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Model Output Discussion - The Start Of Winter


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Well a pretty typical UK pattern once we shift this rather horrid north easterly which is plaguing the south this week. UKMO still looks decent for wintry showers to even low levels in the north, but at least some good sunny spells and a nip in the air.

Beyond that, I'm afraid zonal sums it up, but changes look like occurring to our east where low heights will lift from Russia, this places the polar vortex squarely to our north/north west driving low pressure on a ESE trajectory through the north of the UK towards central Europe. At the same time heights over Siberia should quickly build back westwards to somewhere near the Russian/Euro border. Nothing to worry about at the moment. Just a case of watching for a more amplified and hopefully colder pattern to occur as we head beyond the middle of the month.

gensnh-21-1-240.png?12

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A few of you have asked today about rationale for the (tail-end of) UKMO latest 30-day outlook. There is, of course, a dedicated thread elsewhere for this but I'll just confirm that GloSea5 output rem

Thanks for this Barry   You are however wrong on both counts you suggest :   1) I have explained in extended detail, as much as I am able, the progress of the patterns thus far from autumn (see firs

Hopefully a timely interjection, but UKMO caution (again) that medium range NWP may not be adequately reflecting ultimate broadscale outcome. First tentative signs emerging, they suggest, of *possible

Posted Images

ECM following GFS, GFS P & GEM at t96 with a north westerly flow rather than a northerly

 

ECM1-96.GIF?01-0

 

Will be interesting to see if UKMO maintains the northerly in the morning

Edited by Summer Sun
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The ECM saying no to the northerly but in terms of the upstream pattern at T96hrs its closer to the UKMO than the GFS, it makes more of the shortwave over Arctic Canada and is more amplified over the ne USA however it still manages to deliver a watered down version in terms of cold uppers.

 

At T144hrs the ECM diverges from the GFS P with the low over the west Atlantic which the GFS blows up and moves much further east and differences over the USA with a shortwave.

 

That low has a big impact on the GFS P and because of this the later outputs will likely diverge even more.

Edited by nick sussex
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It's hard to have too much faith in the outputs at longer range but the ECM is similar to this mornings output.

 

The Siberian high re-appearance is welcome as it forces troughing to disrupt near the UK, theres some interesting possibilities at T240hrs onwards but for fear of overdoing any possible excitement we best leave that to another day. Will the ECM actually  stick to one trend and not ditch it a few runs later?

 

The GFS P for coldies is underwhelming and it all starts unravelling as early as T144hrs with that Atlantic low and a less favourable pattern over the Pole and Canada.

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Only one way it can go from that chart and that's cold.

YES INDEED.

 

This was nick L ideas this morning ironic that the ecm throws out the ideas put forward.

 

hope he does not mind but this was his post from this morning....

 

 

.Looking at the 00z GFS ens, certainly worth keeping an eye on trough disruption to the east of the UK over eastern Europe towards day 8-10, later stages of 00z ECM deter and the ENS mean showing this. It appears the polar low over NW Russia goes to allow the Siberian high back into play again, which will act more of a buffer to strong upper westerly energy coming in off the far north Atlantic/Iceland/Greenland, sending the energy SE over central Europe by day 8-10. 00z 8/10 day 500mb HGT comparison shows ECM better in this respect with the trough into central Europe and the Azores ridge further west:

http://mp1.met.psu.e...0z/hgtcomp.html

On another note, Tropical Depression 22W SE of Guam likely to become a Typhoon towards Philippines over coming days and 00z GFS suggests a recurve N towards the Aleutian Low though not making much of it by the time it hits the E Siberian jet, long-way off this potential and probably not another Nuri, but merging with the upper troughing up there will perhaps strengthen ridging north towards the pole.

 

https://forum.netweather.tv/topic/81842-model-output-discussion-1200-hrs-151114/?p=3078510

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evening Gang ,i,v had my fingers crossed all day hoping that tonight would produce a good last 4 frames on ECM ,this was one of the possible Synoptic situations that was possible a couple of days ago ,yet of course even this could change IF by then pressure is lower over the azores and the opposite if pressure is higher of course .And we can throw in uncertain developments over russia ,and any polar hight rise ,not forgetting what is going on in the Stratosphere as i speak ,WE should i would think see some significant changes on our 4 times per day friend GFS ,so gang things getting interesting ,a Few slugs to clear out the way [those annoying areas of high pressure the type we dont need ]So at this point in the proceedings we are looking at more of a mobile further outlook and more Akin to early winter ,But of course we want jam on it ,but i feel its a case of Patience ,and Stellas  :cold:  :drinks:

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If the ECM continues with this trend the key area to look out for is circled red, you want to see those low heights lifting out and the ridge backing over the top of that UK low.

