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

[manutdmatt1986]

The big three are pretty agreed on a general 500 hPa split over the next week, with two vortices setting up shop over Canada/Greenland and central Russia. Positive NAO and Atlantic dominance for the forseeable after around mid-week. No point in looking at the models too much, in fact, probably better to throw them out the window and look at the largescale pattern evolution.

A somewhat misleading post.

[Su Campu]

A somewhat misleading post.

In what way?

[john mac]

Cast your minds back, does anybody remember the beast from the east that didn`t materialise. If you don`t then your memory is worse than mine.

I have that gut feeling that something could go wrong between now and Monday due to the amazing near miss. You can`t blame me?

But shirley it can`t be cry wolf again.

Whos Shirley ? Lol

[Eskimo]

Cast your minds back, does anybody remember the beast from the east that didn`t materialise. If you don`t then your memory is worse than mine.

I have that gut feeling that something could go wrong between now and Monday due to the amazing near miss. You can`t blame me?

But shirley it can`t be cry wolf again.

"Don't call me shirley" Precipitation can be modelled very well up to 5 days away, seeing as this is only 72 hours away, I think we should be fine in that respect.

[Captain Shortwave]

Cast your minds back, does anybody remember the beast from the east that didn`t materialise. If you don`t then your memory is worse than mine.

I have that gut feeling that something could go wrong between now and Monday due to the amazing near miss. You can`t blame me?

But shirley it can`t be cry wolf again.

It's looking pretty good for snow on monday

I am serious, but don't call me shirley

[Tim Bland]

I'm sure GP won't mind me pasting part of his post from yesterday

" Initial downwell response about 15th Jan, brief respite from the cold around 20th -24th (just how much of a respite remains to be seen) before a reload and much more significant impact around 28th Jan (which should come from the NE)."

Stuart should be a millionaire! With His forecasts 99% of the time appear in the NWP after he releases his expectations... Far better than most forecasters who just read the models and write what they currently show!

[weather eater]

I have to say I’m not paying a great deal of attention post 72 hrs, almost every run starts changing rapidly post that point and its difficult to pick out so much as a trend. We have seen an idea or two stick for a couple of runs, or some cross model agreement but not for long, so just when you start thinking you know where this is going, bang the next run lurches off in another direction, personally I blame Shannon she’s a very naughty girl.

This made me laugh and summed up what most of us probably feel about the models!

Its from the extended forecast discussion at NOAA.

RELIED ON THE ROCK-STEADY ECENS MEAN TO FLESH OUT THE SYNOPTIC

PARTICULARS, WHICH ADMITTEDLY IS STILL DIFFUSE WITH ANY GIVEN

PRECIPITATION THREAT OVER THE EAST. THE DETERMINISTIC

MODELS--ECMWF INCLUDED--HAVE NOT PROVEN STABLE ENOUGH TO

INCORPORATE INTO THE MANUAL FORECAST.

Missed this by Nick S before I posted but it backs up my post well.

What they appear to be saying is, we don’t know WTF is going on, so as the ECM is the best verifying model we will go with the mean of that.

Edited January 11, 2013 by weather eater

[manutdmatt1986]

A somewhat misleading post.

Positive NAO and Atlantic dominance for the foreseeable future after mid week? The details for the beginning of the week aren't even sorted yet!

[ChartViewer]

Cast your minds back, does anybody remember the beast from the east that didn`t materialise. If you don`t then your memory is worse than mine.

I have that gut feeling that something could go wrong between now and Monday due to the amazing near miss. You can`t blame me?

But shirley it can`t be cry wolf again.

I must be careful here as these are not drivers but they present a Negative AO .......

Im cautious of AO/NAO forecasts ....non drivers subject to model changes..but im liking the latest forecast

Edited January 11, 2013 by ChartViewer

[mcweather]

For those in the west feeling a bit disappointed. Ian F points west at 6-55 said he wouldn't be at all surprised to see mondays' warnings revised westwards to cover that area. also gave a heads up for a a snow event affecting a much wider area than mondays event next wed /thursday so still some movement in the models yet by the sounds of it.

ps sorry for repitition, just seen nick sussex's post on previous page

Edited January 11, 2013 by mcweather

[UV-RAY]

Positive NAO and Atlantic dominance for the foreseeable future after mid week? The details for the beginning of the week aren't even sorted yet!

