Model Output Discussion 29th December - Into mid-Winter.

[Summer Sun]

Long time since London had 850's below zero this long

[nick sussex]

Just been out panic buying at the supermarket! lol Whatever happens down here I have enough food to last a long time.

Catching up with the GFS 06hrs run, really great to see no dramas and another small increase in amplitude early on.

Still uncertainties though with the strength of that flow into the UK and the 850's still to be accurately modelled at this range. I can barely contain my excitement as if things remain on track we could see the coldest spell for quite a few years.

It would be thoroughly deserved for all the pain and let downs over the last few years!

[snowflakey]

Just a couple of points that has me at bit worried, the first one ,is there to much energy going over the top of the scanty high, and also the south coast / SE only seem to be flirting with only the 528 dam, hardly a big freeze.

 

[carinthian]

4 hours ago, carinthian said:

The latest 06z GFS run showing the same consistency as yesterdays same time run. Important 300 mb wind flow shows core high pressure aligning for a Easterly flow into much of England and Wales. All aided by a developing upper trough that will move from NE TO SW in the continental flow.

c

Morning all. My favourite chart of the morning from ECM for the middle of next week. Plenty of cold air in that Euro flow with bands of snow associated with minor troughs. The deepest of cold uppers not far from the SE of England but surface flow will keep temps close to freezing or below. Outwardly it would appear to be dry for Southern Britain  but the kinks in the isobars would produce some snow showers at times. Very hard to forecast exact timings and locations but will be worth watching developments next week. Anyway , nice charts for most , plenty of snow for the Alps and hopefully the best cold spell for you lot for a number of years starting to evolve today.

C

Nice to see the GFS 06z continue to follow its same track. The latest ECM and GFS now both show the start of Cold air advection towards Southern Britain as early as Wednesday next week. The chart below is wind flow at 300hpa and shows this evolution in process with what will be a progressive colder air mass heading your way. Definitely colder enough for some snow with DAM levels lowering.

 C

[nick sussex]

1 minute ago, snowflakey said:

Just a couple of points that has me at bit worried, the first one ,is there to much energy going over the top of the scanty high, and also the south coast / SE only seem to be flirting with only the 528 dam, hardly a big freeze.

 

You can't just use 850 values with Scandi high pressure. It will be very cold for the UK with severe night frosts and some places staying below freezing all day. The issue re any snow will be resolved nearer the time.

[Catacol]

1 hour ago, West is Best said:

 

Well there's a lot of truth in that and many of us will remember the John Kettley incident.

However this one really does seem to have some plausibility. There's good model consensus and the ensembles are packing a cold punch. The issue I guess now is whether the high holds or slips south into northern Germany. The latter has to be the form horse, but here's hoping otherwise.

Not so with the repositioning of the vortex over Russia. Form horse has to be retrogression to some degree provided the Euro trough establishes itself, and the trend towards a fairly well developed Genoa Low seems strong.

Amazing how much has changed in 11 days since New Year's Day. There was lots of doom and gloom floating around.... and then amplification returned at just the right time and everything else has clicked into place. These charts are the best I have seen for many years for the snow starved populations of the south. The end of next week looks potentially very interesting indeed.

[Methuselah]

It looks - to me at least - that the 'starting pistol' has been fired, and that the teleconnections have at last come into play? Maybe they take a wee while longer to manifest than was hitherto believed? 

Anywho, I'll let Tamara and GP decide on that one!

[snowflakey]

7 minutes ago, nick sussex said:

You can't just use 850 values with Scandi high pressure. It will be very cold for the UK with severe night frosts and some places staying below freezing all day. The issue re any snow will be resolved nearer the time.

Thanks for the reply Nick. I will now take a back seat as the forum goes into meltdown.

[nick sussex]

What I particularly like about the GFS 06hrs run is theres no injection of Med air into mainland Europe. Sometimes with these set ups you can eventually get the high changing orientation and the low pressure over southern Europe pivoting allowing some milder air nw. Here because of the swathe of low heights running quite far east even if the upper air moderates the surface will remain very cold over mainland Europe.

This is good news for the UK, any snow you get you'll keep next week. Anyway I need to refrain from ramping too much!

