Winter Model Output Discussion - 06Z 09/02/13 onwards

[Ryan Dutch Weatherman]

Look The ECMWF 00z ist identiek to the GEM 00z , [ i have posted the charts from Gem }

It wants take the blok towards Iceland.

ECMWF , GEM, CFS , versus GFS !

[AWD]

Well the ECM at 216 is the crumb of comfort this morning at 216 as for the second run in a row it starts to throw heights NW

Ill take a closer look at the ensemble means a bit later, but needless to say those GFS ensembles at face value looking pretty terrible...then again, ECM v GFS sounds a familiar battle now

SK

FWIW the GEM isn't too disimiliar from the ECM at day 10 either;

[Gowon]

GFS 18z took more energy NE last night, so I'm not surprised at this mornings run. Hopefully the models decide on more trough disruption and send energy SE again today.

[TEITS]

Very disappointing runs this morning with the exception of the GEM.

The downgrade occurs as early as +96 as we see less energy going SE and as a result the block to our NE retreats E rather than W as shown on previous runs. However the only straw to clutch is i've seen these situations many times and the models often flip flop around. If the 12Zs show the same pattern then I feel a milder outlook will be more likely but the 144 charts could equally be very different.

Personally im now at the stage where im not really bothered what happens. My ideal cold spell is a convective E,ly bringing powder snow, ice days. Now for this to happen at this time of year we would need upper temps of at least around -12/13C. Even if previous colder runs are right they never looked like bringing upper temps as cold as this.

Would be rather fitting that we don't see a GH for the rest of Feb because we certainly haven't seen one so far this winter. The coldest upper temps I have seen across my region this winter has been -9C which to be honest is very poor!

[Nimbus Nix]

I know it's old but just seen this beautiful setup on the CFS, look at that 1065 greenland high:

Oh wait, it's April...

[Methuselah]

Models still not conclusively showing any noteworthy retrogression, I see. Which, I guess, sort of ties-in with the MetO's expectations...Not many days left until Spring arrives...

[xioni]

Oh good - that means we can sit under some real cold then!

How will this mild second half feb manifest itself? I was just thinking the de bilt ens are convincing re extended cold?

the ecm ens mean has an upper ridge iceland. It doesnt look less cold to me?

Irony is fine, but take a look at today's ensembles: the warming/retrogression trends continue and now the ECM ens mean shows at least normal temps from the 14th onwards. In fact it wouldn't surprise me if the models settle on a warm outlook in the next 48 hours.

I am a cold & snow fan but I prefer to call it how I see it.

[phil nw.]

GFS flattens any ridging north from the Azores High after T144hrs which results in the milder westerly flow after.

This is at odds with the other models which continue to show a trend for those Height rises further north.

It does look though that it will become less cold from mid-week after the next frontal system moves through.This could well result in a snow to rain period as the colder air is finally mixed out.

http://www.meteociel...96-21.GIF?11-06

After this the GFS Op looks a mild solution against it`s ens. with the flatter pattern whereas the ECM and GEM favour heights building further north which would bring a colder outlook with winds turning to the NE.or E.

http://modeles.meteo...gfs-0-168.png?0

http://modeles.meteo...em-0-168.png?00

http://www.meteociel...1-168.GIF?11-12

So the differences are upstream this morning with the GFS reluctant to take advantage of the weak Atlantic to send those heights north at the end of the week.

[TootyFruity]

Morning

The GFS ops and the GFS ens what are they how do they differ ? And are the ens supposed to back the charts up ?

When the ens don't back the ops up which do go with ?

Thankyou

[Gibby]

Good morning. Here is the report on the 00z outputs from GFS, UKMO, ECM and GEM for today Monday February 11th 2013.

