WInter Model Output Discussion 12z- 28/01/2013

[snowking]

Does anyone know what the latest EC 32 dayer is showing?

Lots of scatter from the ensembles this morning

The trend to drier weather seems fairly consistent at the moment

Havnt had a chance to look at the Control run yet in terms of pressure setup, but the temperature profile is the same as the previous 2 runs, ie mean temps around 2-4c from around the 7-10th onwards

SK

EDIT: Just taken a very quick look - control is more keen on toppling ridges with a mean N'ly turning NW'y then back to N'ly flow....but looking at the full temperature suite, it does sit around 2c milder than the mean does for a lot of the run - slight outlier in other words. Would be good to see what the mean height/SLP suggestion from the suite is

Edited January 29, 2013 by snowking

[Jason M]

looking at matt's blog, i'd say its indecisive for second half feb

tbh, its pretty rubbish anyway so not worth worrying about. I'd imagine its useful for days 6-10 but of only limited use thereafter (bit like the GFS ensembles we see).

I get the sense that people are starting to pave the way for a change of opinion regarding greenland Heights. There seems a fair bit less confidence around today. I think the SSW was very well forecast but I don't think anybody could have forecast the resulting weather as influences the UK. I do think that that limitations of teleconnections have been shown this winter. Thats not to say that they are not a useful forecasting tool (as I suspect they are).

We are missing something this winter though. If anyone looked through the charts from last week, they absolutely screamed for strong heights to our NE, but it simply didn't happen. Logically there must be a reason for this, although ive no idea what it is. Equally there will be a reason why throughout the entire winter pressure has stayed low to our NW, but I doubt anyone really knows the answer. There will be one and it won't be 'luck', physics doesnt work that way.

Anyway, nasty storm still possible for this weekend.

Jason

[Methuselah]

Any chance of some model-related contributions, any time soon?

I must be psychic: Jason M just mentioned the GFS!

Edited January 29, 2013 by Rybris Ponce

[Cheshire Freeze]

You need to post a chart to support this. I'll post the ECM mean at 240 again here now - note very little support for a deep trough over Europe unless you are in the Balkans or a ridge moving north and west. There is a low pressure signal to the north of the UK which will aid in NW to N outbreaks perhaps, but not the continental air that a Euro trough over central to western parts might suggest. Hopefully it is only a case of patience required for teleconnections to bite...

That's the op?

[Rocheydub]

That's the op?

And at 216, not 240!

[Cheshire Freeze]

And at 216, not 240!

Aye. You know the old saying....there's lies, damn lies and synoptic weather charts

[Frosty.]

The main reason is because by Mid February onwards the south starts to see milder temperatures, the sun is getting higher and the days are longer so any snow which does fall can often melt a lot quicker than it would in say December and January.

Can anyone remember (excluding the 47 winter) when we last saw a sustained cold and snowy period after February because I can't

NOPE

[Tim Bland]

RE ECM 32 dayer I agree that it has been fairly poor of late. Its updates a couple of weeks ago had a repeated signal for a Greenland high next week. What we are likely to see instead is a weak toppling atlantic ridge with witry showers on hils under a slack NW flow. I think expectations are high after what we have just experienced. I have personaly accepted that the snow in Jan will be the highlight of the winter and anything else is now a bonus. It could be nearly March before we see anything substantial now and as people have said the sun will be stronger and any snow wont last long. I can recall deep snow in March with -8c uppers and suzero air temp and Dew points but once the sun came out it was gone within a few hours.

[Methuselah]

Please put you whinges, gripes and ramps here:

Hard to tell, from its title, I know...

[Timmytour]

I'm seeing posts with people saying that people saying "time is running out" and then putting forward the argument that it's not. There's a hell of lot more of these posts then posts actually saying "time is running out"!! In fact, I can't even find one!

I'm happy with the 6z GFS in that it is consistent with its inconsistency in the handling of the PV. Ii think this emphasises that a great deal of uncertainty still remains and where there is uncertainty, there is a chance anthing could happen. Focusing on the positive side of this, I'm hoping this will be a change that drags us back into a spell in the freezer

Edited January 29, 2013 by Timmytour

[Joe Levy]

_{I'm seeing posts with people saying that people saying "time is running out" and then putting forward the argument that it's not. There's a hell of lot more of these posts then posts actually saying "time is running out"!! In fact, I can't even find one!}

_{I'm happy with the 6z} GFS _{in that it is consistent with its inconsistency in the handling of the} PV_{. Ii think this emphasises that a great deal of uncertainty still remains and where there is uncertainty, there is a chance anthing could happen. Focusing on the positive side of this, I'm hoping this will be a change that drags us back into a spell in the freezer}

I imagine many of those posts have been deleted. I completely agree - the scatter on the ensembles is proof of this inconsistency if nothing else, no matter where you look in the country! http://www.meteociel.fr/modeles/gefs.php

[Man With Beard]

NOPE

As the question has been asked, I believe Kent saw days and days of snowfall in late Feb/early March 2005, someone who lives there could confirm?

Back on topic, looking at GFS London ensembles...

http://www.meteociel.fr/cartes_obs/gens_display.php?ext=1&x=306&y=141&ville=Londres

...you don't often see that many runs hitting -10C at T850. You could almost call that a cluster, and some of the them stay cold several days. Clearly much potential in the weather from about day 8 onwards.

