Winter Model Discussion - 11/01/13 00z Onwards

[Gustywind]

Nick, yes the ECM is the best model but not by a statistically significant amount is it? Just a few % points better than other models. As such you have to back a combo of GFS/UKMO and GEM versus ECM on its own. I've not really known UKMO in particular to be wrong at such short range either. Think we will see the ECM back down tonight.

[TEITS]

Poor ECM mean at +144.

Interesting to see the Met O 6-15 day forecast. They will probably go with the UKMO but even the Met O forecast isn't prone to changes.

[Weather-history]

Can I say something hear. Yesterday I posted what GFS, ECM and GEM New Year's Day runs were showing for now. Not one suggested a cold spell. So regardless whether ECM is right or wrong, we have a potential snow event for Monday. Enjoy it, remember this was not expected this when we were toasting in the New Year. See this is a positive.

[ChartViewer]

CMA T120

[bluearmy]

ECM mean uppers still struggling so, given the reading mean temps, it looks like higher heights holding on on general. I expect the postage stamps will be varied.

[TrickyRicky]

I think the ECM people have bunged in a dodgy run just to keep everyone on their toes! The OP is a billy no mates outlier so everyone can stop panicking.

[ICETAB]

CMA T120

I'll be very interested to see the verification stats for this model after next week has passed. It seems to me that it has been rock solid over the past week, would you agree?

[Cheese Rice]

The ECM is definitely for the bin, the GFS & UKMO are pretty much identical at T144.

Very volatile period of model watching.

[manutdmatt1986]

Latest NAE update is out to 42 hours and has -8 to -10 uppers over London, the South East and East Anglia, -7's over the Midlands and central southern england, and -5's over Wales.

Should make Monday's snowfall less marginal and perhaps more widespread.

Sorry, I don't know how to post a link to it.

[snowblizzard]

He was talking about today's low !! Just chill out and make yourself a coffee and come back lol!! Have a look at the fax , you will see 2 if not 3 frontal systems crossing the country , the first is Sunday night we have the "weaker" band , which is chased readily by the second "main" front , this will double the size of the ppn and significantly strengthen the ppn , then we have a tail to the low pressure that can pack a punch , that will cross us Monday night , just sit back and enjoy the ride.

No, I agree with Pompey Mondays frontal activity appears to be much weaker than was showing yesterday. Everything looks slightly further East and there's very little in the way of 'white' area's on the BBC graphics! Perhaps, even at this stage, they are still sitting on the fence regarding developments?

Also, Sundays max temperatures slightly higher 4c in London

[ChartViewer]

I'll be very interested to see the verification stats for this model after next week has passed. It seems to me that it has been rock solid over the past week, would you agree?

Its a very interesting one Ice , it has thrown a slight wobble on 1 run but as you say has been showing a consistant theme in the main. I suspect many are very wary of it as its new in here for viewing and again i refer to Nicks post over in the strat thread where the MO Paper referred to it as being only model if i remember rightly that has no strat dynamics forecast into its output or will do in future either?.............However i am keen on viewing it to see how it performs over this next few weeks especially as we do have a strat warming going on.................Late Jan early Feb will be an interesting period to see how this model has/is performing. Very unknown though to be honest.

Nice cold charts though .......and by magic T144 CMA

Watching it come out over 5 hours ages you 10 years in one Winter though....lots of coffee needed!.....and you could say as the big 3 models are struggling to get a handle on the strat dynamics and thowing major swings this trop model is much less stressful to watch!!!.....but could turn out to have been consistantly wrong when we look at it in Feb

Edited January 12, 2013 by ChartViewer

[Rocheydub]

Poor ECM mean at +144.

Isn't it best though to discount the mean? I mean it either goes over the top or undercuts! Meaning were still in the freezer, or breaking out the shorts and aircon (allow me some poetic licence)

The results will be poles apart!

[Gibby]

Good morning. Here is the report on the 00z output from the major four models of GFS, UKMO, GEM and ECM for today Saturday January 12th 2013.

All models show a cold spell to come. There is a lot of difference between the models and their specifics from quite an early stage in the runs and by nature of the up and coming cold spell I will not deal with specific synoptics this morning as things will change by the next run but indicate trends shown by the models themselves as they move through the period. In the short term there is some agreement that a trough over Southern England currently is engaging cold air through today with rain, some of which is quite heavy lasts on and off through the day. Later in the day as the front sinks South the rain may turn to light snow before clearing away South tonight. Ice will form behind it as the South joins the rest of the UK in a cold night with some snow showers near the East Coast of NE England. This persists through the early past of tomorrow before a front slips South over Scotland later tomorrow, through Sunday night and Monday with a mix of rain, sleet and snow for many with brighter showery weather in the far West later on Monday with snow mostly restricted to the East.

GFS then shows its trend this morning with a UK battleground with snow a risk throughout with a more general period of cold weather under a cold ridge midweek with snow showers in the east and sharp night time frosts. Then spells of rain and snow occur frequently as Low pressure slides SE over or just to the South of the UK maintaining the cold and wintry theme.

The GFS Ensembles show a cold theme this morning with the average 850's for London remaining between -3C and -9C throughout. With Low pressure around too there is likely to be some snowfall mixed in with cold rain in many areas too North and South.

The Jet Stream shows a flow to the south of the UK for some time to come with a continuation of disruption in the flow as it strengthens to approach the UK, turning South to Southern Europe in a week or so.

UKMO for midnight on Friday shows a Southerly moving Jet and a High centred over Scandinavia with a ridge over the North of the UK in very cold air. Low pressure in the Atlantic is moving SE and would probably replace the snow showers in the East with more prolonged snowfall in the SW later.

