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Model Output Discussion - 23rd Jan - 12z onwards


Paul

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Posted
  • Location: oldham
  • Location: oldham

Can anyone work out the thicknesses over the UK.  I'm guessing 525-530?

 

Looks great to look at but I fear not much precipitation and any that falls will be slushy sleet away from prone spots!

What part of the UK 525 seems to low for the North. ...

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Posted
  • Location: portsmouth uk
  • Weather Preferences: extremes
  • Location: portsmouth uk

although if we had deeper cold to our ne or east then id expect things would have been much better problem is that those uppers are so marginal.

so my ramp has decreased a bit but this pattern could go on to better and better.

 

right at the end of the gfs run the jet is weaker and looping up over southern greenland down the western side of the uk into europe.

if we can lose a little more energy from the jet then its possible heights could get futher north.

 

theres still slight chance that heights could wedge down from the pole and put more pressure on the vortex close by the greenland area.

but still all to play for.

 

gfs-1-192.png?12

gfs-5-192.png?12

gfsnh-5-192.png?12

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

Are there likely to be hard frosts in Northerlies

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Posted
  • Location: Essex Riviera aka Burnham
  • Weather Preferences: 30 Degrees of pure British Celsius
  • Location: Essex Riviera aka Burnham

Not overly impressed by the 12z gfs in all honesty, this run makes less of the low pressure over Europe/Scandi as opposed to the 6z. By and large the UK under a 'chilly' cyclonic air mass (with -4 uppers in general) - only one way this will go thereafter and that's a filling depression whilst the Atlantic rolls in with a ridge of high pressure toppling over the UK..

Edited by Froze were the Days
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Posted
  • Location: west yorkshire
  • Weather Preferences: extreme weather
  • Location: west yorkshire

Think a word of warning to any newbies. The dark purples on the charts isn't deep cold. My worries are that the temps look very marginal away from the favoured spots for snowfall. Obviously this could upgrade. But my feelings on the gfs and ukmo output so far is that it's a very marginal set up.

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Posted
  • Location: Eshaness, Shetland Islands
  • Weather Preferences: Cool and Stormy
  • Location: Eshaness, Shetland Islands

The uppers look like a wintery mix to me? No 'deep' cold (for now), so I would say it will be pretty standard away from the North. Cold nights though.

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Posted
  • Location: Dorset
  • Location: Dorset

I am getting 520 for the midlands to 525 for the south coast from the uk T144 using the (1000-pressure)*.8+500hp.

UKM at T120 and T144 is largely snow.

At T 96 very similar to the GFS 12z precip type i/e the band goes through with the drop in temps at 850 etc, with snow on the back edge digging in and snow showers following closely behind.

For western areas the T100 to T144 period looks very snowy imho barely a few km's away from the coast based just on these two models.

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Posted
  • Location: Banbury
  • Location: Banbury

Think a word of warning to any newbies. The dark purples on the charts isn't deep cold. My worries are that the temps look very marginal away from the favoured spots for snowfall. Obviously this could upgrade. But my feelings on the gfs and ukmo output so far is that it's a very marginal set up.

Very marginal,  wintry showers rather than snow proper I'd have thought

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Posted
  • Location: Broadmayne, West Dorset
  • Weather Preferences: Snowfall in particular but most aspects of weather, hate hot and humid.
  • Location: Broadmayne, West Dorset

I am getting 520 for the midlands to 525 for the south coast from the uk T144 using the (1000-pressure)*.8+500hp.

UKM at T120 and T144 is largely snow.

At T 96 very similar to the GFS 12z precip type i/e the band goes through with the drop in temps at 850 etc, with snow on the back edge digging in and snow showers following closely behind.

For western areas the T100 to T144 period looks very snowy imho barely a few km's away from the coast based just on these two models.