[MR EXTREMES]

1 hour ago, Nick F said:

Milder blip on Sunday/Monday - especially in the west. But turning progressively colder again next week, this time from the east. This time next week looking a bit raw on 06z GFS  max temps - with the increasingly cold and dry flow off a cold near continent:

850-1000 hPa (partial) thicknesses show well the  cold and dry continental airmass advecting west

indeed nick so which was the first model to get this outlook right ecm has flawed the other models gfs has back tracked over and over again.

today we have gem easterly but has hardly sniffed at easterly all week the jma has fair few times gone for easterly the ukmo now has easterly gefs gfs ukmo ecm easterly across the board.

i was quietly confident enough couple of days ago to go for some form of blocking of coarse it may not be overly snowy after this weekend but dont be suprised to see repeated reloads.

its ironic that the met office was confident at the start of the month for colder mid jan almost to the day the colder air is here.

im absolutely so happy to just see winter of old regardless of snow amounts and i expect solar activity to really establish more influence in atmospheric conditions i do really feel a retrogression still on the cards,

excuse the pun this just the tip of the iceberg.

 

i believe the ecm will be first model to retrogress heights by the end of the weekend.

all the time we have lower heights to our south then reloads and retrogression is a valid idea as seen in the classic winter of 09/10

Edited January 12, 2017 by MR EXTREMES

[tight isobar]

Think some perhaps struggling with' synoptics and there  implications/variations. 

ie dams/850s etc.

also very quickly' looking forward to this afternoon/evenings 12z...

to perhaps highlight the variations/probability s in compare to the evolving easterly. .and others previous! 

[MR EXTREMES]

4 minutes ago, tight isobar said:

Think some perhaps struggling with' synoptics and there  implications/variations. 

ie dams/850s etc.

also very quickly' looking forward to this afternoon/evenings 12z...

to perhaps highlight the variations/probability s in compare to the evolving easterly. .and others previous! 

dam and upper 850s will be no problem after the milder blip very cold possibly wintry to.

would love some streamers and undercutting lows to the south.

sod it my ramp bigger than eddy the eagles.

Edited January 12, 2017 by MR EXTREMES

[gottolovethisweather]

On 06/01/2017 at 19:53, gottolovethisweather said:

Hello all, I stated the above when the first round of snow-producing deep cold 850s showed up in the various outputs some seven days ago, the rest is history as they say and you know where the deep cold went, into Central Europe or stay bottled up due North of us. So, in order to NOT pee on anybody's expectations here,I would say currently the next wintry interlude provides us with a slim but reasonable 60/40 percent chance of coming off, given that it is set to begin by D5/D6 (Wednesday 11th/Thursday 12th January). How long will it last? Who will see those beautiful white crystals? Will it settle in lowland England (what a miracle)? All answers to these questions are only likely to be resolved by early next week. Due to my beady little eye watching each of the ECM operational runs roll out this past week and not being distracted by other runs, I can say I am quite confident stating the following given that these dates of interest have shown up repeatedly as timeframes to watch. The first watch date is the 9th January which will likely provide some wintry interest to coldies up North say past Coventry or the Midlands if you like. With my main watch period from 12th January - 16th January being of wider interest to those in England for once, suffice to say Wales, Scotland and Ireland will also likely join in the wintry fun and games IF the broader pattern verifies as currently modelled. 

 

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I know it's been said a great many times before but it just goes to show there is good reason not to follow and jump on each and every run. This post from nigh on a week back, highlighted how it is best not to over-complicate things over when searching for mid to longer-term trends when viewing the models at face value, teleconnections aside, which are outside of my remit (must read more). In fact with the 12th January, today, highlighted by me as a coldie's first date to watch and the subsequent possibility of widespread snow around, I'm well pleased with my original shout/guess, at what I thought might happen by D6 through to D10. So far, so good, it is verifying as broadly suggested. I hope a significant number of us get to see at least a period of snowfall, hoping it settles for some but doesn't cause too much strife for commuters. A cold ole spell is ahead of us guys n gals; those homebound don't forget to feed and water the garden birds and try to assist other wildlife where you possibly can, as it is not all about us and our welfare when cold weather hits. 

Edited January 12, 2017 by gottolovethisweather

[Frosty.]