A poor attempt at a wind up, obviously you couldn't be bothered to look at the latter stages of the ECM.

[Partholon]

In what way?

just to point out this is the guy i quoted a couple of weeks ago, who dismissed the chances of an easterly happening back in mid- December, due to the strat profile at 50hpa and 70hpa. he said because of this the weather would be zonal for the rest of December.

however, for the sake of balance,i should point out he was highly skeptical of a stratosphere warming occuring in January. all in all his views should not be dismissed out right

Edited January 11, 2013 by Partholon

[manutdmatt1986]

A poor attempt at a wind up, obviously you couldn't be bothered to look at the latter stages of the ECM.

You mean the stages that are well beyond the reliable time frame? Nevermind that the ECM is just one model and only the other day was showing a prolonged cold spell on the scale of 1947 in FI. Christ

The early stages of next week are still uncertain so how can prospects beyond that be certain?

Edited January 11, 2013 by manutdmatt1986

[Weathizard]

12z GFS ens are such an improvement, just had a look and they are, compared to the 6z, a HUGE step forward. Although saying that the ENS are very fickle at the moment, most seem to go for more cold. Will be interesting to see which way the ECM ens go after 144. I'd wager its a mild outlier of sorts.

Prior to worrying about what happens after, fantastic oppourtunities for snow in the coming week. Good charts are within reliable this time!

[gaia rules]

"Don't call me shirley" Precipitation can be modelled very well up to 5 days away, seeing as this is only 72 hours away, I think we should be fine in that respect.

I'm not so convinced of their accuracy even at 72 hours. When it comes to modelling snow I wouldn't trust any forecast beyond 36 hours particularly for Monday/Tuesday event that is changing with each run and Ian F is now thinking it will all shift west.

[Su Campu]

just to point out this is the guy i quoted a couple of weeks ago, who dismissed the chances of an easterly happening back in mid- December, due to the strat profile at 50hpa and 70hpa. he said because of this the weather would be zonal for the rest of December.

however, for the sake of balance,i should point out he was highly skeptical of a stratosphere warming occuring in January. all in all his views should not be dismissed out right

I was never sceptical, highly or otherwise, about an SSW in January. I did say though that I felt that that as December had passed our chances of proper cold may have passed. I may have been wrong on that front (no pun intended).

[ANYWEATHER]

"Don't call me shirley" Precipitation can be modelled very well up to 5 days away, seeing as this is only 72 hours away, I think we should be fine in that respect.

Sorry to say precip is difficult to model at 24 hrs generally, let alone 72hrs!

[Su Campu]

You mean the stages that are well beyond the reliable time frame? Nevermind that the ECM is just one model and only the other day was showing a prolonged cold spell on the scale of 1947 in FI. Christ

The early stages of next week are still uncertain so how can prospects beyond that be certain?

As I said, look past the models. There is fairly good agreement at a 500 hPa scale for the next few days, with a dipole setting up either side of the Pole. Projecting that on, retrogression looks unlikely and we should see those dipoles move only slowly. We lie in between, with the Atlantic in relative control.

[Partholon]

I was never sceptical, highly or otherwise, about an SSW in January. I did say though that I felt that that as December had passed our chances of proper cold may have passed. I may have been wrong on that front (no pun intended).

perhaps you did not use the words sceptical, but i'm fairly sure you said you doubted it would happen. you also dismissed the chances of blocking to our north west as the winter progressed. you seem to be now suggesting you may have been wrong about the latter.

Edited January 11, 2013 by Partholon

[manutdmatt1986]

manutdmatt totally agree with you cant believe your still about after our days over at the mail and the moving planet forum! Nice to see someone i know

Hi Rapodo. I remember you from that forum but I don't go on there anymore.

