Model Output Discussion 12z 18/10/2012

[ANYWEATHER]

With all respect, anyone who thinks this is a none event in terms of cold , needs to get a reality check, especially given the time of year! The two charts of ecm and gfs for the end of the week, illustrate graphically how cold the air will be. It will feel like mid Winter! The other chart shows a typical October fest for the Uk, from this time last year and mild/murck comes to mind!! A lot of interesting weather coming up after these few days of mild/mush........

[johnholmes]

Perhaps the most significant change is how the Fax charts are shown this morning. Notice all have been changed to a time issue this morning from T+36 hours. The senior man obviously feels that colder air will push further south than some on here are suggesting. This is caused by them reanalysing the area around Iceland, see T+36 and how another wave is shown as developing off WNW Iceland that then runs into southern Norway. Its not the really deep low that sometimes precedes major cold outbreaks as pressure builds NW of the UK behind this but sufficient to bring colder air well south as the T+120 chart shows.

Last night I was expecting, looking at the then current T+48 to T+96 charts that Exeter would tone down the cold, not so.

As to what happens post next weekend subsequent runs will firm up on this.

Just what some of you were expecting at this time October is hard to understand.

Edited October 22, 2012 by johnholmes

[BLAST FROM THE PAST]

I think now the models IMO are seeing whats ahead. Very good cold shot for time of year. It seems then that the temp gradient could fire up some active LP systems in our nlocale. With pressure rebuilding over Greenland we could see these LPs travel on a path right into us. My thoughts of Nov are no prolonged cold blocking set up but a month of very big swings between pressure and temp. I actually like the FI picture being painted at present which seems feasible. GFS 00Z defo brought things west against the 18z. Some good chart watching over coming weeks

My chart of the day is 00z ukmo t144...that would lead to continued cold and blocking, with LP diving South from our NNW and heights good /reloading to NW.

BFTP

Edited October 22, 2012 by BLAST FROM THE PAST

[Frosty.]

Maybe it's good that its toned down so we have a better chance in decemeber

Unfortunately it doesn't work that way, we need to grab the cold when we can. The fact is that nothing has really changed this morning and the models are still showing a huge drop in temps by friday, a 10 celsius drop is massive at this and any time of year. I still think there will be adjustments in the op runs for the better in terms of longevity and potency, the forecasts this morning are pointing to a significantly wintry end to this week with snow for some and widespread frosts by the weekend into early next week.

[carinthian]

Yes, a real change on the cards. I'm sure that some need to take a step back rather than taking every GFS run as gospel. I've been away over the weekend, come back and looked at the various models GFS, ECM, fax etc and am more than happy with prospects....given the mild muck we usually face at this time of year.

Also looking forward to the blizzards over the weekend....in the Austrian Alps, on account of skiing over Christmas in Russbach...just up the road from Abtenau. Given your local knowledge Carinthian does this sort of northerly flow give good precipitation amounts over this part of the Alps?

Morning,

What a hidden gem you are going to! Not many Brits venture to the wonderful Dachstein West Region. Local forecasts indicate the Arctic front will push through the Austrian Alps by the end of the weekend with cyclonic development further south and east. This set up would generate copius amounts of snowfall in the northern arm of the circulation particularly in the Salzburgerland region. Also latest UK fax charts this morning show this set up is probabale. I am getting excited for the weekend and hope a good base is put down in time for your Xmas vacation, Enjoy !

C

[shedhead]

There's no denying after the initial cold plunge this weekend the outlook looks disappointing compared to what was on offer a few days ago, I suppose it was on the cards really as more often than not these cold plunges tend to end up more to our East. Still quite a drop in temps for all of us come the end of the week which I would say is significant, obviously some others don't .

I don't think anyone feels the drop in temps later this week won't be significant, nor do I think many would call it a non event given the time of year. The point some of us are trying to make is the GFS in particular is starting to show a less cold evolution than it was 48-72hrs ago (no one is saying it won't still be unseasonally cold) and to a degree, albeit small, we have seen tentative signs of a similar set up beginning to emerge on the Euros.

