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Model output discussion - Closing in on Christmas


Paul

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Posted
  • Location: Bury St Edmunds, Suffolk
  • Weather Preferences: Cold, frost and snow
  • Location: Bury St Edmunds, Suffolk

I know the saying is get the cold in and the snow will follow. 

But as amazing as some of these charts looks, when you see the 850s they really don't look too good. I know it's too far out to take too seriously, but I'd definitely prefer those 850s a little lower. Otherwise it looks like such a waste of great synoptics. Just my opinion though of course.

But overall great charts and a wonderful position to be in!

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Posted
  • Location: Leicestershire (hinckley)
  • Location: Leicestershire (hinckley)

The issue with the 18z is the lack of an organised area of low pressure off eastern united states. That then leads to the high pressure failing to push as far into greenland. The pattern there after is not as good for a sustained cold spell. That period should come into the reliable early next week so we still have a few days for things to chop and change. 

Better organised low pressure system where i have circled should result in the high pressure heading further into greenland. 

Screenshot_20201218_230822.jpg

Edited by MKN
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Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.
4 hours ago, nick sussex said:

We need more se movement not southerly from the low over Greenland .

Any low needs to get se of the UK . 

wasn't too bad actually even though it moved south, drew an Easterly, usually when this happens though i do agree the trough doesn't elongate enough to allow anything better than a lee Easterly and it sinks too quickly and doesn't prop the high up enough.

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Posted
  • Location: Nutley, East Sussex 120m ASL
  • Location: Nutley, East Sussex 120m ASL
10 minutes ago, nick sussex said:

Founder member CAS . Coldies Against Slush !

Ice days and crunchy snow is what the vast majority of members here want to see so as much as we’ve seen some very encouraging outputs my crunchy snow alert hasn’t  been activated yet for the UK.

Given the horrors that could have been dished up with mild crud then the trends are good overall but let’s aim high and not have to put up with buffet scraps .

Long suffering UK coldies deserve first dibs . :santa-emoji:

 

 

Nick where are you on your traffic light system for this setup? 

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Posted
  • Location: Caterham-on-the-hill, Surrey, 190m asl (home), Heathrow (work)
  • Location: Caterham-on-the-hill, Surrey, 190m asl (home), Heathrow (work)
4 minutes ago, NewEra21 said:

I know the saying is get the cold in and the snow will follow. 

But as amazing as some of these charts looks, when you see the 850s they really don't look too good. I know it's too far out to take too seriously, but I'd definitely prefer those 850s a little lower. Otherwise it looks like such a waste of great synoptics. Just my opinion though of course.

But overall great charts and a wonderful position to be in!

Low heights of the trop vortex  (blues on the 500mb/slp charts) might compensate for that, as they suggest a low freezing level, so long as surface dew points are low (0c or below) too, not all about the T850s. Anyway I'm more concerned about getting the northerly direct from the arctic in the first place, then worry about whether it'll be cold enough for snow, long long way off and lots to go wrong, but looking promising for now synoptically with today's medium range evolution.

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Posted
  • Location: Crewe, Cheshire
  • Weather Preferences: Snow, storms and other extremes
  • Location: Crewe, Cheshire

Control run taking longer to get there than its 12z run but the air available to tap into has the potential to be colder...IF that HP can get sufficiently N

image.thumb.png.5d5249984ba188e47f9ff4ac8c936142.png

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Posted
  • Location: Hertfordshire
  • Weather Preferences: SNOW AND FREEZING TEMPS
  • Location: Hertfordshire
1 minute ago, Nick F said:

Low heights of the trop vortex  (blues on the 500mb/slp charts) might compensate for that, as they suggest a low freezing level, so long as surface dew points are low (0c or below) too, not all about the T850s. Anyway I'm more concerned about getting the northerly direct from the arctic in the first place, then worry about whether it'll be cold enough for snow, long long way off and lots to go wrong, but looking promising for now synoptically with today's medium range evolution.

At least I’m not the only one worried . It’s so nerve racking watching the runs dribble out . Just thinking please don’t go balls up . 

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Posted
  • Location: Rotherhithe, 5.8M ASL
  • Location: Rotherhithe, 5.8M ASL

I’m almost disturbed by the complete lack of mild charts even far in FI usually the progressive nature of models becomes more apparent...

