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Model output discussion - winter proper underway

Paul

Please only post model discussion in this thread. 

For more general chat and banter, or moans and ramps loosely around the models, please head to the banter thread:
https://www.netweather.tv/forum/topic/86721-model-moans-ramps-and-banter/

For general weather chat including about the snow/cold chances around the country, please go to the regional threads:
https://www.netweather.tv/forum/forum/142-regional-discussions/

Thank you!

Message added by Paul

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1 hour ago, bluearmy said:

I think the algorithm assumes all snow falling settles and accumulates 

some hefty showers due tomorrow afternoon and evening !!

Most of the algorithms I’ve looked over keep it fairly simple: precipitation intensity over time period = rough depth calculation. I’m yet to see any model which introduces soil temperature feedback to calculate an accurate melt rate, and therefore a modifiable depth (assuming further snow was within the forecast) UKV has an experimental field [water_equiv_lapse] which tries to establish this but I wouldn’t say it’s conclusive, reliable or widely used within output.

SB :)

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12 minutes ago, CanadaAl said:

Yeah I think high pressure becoming the form horse but probably sitting closer to the UK. Not overly mild at least for the south anyways, fog and frost with highs around 5/6 (2/3 under fog patches) 

its still some way of any HP could easily be 500 miles further north nearer the time which would make a big diff in weather and temps for us but on the other hand any further south and we are in the dreaded bartlett territory

Edited by igloo

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2 minutes ago, feb1991blizzard said:

That wil be countered by LIA - starting within 15 years I believe.

Ah, that, the good old LIA...I can still remember when it was due to start in 2007...if you ask me, LIA-predictions are about as accurate as Jehova's Witlesses' Doomsday prophesies...?:D

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Just now, Ed Stone said:

Ah, that, the good old LIA...I can still remember when it was due to start in 2007...if you ask me, LIA-predictions are about as accurate as Jehova's Witlesses' Doomsday prophesies...?:D

Pretty sure it has always been forecast close to the solar cycles and the predicted slumber of the sun, Pete. Think 2020 has been the approximate start date for many years now.

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The GEM (yes, I know) offers more northwards movement of the High

GEMOPEU12_240_1.png

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9 minutes ago, Higher Ground said:

You might also want to look at Arctic summer snow cover, which was the highest for over 10 years this June and July, and the highest for nearly 20 years this August https://climate.rutgers.edu/snowcover/chart_anom.php?ui_set=1&ui_region=nhland&ui_month=8

Also Arctic ice volume which is still up if anything since 2011 http://psc.apl.uw.edu/wordpress/wp-content/uploads/schweiger/ice_volume/cryosat_piomas_awi_ts.2011.2017.Oct.png

How can you be sure high sea surface temperatures around Svalbard aren't a release of heat (cooling), rather than a warming? Bear in mind that the North Atlantic at 0-700m depth is still the coldest for 15 years despite an upturn this year www.climate4you.com/SeaTemperatures.htm#North%20Atlantic%20(60-0W,%2030-65N)%20heat%20content%200-700%20m%20depth

Not wanting to go off topic either, just trying to add some more pieces to the jigsaw in understanding how it's still possible to get severe cold despite longer term warming.

 

 

 

So the arctic isn't warming then? Is that what you're saying? Or have I misunderstood? As I say severe cold or not (in the UK) a warming arctic is a worry

Edited by LRD

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Just now, CreweCold said:

Pretty sure it has always been forecast close to the solar cycles and the predicted slumber of the sun, Pete. Think 2020 has been the approximate start date for many years now.

Yes, if you look at the solar patterns now, very similar to the Dalton minimum, I believe was 5 and 6, thus the next one should be even lower.

400px-Sunspot_Numbers.png

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2 minutes ago, LRD said:

So the arctic isn't warming then? Is that what you're saying? Or have I misunderstood? As I say severe cold or not (in the UK) the warming arctic is a worry

I can't say on what timescale the arctic is warming, but I think those links provide some balance when it comes to understanding the teleconnections in the short to medium term.

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Meanwhile the EPS FI mean pulls the Atlantic trough a tad further west with a possible weak ridge into scandi albeit far too far East. baby steps though - better than the 0z.

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Tonight's Ecm 12z ensemble mean is as emphatic as the operational about high pressure building in strongly next week, especially across the southern half of the uk. 

ECMAVGEU12_144_2.png

ECMAVGEU12_168_2.png

ECMAVGEU12_168_1.png

ECMAVGEU12_192_1.png

ECMAVGEU12_192_2.png

ECMAVGEU12_216_1.png

ECMAVGEU12_240_1.png

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1 minute ago, Frosty. said:

Tonight's Ecm 12z ensemble mean is as emphatic as the operational about high pressure building in strongly next week, especially across the southern half of the uk. 

ECMAVGEU12_144_2.png

ECMAVGEU12_168_2.png

ECMAVGEU12_168_1.png

ECMAVGEU12_192_1.png

ECMAVGEU12_192_2.png

ECMAVGEU12_216_1.png

ECMAVGEU12_240_1.png

All the proof we need, so as to really know that 'winter proper' is now well-and-truly 'underway'!:D

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10 minutes ago, Higher Ground said:

I can't say on what timescale the arctic is warming, but I think those links provide some balance when it comes to understanding the teleconnections in the short to medium term.

With respect don't those links just show blips in an otherwise upward trajectory of temperatures - especially in the Arctic?

https://www.metoffice.gov.uk/research/monitoring/climate/surface-temperature

 

Edited by LRD

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9 minutes ago, LRD said:

With respect don't those links just show blips in an otherwise upward trajectory of temperatures - especially in the Arctic?

https://www.metoffice.gov.uk/research/monitoring/climate/surface-temperature

 

I think you're debating an argument that I'm not making. Will say no more

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27 minutes ago, feb1991blizzard said:

Meanwhile the EPS FI mean pulls the Atlantic trough a tad further west with a possible weak ridge into scandi albeit far too far East. baby steps though - better than the 0z.