 

I agree with you there Iceberg, based on this run even I might see some snow next weekend

Edited by mcweather
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Posted
  • Location: near dalmellington E ayrshire 302m asl
  • Weather Preferences: mediterranean summer
  • Location: near dalmellington E ayrshire 302m asl

Are there likely to be hard frosts in Northerlies

in my area northerlies tend to bring clear skys and harsh frosts more so than a easterly temps can fall here to -14c or under looking at this evenings run the east looks the most likely this time round for snow with low presure over the low countrys

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Posted
  • Location: Essex Riviera aka Burnham
  • Weather Preferences: 30 Degrees of pure British Celsius
  • Location: Essex Riviera aka Burnham

@240z a very 'flabby' looking area of nothingness to our west and only meaningful area of high pressure surprise surprise is our ol friend the Azores High - looks a bit strange, probably more of a distinct ridge of HP I would have thought.

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Posted
  • Location: portsmouth uk
  • Weather Preferences: extremes
  • Location: portsmouth uk

I am getting 520 for the midlands to 525 for the south coast from the uk T144 using the (1000-pressure)*.8+500hp.

UKM at T120 and T144 is largely snow.

At T 96 very similar to the GFS 12z precip type i/e the band goes through with the drop in temps at 850 etc, with snow on the back edge digging in and snow showers following closely behind.

For western areas the T100 to T144 period looks very snowy imho barely a few km's away from the coast based just on these two models.

thanks for that ice as was still learning about thickness and so on.

this also has to be said the speed in which the models are throwing out these charts is pretty incredible and as stated by the earlier post saying about similar evolution to nov 09 i agree very much.

 

but its the speed in which this is setting up is incredible considering a week ago we had the azores ridging over the south of the uk with mild sw flow.

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Posted
  • Location: Dorset
  • Location: Dorset

Yep, very little point looking beyond T144 imho.

At T144 Meto has thicknesses around 3-4 lower than GFS.....GFS obviously has more energy in the N/S flow effecting the straight drag of the colder air (however it does have more precip). This kind of detail is really 48 hr stuff, at the moment the general trend is very good for a very cold and potential wintry set up from T100 thru to at least T144 and possible beyond T196...

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Posted
  • Location: Manchester
  • Weather Preferences: Sunny and warm in the Summer, cold and snowy in the winter, simples!
  • Location: Manchester

GEM sets up an unstable cold N/NE flow. Synoptic looking very good.

 

gemnh-0-192.png?12

 

GFS essentially has us in a NW/N/NE flow for several days and yet never programs the 850's across England to be lower than -4C - yes there will be milder sectors but that seems rather far fetched and given the general synoptic being modelled across the output I think we can expect some decent upgrades to this GFS 12z Op ouput.

 

If we don't get caught worrying about will it snow IMBY and unknown detail the big picture is that a potential cold snap is being upgraded to a cold spell (and yes it suits Northerners better initially but the South doesn't look excluded later)

Edited by Mucka
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Posted
  • Location: Epsom, Surrey, 100 Meters above sea level
  • Weather Preferences: Anything Extreme
  • Location: Epsom, Surrey, 100 Meters above sea level

This is going to turn into a winter that only really existed in a computer chart, gone are the deep cold charts on offer only a few days ago which always only ever seem to exist in FI these days. 

 

Replaced are watered down uppers that will not be condusive of snowfall in nearly all low lying areas...this the uppers on the GFS at + 144

 

Not even a hint of a -6 there !!

 

gfs-1-144.png?12

 

The UKMO evolution is better at + 144 with more of an Easterly component, but it's still only good for favored areas. 

UW144-21.GIF?24-17

 

The overall trend today is to keep that damn Azores high waiting in the wings to ruin everything , IMO a short lived cold spell that will not be remembered this time next year as being any significant. 

This is the time when you start looking at trends to see if a decent cold spell is coming or if another 3 day cold snap is coming and the balance for me has shifted very much toward a cold snap of maybe 4 or 5 days at best before a return to westerly driven weather, to be honest the UK weather has become very predictable in the past 12 months, it's getting a bit boring now

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Posted
  • Location: Clwydian Hills 210/300 Metres ASL
  • Weather Preferences: Seasonal
  • Location: Clwydian Hills 210/300 Metres ASL

GEM sets up an unstable cold N/NE flow. Synoptic looking very good.

 

gemnh-0-192.png?12

 

GFS essentially has us in a NW/N/NE flow for several days and yet never programs the 850's across England to be lower than -4C - yes there will be milder sectors but that seems rather far fetched and given the general synoptic being modelled across the output I think we can expect some decent upgrades to this GFS 12z Op ouput.

