Model Output Discussion

[reef]

A new thread for the morning's runs.

Please remember this thread is for discussing the models. Due to the sheer volume of traffic the workload for the team has been massive recently. If a post is off-topic, adds nothing to the discussion or is baiting/arguing with other members it will be deleted without warning. Those who's names continue to pop up will be sent on vacation.

Thanks.

Old Thread:

[Lewis]

Fantastic fax charts;

http://www.wzkarten3.de/pics/brack0a.gif - T 36

http://www.wzkarten3.de/pics/brack1.gif - T 48

http://www.wzkarten3.de/pics/brack2.gif - T 72

http://www.wzkarten3.de/pics/brack2a.gif T - 84

http://www.wzkarten3.de/pics/brack3.gif T - 96

http://www.wzkarten3.de/pics/brack4.gif T - 120

[asjmcguire]

Just for info....

Just had heavy snow here mixed in with heavy rain

Temp dropped from 3'C to 2.2'C and dew point fell from 2.8'C to 1.5'C

NMM for this time-period on NW not forecasting snow for my area, but GFS has been for the last 2 days...

Make of that what you will..

Similar story with the Jan snow - NMM forecasted nothing for me

[cheeky_monkey]

Fantastic fax charts;

http://www.wzkarten3.de/pics/brack0a.gif - T 36

http://www.wzkarten3.de/pics/brack1.gif - T 48

http://www.wzkarten3.de/pics/brack2.gif - T 72

http://www.wzkarten3.de/pics/brack2a.gif T - 84

http://www.wzkarten3.de/pics/brack3.gif T - 96

http://www.wzkarten3.de/pics/brack4.gif T - 120

decent charts but not fantastic IMO..lots of dissapating fronts and troughs that wouldnt deliver too much snagged up in the high pressure..lots of areas would be cold and cloudy..but thats about all.

[MR EXTREMES]

decent charts but not fantastic IMO..lots of dissapating fronts and troughs that wouldnt deliver too much snagged up in the high pressure..lots of areas would be cold and cloudy..but thats about all.

totally dissagree something though i did notice the high trying to retrogress towards greenland one problem deep area of low pressure running over the top is that likely to topple the high or could that work in our favour just something im wondering about thats all?

inregards to snowfall the county file think different and there forecasts have been fairly good all winter i dont think there any fear of somewhere getting a covering through the week and judging by the latest charts tonight later in the week is where the fun starts.

although i have not yet looked at tonights gfs 18z pub run i expect it was a nightmare run once again.

comment when ive read through some older posts.

[FENDER.]

The 18z was OK, pretty good in fact. The high worries me, would like to see it bugger off the Greenland ASAP. The sooner it goes the less time we waste.

0z out soon lets hope for upgrades

Edited February 8, 2010 by At least it will be mild

[cheeky_monkey]

No real change on the GFS run this morning that i can see in the short term to medium term from the last few runs..if anything the high when it does retrogress away to the north west pull to far west into greenland and north east canada..with eventually lows pushing up from the south west.

Very slack easterly flow later this week..but seems most of the energy being pushed away south into north and eastern france and switerland.

[aspire27]

No real change on the GFS run this morning that i can see in the short term to medium term from the last few runs..if anything the high when it does retrogress away to the north west pull to far west into greenland and north east canada..with eventually lows pushing up from the south west.

Very slack easterly flow later this week..but seems most of the energy being pushed away south into north and eastern france and switerland.

Sounds like the easterly is non existance at the moment with regards to its potentness. Last nights fax charts didnt seem amazing, a NE flow with showers across the east, dry with sunny spells out west with temps just below average at least until the end part of the week.

This week looks like turning out a different from what last weeks charts predicted. Lots of people looking to next week now for more cold and snow which is just crazy. This must be due

to this week not turning out to be as cold or snowy as most would of liked. Might even feel spring like in the sunshine out west this week.

I hope more cold and snowy synoptics turn up in the reliable rather than just slight downgrades in the reliable and people still chasing the FI.

[john mac]

The ECM12Z looks a bit progressive this morning with the high retrogressing too far leaving all the cold going into the atlantic, plenty of time for change though as it is in deep FI.

[bluearmy]

The ECM12Z looks a bit progressive this morning with the high retrogressing too far leaving all the cold going into the atlantic, plenty of time for change though as it is in deep FI.

with the possibility that many areas will see zip from the 'easterly' later this week, the pattern emerging for next week looks interesting to say the least. very similar to december when the trough came sw which wasnt good for the south as uppers went too high but good for the north midlands northwards as they stayed in the cold air and made the most of an onshre flow where it occured. to add to that, we have a likely atlantic incursion from the south, at which angle is dependant on the block to the northwest having an orientation to deflect the jet far enough south. at the moment, GEM is just about the best on the table and this is close to being too west based. ECM is very borderline - just good at present, and GFS is too far west and allows the atlantic trough to merge with the scandi shortwave (remember that one from december?)

the decmeber trough was modelled better for us to begin with and then corrected a bit further west as verification approached. this one looks to be too far west to start with so i am rather nervous that for areas south of the midlands at least, we need to get something from this week rather than waiting for next. at least we can hope that the model are struggling a little with strat developments and being a tad too progressive with the neg zonal winds to our north.

