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Model Output Discussion - 23rd Jan - 12z onwards


Paul

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Posted
  • Location: (Previously Mitcham) North End, Portsmouth
  • Weather Preferences: Warm sunny days with the odd cloud.
  • Location: (Previously Mitcham) North End, Portsmouth

you are right there is no spoiler low but there is zero chance of it transfering to greenland just the same with the state of the PV as it is. still it does look good with repeats of northerly topplers if the ECM went out a few more frames

Thank you for the answer.... Every day is a school day. :)
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Posted
  • Location: Eastbourne and Larnaca,Cyprus .
  • Location: Eastbourne and Larnaca,Cyprus .

The charts this last 48rs seem to be firming up on the best 'potential' so far 'countrywide' this winter for wintery conditions.

Those in Northern England and Scotland have of course had two bites at a wintery cherry this season ( friends in Sheffield report two seperate decent snowfalls this winter) here in the Southeast ive been reduced to spotting a few snowflakes amongst a rain shower twice! (Although the sussex coast had a temporary localised snowfall the other day)

My concern would be Northerlys shown by the models at this range in the past seem to have a habit of becoming Northwesterlies nearer the time,perhaps just my imagination! A Northerly would be of interest given the possibilities of troughs running through in an arctic flow,A Northwester pleases the favoured few but leaves the rest in a marginal slushfest at best.

Yes you make a good point re northerlies becoming nw'erlies. Its a model bias at longer range but it depends on the set up. It's often quite difficult to get that true northerly, even more so with a ne.

 

The issue at the moment is really the depth of cold although the sourcing of the flow on the ECM if you follow the isobars is from the ne at T192hrs.

 

Upstream NCEP are 5 out of 5 in terms of confidence in the set up over the USA for day 6 to 10. Given the very strong signal for the Euro trough the more uncertain area of the forecast is the Atlantic sector so what happens to the Azores high, how amplified and will we see a high pressure cell setting up Iceland/ se Greenland. For the timebeing I don't see a proper Greenland block scenario, more a chance of high pressure orientated ne/sw in that vicinity.Of course that's the best case scenario we're a long way from that given the timeframes.

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Posted
  • Location: North East Cotswolds, 232m, 761feet ASL
  • Location: North East Cotswolds, 232m, 761feet ASL

Excitement building, page 100 by Monday if this spell materialises....

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Posted
  • Location: Fleet, Hampshire
  • Location: Fleet, Hampshire

Uppers don't look too cold to my untrained eye.2-3c maxes in the south? What I would class as cold not very cold?

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Posted
  • Location: Peterborough
  • Weather Preferences: Hot summers /snowy winters
  • Location: Peterborough

no sign? Every single model is going for a displaced azores high west of the uk amplified and building north towards greenland. your talking out your backside mate.

so that will be a MLB your talking about then ??? .and is there really any need to be rude to other members , We are all on here to learn from one another .

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Posted
  • Location: Abingdon - 55m ASL - Capital of The Central Southern England Corridor of Winter Convectionlessness
  • Weather Preferences: Winter: Snow>Freezing Fog; Summer: Sun>Daytime Storms
  • Location: Abingdon - 55m ASL - Capital of The Central Southern England Corridor of Winter Convectionlessness

post-992-0-64277100-1422046868_thumb.png

 

Circled area shows a rather tenuous link between Azores High Pressure system and Greenland High Pressure system, where there is concern that in future runs the Jet Stream may be able to force Low Pressure systems coming off eastern coast of Canada, as indicated by the arrow, which would deflect the cold air too far to our west.

Edited by The Enforcer
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Posted
  • Location: Rogerstone/Risca South Wales
  • Weather Preferences: Blizzards in winter Hot and sunny in summer...other is simply boring!!
  • Location: Rogerstone/Risca South Wales

airpressure.png

 

My chart of the day, look at the SW bulge over Biscay shoving that AZH west away from us and the air sourcing from N of Lapland.  Elongating the cold pattern...very unstable cold airmass and it would feel bitterly cold with colder air feeding down.    

 

BFTP

Just need it to squeeze up towards Greenland!!! :-D

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Posted
  • Location: Wildwood, Stafford 104m asl
  • Weather Preferences: obviously snow!
  • Location: Wildwood, Stafford 104m asl

Uppers don't look too cold to my untrained eye.2-3c maxes in the south? What I would class as cold not very cold?

 

They don't, they look pants for the south, thicknesses not great either, but still FI, so hope for upgrades, as there cannot really be downgrades for my location

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Posted
  • Location: South Essex
  • Location: South Essex

There's a lot of folk on here who can look at the negative side when most folk are being positive, and they add insight and reason to their "downbeat" posts. These guys I admire and respect.Some are not like that and the relentless frequency of their negative posting comes across a bit like the intent is to troll rather than add to the discussion.I seem to recall this poster earlier today put up a chart from the GFS 06z for 8th Feb with the comment... Well let's see what's happening to itAs was on 6zpost-2553-0-22902600-1422011189.jpgAs is nowh500slp.pngSeems to have "shifted" quite a bit in just six hours to my eyes.....

Whilst you make a perfectly valid point, oddly I'm not reassured by that example :-)

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Posted
  • Location: Peterborough
  • Weather Preferences: Snow and frost in the winter. Hot and sunny, thunderstorms in the summer.
  • Location: Peterborough

Firstly, in the last 5 years we have have seen charts like not only materialise but upgrade significantly, so just because the last cold spell may have not lived up to your expectations, doesn't mean that this one won't. (Not that the last cold spell was anything other than modelled pretty well - it was just us who looked at the more severe runs and dreamed).

