My Model Summary

[Paul]

The aim of this new thread is to give those who want it the opportunity to take part in a slower paced model discussion with the emphasis on summaries of entire runs, or even entire day's runs. These don't have to be technical if you don't wish them to be, but hopefully this will be a good place to call in to once you've had a chance to look at an entire run and take a view on it overall.

It should also hopefully be a good place for those looking for an at glance view of the current models without a whole heap of more chatty discussion wrapped around it.

All the latest model runs are available here on Netweather:

Model Viewer

GFS, Ensembles, Fax, UKMO, ECMWF, NMM + coming soon GEM all within a click:

http://www.netweather.tv/index.cgi?action=charts;type=home;sess=

Model comparison - compare the 'big 4'

http://www.netweather.tv/index.cgi?action=modelcomp;sess=

[Ben_Cambs]

This thread is a good idea for amateurs like me!

So a very good ECM 12z, and a very good METO run aswell. A slight downgrade in respect for the GFS 12z, hopefully the 18z GFS run will bring a upgrade

Very happy with this chart below:

[Lewis]

I'm an amateur - In models that is

To be honest the 18z brings the colder air in much quicker, and obviously the uppers are generally -5 to -6 at best.

Forget about this chart, it might be the worst for snow lovers etc, but in modeling terms it's a very good run, as it will bring a different pattern of weather to our shores.

http://www.wzkarten....s/Rtavn2761.png

Thats the re-load point on that chart. The jet will be further south, there is a reason there's such bold predictions for deeply negative AO, the northern blocking will be more pronounced.

Another benefit is that nothing changes drastically in the stratosphere according to GP, so theres no reason the PV should reform as suggested in the 18z. I suspect the 18z will be one of the warmer ensemble members, the parallel looking much better.

Good news operational is on the warmer side but too much disagreement from day 3

Day 5 its ridiculous;

Lewis

Edited December 8, 2009 by Storm Force Lewis

[LomondSnowstorm]

Overall a good day, with the european models and ensembles providing good support, though the 18Z gfs, although fairly similar in the short range, doesn't bring any cold. Still, very rare to see such cold charts, we may well be on for something very special, particularly in December, with the added possibility of shortwaves bringing in some severe cold and precipitation behind it.

[Southender]

Our HP seems to be outstaying it's welcome a tad on this run?

More of a Northerly feel...

Edited December 9, 2009 by LeighShrimper

[Eugene]

Our HP seems to be outstaying it's welcome a tad on this run?

Better for long term prospects.

[Nick L]

We never seem to get the cold air on this run, a tad worrying?

[January Snowstorm]

A terrible run with everything delayed

Cold dry and frost in sheltered spots is all I see

[Tim Bland]

I quite like this run so far, lots of longer term potential. low to the East startsing to slip south / south west over the UK. This will be better for snow prospects. Aftyer all there is no point IMO of having freeaing cold tems and drizzle!

[TEITS]

I wish the LP would hurry up and move S. :blink:

The cold might be delayed on this run but the longer term potential is better.

[Nick L]

Not at all. Read bluearmy's post. The Scandi shortwave act's as a block preventing the cold from reaching us sooner. But it will be poorly modeled at that range. It would only require a slight change in the modeling for full on cold to actually reach a lot sooner. As ba says the bones are brilliant!

I wish the LP would hurry up and move S.

The cold might be delayed on this run but the longer term potential is better.

Ok that put my fears at rest, only a complete amateur so your comments are appreciated!

[Southender]

England and Wales gets buried in snow in FI as that low crosses to our South!

[Altostratus]

Stunning FI - I'm speechless! Hard not to get a little excited with runs like these.

[Eugene]

LOL i think we can all agree on there being a downgrade from GFS 06Z FI on future GFS runs, that run is just crazy.

[Thundery wintry showers]

Here's my rundown on the three most accurate models this morning.