 

post-1206-0-96578900-1417462432_thumb.gi

 

There could still be some issues with the next upstream low phasing with that one over the UK so its a long slog to get to anything that gets the thread buzzing but the ECM in terms of at least keeping the Azores high displaced is far better  than the GFS's if you're a coldie.

Edited by nick sussex
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CFS joining the possible mid/late december fun. (Week 3 chart right, week 4 chart left) Not that i trust this model, just an observation and see if a trend grows. Cold end to the ECM, -6 uppers over the UK with the high to the east having much more influence once again. 

post-16336-0-09941800-1417464141_thumb.g

Edited by bradythemole
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Only one way it can go from that chart and that's cold.

Sorry, but i dont think thats true. Theres no reason why the mid atlantic ridge collapse and allow further systems exiting the eastern seaboard of america through. Theres no reason why the whole pattern shouldnt slip eastward, making that cold snap a short lived affair.

Theres no support on the 500mb charts for such a western block/scandinavian trough.

But IF the mid atlantic ridge holds linking the greenland and azores highs we would be in for a prolonged cold spell.

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its generally about the heights into europe. will be interesting to see the extended ecm and naefs later. both were not too enthused about low heights to our south in the 11/15 day period on the 00z suites.

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Sorry, but i dont think thats true. Theres no reason why the mid atlantic ridge collapse and allow further systems exiting the eastern seaboard of america through. Theres no reason why the whole pattern shouldnt slip eastward, making that cold snap a short lived affair.

Theres no support on the 500mb charts for such a western block/scandinavian trough.

But IF the mid atlantic ridge holds linking the greenland and azores highs we would be in for a prolonged cold spell.

 

That is true. If you look at the extended version at T264 the low has filled and been absorbed, with HP still in position in the Atlantic and a westerly flow with slightly below average temps.

Edited by knocker
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its generally about the heights into europe. will be interesting to see the extended ecm and naefs later. both were not too enthused about low heights to our south in the 11/15 day period on the 00z suites.

 

As you know doubt will have noticed blue the ECM does have a weak trough into Europe at T276 that gradually fades. But it's too weak to effectively alter the basic surface setup. Perhaps a brief perturbation.

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As you know doubt will have noticed blue the ECM does have a weak trough into Europe at T276 that gradually fades. But it's too weak to effectively alter the basic surface setup. Perhaps a brief perturbation.

Actually knocks, the euro anomoly is more notable than I thought though still nothing special (it is a post day 10 timeframe though). The story of the day on the ecm extended is the development of the upper ridge over nw Siberia. this has grown from what was shown on the 00z run and looks like it could become a big player now that the upper trough is departing that locale. whether it can prove strong enough to push as far west as nw Europe, given the Atlantic ridge is the question. Remembering how poorly the models did with it's strength last time, I would wonder if we might see the whole pattern retrogress from what we currently see progged for two weeks time on the ens anomolys. Maybe the zonal train that looked likely early today may hit the buffers again ??

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Day 9 and 10 on the ECM are very good for several reasons:

 

1. Very weak Polar Vortex - with the low heights moving away from Greenland.

2. Atlantic HP well west of us, with heights moving NW towards Greenland.

3. Low heights moving into Europe

4. A cold NW flow - with -6 uppers moving into a large swathe of England. Snow would be possible relatively modest elevations.

 

ECH1-216.GIF?01-0ECH1-240.GIF?01-0ECH0-240.GIF?01-0

Unfortunately not supported by the ensembles

EDH1-240.GIF?01-0

The dominant lobe is still positioned over Greenland. So we will probably have to wait longer for a significant cold spell aside from the occasional polar maritime flow. The Siberian high needs watching as we move deeper into December.

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The NOAA 6-10 and 8-14 has a  weak trough north of the UK with slack low pressure over Greenland and the Pole. HP south of the low pressure across the Atlantic producing a surface analysis not dissimilar to the current set up with HP dominating the Atlantic west of the UK and most of the latter but the low perhaps impinging on Scotland. Temps average or below.

 

The ECM and GEFS both push a weak trough SE into Europe just to the east of the UK; the ECM with more emphasis and a more intense Canadian low. At the end of the day this still leaves the surface analysis with HP in the eastern Atlantic with a very weak area of low pressure Scandinavia into Europe.

 

Upshot of this no apparent indication of major changes in the next fifteen days.

 

Charts courtesy weatherbell

post-12275-0-89361900-1417469192_thumb.g

post-12275-0-88081300-1417469198_thumb.g

post-12275-0-05395800-1417469208_thumb.p

post-12275-0-62176200-1417469222_thumb.p

Edited by knocker
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That CPC 8/14 could look a bit different tomorrow if the Siberian ridge repeats on the ECM extended. Also an interesting day for the ECM 32 dayer to run!

 

Yes it will be interesting to see what that comes up with tomorrow

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