I think most of us knew the 'too good to be true' synoptics I allued too a few days ago were bound to change a little, but that does not mean those wanting early cold are going to be disappointed, far from it in fact....unless of course expectations are set way, way to high in the first place.

[chionomaniac]

A wonderful plunge in the London 850's. I make this almost 18C drop in just over 24hrs!

Also stiil a disrupted NH vortex profile forecast out into FI so future possibilities will remain whilst this is the case.

I love the up and down escalators of a meridional pattern!

[shedhead]

A wonderful plunge in the London 850's. I make this almost 18C drop in just over 24hrs!

Also stiil a disrupted NH vortex profile forecast out into FI so future possibilities will remain whilst this is the case.

I love the up and down escalators of a meridional pattern!

Sure is a staggering drop, what a pity London is not at the same elevation as Jo'burg, then thing would have been really interesting. The meridional pattern definately gives more options and the chance of more extremes, so the longer the models keep progging it the better, but I'm not sure it can last much past the turn of the month.

Edited October 22, 2012 by shedhead

[latitude]

I don't think anyone feels the drop in temps later this week won't be significant, nor do I think many would call it a non event given the time of year. The point some of us are trying to make is the GFS in particular is starting to show a less cold evolution than it was 48-72hrs ago (no one is saying it won't still be unseasonally cold) and to a degree, albeit small, we have seen tentative signs of a similar set up beginning to emerge on the Euros.

I think most of us knew the 'too good to be true' synoptics I allued too a few days ago were bound to change a little, but that does not mean those wanting early cold are going to be disappointed, far from it in fact....unless of course expectations are set way, way to high in the first place.

The models are showing a very suprising pattern for this time of year. The drop in temperature is very considerable and just shows how things can change. This could be an emerging pattern for the rest of winter, especially with so much blocking being touted around.

Edited October 22, 2012 by Osbourne One-Nil
I agree, but it could take the thread off track

[snowfall09]

Below is a link to the latest Met office FAX charts updated at & 7:30 this morning. Do these FAX charts show the initial surge of cold air further east or actually further west??

http://www.metoffice.gov.uk/weather/uk/surface_pressure.html

[gottolovethisweather]

Although it cannot be done with the netweather free charts, is there a website where I compare "like by like runs", e.g. yesterdays GFS 00z with today's 00z.

[johnholmes]

Although it cannot be done with the netweather free charts, is there a website where I compare "like by like runs", e.g. yesterdays GFS 00z with today's 00z.

Weather Online go to expert charts, GFS and others are available for each run they make back about 4 maybe 5 days.

[bluearmy]

It does being to look as though the lower heights end up over or west of the uk next week. we still have our 3 main hemispheric features - aleutian ridge (strong), greeny ridge(to some degree), scandi trough (of sorts). some signs that the models want to introduce a less blocked NH pattern in the second week but much too early to take this too seriously.

[lorenzo]

Although it cannot be done with the netweather free charts, is there a website where I compare "like by like runs", e.g. yesterdays GFS 00z with today's 00z.

Also on Meteociel, where you normally vie a chart, click archive.

[legritter]

Charts and data still showing some very interesting synoptics over coming weeks .If the first surge of Arctic air only brings frost and occasional wintry showers this will be brilliant as a start .as for next week 29th onwards almost anything in my opinion is possible .pressure over greenland could intensify sending lows further south , and there are hints in some of the charts of a cold zonal which could deliver wintry weather . im concentrating on charts for 168 HRS max as i feel 7 days plus is too far ahead with cold air to our north .any new posters make sure you read all the posts especially from people who have been around for a long time .And take a look at NET weather learning area where charts and data are explained .

[Robbie Garrett]

As some have mentioned the temperature gradient might make for some interesting model watching soon. Don't look to far beyond Friday on the GFS etc, with regards to a failed northerly or anything like that. I think as we get closer to early next week. Tuesday 30th and Wednesday 31st might be slightly wet for the UK, but under grey cloud with temperatures probably suppressed around about -2*C snow cannot be ruled out.