That's a long range mean Feb - expect larger ridge clusters to our east than the 00z run. Question will be how far north these clusters take any ridge. Sniffs that the Atlantic trough could undercut on the mean although with 51 members detecting much from the xtended eps mean/anomoly is tough (apart from the Alaskan ridge )

note the spread at day 10 in the Atlantic seems to take the ridge further north. That was true on yesterday's 00z run but it didn't gain any traction 

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1 hour ago, knocker said:

The ecm det run this evening is more or less showing the pattern  lndictated  by this mornings anomalies before the upstream pattern change and the corresponding knock on affect downstream. If that continues to be indicated this evening then we should see a developing trough in the eastern Pacific, stronger Alaskan ridge of over the Pole and a reorientation of the Canadian vortex lobe and associated  troughs which would suppress the Azones HP being shown here. Ergo a strong westerly upper flow tending unsettled weather with Temps in general around normal, perhaps slightly above

ecm_z500a_5d_nh_11.thumb.png.424bd66f98663edcf6d90287229d2186.png

Further to my earlier post the GEFS, NOAA and EPS anomalies this evening  illustrate the point, vis the pattern change quite well. Can't post the 10 15  EPS anomaly but it does extend the vortex trough east to connect with the trough to our east and thus restricts the Azones pushing north. Thus as previously mentioned we are looking at a fairly strong westerly upper flow with possibly the key players being the interaction between the trough to the NW and the HP to the south West.  So something for the det. runs to get their teeth into but the percentage play remains a period of unsettled weather with Temps in genearly around average or a little above.

  610day_03.thumb.gif.e579382803e1405abe32ba40b825366c.gif814day_03.thumb.gif.b5ac8277e237a6896ebfdc1012cc3f6a.gif

gefs_z500a_5d_nh_41.thumb.png.31ad79488d75fa1dbd453388d9e467cf.pnggefs_z500a_5d_nh_63.thumb.png.5a220c92dceaa35ecfbe82f4631e54c4.png

 

eps_z500a_5d_nh_61.png

Edited by knocker

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Looking at the ECM De Bilt ensembles shows next Monday and Tuesday showing some east/se/ne  solutions for there which means a cluster do have the high further north.

The spreads also showing the main spread to the nw and se of the UK between T144 and T168hrs.

 

 

 

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21 minutes ago, nick sussex said:

Looking at the ECM De Bilt ensembles shows next Monday and Tuesday showing some east/se/ne  solutions for there which means a cluster do have the high further north.

The spreads also showing the main spread to the nw and se of the UK between T144 and T168hrs.

 

 

 

Optimism -remains-supreme!..

@[email protected]?!

ensemble-ff-london.gif

ensemble-tt6-london.gif

eps_pluim_tt_06260.png

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 Is this the first signs of the major pattern change? Alaskian/Aleutian ridge returning this side of Christmas. How often do we see such agreement between ensembles at that range, may not lead to anything and could be gone tomorrow but signs are at least being sniffed out although not surprising based on thoughts on here and Twitter.

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2 hours ago, LRD said:

Totally agree BB62-63. Very worrying. 

It isn’t worrying as the ‘records’ used are minuscule.  And I think the ‘dampened down’ northerly discussion has had food for thought...

 

BFTP

Edited by BLAST FROM THE PAST

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Away from the hunt for the return of cold in the long term, keeping my eye on tomorrow evening on the frontal system / low pressure trough moving SE bringing rain, sleet and snow.

spIY1eFcZG.thumb.gif.2a3918a443d829c7d0ecd24037c03592.gif

IMO GFS, as usual, looks like overdoing the snow in southern extent, ECMWF snow charts showing N. Ireland, parts of Wales, NW England and parts of the Midlands seeing snowfall from this system. Though no snow to the south of this unlike GFS.

The issue with GFS, I think, is that it has dew points too low for a NWly flow, given long seatrack, so the  model assumes all snow inland right to the south coasts as the system and it's precipitation moves SE.

The 2 charts below highlight the precip and dew point in 5C increments together in one and just the dew point in 1C increments in the other, these DPs too low IMO ...

ppn_weds21z.thumb.png.655bae38e26f2a15999b8ad17c1e5d3b.pngdewp_w21z.thumb.png.61b9a5942e254159a6df64c5df386f3e.png

 

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18z..

Showing mild can wait...

A few tweaks and its game over-again- mobile/zonal...via 18z..

Sun-17 dec.

gfs-1-102.png

Edited by tight isobar

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Huge differences between the ECM and GFS anomolies at day ten upstream. 

Ecm shows a weak Alutian/Alaskan ridge , with an obvious stagnating HP over the uk , energy exiting Canada rides over the top , but also tries to dig south mid atlantic. 

Gfs shows a whopping Alutian/Alaskan ridge with the high the ECM has now retrogressing towards Greenland , with energy exiting Canada either stalling out west or possibly heading south east.

gfs_z500_anom_noram_240.thumb.png.8afb20b7252b7f881565bcaa1372b035.png   ecmwf_z500_anom_noram_240.thumb.png.b701c98c7e9203b1a2fdfafe39e346c8.png

Obviously one of these are very wrong ( or both) 

Heres the European look 

gfs_z500_anom_europe_240.thumb.png.0ee6b324187107dc1be67473c8f90a63.png   ecmwf_z500_anom_europe_240.thumb.png.9615e09ab9c9dea7eb5b9d9db1d93680.png

 

 

 

 

 

Insert

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