All models show a slowly weakening cold and cloudy Easterly flow over the UK today and tomorrow with occasional drizzle or light sleet and snow in placed though amounts will be inconsequential. Through Wednesday a trough of Low pressure will move East over the UK with rain preceded for snow for some followed by clearer and more showery weather in more Northern and Eastern areas while Southern and Western areas become mainly dry nearer to High pressure to the SW. It will become less cold everywhere later in the week.

GFS then shows a light SW flow over the UK during the weekend with weak troughs around, especially towards the North while High pressure to the South and East keep things potentially brighter and colder here with the risk of night frost. Through FI the milder theme continues with High pressure never far away from the South with winds flowing from between South and West for much of the time. Rainfall will be confined more towards the North and West at times as troughs brush by.

The GFS Ensembles show a milder spell on the way after Wednesday agreed upon by nearly all members. Thereafter, uppers slowly fall back towards the seasonal average. There are a few colder options but the vast majority show temperatures above normal with the operational one of the mildest for the second half of the run. There is some precipitation shown by most members off and on with an Atlantic influence dominant.

The Jet Stream shows the flow arching over the Atlantic and down to Southern Europe to the SW of the UK currently. The pattern moves East towards the UK later in the week before weakening and collapsing to virtually nil over the UK and Northern Europe with a renewed surge of energy moving NE across the Atlantic towards Iceland by the start of next week.

UKMO today shows less cold weather to end the week with some sunny spells but with a night frost on Thursday and possibly Friday night as a ridge of High pressure moves across followed by milder Southerly winds on Saturday with the milder air encroaching East and North slowly over the UK.

ECM finally shows a lot of High pressure around from the weekend until the end of it's run but it's position this morning is less favourable for notable cold weather for the UK. With no deep Continental feed of air this morning and High pressure sat over or in the vicinity of the UK the best we can hope for is dry and settled conditions with sunny spells by day and clear spells at night with some frost where skies stay clear. Otherwise temperatures by day at least won't be tht far from the seasonal normal.

In Summary this morning the weather looks like becoming High pressure based from the end of this week with a centre either close to or over the UK giving dry and bright daytimes but with some frost at night. Cold weather from the Northern European High is not far away to the East but on this morning's runs it looks less favourable for the UK to tap into anything really cold from there through the model run period. Still at least after the midweek precipitation there looks a strong chance for some drying up of the ground under better evaporation conditions than of late which I'm sure farmers and growers will welcome.

[Frosty.]

The latest GEFS 00z mean shows our weather will be coming in from the west and southwest for the next few weeks as the pattern returns to normal mode with low pressure to the northwest/north and high to the south, winds tending to become more swly with time as the jet tilts sw/ne with pressure higher to the south of the uk with drier, brighter and mild spells between the unsettled periods, the further north and west you are, the more unsettled it looks with rainfall being the highest in nw britain and also the windiest weather too.

[phil nw.]

Morning

The GFS ops and the GFS ens what are they how do they differ ? And are the ens supposed to back the charts up ?

When the ens don't back the ops up which do go with ?

Thankyou

Her`s the ens graph from the GFS 00z outputs

http://modeles.meteo...run=0&runpara=0

the black line-Op run-goes above the mean-red line- around mid-way through the run.

There`s no hard and fast rule but usually if the Op moves away from the mean then it`s either leading the way on the future pattern or it`s moving away from the correct outcome.

Of course we wont know yet but in this case it goes away from the favoured evolution at the point where it sends more energy over the Azores high and flattens the whole flow to a westerly-milder outlook beyond-around T168hrs.If you see my earlier post it goes against the other models from that point too.

It may end up being correct but as the GFS Op has those differences i pointed it out as it alters the further outlook beyond compared to other outputs.

I hope you followed that OK.TF.

[Nick F]

Morning

The GFS ops and the GFS ens what are they how do they differ ? And are the ens supposed to back the charts up ?

When the ens don't back the ops up which do go with ?

Thankyou

The GFS operational is run at high resolution out to T+192 then lower res up to T+384, while the the 20 ensemble members are run at low res throughout the whole run.