415B3844-FA71-49B1-90E7-CFD47C3FDE22.thumb.png.e42700923a2200e081c98762aa345455.png

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Posted
  • Location: Crewe, Cheshire
  • Weather Preferences: Snow, storms and other extremes
  • Location: Crewe, Cheshire

There has been a shift in the GEFS around day 8- Scandi trough further E and so is the HP anomaly. Looks like a slowed down evolution

image.thumb.png.9a96ae3fcc1e02efc332a99a44ef5a50.png

This was the 12z mean-

image.thumb.png.323725a6aa6f9bdb35144e9e956b8dd6.png

Edited by CreweCold
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Posted
  • Location: Live in NW Kent by the Thames & work in SE London
  • Weather Preferences: Snowy November to March and Sunny and warm April to October
  • Location: Live in NW Kent by the Thames & work in SE London

In the short range 18z ensembles for London the op is above the mean upper air temps with the vast majority of the ensembles considerably colder on Christmas day, we await the longer range ensembles 

graphe3_0000___-0.12574_51.5085_Londres.png

Edited by Kentspur
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Posted
  • Location: G.Manchester
  • Location: G.Manchester
20 minutes ago, Downburst said:

This spring was remarkable, records broken for sunshine, drought and warmth for many. Now the models are showing signs of another possible 2010 (subject to actually happening, and who knows how much change is yet to come) with low orbit MJO and nevertheless a crazily massive atlantic block high pressure, one has to wonder what’s going on with the weather

It's like the current global debt crisis evolving. On the other side, expect there to be a considerable debt owed reciprocally as a net result for all of the fun (sarcasm of course)

But that shouldn't detract us from enjoying it whilst it's here. 2050 could be a totally different story....

Edited by Optimus Prime
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Posted
  • Location: Rotherham, East Dene
  • Location: Rotherham, East Dene
3 minutes ago, CreweCold said:

There has been a shift in the GEFS around day 8- Scandi trough further E and so is the HP anomaly. Looks like a slowed down evolution

image.thumb.png.9a96ae3fcc1e02efc332a99a44ef5a50.png

This was the 12z mean-

image.thumb.png.323725a6aa6f9bdb35144e9e956b8dd6.png

Its all upstream the heights near alaska and subsequent strength of the north east American trough. Models flipping around with levels of amplification. All to be expected as they settle on the way forward. 

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Posted
  • Location: Hoyland,barnsley,south yorkshire(134m asl)
  • Weather Preferences: severe storms,snow wind and ice
  • Location: Hoyland,barnsley,south yorkshire(134m asl)
4 minutes ago, CreweCold said:

Control run taking longer to get there than its 12z run but the air available to tap into has the potential to be colder...IF that HP can get sufficiently N

image.thumb.png.5d5249984ba188e47f9ff4ac8c936142.png

It's on it's way but slower☺️

gensnh-0-1-204.thumb.png.27432ca2f4d5d0156e13c1198d193016.pnggiphy.thumb.gif.1a8b7eb06fd02bf1f1f5156682623665.gif

 

 

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Posted
  • Location: Caterham-on-the-hill, Surrey, 190m asl (home), Heathrow (work)
  • Location: Caterham-on-the-hill, Surrey, 190m asl (home), Heathrow (work)
3 minutes ago, ICE COLD said:

At least I’m not the only one worried . It’s so nerve racking watching the runs dribble out . Just thinking please don’t go balls up . 

I try not to get too excited at charts screaming cold and snowy potential over 7 days out, even if it keeps re-occuring, been too many let downs in the 16-17 years I've been model watching. Just hope the arctic and upstream over N America is being modelled correct, as developments here are crucial with regards to the promising pattern unfolding our side of the Atlantic as per this evening's runs. Need more runs until I grease the runners on the sledge.

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Posted
  • Location: North West
  • Weather Preferences: Anything but the prevailing wind!
  • Location: North West
1 minute ago, Mike Poole said:

So, last one from me, the 18z backs up the 12z with a split SSW on the way:

0AC61B1B-4396-492B-9070-0CBD0437E22B.thumb.png.2f097f11ace25a4ada796109e81fc19b.png

Just another factor in trying to predict where the winter will go.  But here’s the conundrum:

Are the events that cause a SSW responsible for a cold blocked spell for the UK before the event, or are they responsible for a cold blocked spell for the UK after the event?  

Not sure Mike, but the wave 1 attack is going to weaken the vortex from 21st onwards then lo and behold trop amplification flourishes. Not sure we can call it a QTR but it’s not a coincidence. 
 

None of this would be happening if the canonical late December vortex intensification was occurring. That’s for sure.

Just putting it out there but this iteration of the GFS (and now it’s ens set) using the FV3 core was never, ever this solid about last winters botched warming. It has been on this for days now in the sub 2 week range, if it’s still there in what, 2 days time, is it happening? Will the bigwig boys and girls in Stratospheric Wx twitter land call it? Could we know by Christmas Eve that we’re getting an SSW for V early Jan?

Its literally the only thing on my Christmas list! Apart from socks of course, The joys of being a dad lol.

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Posted
  • Location: Home: Chingford, London (NE). Work: London (C)
  • Weather Preferences: Winter: cold and snowy. Summer: hot and sunny
  • Location: Home: Chingford, London (NE). Work: London (C)
34 minutes ago, NewEra21 said:

I know the saying is get the cold in and the snow will follow. 