GFS and ECMWF are both broadly agreed on a settled spell starting today, with plenty of dry sunny weather. Towards the latter part of the weekend and early part of next week we pull in an ENE'ly off a near-average continent (a modest cold pool that will be developing due to lack of Atlantic activity). The likely outcome is dry and cloudy initially followed by a transition to sunshine and wintry showers in eastern, particularly south-eastern, areas. Showers will fall as rain, hail, sleet and graupel with accumulations limited to high ground.

Towards midweek next week the Arctic shortwave slips south bringing the cold air in from Russia (possibly as far east as Siberia) bringing northerly winds initially with increasingly wintry showers in the northeast, and then north-easterly winds and a mix of sun and snow showers, the showers heaviest and most prolonged in the east, and a likelihood of widespread snow cover.

The GFS 06Z run would produce the most widespread white Christmas since at least 1995 and possibly since 1981, the 850hPa temperatures look quite marginal but with fronts spreading down from the north and temperatures around freezing, snowfalls would be quite widespread even at low levels. All fantasy at this range, but interesting all the same.

However, UKMO throws a spanner in the works. The high never really gets far north enough around Sunday/Monday to pull in that cool north-easterly flow, and by next Tuesday Atlantic systems are already knocking on our doorstep bringing milder conditions and rain, with the cold continental air held out to the northeast. As I am not convinced by UKMO's record at T+144, I think it is unlikely that this is the start of a trend- in particular the evolution from T+96 to T+144 is extremely unusual for an omega blocking situation- but it again shows that some caution is needed.

[WhiteXmas]

Once again... The setup on the GFS run looks great for Xmas day which I know is in FI but what is Christmas all about!?!? :winky: I think there will be a few bets on a white xmas now to say the least. At least now we know there will finally be some settled high pressure influencing our weather in the next few days. Will be nice to see some more frosts as the weather has been Atlantic dominated this Autumn!

[Duncan McAlister]

This run is better for Scotland in the short term and looks like a good setup in the longer term as well

[andy_leics22]

The GFS sticks 2 fingers up to the UKMO with that run. So theres a battle on here, it's GFS/ECM vs UKMO, which one will be the winner?

It's also worth pointing out that as it stands on the GFS the South East could be seeing sleet/snow flurries as early as Saturday night/Sunday morning!!

[Cecil Hogmanay Melchett]

Well i think you guys summed that run up perfectly.The 12z would simply be the best freeze up since 1995 .

Some places north and east could be absolutely hammered with the white stuff.

Thats 1 out of 3 firmly in the bag.

We now await biting our nails for ukmo to confirm,i repeat,possibly the best spell of winter weather since 1995.

Im in shock guys.

I almost dont want to look at 12z ukmo due to be absolutely petrified it will say no.

[Thundery wintry showers]

Copied from the model output thread:

Looking through the models, once again the ECMWF has gone for a somewhat watered-down solution- the high stays close to Britain and most places would stay cold and dry on the basis of that run, with a few sleet/snow flurries for the SE early in the run, and the NE late in the run.

The GFS run brings the easterly air in sooner but the coldest air struggles to reach us- the cold air we pick up from the east is mostly relatively moderate stuff that is currently forming over the continent due to lack of Atlantic influence- and then the shortwave heading S down the North Sea is delayed and struggles to bring the coldest air in. Still, I would expect widespread falls and accumulations of snow away from the east coast from early next week onwards (probably a haily, sleety mix by the coast itself) from that setup.

UKMO looks similar to yesterday's runs with a relatively half-hearted ENE'ly to begin with (a wintry mix of showers towards the SE) and then a shortwave moving south bringing in the very cold north-easterlies.

It is notable that all three models keep cold, and potentially snowy, synoptics going right until the end of the run. The ECMWF shows that a cold but mainly dry outlook is still possible, and so while my estimation of the chances of a snowy spell has inched up to 60%, I am still feeling quite wary of that possibility.