If a big chunk of ens don't back the op, then it maybe wise to go for the evolution which the ens cluster most around.

On to the models this morning, there looks to be a few days of milder and wet weather later this week and into the weekend as fronts move in from the west.

But the milder and unsettled spell may not last and GFS may have the influence of Atlantic low pressure too far east and that high pressure will take control again into next week, as height build N and NE towards Scandi ahead of slow-moving trough over the Atlantic. We may see a cold feed return from the continent with a SE'erly drift, though don't expect much snow from any HP set-up near the UK.

Edited February 11, 2013 by Nick F

[Hotspur62]

The models are just all over the place at the moment with no consistency.Yesterday it seemed that after mid-week milder blip it would turn colder again from weekend,this morning it seems it will get milder mid-week and stay mild for the next 10 days(GFS).one thing i have noticed is that although we have had Scandi High in right place for us a few times this winter there has never really been very cold air that has come with it or is that just me reading it wrong?

Still dont think we are done with winter yet and think we will have one more cold spell(5-7 days) before 15th March.Indeed,aren't most models pointing to a below average March?Whatever happens,i have thouroughly enjoyed following the Models this winter and thank everyone on this forum for their knowledgable posts,i know i have learnt alot and although being a cold lover i feel the models have failed to deliver their potential on at least 3 occassions this winter,it has been fun following it all on NW.

[TEITS]

Could not disagree more had few inches last nite, this winter has been really kind to us midlanders, and the models are flip flopping from run to run no one truly knows what the rest of feb and early march will bring not even the models so why people are down in the dumps for when things are turning interesting

Yes the Midlands have done well this winter and so has my location, however some members haven't done so well.

I don't think members are down in the dumps but just giving an honest appraisal of the model output. What you have to remember is once we enter late Feb, early March we need colder upper temps to counteract the effects of the longer days, stronger sun. So what might of given snowfalls in Dec, Jan might not be the case at this time of year.

Due to the time of year and our current weather pattern, the ideal scenario would be the block to our NE to back towards Greenland with a trough sinking S into Scandinavia. Unfortunately that doesn't look like occurring right now. The word "Retrogressing" has been mentioned many times recently but the reality is the model output has only really hinted at this without any conviction.

You will also find that come this time of year members begin to seek some warmth and sunshine even from those members who enjoy the cold, snow. Must admit even im tipping that way!

[fUnKy]

Morning

The GFS ops and the GFS ens what are they how do they differ ? And are the ens supposed to back the charts up ?

When the ens don't back the ops up which do go with ?

Thankyou

My uncle is probably your milkman.. lol

http://www.weathercast.co.uk/services/ensemble-forecast.html

[TootyFruity]

Thankyou Nick and Phil

I'm I right in saying that the Atlantic tends to be weaker in febuary which can allow the blocking to form better ?

And if the system that's comingbin from the Atlantic is meeting and bumping into the cold block will it have the energy to make any dent on it ! I understand that the models are showing milder end of week so the models must think so but they can be wrong !! Can't they ???

Thanks

[Summer Sun]

ECM is high pressure dominated once more from the end of the week

A few quotes from Matt hugo on Twitter

EC32 update from Fri last wk, signaled a persistently cold/slightly below avg temp outlook well into early March, but I doubt that now.

At 240hrs; EC settled, not cold, GEM settled, but cold, GFS more unsettled and much milder!

00z EC ENS mean supports the GFS ENS and the EC model with 850mb temps near or above 0C early next week, so a milder outlook is likely.

Overall temp trend for the UK next 7 to 14 days is likely to be for temps to be near or slightly below average.

The GFS ensembles certainly show a milder trend next week

The ECM ensemble also have a lot of mild members this morning

Precipitation remains very low through out will will be welcomed by many I certain

[TEITS]

I feel ensembles are a waste of time at the moment. Like I said earlier the operationals are showing some inconsistency between +96/+144 with regards to how much energy goes SE. If they have this wrong then the +192/+240 charts could look very different. The ensembles could easily flip just as easy as the operationals.