 

If we don't get caught worrying about will it snow IMBY and unknown detail the big picture is that a potential cold snap is being upgraded to a cold spell (and yes it suits Northerners better initially but the South doesn't look excluded later)

 

 

This is going to turn into a winter that only really existed in a computer chart, gone are the deep cold charts on offer only a few days ago which always only ever seem to exist in FI these days. 

 

Replaced are watered down uppers that will not be condusive of snowfall in nearly all low lying areas...this the uppers on the GFS at + 144

 

Not even a hint of a -6 there !!

 

gfs-1-144.png?12

 

The UKMO evolution is better at + 144 with more of an Easterly component, but it's still only good for favored areas. 

UW144-21.GIF?24-17

 

The overall trend today is to keep that damn Azores high waiting in the wings to ruin everything , IMO a short lived cold spell that will not be remembered this time next year as being any significant. 

This is the time when you start looking at trends to see if a decent cold spell is coming or if another 3 day cold snap is coming and the balance for me has shifted very much toward a cold snap of maybe 4 or 5 days at best before a return to westerly driven weather, to be honest the UK weather has become very predictable in the past 12 months, it's getting a bit boring now

 

Glad to see we're all on the same page. .  :cc_confused:

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Posted
  • Location: Banbury
  • Location: Banbury

Hold on there. No , those charts from UKMO  would produce snow at lower levels on Friday and maybe into the weekend.

 C

With thicknesses for 500-1000hPa at c. 523dam in a few places it may be cold enough for snow.

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

This is going to turn into a winter that only really existed in a computer chart, gone are the deep cold charts on offer only a few days ago which always only ever seem to exist in FI these days. 

 

Replaced are watered down uppers that will not be condusive of snowfall in nearly all low lying areas...this the uppers on the GFS at + 144

 

Not even a hint of a -6 there !!

 

gfs-1-144.png?12

 

The UKMO evolution is better at + 144 with more of an Easterly component, but it's still only good for favored areas. 

UW144-21.GIF?24-17

 

The overall trend today is to keep that damn Azores high waiting in the wings to ruin everything , IMO a short lived cold spell that will not be remembered this time next year as being any significant. 

This is the time when you start looking at trends to see if a decent cold spell is coming or if another 3 day cold snap is coming and the balance for me has shifted very much toward a cold snap of maybe 4 or 5 days at best before a return to westerly driven weather, to be honest the UK weather has become very predictable in the past 12 months, it's getting a bit boring now

I do not think the models factor in the longer lasting the N'ly component further 'injections' of colder air, will come south so what you see right now is not impressive but I'm sure by when the charts come within 96hr 850s will be more appropriate for the synoptic. So what you are seeing is not being addressed at this stage until at a closer timeframe. I think it can deliver for everyone, small margins - but it ain't shabby by no means. With arctic much colder than December it is the optimum time, for such northerly bouts.

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Posted
  • Location: Manchester
  • Weather Preferences: Sunny and warm in the Summer, cold and snowy in the winter, simples!
  • Location: Manchester

Glad to see we're all on the same page. .  :cc_confused:

 

LOL that's opinions for you. It depends on the context ,maybe or perhaps ones initial expectations but if we were to compare ensemble sets over the last few days I think it would be pretty clear that the longevity of any cold being modelled has generally been increased.

Perhaps if one were to take GFS 12z Op as being certain to verify one could argue it will only be chilly/cold for a week but that seems longer than the 3 day toppler originally modelled? 

 

I think perhaps the lack of cold uppers to our NE to tap into is what is causing a more downbeat mood. If the cold air was in place there we would be seeing -8 to -12 uppers for several days on GFS Op instead of -4 to -6 and I doubt there would be much talk of downgrades then.

Edited by Mucka
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Posted
  • Location: Essex Riviera aka Burnham
  • Weather Preferences: 30 Degrees of pure British Celsius
  • Location: Essex Riviera aka Burnham

This is going to turn into a winter that only really existed in a computer chart, gone are the deep cold charts on offer only a few days ago which always only ever seem to exist in FI these days. 