[tinybill]

i think we should be more worried looking at the big storm that going to hit the u,k, sometime Friday ,could this do more damage them the great storm did as its so flooded and wet at the moment

[SomeLikeItHot]

Back on topic, looking at GFS London ensembles...

http://www.meteociel...1&ville=Londres

...you don't often see that many runs hitting -10C at T850. You could almost call that a cluster, and some of the them stay cold several days. Clearly much potential in the weather from about day 8 onwards.

Yes the mean is certainly above the majority of members due to a couple of very high near +10 solutions. The mean can be a poor measure if you have a bi-modal distribution. When people are saying there is no cold they are talking about getting the synoptics for prolonged cold not 1-3 days shots of cold interspersed with mild temps which seems to be mostly what is showing. I think some ensembles and the OP got to a blocked synoptic in the end so there is some hope for all.

Personally I am happy with a bit of cold and maybe a snow shower or two, but then again I lived most of my life in Sydney so I get excited at a light frost. Just so long as we don't get 13 degrees and raining, as I could have done that back home.

[surrey slush]

i think we should be more worried looking at the big storm that going to hit the u,k, sometime Friday ,could this do more damage them the great storm did as its so flooded and wet at the moment

Is this storm possible, it doesn't seem to be showing up on UKM, and no warnings from them either... Is this another MFish storm, or is it just the GFS playing with it's spirograph?

[Captain Shortwave]

i think we should be more worried looking at the big storm that going to hit the u,k, sometime Friday ,could this do more damage them the great storm did as its so flooded and wet at the moment

It's a strange one this as it seems the metoffice and other people such as weatheronline seemed to not be very concerned about it. Charts I've seen seem to suggest the low will have a big impact in Northern France with us relatively untouched, strange considering both GFS and ECM show a direct hit for southern England.

[MR EXTREMES]

ive read enough to convince me that the models are wrong totally wrong theres no way of a cold evolution.

but i dont see blowtorch sw flow and possible evolution but there of coarse those that rejected the recent cold never was going to evolve but trust me it did and its always possible it will happening again there is a strong signal pointing towards a cool down and ive seen the alantic block evolve into something very spectacular 09/10 winter still four weeks or a little more of winter.

seen snow in april and cold easterlies at easter so id rather not get into the model output slagging match sorry mods.

[SomeLikeItHot]

AS I understand it the storm doesn't show on all ensembles or models (didn't show on the 0Z) and the GFS Op is towards the most extreme end of models when it does show so they are probably waiting to get a better fix on it.

[Summer Sun]

This is how GFS sees the rain totals for Friday

CMC

Remember these are the totals by Friday and not what falls in one day

GME's take on Friday's low

Edited January 29, 2013 by Gavin.

[Mucka]

No change from me.

for the period Feb 8th to 15th.

Pattern to become more amplified with ridging forced west as deep troughs move down the eastern flank eventually creating a strong Atlantic ridge with ever reducing residual PV energy in the region being forced NE of Greenland instead of east, possibility of Greenland or Iceland high not as remote as being suggested by mid month but more likely at this stage a 4 to 5 day cold shot with collapsing ridge supported by low pressure over the continent - possibility of a diving trigger low from there or return to flat.

ECM 00z 240 chart shows no quick return for the Atlantic, PV moving East out of Greenland - cold spell looming as low pressure moves South on Eastern flank of AH and develops, ridge pushes into Greenland and straightens and narrows as squeezed bringing first N then NE flow, min 4 days cold shot with potential snow.

GFS 06z 240 faster and flatter, shallow angle of attack. Worse case scenario though maintains pattern and increases amplification of pattern with time.

Ensemles.

Becoming cold as troughs dig down Eastern flank of ridging AH before becoming less cold as ridge moves over UK - pattern to amplify or flatten from there?

Summary.

It won't be mild.

No significant cold spell currently modelled but below average temps with snow likely for some at least for a time. Possibility of significantly colder weather, at least for a time toward mid month.

Edited January 29, 2013 by Mucka

[Tom Montalbano]

As the question has been asked, I believe Kent saw days and days of snowfall in late Feb/early March 2005, someone who lives there could confirm?

Back on topic, looking at GFS London ensembles...

http://www.meteociel.fr/cartes_obs/gens_display.php?ext=1&x=306&y=141&ville=Londres

...you don't often see that many runs hitting -10C at T850. You could almost call that a cluster, and some of the them stay cold several days. Clearly much potential in the weather from about day 8 onwards.

Re Feb 2005, Bromley, S.E.London/N.W.Kent saw 13 days consecutive with snow falling, albeit most days light and of the flurry variety, although 2 Thames Streamer events saw a temporary snow cover of 3 to 4 inches. Had the previous weeks been colder, with resultant lower soil temps and also source region of the easterly, E.Europe and Russia colder, snow depths would have been greater.

The stat of 13 days consecutive snow falling, is truly remarkable for this area.

Regards,

Tom.

Edited January 29, 2013 by TomSE20

[Summer Sun]

High pressure slowly builds through Saturday as the low clears away

[Rocheydub]

Not much change out to 126 hours on the 12z GFS, HP close by our southern coasts, with low pressures riding over the top across Iceland into Scandinavia. No signs of pressure rising in northerly latitudes in the reliable time-frame... Very flat pattern.

[TEITS]

. No signs of pressure rising in northerly latitudes in the reliable time-frame... Very flat pattern.

You won't see this at this timeframe.

What you will see in the next frames is a colder NW,ly.

This is the first of two NW,ly outbreaks the second will occur around +200 onwards.

[bluearmy]

jet weaker both sides of the ridge to our west on the 12z than the 06z. what differences will that make ? find out soon .................................................................