Model Output Discussion 26/10 2012 >

[bluearmy]

NAEFS around 400 miles west on the 12z re the trough and building heights north scandi around day 10. infact, the heights n scandi were pretty well non existent on the 00z run. the trend growing and likely to continue. i wonder if we have a win/win here? either the heights over nw russia dont retrogress and we get a greeny ridge or we do indeed get the scandi ridge with any greeny ridging held in the nw atlantic. dont want to be greedy yet and ask for the full blown ridge all the way across!!

just to add that mean slp over the asian side of the NH is pretty high at the end of the run and even on the canadian side, we dont have any appetite for low surface pressure or even very low heights as the mean p/v lifts further out from n greenland to n canada and weakens somewhat. seeing as a couple of days ago, many were expecting that by now, we would see the fi modelling showing a strengthening p/v and more zonal appearance, we seem to be headed somewhere very interesting.

Edited November 4, 2012 by bluearmy

[peterf]

very good interpretation and numbing down at it's best

[SMU]

1878 Steve ?? How on earth did you dig that out - are you Derren Brown?

LOL was trawling Low NOV CET;s & saw the 1878 winter & the rest is........

Anyway as some have said lets not count our fully chested chickens yet- although the monthly update from the UKMO is certainly an eyebrow raiser!!

S

[damianslaw]

The models continue to offer interesting viewing, in terms of very variable synoptics, changing from day to day just beyond the reliable timeframe, always a sign they are struggling against conflicting signals.. the northern hemisphere is certainly not behaving in the way it normally does at this time of year, take the past 7 days, we have had a very stubborn trough dominate proceedings dropping south into the country and hanging around forever - not normal for late October/early November, which usually sees a very mobile pattern. We've been here before in 2009 and 2010, when the atlantic failed to get its act together on its usual west-east trajectory, in 2009 whilst we saw a very mild Nov, it was dominated by southerlies with a blocking high to the east, and we know what happened in 2010...

In terms of the coming days - a return to nearer normal temperatures, and very cloudy with drizzly rain at times- an uninspiring outlook it has to be said, a dull dreary spell very apt for November. However, by the end of the week we will see another deep low pressure move into western areas, but once again, there are indications the low won't crash into scandi, and instead either send its energy to the NE or quite possibly to the SE, as we see heights building into scandi.. its a messy very unclear picture. I wouldn't be at all surprised to see a 'cut off low feature develop' to the SW, we have seen low heights to our SW for very lengthy periods since April, much like we have at the moment, which would help to lock heights to our NE into position..

The BBC didn't appear very confident in their countryfile forecast for Friday.

[SteveB]

LOL was trawling Low NOV CET;s & saw the 1878 winter & the rest is........

Anyway as some have said lets not count our fully chested chickens yet- although the monthly update from the UKMO is certainly an eyebrow raiser!!

S

November 1683 & the following winter would be a interesting....

[gottolovethisweather]

LOL was trawling Low NOV CET;s & saw the 1878 winter & the rest is........

Anyway as some have said lets not count our fully chested chickens yet- although the monthly update from the UKMO is certainly an eyebrow raiser!!

S

And the highlighted comment above, should perhaps be added to a few more posts.

I am NOT having a dig, before anybody spits out their dummy, I am stating that we (as in all of us, newcomers or the more seasoned pros) should not take posts literally at t+48, t+120 or t+1080 or whatever timeframe as a DONE DEAL. Today being a case in point, with the will it, won't it snow scenario

I best now go back to lurking but I must say this MOD thread is proving to be a most interesting and informative read.

Eyes down for the GFS pub run.

Thanks go out to each and every one of you.

[Methuselah]

Nov 12 1965 onwards...Another retrogressor?

http://www.wetterzentrale.de/archive/ra/1965/Rrea00119651112.gif

[mulzy]

A few colder ensembles have started appearing in the De Bilt ECMWF ensembles - baby steps maybe?

http://www.knmi.nl/e...agse/index.html

Edited November 4, 2012 by mulzy

[lorenzo]

One for the newer PPL viewing... ( & FOR PIXEL )

PS the GFS bias of loading up the northern arm is why it doesnt look like the UKMO....

Its fast by maybe 5 M/S in its estimations...

S

Steve, thought these would be of interest. GFS vs ECM in terms of speed..

120 hrs

240 hrs

I emailed Ryan Maue today asking if there were plans to include more NH view maps to the suite available on this site as there is only one sole chart in this format for GEFS. Here are the AO NAO also.