 

Replaced are watered down uppers that will not be condusive of snowfall in nearly all low lying areas...this the uppers on the GFS at + 144

 

Not even a hint of a -6 there !!

 

gfs-1-144.png?12

 

The UKMO evolution is better at + 144 with more of an Easterly component, but it's still only good for favored areas. 

UW144-21.GIF?24-17

 

The overall trend today is to keep that damn Azores high waiting in the wings to ruin everything , IMO a short lived cold spell that will not be remembered this time next year as being any significant. 

This is the time when you start looking at trends to see if a decent cold spell is coming or if another 3 day cold snap is coming and the balance for me has shifted very much toward a cold snap of maybe 4 or 5 days at best before a return to westerly driven weather, to be honest the UK weather has become very predictable in the past 12 months, it's getting a bit boring now

 

Spot on - I think we've been here before! 12z GFS might be closer to the outcome and some of the other models might be over complicating the synoptics.

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Posted
  • Location: Reigate Hill
  • Weather Preferences: Anything
  • Location: Reigate Hill

A 6-7 day cold spell from the GFS and GEM OPS. Again the ridge topples around D10. The uppers look nothing special, a bit like the spell we have just had, so no deep freeze (Look to the US for that) and any snow could be marginal by the time we get closer to T0, though hills and up north will likely be favoured again. Nearer the day to see what develops in the flow as the GFS has a Channel and North Sea low as well as troughs popping up:

 

post-14819-0-82238800-1422119304_thumb.p post-14819-0-33824500-1422119305_thumb.p

 

Big changes from the GFS op from only 6 hours ago so by the 0z probably different again (good or bad). However it looks for the south how the current spell evolved with a watered down upper flow and snow chances at sea level hard to come by. Certainly the GFS is showing no sign of upgrades at the moment, especially if you look at the GEFs which continue to kill the cold sell earlier than the op. The mean at T180 has uppers -2 to -4c for the south:

 

post-14819-0-25491800-1422119861_thumb.p

 

The op was -4 to -5c. Some of the D8 GEFS:

 

post-14819-0-81472700-1422120058_thumb.ppost-14819-0-62201100-1422120059_thumb.ppost-14819-0-19187300-1422120060_thumb.p

 

post-14819-0-61941600-1422120060_thumb.ppost-14819-0-65180400-1422120061_thumb.ppost-14819-0-12991700-1422120062_thumb.p

 

post-14819-0-63637900-1422120062_thumb.ppost-14819-0-13657100-1422120063_thumb.ppost-14819-0-65034300-1422120063_thumb.p

 

post-14819-0-14067300-1422120064_thumb.p

 

Continuing the theme from the 06z.

Edited by i'm dreaming of...
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Posted
  • Location: portsmouth uk
  • Weather Preferences: extremes
  • Location: portsmouth uk

This is going to turn into a winter that only really existed in a computer chart, gone are the deep cold charts on offer only a few days ago which always only ever seem to exist in FI these days. 

 

Replaced are watered down uppers that will not be condusive of snowfall in nearly all low lying areas...this the uppers on the GFS at + 144

 

Not even a hint of a -6 there !!

 

gfs-1-144.png?12

 

The UKMO evolution is better at + 144 with more of an Easterly component, but it's still only good for favored areas. 

UW144-21.GIF?24-17

 

The overall trend today is to keep that damn Azores high waiting in the wings to ruin everything , IMO a short lived cold spell that will not be remembered this time next year as being any significant. 

This is the time when you start looking at trends to see if a decent cold spell is coming or if another 3 day cold snap is coming and the balance for me has shifted very much toward a cold snap of maybe 4 or 5 days at best before a return to westerly driven weather, to be honest the UK weather has become very predictable in the past 12 months, it's getting a bit boring now

4 or 5 days suit me and perhaps thunder snow in unstable northerly.

this could still develop futher and is the best charts seen for sometime better than fake easterly 

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Posted
  • Location: Essex Riviera aka Burnham
  • Weather Preferences: 30 Degrees of pure British Celsius
  • Location: Essex Riviera aka Burnham

Looking at the polar NH profile I'd suggest this is a 14 to 21 day cold spell with heavy snow showers cold and ice days galore....A very cold Feb is in the offing!

Like to bet on that? - a virtual one :)

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