[Neilsouth]

The forecast is going as planned so far from sunday with the more likely of snow towards the east and south east. The models do show a good enough cold pool moving more especially through the south east so expect a possibility of a good covering there

[Polar Continental]

The models still maintain that the cold outlook remains in to the foreseeable future.

Mostly dry for the bulk of the country with frost, but the high is shown to regress far enough north west on Wednesday and Thursday to allow the low to the east to influence the weather in the south east. The 0z GEM shows this best this morning, tightening the isobars over the south east, thus helping to advect the cold unstable uppers there, so a chance of some snow.

GEM Thursday

GEM 850's Thursday

The best of the bunch this morning is the GEM, followed by the ECM. The GEM takes the high just far enough west and north west to allow cold arctic air to flood the UK, around T168. The ECM shows a similar scenario, but tends to regress the high a bit to quickly and to further away north west, thus the cold arctic plunge is diverted closer to Iceland and in to the Atlantic.

ECM

GEM looking good at T168

Edited February 8, 2010 by Polar Continental

[Neilsouth]

Wednesday night onwards , south east england more especially

http://i47.tinypic.com/1zob02w.jpg

http://i47.tinypic.com/11b57k8.jpg

http://i48.tinypic.com/6o0gub.jpg

http://i49.tinypic.com/oq9dhy.jpg

[Turnedoutniceagain]

The models still maintain that the cold outlook remains in to the foreseeable future.

Mostly dry for the bulk of the country with frost, but the high is shown to regress far enough north west on Wednesday and Thursday to allow the low to the east to influence the weather in the south east. The 0z GEM shows this best this morning, tightening the isobars over the south east, thus helping to advect the cold unstable uppers there, so a chance of some snow.

GEM Thursday

GEM 850's Thursday

The best of the bunch this morning is the GEM, followed by the ECM. The GEM takes the high just far enough west and north west to allow cold arctic air to flood the UK, around T168. The ECM shows a similar scenario, but tends to regress the high a bit to quickly and to further away north west, thus the cold arctic plunge is diverted closer to Iceland and in to the Atlantic.

ECM

GEM looking good at T168

Good post PC. It's the model "slippage" that's worrying me. Everytime I check we seem to have gone back another 24hrs !!

[cooling climate]

Good model outputs again this morning although towards the weekend the GFS has us in

a slack northerly airflow with temperatures returning to rather cold levels, unlike the Euro

models which keep the majority of the country in a colder airflow.

I would prefer to go with the Euro's here.

Looking ahead t144 onwards and the UKMO model clears the vortex up north away to

the east more which ties in with the stratosphere models better and would allow a

potent north, northeasterly to develop further down the line.

http://strat-www.met.fu-berlin.de/cgi-bin/ecmwf?alert=1&level=100&forecast=f192

http://strat-www.met.fu-berlin.de/cgi-bin/ecmwfpv?alert=1&level=400&forecast=f192

[Neilsouth]

Looking good late wednesday as pools of -12 move across the east and south east and unlike last time a much wider area

http://www.wzkarten.de/pics/Rmgfs752.gif

[TEITS]

Looking dry and sunny for my location with temps just below average with nothing remotely that cold or snowy on the horizon. Where's the easterly so many were talking about? There might be one, but the word SLACK will probably sum it up.

How is a max temp of 1C only just below average because this is whats predicted for Friday. Also worth mentioning that its currently snowing here and my temp is unlikely to reach above 2C.

Nothing has changed as far as im concerned with the outlook. The snow showers becoming more frequent from Wed onwards with E Anglia/SE likely to see the heaviest snow showers. At this stage unlikely to move that far inland but I did say in my summary a few days ago for some this week will only be sunny, dry. cold.

Moving beyond the E,ly and much uncertainity this morning in the models. I feel the UKMO would be best if the run went out to +168/+192. Im just hoping the pattern doesn't become too far W which is what the GFS shows.

Edited February 8, 2010 by THE EYE IN THE SKY

[bluearmy]

Looking dry and sunny for my location with temps just below average with nothing remotely that cold or snowy on the horizon. Where's the easterly so many were talking about? There might be one, but the word SLACK will probably sum it up.

aspire, i seem to recall many posts such as yours before the last cold spell. if you cant be patient and take a let down, best not bother looking at the models at all. the best snowfalls are the ones that surprise you. for what its worth, the ecm precip shows a band coming down the western side of the uk late in the week.

the NAEFS 00z update, shows the day 10 meeting of the arctic and the atlantic firmly in our part of nw europe. some will be upset and some may well be snowed in!!

beyond, and after the atlantic trough makes headway as far as the north of england, there are signs that pressure will build again to our north and northwest and we may go through the whole thing again. here's a thought - this current spell is evolving in a very similar way to december. any chance that we may go through a complete repeat cycle with the jan sypnotics to follow ??

