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Model output discussion 25th Jan - The final third of winter beckons..

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15 minutes ago, Connor Bailey Degnan said:

I can't see much if any excitement in today's 12z runs for snow.  Gem the exception. Though the ecm is very cold and frosty, it's a very dry easterly with maybe light snow showers affecting east, maybe some sort of 'event' in south West at 192 but that's a while away. As a snow lover, I'm very underwhelmed by today's output. Lets hope for upgrades, big ones!!!

Best post of the evening IMO. Yes, the ecm is an improvement on this morning's run and to be honest I wasn't expecting that. However, we need further upgrades to quench our snow starved appetites.

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4 minutes ago, craigore said:

Whats wth the milder air in the S.E ?

 

 

That's how the run ends from ECM

ECM0-216.GIF?03-0ECM0-240.GIF?03-0

ECM1-216.GIF?03-0ECM1-240.GIF?03-0

I wouldn't worry about that though short term it should turn colder as they say the 1st stage is get the cold in 2nd stage is to see how long it will last

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7 minutes ago, weatherguy said:

Incredibly fine margins,  Lets take a look at the GEM against the ECM for the "perfect" run easterly.

gemnh-0-72.png?12 ECH1-72.GIF?03-0

ECH1-96.GIF?03-0gemnh-0-96.png

Here we see the orientation of the LP to our west at +72h making a key difference by +96h.  Simply put, the GEM LP "squashes" more against the block and you get a greater negative tilt, which effectively spins the axis of the Scandy HP faster and rips that PV segment out over siberia straight for us.  With a very similar set up shown on the ECM, this does not happen as sharply, and therefore things don't pan out in quite so extreme a fashion.

This really shows by +120h.

gemnh-0-120.pngECH1-120.GIF?03-0

The orientation of the Scandy high is less favourable, and the PV segment isn't dragged along with it.  Still a good chart for us, but nowhere near the "beasterly" of the GEM. 

Hopefully this rather simple explanation shows to the newer members how finely balanced these setups are for the UK, and how the models can "get it wrong" at such short range.  Minor differences by +72h can alter things drastically by +120h when trying to get the elusive beast from the east to our shores. 

These charts are about as good as it gets for us to be fair! The ECM has filled me with greater confidence now after today's slight blip! 

As for the GEM, that is an unprecedented output and rather bullish in all honesty. If that were to come off, it would easily rival the great 1987 blizzard and Feb 1991 without question! 

Should make for an interesting pub run later on! 

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3 minutes ago, s4lancia said:

Firstly, if your benchmark for a good run is the GEM, may I politely suggest you relocate to the Arctic Circle because the times in recent years that such a run for the uk has come to fruition, you could count on one hand and still have fingers remaining.

Secondly, the rest of your post.

 

Lol, although the gem is an extreme option, it's the only one to bring in decent snow.  It's not my benchmark and I'm merely stating facts.  Out of the 12z, the gem is the only decent one for proper snow and the rest aren't, they're all predominantly dry easterlies. 

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It looks from the models (all of them as a bunch, I think) as if we'll all experience some markedly colder weather, from around next Wednesday...So far, so good. But does that mean we'll all be knee-deep in snow, by next weekend? My guess - based on my being an old codger - is that it most likely will not; at least for places away from either the South-West (possible Atlantic incursions) and the East Coast, north of about Norwich, that is...

I may well be wrong - I hope I am - but???:sorry:

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ECM weekly anomalies which were issued overnight show temps remaining below average till at least the 19th

5894d7dfcc029_meTz20170202_000026400.thumb.png.ef1ffe31fb8356005f27bcf280b84fc6.png5894d7e11fa5c_meTz20170202_000043200.thumb.png.3055d9ab8f60c56b7dd5d4d9902ceb24.png

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11 minutes ago, East_England_Stormchaser91 said:

These charts are about as good as it gets for us to be fair! The ECM has filled me with greater confidence now after today's slight blip! 

As for the GEM, that is an unprecedented output and rather bullish in all honesty. If that were to come off, it would easily rival the great 1987 blizzard and Feb 1991 without question! 

Should make for an interesting pub run later on! 

Anytime cold weather spreads from the east we (coldies) should be delighted because it doesn't happen often..I agree, realistically it's as good as it gets in a British winter..hope the Gfs 18z is a stonker like last night.:cold-emoji:

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44 minutes ago, Steve Murr said:

Heavy snow for cornwall on the 192 ECM-

Thats a hens teeth special !!

...which in itself means it has a minuscule chance of verifying, like all output at that range.

to me the odds on a "cold outbreak" are very good which, given recent years, is hugely positive. I remain massively unconvinced that snow is going to be a major feature. 

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Some rather exciting output this evening, GEM has some incredibly cold air for the South, ECM nearly as good further North, a combination of the two will do nicely, its getting closer to the reliable but not in the bag yet.