Well, winter 2016 / 17 was asleep through December but it's sure waking up now, the models show a big risk of snow today and tonight with the SE likely to get a good covering, especially on high ground and more snow tomorrow, especially for the east as a Northerly flow develops, frosty, icy nights and more snow showers for the east, especially coastal counties on saturday and a further risk of forward edge snow on sunday before milder air briefly pushes in but next week looks like ice days and snow flurries are on the way for southern uk with a strong block in place..coldies deserve this following last winter's absolute dross!

[nick sussex]

This threads quite funny. Before any cold comes into the reliable its full to capacity and then when we get to the day of any possible snow it empties quickly as most people head off to the regional threads.

Sadly I have no regional thread! lol of my own and it would be very dull with just me and a few other people who have homes in France so for that reason expect to find me mostly setting up shop in here with the occasional venture into the regionals to enjoy what hopefully will be an exciting few weeks coming up.

Fingers crossed we see the snow shared around, if we can keep the cold long enough and the right synoptics that does give more time for the snow Gods to be kind to all.

[snowy weather]

When I go onto the weather outlook weather charts I get to this page here https://www.theweatheroutlook.com/twodata/datmdlout.aspx

 

Then I click on UK precip type to see the snow forecast.

On this page do I click on the GFS 0z, GFS6z,GFS12z or GFS18z?

 

GFs12z looks incredible for where I am. 

Edited January 12, 2017 by snowy weather

[ArHu3]

5 minutes ago, snowy weather said:

When I go onto the weather outlook weather charts I get to this page here https://www.theweatheroutlook.com/twodata/datmdlout.aspx

 

Then I click on UK precip type to see the snow forecast.

On this page do I click on the GFS 0z, GFS6z,GFS12z or GFS18z?

 

GFs12z looks incredible for where I am. 

HIRLAM is your best bet for best forecast for the next 48h

Edited January 12, 2017 by ArHu3

[Tom Jarvis]

3 minutes ago, nick sussex said:

This threads quite funny. Before any cold comes into the reliable its full to capacity and then when we get to the day of any possible snow it empties quickly as most people head off to the regional threads.

Sadly I have no regional thread! lol of my own and it would be very dull with just me and a few other people who have homes in France so for that reason expect to find me mostly setting up shop in here with the occasional venture into the regionals to enjoy what hopefully will be an exciting few weeks coming up.

Fingers crossed we see the snow shared around, if we can keep the cold long enough and the right synoptics that does give more time for the snow Gods to be kind to all.

Nick your presence is more than welcome in the south east regional we don't bite realy!!!

people don't forget the models like to find false dawns in these set ups for removing the block so if it shows the block disappear out past 144h take it with as much salt that they will be using over this period and beyond

[Alexis]

36 minutes ago, snowflakey said:

Just a couple of points that has me at bit worried, the first one ,is there to much energy going over the top of the scanty high, and also the south coast / SE only seem to be flirting with only the 528 dam, hardly a big freeze.

The 528 dam line is of no significance with a continental flow. It's not even very useful in a polar maritime - I've seen 100% rain at levels well below 528dam.

[snowy weather]

Just now, ArHu3 said:

HIRLAM is your best bet for best forecast for the next 48h

But out of interest, is the gfs12z more accurate and up to date then gfs 06z?

[ArHu3]

1 minute ago, snowy weather said:

But out of interest, is the gfs12z more accurate and up to date then gfs 06z?

6z is the most recent atm

[Backtrack]

2 minutes ago, snowy weather said:

But out of interest, is the gfs12z more accurate and up to date then gfs 06z?

12z isn't out yet 

00z roughly starts at 3:30am, 06z at 9:30am, 12z 3:30pm, 18z 9:30pm. 

The 12Z run has added weather balloon variables so can be seen as slightly superior over the other three runs. 

[EastAnglian]

8 minutes ago, ArHu3 said:

HIRLAM

Do we have access to the model, I can see the homepage but no signup or link to the model output?

Thanks.

 

[Polar Maritime]

1 minute ago, EastAnglian said:

Do we have access to the model, I can see the homepage but no signup or link to the model output?

Thanks.

Here we go http://www.meteociel.fr/modeles/hirlam.php?map=430

[mb018538]

As expected the 6z OP was probably the coldest of all the members. Hopefully nobody will start being equally as crazy and saying 'massive downgrade' 'letdown' and the like if the 12z OP ends up being one of the milder members.