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Model output discussion - 5th December 2016 - Into Winter we go

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13 minutes ago, sawan said:

I do apologies in advance, most probably, I am wrong. But have we not seen over the past 4-5 weeks that ECM has been consistently outplaying GFS? Why should we trust GFS again?

Thanks

Agree 100%

however the ECM feels like it goes to flat @192-216 so the median point between the 2 at the moment seems the best

S

Edited by Steve Murr
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1 minute ago, fergieweather said:

We shall see how it unfolds. ECMWF Monthly also raises +ve MSLP/GPH anomaly to NW (S of Greenland) into week 2; interestingly it supports GloSea5 on broad idea of a colder than average spell much/most of Jan, with varying NW/N/NE flow (perhaps E'ly later in month); even by week 4 with unusually prominent -ve temp anomalies for southern UK (given the lead time). One way or another, model output looks an awful lot more interesting versus this time a week ago. 

How do the euro low anomolies weeks 2 and 3 offer continuity with the 12z suite though? If the 12z has found a new path re less defined low anomolies to our south hen the 46 could be out of date on week 3 already! 

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2 minutes ago, fergieweather said:

We shall see how it unfolds. ECMWF Monthly also raises +ve MSLP/GPH anomaly to NW (S of Greenland) into week 2; interestingly it supports GloSea5 on broad idea of a colder than average spell much/most of Jan, with varying NW/N/NE flow (perhaps E'ly later in month); even by week 4 with unusually prominent -ve temp anomalies for southern UK (given the lead time). One way or another, model output looks an awful lot more interesting versus this time a week ago. 

Now - this is a very good update. With the right Synoptics Jan can deliver colder weather than any other month, and with a weak sun snow can linger given low temps if it does fall

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23 minutes ago, Steve Murr said:

I think at this stage I would tend to discount the ECM- ( past 192 ) as it does has it moments-

GFS out to 108 - is another step of amplification - so thats 00z > 06z > 12z >18z all making pidgeon steps NW which is good-

hopefully the 138 will be like the 144 UKMO - every bit as likely! :)

But 12z ECMWF DET sits well in the ensemble spread, with below average temperatures from start of Jan on throughout it's 15d run... why discount it? It's as plausible as any other solution at the moment.

EDIT Whoops sorry, was reverted to 00z ENS - yes, 12z milder end of ENS

Edited by fergieweather
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12 minutes ago, fergieweather said:

But 12z ECMWF DET sits well in the ensemble spread, with below average temperatures from start of Jan on throughout it's 15d run... why discount it? It's as plausible as any other solution at the moment.

Not the temps - the way the high slips SE @192-216 just feels a tad to far- GFS looks more plausable inline with the -PNA pattern you cited earlier...

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2 minutes ago, Steve Murr said:

Not the temps - the way the high slips SE @192-216 just feels a tad to far- GFS looks more plausable inline with the -PNA pattern you cited earlier...

See edit above Steve (NB doesn't alter median temps - remaining below avg)

Edited by fergieweather
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GFS  18z has moved towards the ECM 12z

Cold dry picture temperatures slightly below average .

Edited by cold snap
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15 minutes ago, fergieweather said:

See edit above Steve (NB doesn't alter median temps - remaining below avg)

It just felt a bit to much swing away from the 00z & the means of the GFS..

18z has moved more towards the ECM with not enough retrograde so overnights will be interesting- but yes for day 6 onwards to about day 10 the locale of high pressure probably wont make to much difference other than frost locale around the coastlines...

lets see what tomorrow brings...

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1 minute ago, cold snap said:

GFS  18z has moved toward such the ECM 12z

Cold dry picture temperatures slightly below average .

Well the OP has but lets see what the ENS say

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GFS flattened out too, be nice to have a few cold days but that looks about it going off tonight's charts - EC monthly must have different ideas later on as heights on latest ECM and GFS at day 8 are sinking, nowhere near Greenland anymore.

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18z not a great run tbh and ecm is looking not so bad now!!!.on to tom it is then

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5 minutes ago, Steve Murr said:

It just felt a bit to much swing away from the 00z & the means of the GFS..