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UKMO @168 - Also a corker, low off the NW corner of spain, further east than the ECM so less chance of it swinging down to the azores a la ECM at 192, thus propping up our high.

 

 

Screen Shot 2017-02-03 at 19.38.07.png

Edited by -uksnow-

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4 minutes ago, Steve Murr said:

Also if you go back to the ECM 72 V GEM 72 you will see that the GEM has no phasing with the energy moving NE - 

( we are looking at the PV lobe breaking away SW east of Finland )

both models have a 1015 wave getting close to the Upper air cold pool- GEM keeps good seperating allowing the upper air cold pool to continue travelling on its perfect course where as ECM has enough phasing of the 2 streams to allow a 'tug' off course of our cold pool by the 1015 MB wave- ( a bit like the fujiwhara effect ) 

This small tug pulls the allignment more Southerly & allows a kink to build in the Scandi High in the SE quadrent- The upper air cold pool does not travel around kinks / sharp angles - it follows a smooth contour- so as long as that contour remains smooth like the GEM it will travel all the way to the UK-

The ECM on the other hand kinks the flow & this stops it moving SW- & we get a small chunk of cold air breaking off this original chunk of vortex ( think Asteroids game 1980 - chunks off chunks )

It should be notes that this was the ECMs yesterday at 96 V today @ 72

IMG_2281.thumb.PNG.b5e363357aac8a9aacef00791a4ed002.PNGIMG_2282.thumb.PNG.0f2d64906ad7353722dcce2f22fc7c3d.PNG

If you look very close - todays has a smoother contour & a flow about 3-5 degrees more SW- we need another 5 @ 48 tomorrow !

best 

S

 

 

 

Yes Steve, you're bang on as per.  I really do find it fascinating actually analysing the minor differences which can have such large impacts down the line - for every frustration, there's an explanation!

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6 minutes ago, -uksnow- said:

UKMO @168 - Also a corker, low off the NW corner of spain, further east than the ECM so less chance of it swinging down to the azores a la ECM at 192

 

 

Screen Shot 2017-02-03 at 19.38.07.png

This looks very very good , way better than the ECM I think

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5 minutes ago, -uksnow- said:

UKMO @168 - Also a corker, low off the NW corner of spain, further east than the ECM so less chance of it swinging down to the azores a la ECM at 192, thus propping up our high.

 

 

Screen Shot 2017-02-03 at 19.38.07.png

Hard to tell for sure but that looks more like a straight easterly into the UK. Very encouraging if so.

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3 minutes ago, Allseasons-si said:

I love the gem in animation,i can not stop watching it lol:D

tempresult_jtx1.gif

A chart of Beauty

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5 minutes ago, That ECM said:

A wonderful illustration of how far the cold needs to travel and why such events are as rare as rocking horse poo.

Very true and also shows how quickly the PV re-groups but deffo the best effort soo far, my straw is really firmly clutched this time.

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The ecm op was a massive outlier against the ens this morning,let's see what it will be like on the 12z soon.

graphe_ens3_php.thumb.png.ae6e9cd2df3e86aab436f609ba1736dd.png

 

Edited by Allseasons-si

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In a way GFS has gone hero to zero and ECM the other way - classic.

ECM's day 10 offers more chance of the vortex breaking apart again with a wedge of HP heading NW from Scandi - that being what the MJO should encourage - so I'm happier with the longer term trend as well.

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3 minutes ago, Allseasons-si said:

The ecm op was a massive outlier against the ens this morning,let's see what it will be like on the 12z soon.

graphe_ens3_php.thumb.png.ae6e9cd2df3e86aab436f609ba1736dd.png

 

Don't do that to me my heart sank when I read your first sentence.

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We know what's coming next.That run was on the cold side of the ens.

Followed by a different outcome next run then the doom n gloom lol.

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5 minutes ago, Mark wheeler said:

Don't do that to me my heart sank when I read your first sentence.

Lets hope it is an outlier, a warm one again. If It isn't a colder outlier this has gone up a notch on the potential scale!! Tomorrow I feel is the day we should know what willpan out with regards the initial Easterly - around five days out. Snow maybe not as that maybe a 24/48 hour thing but a rough idea if we'll miss out or not on -8c uppers or colder!!

Edited by Ali1977

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GEM shows how a classic easterly could develop when a chunk of the Siberian vortex breaks off and heads west under the block- very much like Feb'91 in fact.

Currently we look like heading for a mainly dry cold south easterly flow though with the 3 main models showing a less favourable orientation of the high which leaves us with a slacker continental feed.Trough disruption towards Iberia showing further on in the ecm run may develop something wintry from the south west but we really need to see Low pressure establish further east in the med to hold the block in-situ and prevent warmer air eventually coming north from S.Europe.

Not to say further changes can still improve the pattern for a convective easterly down the line,we are still in the game whilst the block persists to the north east.

 

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