In the reliable timeframe, temperatures averaging to around about 6-0*C which would say to me frontal snowfall into next week cannot be ruled out.

A good indicator of the upcoming conditions looked fairly blocked. Looking at all the models, I can say that it looks fairly likely that low pressure going south of Greenland with a southerly, slightly angled jetstream NW/SE coming into November will only most likely strengthen the Greenland block. With some ensembles and models showing a Greenland block of 1060hPA into mid November as it links up with warmer air from the Azores high, which will put the jetstream into a position good for cold.

Whilst Alex below has mentioned a stronger vortex, it's positioning looks great this year, that if we come into near end of November with blocking as good as it is... the conditions that prevail will be spectacular. For me, NAO/AO remaining negative at this stage coming into winter is fantastic, having an upcoming cold spell is a bonus and clearly enlightens that point that Winter may provide....

My take on the weather beyond October doesn't bode well for cold lovers, the stratosphere is looking likely to stay average/below average and this will help aid a Stronger PV during November.

[weatherobsuk]

The 29th October 2008 was more/less the same synoptic situation in that a cold front had just cleared into continental Europe plunging sub-528DAM arctic winds from the north. Warm North Sea SSTs at the time created their own environmental troughs which crossed the country along with the cold pool and giving many mid-to-higher parts 3-5cm of lying snow. There was also another similar setup on the 31st Oct a few years before this aswell although the date escapes my memory.

http://www.metoffice.gov.uk/climate/uk/interesting/28_30october2008/

[Adam lufc]

The gfs 6z is a a stonker run right through!! Can't believe no comments on it.

[Frosty.]

A look at the next 5 days in picture snapshots shows the early hazard is fog, rather dull and dank further south with fog slow to clear and some areas remaining dull with some drizzle but very mild, warm in parts of the southeast where the sun breaks through the gloom with temps closer to 19c, less mild the further north you go but still above average, nearer average in scotland and n.ireland, a very mild night in southern areas and another very mild day tomorrow and wednesday but less mild further north. Then slowly turning colder from the north from thursday onwards, by the weekend it will be even colder with widespread frosts by then and a risk of wintry showers to northern and eastern districts.

[latitude]

The gfs 6z is a a stonker run right through!! Can't believe no comments on it.

Have to agree, its better than the 0z. Problem is, this output is now disregarded by most here.

[AWD]

The gfs 6z is a a stonker run right through!! Can't believe no comments on it.

It's better than some previous GFS output yes, but I wouldn't call it a stonker.

A stonker would be the UKMO output from last night.

[BLAST FROM THE PAST]

The gfs 6z is a a stonker run right through!! Can't believe no comments on it.

I have never seen such an accurate run........its beautifully spot on

BFTP

[Gibby]

Have to agree, its better than the 0z. Problem is, this output is now disregarded by most here.

i can never understand why it should be disregarded more than any other run. It must have some worth as they wouldn't spend thousands of dollars on running it 4 times per day. I here often said that lack of data issues are relevant to the 06z and 18z runs but has it ever been proven to affect the reliability of the other runs. I'm not sure.

Anyway the 06z does indeed look good for coldies and had I beeen doing a report on it I would be mentioning the 'S' word frequently.

Edited October 22, 2012 by Gibby

[Summer Sun]

06z is loooking much better than the 00z for cold and possible snow however as said above we've been told to "bin" the 06z run in the past which I fail to see why as its another run with more possibilities

Edited October 22, 2012 by Summer Sun

[Methuselah]

I have never seen such an accurate run........its beautifully spot on

BFTP

It hasn't happened yet?

i can never understand why it should be disregarded more than any other run. It must have some worth as they wouldn't spend thousands of dollars on running it 4 times per day. I here often said that lack of data issues are relevant to the 06z and 18z runs but has it ever been proven to affect the reliability of the other runs. I'm not sure.

Anyway the 06z does indeed look good for coldies and had I beeen doing a report on it I would be mentioning the 'S' word frequently.

It's only 'binned' when it's showing anything other than Snowmageddon. Today, however, it's everyone's best friend!