Found this link from one of the Strat sites I have bookmarked. One that loops really well courtesy of Greg Hakim.

[bluearmy]

A few colder ensembles have started appearing in the De Bilt ECMWF ensembles - baby steps maybe?

http://www.knmi.nl/e...agse/index.html

indeed though note that the control was easterly this morning but seems westerly this evening!

[andymusic]

nice looking northerly - for next weekend - so the slightly milder blip this week won't be lasting too long

Edited November 4, 2012 by andymusic

[SMU]

Cheers Lorenzo-

well the 18z is further amplified but cant get the Scandi high on the first hit although its edging closer-

either way seems a double 6 as the amplification delivers a stinger Northerly then post that probably an easterly- ahh the pub run..

S

[chionomaniac]

Houston - we have a problem. Scandi High engine has failed to ignite.

Azores ridge comes to the rescue.

Press the reignite button!

Edited November 4, 2012 by chionomaniac

[Snowman.]

nice looking northerly - for next weekend - so the slightly milder blip this week won't be lasting too long

Ahhh you beat me to it!

Now lets see if that Trough will play ball.

Edited November 4, 2012 by SN0WM4N

[ITSY]

current output definately brings back the weekly cold northerly spell (perhaps a tad more potent this time) bringing with it the chance of a white rememberence Sunday. although it's way too far out to get remotely excited about, it's what happens next that is of interest to me - looks like the possibility of a developing scandi, as has been the case for a few days. I see a lot of negativity about this thread (and the same on the TWO) lately, which really surprises me given the current output:

- no organised PV

- virtually weekly northerlies for the last 2/3 weeks with another progged

- northern, eastern and now SWestern have already seen the first (albeit very brief) snowfall. It's not even mid November yet!

also, with regards to those charts above - the scandi high has not yet been predicted to come from that particular attempt. I can't recall a run showing that turning into a scandi, the last run for example was the second attempt. (which originated in the azores).

PATIENCE GRASSHOPER, PATIENCE

Edited November 4, 2012 by ITSY

[Ice BIast]

the monthly update from the UKMO is certainly an eyebrow raiser!!

S

Could you provide a link please? I cant find it.

[SMU]

Could you provide a link please? I cant find it.

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

S

[Ice BIast]

http://www.metoffice...st_alltext.html

S

Oh I thought you meant the seasonal model (glosea) . I must be too tired to post! Thanks anyway.

[BLAST FROM THE PAST]

Just to say and put another perspective on it. I forecast/suggested as a scenario that we'd have masssive block to east with trough not progressing east and we'd be under southerly flow with any -ve NAO signal being west based. What we see models showing IN FI is similar set up and in situations like this we could be pretty chilly or very mild. Date remains for last 12 days of Nov. I feel we are stepping closer to this very mild 'flip'.....but its a good pattern as its an amplified pattern.....still a long way off though....and just a possible alternative.

BFTP

Edited November 5, 2012 by BLAST FROM THE PAST

[Robbie Garrett]

Good morning All, Just before I got to bed.

I've just had a look back at the archive again for November 2010 and the colder end that we witnessed never started to really appear on the models until 11th-14th where it was pretty much showing a Scandinavian Ridge moving onto a Greenland block scenario. Interesting to note over the last few pages, comments from GP and co, it does look likely that we may start to see something appear more conclusive for cold as we near mid-November.

GFS currently not showing this in the FI, but neither did it in 2010.... up until the 11th onward.

UK Outlook for Monday 19 Nov 2012 to Monday 3 Dec 2012:

As is usual, there are uncertainties in the forecast for this period, but there are signs that the unsettled conditions will continue through the remainder of the month. Rainfall amounts are more likely to be above the seasonal average rather than below, especially across England and Wales. In addition, there is a stronger signal for temperatures to stay largely below average for the time of year, with a risk of frosts in any overnight clear spells. Accompanied with such conditions, there is the threat of precipitation being wintry in nature at times, especially over higher ground.

[IDO]

It looks like, according to the experts, that everything is set up for a potential cold spell. Whether that comes off in our back yard is another question.

Again the 0z has potential but never really gets there. It is a relative milder outlier compared to the mean from around T168, so cooler options there:

t850Aberdeenshire.png

For the short term (till weekend), a cool zonal flow bringing more settled weather to most, as HP edges in to southern areas of the UK; SW winds for the far south so milder feeling here. The rainfall totals till Friday highlight this:

gfsopuktotpcp108.gif

Then we have a weakening trough for the weekend, though this is where some ensembles vary, having this pattern for slightly longer. Again no real cold uppers and just drizzle to contend with.