Just thought I would quote this as this is a pertinent point here.

We should be judging the potential upcoming cold spell on its own merits rather than the rather underwhelm (for some) cold spell we just had. The last cold spell was a complex situation which meant cold air couldn't properly advect over the UK. In this upcoming spell, I don't think this will be such an issue as this is being driven by an unusually deep Euro trough.

The models are in decent agreement for the winds to veer north westerly in 6 days time as heights lower significantly over Europe. Shown by the ECM ens mean

EDM1-168.GIF?23-0

As low heights clear to our east we get a fairly modest amplification in the Atlantic, but given the deepening trough over Europe, then I expect the pattern will try to sharpen up upstream as the Euro trough allows further pulses of cold air to feed into it and re-inforce north/north westerly winds over the UK. Though the exact details are still up in the air, given the differing solutions at day 10. ECM and GEM as examples.

ECM1-240.GIF?23-0

The ECM shows another low rolling over the ridge and engages the deep Euro trough, this will sink south  east and then usher in another northerly blast behind.

 

GEM

gem-0-240.png?12

This model shows a strong ridge and hence blocks the progression of the low on the ECM, hence a cleaner northerly solution, by this time we would have seen a good 3 or so days of Arctic air, given the chances of troughs or even secondary features pushing south along the western flank of the trough, I would expect the GEM to be a rather snowy solution (especially near the coasts but not exclusively).

 

All in all, a lot to be positive about. The anomaly charts say it all, trough over and east of the UK, high to the west. Simples :)

Edited by Captain shortwave
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Posted
  • Location: Catchgate, Durham,705ft asl
  • Location: Catchgate, Durham,705ft asl

no sign? Every single model is going for a displaced azores high west of the uk amplified and building north towards greenland.

Welcome to Netweather,but remember to post with a smile...... :D

Pretty much universal agreement across ensembles,anomalies and operational runs for a deep trough just East of the UK as we head for the end of the month giving cold and unsettled conditions.

gefs day 10..post-2839-0-54367100-1422046989_thumb.pn ecm mean day 10..post-2839-0-44376800-1422046988_thumb.gi

noaa 8-14...post-2839-0-17811100-1422046986_thumb.gi gfs/ecm op.mean..post-2839-0-39843100-1422046991_thumb.gi

No surprise that NOAA have high confidence in their forecast.

http://www.cpc.ncep.noaa.gov/products/predictions/610day/fxus06.html

How cold?.....Will it snow in Carlisle?.....How long will it last?....Stay tuned. :D

Edited by Polar Maritime
To move discussion on..
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Posted
  • Location: st albans
  • Location: st albans

those of you who have viewed the NH chart for the ecm ens anoms will have noted the small bulge as the siberian vortex shoves a bit of fuel in from the ne around day 10. that works south and extends the trough back west, thus extending the period of cold for the uk.  thereafter the torugh gradually sinks se and upstream flattens out as the siberian vortex is absorbed into the canadian which, surprise, surprise, ends up around baffin.  the azores anomoly by then prime player for the south of the uk with the jet on a west/east axis (bit more n than s) and cool zonal extending into the e euro trough. 

 

i cannot make a confident call on the longevity of this cold spell until i see the split vortex going within day 10. the low res eps seem too keen to rebuild the canadian prime segment around baffin.  what should be noted is that naefs and ecm extended have been consistent in this trend to rebuild the 'prime' canadian vortex in that locale. the siberian master all too short a feature for us this side of the NH.

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Posted
  • Location: North East Cotswolds, 232m, 761feet ASL
  • Location: North East Cotswolds, 232m, 761feet ASL

Welcome to Netweather,but remember to post with a smile...... :D

 

 

Pretty much universal agreement across ensembles,anomalies and operational runs for a deep trough just East of the UK as we head for the end of the month giving cold and unsettled conditions.

 

gefs day 10..attachicon.gifgensnh-21-5-240.png  ecm mean day 10..attachicon.gifEDH101-240.gif

Heading to Carlisle for 6 days on Thurs-could be good timing.

 

noaa 8-14...attachicon.gif814day.03.gif   gfs/ecm op.mean..attachicon.giftest8.gif

 

 

No surprise that NOAA have high confidence in their forecast.

 

http://www.cpc.ncep.noaa.gov/products/predictions/610day/fxus06.html

 

How cold?.....Will it snow in Carlisle?.....How long will it last?....Stay tuned. :D

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Posted
  • Location: Broxbourne, Herts
  • Weather Preferences: Snow snow and snow
  • Location: Broxbourne, Herts

Whilst you make a perfectly valid point, oddly I'm not reassured by that example :-)

haha :) When someone takes a T384 post as a means of posting negatively, it's interesting to see how that will look by T324!! GFS is just as capaable of modelling the dreadful as it is the fantastic in deep FI :)

Edited by Timmytour
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Posted
  • Location: Abingdon - 55m ASL - Capital of The Central Southern England Corridor of Winter Convectionlessness
  • Weather Preferences: Winter: Snow>Freezing Fog; Summer: Sun>Daytime Storms
  • Location: Abingdon - 55m ASL - Capital of The Central Southern England Corridor of Winter Convectionlessness

haha :) When someone takes a T384 post as a means of posting negatively, it's interesting to see how that will look by T324!! GFS is just as capaable of modelling the dreadful as it is the fantastic in deep FI :)

Or incapable, depending on one's perception of the accuracy of the GFS at such range.

Edited by The Enforcer
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