Lets wait for todays output before we write off any potential cold next weekend. Been around far too long to assume the 0Zs are correct.

[xioni]

The word "Retrogressing" has been mentioned many times recently but the reality is the model output has only really hinted at this without any conviction.

You will also find that come this time of year members begin to seek some warmth and sunshine even from those members who enjoy the cold, snow. Must admit even im tipping that way!

The pattern is retrogressing but not in a good way, the ensembles now have the mean trough west of Europe in the 240-360h window.

I agree with your other comments, in fact the way the models are currently trending I'd put money in 20C being reached in early March

[bluearmy]

The pattern is retrogressing but not in a good way, the ensembles now have the mean trough west of Europe in the 240-360h window.

I agree with your other comments, in fact the way the models are currently trending I'd put money in 20C being reached in early March

is the mean trough retrogressing xioni ? i see the mean trough still well to our west whilst the mean ridge, currently nw russia/scandi slowly retrogresses to sit nw europe/iceland by day 10. My take on the latter stages of the ecm ens mean is another stand off developing but with blocking much closer to the uk and possible undercutting (maybe not close enough to our locale to generate frontal precip but possibility of a stiff flow east of south with chance of embedded cold pools courtesy of energy dropping around the back of the block - of course could just be a stagnant weakish flow).

[Captain Shortwave]

Models still not conclusively showing any noteworthy retrogression, I see. Which, I guess, sort of ties-in with the MetO's expectations...Not many days left until Spring arrives...

aye but aren't the seasons as fickle as the weather. I remember summer happening more in spring than during last summer

Kind a shocking model flip overnight, not helped by two upstream lows phasing with each other instead of one going south and digging into the Azores high giving us retrogression.

[MR EXTREMES]

another day another poor outlook although atleast its dry.

the main thing is here that the alantic is finally going to settle but its worth noting that none of the model outputs suggest anything but average in terms of temp so frosts likely settle cool days but nothing remotely cold with either slight sw flow or slight east flow.

over all anyone looking for any sting in winters tail really may need to wait for awhile yet.

[Tom Montalbano]

Havnt got much to add to what's been said already. Big turnaround in the models overnight and pretty surprised really!

But a straw to clutch is that they've been pretty volatile all winter.

Cant get away from it though as things stand, will enjoy the snow still falling outside my window, could be the last I see

for a good while. Oh, its just stopped snowing now!

Regards,

Tom.

Edited February 11, 2013 by TomSE20

[snowking]

A quick look at the ensemble means favours a dry but cool outlook for the UK, though not too much of a shift required for something a little more interesting.

Biggest stand out factor for me is this:

ECM Op and Ensembles favouring an east based neg NAO signal rather strongly it seems, with the GEM not far behind - the GFS ensemble suite is least keen on this idea (along with - surprise surprise - the op) but it looks out of kilter with GEM/ECMWF consensus at present (i.e. GFS favours a milder SWly flow for the UK locale, where as ECM/GEM favour a cooler E'ly flow)

GEM 6-10 day mean highlighting the potential signal for height rises around the Iceland/Greenland area:

Whilst ECM (unfortunately the 6-10 day mean still not publishing on Raleigh Wx at present) shows stronger tendencies:

So the favoured outlook at present towards the weekend and beyond is cold but dry. Given the time of year, you would suggest values of around 4-7c by day, with overnight frosts. As Gavin points out, i'm sure at thus juncture many would be grateful for something drier, especially down towards the SW.

With my optimistic cap on, it really would take much of a shift NW to encourage the mean trough through Scandinavia solution, though going by the 0z output, that seems an outside bet.

To re-iterate though, the GFS suite looks out of kilter with the rest of NWP guidance at present

SK