18z has moved more towards the ECM with not enough retrograde so overnights will be interesting- but yes for day 6 onwards to about day 10 the locale of high pressure probably wont make to much difference other than frost locale around the coastlines...

lets see what tomorrow brings...

By T+192, 23 members support the flatter solution; 15 centre the high effectively over the UK; and 13 offer a more amplified solution with high pressure to the NW and a markedly colder NE'ly flow. 

Edited by fergieweather
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Cheers

I will go with a blend of the 28 then.., Thinking that the OP was in cluster 1..

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The trend is clearly not being our friend not seeing the second bite of the cherry as seen in 12z with that lobe of vortex off the coast of Newfoundland.

Disheartening, lets see what the morning brings...

image.png

Edited by Changing Skies
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3 minutes ago, fergieweather said:

By T+192, 23 members support the flatter solution; 15 centre the high effectively over the UK; and 13 offer a more amplified solution with high pressure to the NW and a markedly colder NE'ly flow. 

What about by 360?

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2 minutes ago, Changing Skies said:

The trend is clearly not being our friend not seeing the second bite of the cherry as seen in 12z with that lobe of vortex off the coast of Newfoundland.

Disheartening, lets see what the morning brings...

image.png

:wallbash:

Its just one run , with the above chart well into FI

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Big block in FI coming, looks like building far enough north to benefit us moving forward too

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Here's the free to access EC monthly anomalies. D8-D14:

ec-ens_nat_taem_gh500_anom_2016122600_33

Almost perfect for UK cold. The chart for this timeframe has been very close on 8 of the last 10 occasions, so good odds but not without any risk. Have to say, for this timeframe, the EC monthly has performed reasonably usefully over the past few weeks as far as the UK is concerned.

D15-D21 / D22-D28

ec-ens_nat_taem_gh500_anom_2016122600_50

ec-ens_nat_taem_gh500_anom_2016122600_67

Looks nice but, for me, not enough to build any sort of forecast or even hopecast on - especially as it follows on from a directionless run on the previous EC monthly. But we're not facing an overwhelming zonal signal - at. this. stage.

 

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The 18z op was the second cluster at D10 on the 12z, but only had 20% support. So not something that we can rule out. We will see if the clusters on the 18z has trended the flatter route. It is such a messy picture after D6, with developments of shortwave troughs changing the flow and the push of higher heights. We still have a strong wave in the East Pacific region so height rises in the Atlantic after D10 is still the call, though on the 18z it's the return of the dreaded U.K. High in FI, so Surface cold rather than cold uppers.

i suspect changes tomorrow as this is quite fluid, but cold be it faux or Arctic or a mix still looks the right call for early January.

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9 minutes ago, Banbury said:

:wallbash:

Its just one run , with the above chart well into FI

I'm quite aware of that.

It just seems ECM/GFS have backed off, it's quite odd since the EPS and gefs 0z mean was very decent & consistent w/each over now we're seeing consistency with unsavoury output...

nothing's assured yet it must be stressed

Edited by Changing Skies

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7 minutes ago, Ali1977 said:

Big block in FI coming, looks like building far enough north to benefit us moving forward too

Yes, its not as bad a run as it looks, if that run doesn't obliterate the lower to mid strat vortex and subsequently cause a month of blocking then nothing will.

 

And its underway!!!!!

npst30.png

Edited by feb1991blizzard
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That lack of deep cold threat from the 12z EC and now 18z GFS high res runs a product of what happens when you lose the cross polar ridging, and movement SE of the upper high, though at least the 18z GFS op does look fairly blocked in the longer range, just without the deep cold and snow potential thanks to high pressure over/near the UK. Still chance that the models past day 7 aren't handling well changes upstream, so we may see more favourable runs for deep cold tomorrow.

On a more upbeat note, the EC weeklies temp anomalies for 1st and 2nd weeks of Jan look ok, cold in week 1 then average week 2

meTz20161226_0000+33600.pngmeTz20161226_0000+50400.png

 

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Worth keeping in mind that for most folk the hunt for cold coincides with snow. Cold and effectively dry is not what most want. We primarily look for snow not minus 10 and a frosty garden!  (At least I do)

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