. Time will tell. But those are the key signatures to watch for in the troposphere should the current ECM det. Stratosphere guidance prove to be correct...and of course that is still a huge assumption at this stage, but not without support.

Also worth noting with warnings that sometimes we see an initial response, and then a lagged response too - tonight's ECM control certainly hints at that sort of scenario at least in terms of the initial response with a brief collapsing mid atlantic ridge around days 11-15

Plenty to keep us interested if people know the right places to look in :)

SK

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No point even trying to hope that the day 10 ECM will be correct, it will likely be gone tomorrow. It does looks like a strong westerly pattern will dominate for the next week or so. All we can hope is the westerly express has a return ticket  :smiliz19: .

gens-21-1-120.png?18

gens-21-1-168.png?18

gens-21-1-216.png?18

Yes it remains a problem of highs to the SW if you are looking for cold for the whole of the UK.  Far North to be hit with transient colder periods.  Not much to bottle up the atlantic.  The SSW effects seem to be, based on my prior observations, to be like smacking the white in to a pack of reds in snooker - a big variable but how it shakes out in the troposphere  seems complicated.  I'll leave that to those with more knowledge on the subject than me.

Edited by Trom
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UKMO quite a bit flatter at  day 5/6 this morning but conversely GFS and GFSp are more amplified. I gues we could say they are moving toward a middle ground solution but hard to filter out run to run variability.

 

UKMO, GFS, GFSp 144h

 

UN144-21.GIF?30-05gfsnh-0-144.pnggfsnh-0-144.png?0

 

With GFS the split PV is much more apparent than previously modelled and at 168 the Op shows some decent WAA toward the pole and a very weak arctic high and although it goes into zonal melt down in FI these are quite interesting changes in hi res.

 

gfsnh-0-168.png?0

 

GFSp not quite so eye catching but quite different from the relatively organized PV of the 18z at the same stage.

 

gfsnh-0-168.png?0

 

But it does have the first hints of a buckling jet.

 

gfsnh-5-174.png?0

 

Ultimately though I think the upcoming zonal spell will take some breaking so we need to see big improvements and hope the models haven't got to grips with the impact of strat warming yet.

Edited by Mucka
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Hi Civil,

 

The 850's are approx 1.5km up - so it's not a good way to see how warm/cold it will be at the surface.

 

It's actually going to be freezing for the majority. A bit like today.

 

ukmintemp.png

 

So + 850's do not indicate warm weather at surface level.

Hi
But look at what  temperatures have above the sea!
There could not be snowed ever with such temperatures in 850hpa
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Last night's ECM teaser at D10 was just that: post-14819-0-56247600-1419923902_thumb.g

 

Why break a habit of a lifetime! GEM at D10: post-14819-0-10117800-1419923952_thumb.p

 

The only variation on the zonal onslaught (till at least mid-Jan barring Strat intervention) is maybe a N/S split, like the GEM at times.

 

Any amplification is quickly squashed by the next spurt of lower heights from the W/NW. So yes the ops sometimes may show a baby ridge but these clusters (consistent) over the last three days are always over ridden by the zonal long wave pattern. Until some members develop them further I will assume that they won't lead to anything but 24-48 hours of calmer waters.

 

The GEFS go up to mid Jan now so I am hopeful we should start seeing some changes in deep FI. This morning very little that would make much impact on the UK but certainly a cluster on the NH profile showing potential:

 

post-14819-0-91951200-1419924453_thumb.p

 

The London 850s  mean now picking up the ridge/trough combo as the ensembles timing's become more aligned and we see agreement right out to D10 at least:

 

post-14819-0-11686900-1419924560_thumb.g

 

So I am looking forward to the next week of model watching as there is potential on several fronts for  some sort of mid-lat cold to develop, hopefully towards the UK from the last half of Jan. No banker but better chances than the upcoming 2 weeks.

Edited by i'm dreaming of...
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