But as amazing as some of these charts looks, when you see the 850s they really don't look too good. I know it's too far out to take too seriously, but I'd definitely prefer those 850s a little lower. Otherwise it looks like such a waste of great synoptics. Just my opinion though of course.

But overall great charts and a wonderful position to be in!

To get the cold in, you need the right synoptics. Models won’t necessarily pick up on 850’s until nearer the time. 

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Posted
  • Location: west yorkshire
  • Weather Preferences: extreme weather
  • Location: west yorkshire

Not been funny but we are seeing these great charts but the temps are nothing special are they. Certainly not conductive to snowfall that for sure. 50469266-245F-41E9-97A2-B5B95CDEFDC1.thumb.png.00454eb2a61705f9bab8e9c5422e82df.png

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Posted
  • Location: Crewe, Cheshire
  • Weather Preferences: Snow, storms and other extremes
  • Location: Crewe, Cheshire
4 minutes ago, terrier said:

Not been funny but we are seeing these great charts but the temps are nothing special are they. Certainly not conductive to snowfall that for sure. 50469266-245F-41E9-97A2-B5B95CDEFDC1.thumb.png.00454eb2a61705f9bab8e9c5422e82df.png

Control gets the proper cold in by 276 hrs...a long way to go yet like Nick has said. Let's just get that N Atlantic amplification locked in first before worrying about snow conducive uppers.

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Posted
  • Location: Hoyland,barnsley,south yorkshire(134m asl)
  • Weather Preferences: severe storms,snow wind and ice
  • Location: Hoyland,barnsley,south yorkshire(134m asl)
12 minutes ago, terrier said:

Not been funny but we are seeing these great charts but the temps are nothing special are they. Certainly not conductive to snowfall that for sure. 50469266-245F-41E9-97A2-B5B95CDEFDC1.thumb.png.00454eb2a61705f9bab8e9c5422e82df.png

I am not too sure about that,the 528 dam line almost clears the country.

gfs-3-210.thumb.png.792c6afb91ac18aefbc958d8ea5eb1c2.png

it is a bit marginal though so most of the snow if any would be reserved for the hills and lower ground in the north.

Edited by Allseasons-si
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I think one thing that needs to be considered is that even since 2010 the world is a warmer place, for the UK even a tiny fraction makes the difference. The current Synoptics look tasty, but really don’t pack a punch, not to mention them still being 7-10days away. Extreme caution needed and it’s possible, probable many areas still won’t see snow. 

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Posted
  • Location: Crewe, Cheshire
  • Weather Preferences: Snow, storms and other extremes
  • Location: Crewe, Cheshire
1 minute ago, Alderc said:

I think one thing that needs to be considered is that even since 2010 the world is a warmer place, for the UK even a tiny fraction makes the difference. The current Synoptics look tasty, but really don’t pack a punch, not to mention them still being 7-10days away. Extreme caution needed and it’s possible, probable many areas still won’t see snow. 

Looking through the ensembles and there are very few, if any, true Greenland HPs. Not going to dislodge enough truly cold air without. Would still feel raw though in those N'lys.

I think for a true spell we are going to have to wait for the effects of the SSW. However, there should be chances to see snow for many before then.

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Posted
  • Location: Ireland - East Coast
  • Location: Ireland - East Coast
13 minutes ago, Allseasons-si said:

I am not too sure about that,the 528 dam line almost clears the country.

gfs-3-210.thumb.png.792c6afb91ac18aefbc958d8ea5eb1c2.png

These days on this channel the 528 dam level is not something folk will be interested in. That’s unfortunate of course, but there you go. I have to say though that not only does this not guarantee snow, it’s also demonstrated on a model forecast more than 48hrs out. Ask a former met employee anyone reading this, there’s a couple on here. They don’t hind cast teleconnections typically so can be taken seriously.

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Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.
21 minutes ago, CreweCold said:

Looking through the ensembles and there are very few, if any, true Greenland HPs. Not going to dislodge enough truly cold air without. Would still feel raw though in those N'lys.

I think for a true spell we are going to have to wait for the effects of the SSW. However, there should be chances to see snow for many before then.

GEFS - SCANDI  HIGH ALERT!!  Right at end - one ridiculous big one.

image.thumb.png.e894810a1422465e8df754b6a6bc0989.png

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Posted
  • Location: Manchester
  • Weather Preferences: Sunny and warm in the Summer, cold and snowy in the winter, simples!
  • Location: Manchester
5 hours ago, mountain shadow said:

It's always a good sign when all routes appear to be leading to cold.

It is but the ensembles certainly don't show all routes leading to cold unfortunately

graphe3_1000_253_85___.gif

http://www.meteo24.fr/meteo/eps/ensemble-tt6-london.gif

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