GEM shows Low pressure to the NW disrupting and sliding SE with outbreaks of rain and snow with the risk of a strengthening cold setup at the end of its run as pressure builds over Scandinavia.

ECM shows a totally different setup ending the cold spell but sooner as the Jet charges NE around a sinking High over the UK next week with a return to mild SW winds everywhere with rain at times later next week and onwards.

In Summary the models are still struggling on how to handle the complex synoptic patterns over the UK from now on and through next week. With the lack of High pressure to the North we rely on the positioning of Low centres as to whether any one area receives snow or not and it may well be that some Western areas see very little snow from this cold spell. The East may well see plenty through next week but the specific detail of movement of depressions is entirely dependant on that even here. Longer term there is an enormous difference in the models with ECM seemingly out on its own pushing the Jet flow over a sinking UK high and returning milder and windier weather to all areas late next week. The other three show a Jet well South of the UK steering Low pressure SE across the UK with further wintriness for some at times in fairly cold conditions. Which one is right? Is ECM barking up the wrong tree given that its last few operationals have indicated a quicker route to milder weather than it's colleagues? These are the questions the forecasters have to work out over the coming week or so.

[Severe Siberian icy blast]

No, I agree with Pompey Mondays frontal activity appears to be much weaker than was showing yesterday. Everything looks slightly further East and there's very little in the way of 'white' area's on the BBC graphics! Perhaps, even at this stage, they are still sitting on the fence regarding developments?

Also, Sundays max temperatures slightly higher 4c in London

Regardless of weather you agree , Ian f was referring to today's event not Mondays, as for Monday , the last forecast on the breakfast show verified what I said, there is a band of snow pushing across us Sunday night , then Monday we have a second stronger front , what you see on the nae is the first front , as the main one pushed through it will intensify . The only places having rain will be southwest Wales and areas west of Bristol .

[Cecil Hogmanay Melchett]

Bloody excruicating this!! UKMO/GFS are as good as it gets and bring at least a full week of bitter weather,and then ECM comes out and says game over by thursday.

Good grief i hope ecm is off one one.

[ICETAB]

Anyone got a link to the ECM ensembles. I need to see them because the comments on here are not consistent. Some saying its an outlier and others saying it has plenty of support.

[phil nw.]

So it`s the ECM Operational that casts doubt on the longevity of the cold this morning.

Looking at the mean 500 and 850 charts at T168Hrs just shows a lessening of the depth of cold but no mild setup

looking to the next frame at T192hrs shows the Ens means Ht anomls.

Obviously these are forecasted negative(low) and positive(high) pressure placementss against the average and not exact pressure patterns but even so these would not suggest a mild south westerly pattern at the end of next week.

There have been quite a few Ens graphs recently-both GFS and ECM that do suggest a less cold period towards next weekend but nothing above average so maybe the ECM Op. has some merit beyond T96hrs but perhaps it`s milder signal in the medium term is rather too strong.

[IDO]

Regardless of weather you agree , Ian f was referring to today's event not Mondays, as for Monday , the last forecast on the breakfast show verified what I said, there is a band of snow pushing across us Sunday night , then Monday we have a second stronger front , what you see on the nae is the first front , as the main one pushed through it will intensify . The only places having rain will be southwest Wales and areas west of Bristol .

Latest NAE highlights this:

[Shunter]

Seems that the US have discounted this mornings Ecmwf for the us weekend forecast, it may be the cause of our downstream issues with the ECM op this morning.

http://www.hpc.ncep.noaa.gov/discussions/hpcdiscussions.php?disc=pmdhmd

[seabreeze86]

When i looked at the models this morning i smiled and shock my head thinking i will have to wait for the 12z the sort this out but that has happened every morning for the last week of so no change there.

UKMO is the pick of the bunch at 144hrs

Closely followed by the GEM and GFS

The ECM on the other hand has the Azores high ridging up and joining with the heights other scandi therefore no undercut

This is a very delicate situation and i wouldent want to call it as the ECM has shown this outcome its its last few runs. But the UKMO and GEM have been consistent

with showing energy going south. Wouldent want to be doing the countryfile forecast if this uncertainty remains

[IDO]

The De Bilt showing split scatter late next week and the op as an outlier:

[Severe Siberian icy blast]

Latest NAE highlights this:

I think people are panicking a bit I can understand that but I think those that are worried about been too far west will see a nice supprise , not forgetting nearly all of us will have snow cover after Sunday nights front comes down so any marginal set up when the second front comes down will be affected by the existing snow cover .even if its just an inch it makes all the difference to dew points , wet bulb , air temp .

[bradymk]

Ok so i looked at the GFS and UKMO and got a bit excited but then checked the ECM. Like Nick said, the problem arises at the t72 period and very rarely is the ECM wrong here however it is possible and it will be interesting to look at the NAM like the other day when it disagreed with GFS, hopefully it disagrees with ECM now. A quote from Ian Ferguson last night makes me happy "Plenty of time ahead given UKMO tells us latest FORMOST forecast offers below or well below average temps thro to early Feb... this currently steers their 15d forecast opinions"

[Duane S.]

Latest NAE update is out to 42 hours and has -8 to -10 uppers over London, the South East and East Anglia, -7's over the Midlands and central southern england, and -5's over Wales.

Should make Monday's snowfall less marginal and perhaps more widespread.

Sorry, I don't know how to post a link to it.

[IDO]

The snow cover after the first front passes through the Midlands north (just updated):

The snow border for +T48:

Edited January 12, 2013 by i'm dreaming of...