[Neilsouth]

How is a max temp of 1C only just below average because this is whats predicted for Friday. Also worth mentioning that its currently snowing here and my temp is unlikely to reach above 2C.

Nothing has changed as far as im concerned with the outlook. The snow showers becoming more frequent from Wed onwards with E Anglia/SE likely to see the heaviest snow showers. At this stage unlikely to move that far inland but I did say in my summary a few days ago for some this week will only be sunny, dry. col.

Moving beyond the E,ly and much uncertainity this morning in the models. I feel the UKMO would be best if the run went out to +168/+192. Im just hoping the pattern isn't too far W.

Are we likely to see the same amounts as last time , 10cm in some areas of kent?. I feel this is possible from thursday onwards

[Hammer]

Looking dry and sunny for my location with temps just below average with nothing remotely that cold or snowy on the horizon. Where's the easterly so many were talking about? There might be one, but the word SLACK will probably sum it up.

Snow risk increasing as the week goes on, in the east, later the risk grows in other locations, likely also yours.

[snowray]

Wednesday night onwards , south east england more especially

http://i47.tinypic.com/1zob02w.jpg

http://i47.tinypic.com/11b57k8.jpg

http://i48.tinypic.com/6o0gub.jpg

http://i49.tinypic.com/oq9dhy.jpg

Indeed Neil, as I was saying last night, this has gone from an Eastern ENGLAND event to an Eastern KENT one! Be dry over this end undoubtedly.

Wednesday might be the only day that will produce a few Wintry showers to other parts of the country though.

I sincerely hope to see more of an Easterly effect larger areas of the the country on this mornings 06z and not a flabby hp sitting of the UK.

Edited February 8, 2010 by snowray

[TEITS]

the NAEFS 00z update, shows the day 10 meeting of the arctic and the atlantic firmly in our part of nw europe. some will be upset and some may well be snowed in!!

Yes that is the general pattern I have been seeing in recent days on the GEFS ensembles. An absolute nightmare for the models because its very difficult to say how far S the arctic airmass will be but then its difficult to know the exact track of LP. As you rightly say some will be snowed in whilst others are upset.

At the moment the detail probably isn't worth discussing at the moment. Back to this week and members need to realise that surprise snowfall can occur. We really need to be focussing on the NAE/NMM for this week and even these are subject to change!

[Polar Continental]

Good post PC. It's the model "slippage" that's worrying me. Everytime I check we seem to have gone back another 24hrs !!

Hi mate,

I know what you mean, at one point, early runs showed the colder 850’s flooding southern England around Wednesday. Later runs then put back until Friday, and I think one GFS run yesterday showed them missing the UK completely. This morning’s GFS and GEM have returned them for Thursday. This is still not settled as yet. It is sometimes better as John H mentions, not to view every single GFS run, just view the runs twice a day, that way you don’t see so many twists and turns which can get very confusing.

[Nick F]

Morning all, there seems to be a continuing consensus this morning between GFS and ECM into the medium range of more of a west-based -ve NAO developing, which may tend to pull the PV moving down across Scandinavia next weekend SW and the ridge to pull NW/W in across the NE Canadian arctic. ECM tends to pull the expanding PV further W than GFS, looking at the 8-10 day mean H500 comparisons, which may mean southern areas may lose the cold air eventually, but the cyclonic flow and maritime air getting pulled in by a low sat to the north of the UK may mean some significant snowfalls in places where the cold air holds on:

This tendency for the PV dropping down from the higher latitudes and shifting SW to the north of the UK is by no means certain IMO, particularly as the modelling of the PV is an area within the arctic circle with very sparse observations.

On to the weather this week, any snow over the next few days looks to be mainly light as thicker cloud advects in from the N Sea, so a slight covering at best towards eastern areas. Perhaps snow showers pepping up towards the east coasts on Wednesday, as a low-level disturbance runs SSW down the N Sea towards Low Countries. Thursday models suggest a shallow low with fronts affecting Scotland which may bring a spell of snow, further S a more cyclonic and strengthening flow with troughs moving west as colder uppers arrive - which may bring some heavier snow showers Thursday and Friday towards E and SE England.

[NorthantsSnow]

Are we likely to see the same amounts as last time , 10cm in some areas of kent?. I feel this is possible from thursday onwards

Not according to the ensembles. Just light intermittent flurries. Best chance of snow Wednesday night into Thursday, more especially for eastern Kent.

http://charts.netweather.tv/ensimages/ens.20100208/00/prcpKent.png