I would also like to add that the ECM actually shows another blast of cold air from the North East right at the end of FI. Hardly Atlantic driven!

Edited January 11, 2013 by manutdmatt1986

[phil nw.]

Can we stick to whats in the models-there`s too many posts making unsupported views or straying off topic.

This thread is only as informative as you the members make it.at the end of the day.

Please think before posting in here-thanks.

[J10]

About 40 minutes ago I posted the synoptic extract from the Ski Blog it is now out in full here. http://forum.netweat...h-january-2013/

Turning very cold over the Alps this week, but with variable precipitation, the most of any precipitation in Eastern parts of the Alps.

[kev238]

I think this precipitation is well modelled as it is passing southeast... I am always dubious when it comes to precipitation when pushing in from the south from sliding low pressures but this looks well modelled by all now in the 72 hour range

[Frosty.]

I don't think GP was buying the Ecm sinking high solution this morning so i'm expecting a lot more changes in the coming days and maybe the very cold spell will be extended much longer with no mild blip inbetween. Meto update today was not even hinting at sinking high later next week despite what the ecm 00z was showing, so we start again with the 00z tomorrow on a fresh page with probably an even better outcome.

It looks like there will be significant accumulations of snow in the next five or six days at least, more especially for the southeastern quarter of the uk. freezing spell coming up, hope everyone enjoys some real winter weather for a change

[Gibby]

Good evening. Here is the report from my perspective on the 12z output from GFS, UKMO and ECM for tonight Friday January 11th 2013.

All models show a colder flow from the East gradually developing over the coming 24 hours. A low pressure gradually moves into the SW approaches tonight and on into Europe later tomorrow. An occlusion will move North into the South of the UK by morning with rain which may turn to snow on higher elevations tomorrow evening and night. On Sunday a cold NE flow gives way to slack winds as a weak ridge comes down from the North. This will be followed by a wave depression running SSE over the British Isles over Monday with some widespread snowfall for many Central and Eastern areas at least.

GFS then shows Low pressure sliding away into Europe by midweek with a bitter cold and wintry NE flow establishing briefly with snow clearing to snow showers over the period. Late in the week the weather moderates though with some hard overnight frosts persisting with the least cold conditions likely in the NW over the weekend. Through the start of FI the weather will remain on the cold side of average in the South and East close to High pressure just to the SE. The North and West would see less cold and rather cloudier if largely dry weather before a cold front crossing East over the UK later brings fresher and milder conditions for all with a little rain at times but some good drier spells too.

The GFS Ensembles show a rather cold picture for the next few weeks though the deepest cold weather will be reserved for the early days of next week. The weather looks unsettled at times with some wintry precipitation expected for many at times though with some milder interludes likely in the West especially.

The Jet Stream shows a disorganized pattern for the next three or four days before it looks like a strengthening flow comes across the Atlantic, ridging High over the Eastern Atlantic and down over the UK towards Southern Europe late next week.

UKMO for midday on Thursday shows High pressure near the Shetland Islands with a ridge South over the UK. A depression in the Atlantic looks like sliding SE towards the SW approaches pushing a band of rain, sleet and snow into SW areas later in the day and the following one.

ECM tonight shows High pressure slipping South over the UK later next week with the cold and frosty conditions associated with it releasing their grip as milder Atlantic winds return to the UK late next week and through the weekend with troughs bringing rain East in the flow. A return to rather cold conditions look like developing in the late stages of the run with rain at times and snow on the hills, especially in the North with the days to follow showing potential for a return to the freezer.

In Summary the pattern remains a cold one for at least the next 5-7 days. Snowfall is much harder to predict and is totally dependant on the track of the Low pressures tracking down from the NW. There will always be a trend for Mondays event to be a messy wintry mix over Western Britain while the East look guaranteed for a good snow event. Later in the week there are more opportunities shown from UKMO in particular but thereafter it looks like milder air will gradually develop over the UK though probably not as pronounced as GFS shows. ECM shows great potential for a return to deeper cold following Day 10.