From there it is FI, with a battle between the HP, that is heading to Scandi and the associated trough, on our doorstep. The positioning of these are fundamental to the following pattern. On the Op run, rather bland (av temps and wet), though with a NW'ley (for some) at the end of FI:

h500slp.png

A week of many permutations I suspect...

Edited November 5, 2012 by i'm dreaming of...

[MR EXTREMES]

Ensembles showing a lot of below 0 scatter.

But all models looking like a horror show if u want blocking to deliver it trys but fails.

Although not mild still a continuation of zonal typical autumn pattern for awhile yet.

Does the scandi. High slip into Europe by no means uncle bartty but possible milder sw on the gfs t168.

Edited November 5, 2012 by badboy657

[Gibby]

Good morning. Here is my look at the review of the 00zs from GFS, UKMO, GEM, and ECM plus the GFS Ensembles and Jet Stream forecast for today Monday 5th November 2012.

All models show an agreed upon basic pattern through the working days of this week. The Low pressure that has been instrumental of conditions over the UK since the middle of last week is now moving away East taking the last of it's rain and showers away with it. A brief ridge crosses over the next 24 hours followed ny a West to NW flow of winds carrying a lot of cloud and a little rain here and there chiefly in the North and on Thursday. By Friday another brief ridge of High pressure ahead of Atlantic fronts approach from the West later in the day. Apart from the today and a risk of a slight frost tonight it will be a milder if rather breezy week this week, though without much in the way of sunshine.

GFS then shows the weekend as rather cloudy with a spell of rain as the fronts approaching on Friday cross the UK while weakening as they go. By Monday another ridge brings a drier and brighter 24 hours before a deep depression develops out to the NW. With High pressure over Europe and the remains of the weekends fronts to the South a SE flow develops with fronts moving up against the High, disrupting and remaining West of the UK. They would be close enough to Western areas to produce rain at times and the air will not be that cold so temperatures at worst would be near normal. Later in FI the trend is for High pressure to remain over Europe blocking the passage of Atlantic fronts whilst leaving them to come in and decay in situ over Britain with rain at times in temperatures close to normal.

The GFS Ensembles data shows a couple of Average weeks coming up with changeable winds from off the Atlantic bringing rain at times with near normal temperatures. The operational was a mild outlier in it's later stages not agreeing with the warmer than average uppers in association with High pressure to the East.

The Jet Stream flow shows the ridging pattern through the Atlantic continue for a while as the Southern arm South of the UK weakens and disrupts after 72hrs. By a week or so time the ridging in the Atlantic changes to troughing before a sharp North turn in the flow takes it up the Western side of Britain to Northern latitudes.

UKMO for midnight on Sunday shows a trough having crossed the UK on Saturday out to the East with a showery flow back across Britain in association with Low pressue centred near the Faroe Islands.

GEM shows Low pressure just to the North of the UK with troughs down over the UK at 144hrs moving on to show a deepening Low out to the NW setting up several days of strong SW winds and rain at times in quite mild conditions.

ECM too shows this same pattern later in it's run as a deep Low becomes influential out to the NW with a SW flow with rain at times and temperatures well up to the seasonal normal.

In Summary a period of typical November changeable weather is likely over the next few weeks. Most areas will see some rain at times over the output period with temperatures reaching the seasonal normal for most. There will be a few brief ridges of High pressure particularly over the middle period of the run when a drier 24 hours might develop and if this happens overnight with skies clearing then a slight frost with some fog patches could develop. However, the prolonged and rather cold conditions of late look likely to stay away from the British Isles for the moment.

Edited November 5, 2012 by Gibby

[johnholmes]

The anomaly charts generally support the idea of an upper flow from a westerly point across the Atlantic with any ridges being some distance from the UK area, be it east or west. Heights would indicate surface temperatures being rather higher than for the past 7-10 days as we progress through the week.

As to beyond then, the weekend and further out? Hard to call at the moment; indications that the flow is going to buckle again, with the odds probably on an upper flow from north of west rather than anything from the east, turning less mild possibly colder might be the right word again?

2-3 days down the line should give a clearer idea.

Edited November 5, 2012 by johnholmes

[Radiating Dendrite]

Well good consistency from the GFS.

Even in FI, both the 00z and 06z are showing similar synoptics, big high to the east and a trough to the west with us pretty much in no mans land.

Certainly not mild, but not frigid cold either.