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

[Snowman.]

http://www.meteociel...H1-240.GIF?31-0

& finally a difficult chart to acertain the surface conditions- very cold in the SE, warming up in the NW- energy trying to undercut- scandi pressure could be higher -

that chart could be a small tweak away from being a lot better- again similarities to feb 12

S

We both know steve that SE did well from that but only on the break down.

[MR EXTREMES]

http://www.meteociel...H1-240.GIF?31-0

& finally a difficult chart to acertain the surface conditions- very cold in the SE, warming up in the NW- energy trying to undercut- scandi pressure could be higher -

that chart could be a small tweak away from being a lot better- again similarities to feb 12

S

steve i think its to progressive it certainly sinks very quick and im firmly going for changes on the ecm on tomorrows runs i think its still a good progression up until t216.

very happy with tonights outputs.

[shotski]

Mmmmmm.... are we seeing something developing here ? All models seem to be performing well now

out to about day 5 at least, are we seeing or expecting anymore impact from the strat warming ?

Shotski

[MR EXTREMES]

We both know steve that SE did well from that but only on the break down.

im sorry but could you post some charts and explain a little clearer your thinking.

[mountain shadow]

Surely the 240 chart is a poor one?

A brief flirt of cold air followed by the Atlantic tearing back in with a renewed Greenland vortex.

Hardly the bitterly cold mid February promised.

[bluearmy]

people - dont analyse a day 10 chart so deeply. it wont look like that. more food for thought. we do need to get some energy into the cut off euro trough though otherwise it just fills and cant advect any deep cold west. within a broad pattern, some interesting options are there (including the ridge sinking and the atlantic rolling in!). wonder if we'll get a decent clustering at day 7 tonight on the postage stamps?

[MR EXTREMES]

Mmmmmm.... are we seeing something developing here ? All models seem to be performing well now

out to about day 5 at least, are we seeing or expecting anymore impact from the strat warming ?

Shotski

looking from the northern hemisphere charts that looks mighty impressive wedge lol.

[nick sussex]

In terms of the Icelandic wedge , it would be good if we could get this a bit bigger and further west!It's not worth worrying too much about the later stages, that wedge at 144hrs could prove pivotal and its the first sign of it appearing in the more reliable timeframe.

So big wedge further west gives us more margin for error and a stronger foundation going forward.

[bluearmy]

We both know steve that SE did well from that but only on the break down.

not on the break down. it snowed after a few days of cold and the snow lay for a further week. the break down was rubbish as i recall.

[winterof79]

http://www.meteociel...H1-240.GIF?31-0

& finally a difficult chart to acertain the surface conditions- very cold in the SE, warming up in the NW- energy trying to undercut- scandi pressure could be higher -

that chart could be a small tweak away from being a lot better- again similarities to feb 12

S

You can sense when things are looking up for the s/e.Here was i thinking there was to be no outlook for cold.

Looks ok for other parts of the UK too http://www.meteociel.fr/modeles/ecmwf/runs/2013013112/ECH1-120.GIF?31-0

http://www.meteociel.fr/modeles/ecmwf.php?ech=120&mode=0&map=1&archive=0

[ANYWEATHER]

Really no point in going further than early next week, but it seems the cold is coming back and being upgraded from the ecm and gfs in the last few days, some very interesting model watching in the days ahead as well as some interesting weather!

[bluearmy]

Surely the 240 chart is a poor one?

A brief flirt of cold air followed by the Atlantic tearing back in with a renewed Greenland vortex.

Hardly the bitterly cold mid February promised.

bit imby MS. please lets not over disect a day 10 chart. fwiw, most of the energy is headed well to our ne and the ridge is reforming out west. the weak trough coming in could easily disrupt and send a shortwave se into france. its such a messy looking chart that it really doesnt derserve such attention. if it were gfs we would prob ignore it.

[Snowman.]

im sorry but could you post some charts and explain a little clearer your thinking.

Sure

Very cold uppers reach us a few days later the breakdown begins.

That dumped around 6-8" around the SE didn't stay long as it was a breakdown event but was good while it lasted.

The only snow to fall that year and a lot too just wasn't sustained and was a very dry easterly as it build over us leaving the northern half exposed to mild temps.

[SMU]

You can sense when things are looking up for the s/e.Here was i thinking there was to be no outlook for cold.

Looks ok for other parts of the UK too http://www.meteociel...H1-120.GIF?31-0

http://www.meteociel...map=1&archive=0

I think you will find I commented on the other charts with the snow risk for various regions

Perhaps the thread is moving along to fast for you

S

Edited January 31, 2013 by Steve Murr

[Snowman.]

Surely the 240 chart is a poor one?

A brief flirt of cold air followed by the Atlantic tearing back in with a renewed Greenland vortex.

Hardly the bitterly cold mid February promised.

Promised by who the weather gods?

[winterof79]

I think you will find I commented on the other charts with the snow risk for various regions

Perhaps the thread is moving along to fast for you

S

Probably Steve its my age Things slowly coming together i feel.

[Frosty.]

I'm hoping the ecm 12z is setting the trend for later next week and beyond, synoptically way superior to gfs and prolonging the cold and snow risk, the gfs continues to have a love affair with the Azores high, we can't say which way things will go yet but at least next week will be turning cold with increasing risk of snow and widespread frosts after the less cold sunday, there is still plenty of time for the period beyond T+240 to show the cold block to the NE winning,,mid feb onwards is still there for the taking despite the best efforts of the gfs.

[nick sussex]

Its better to see small positive changes in the earlier timeframe than wonderful output well into FI which is liable to implode because of dodgy foundations.

So lets think positively both the ECM and UKMO are upgrades at 144hrs that's our walls put up, now we need a strong roof to support all the snow that should hopefully be falling!

[Tim Bland]

Sure

Very cold uppers reach us a few days later the breakdown begins.

That dumped around 6-8" around the SE didn't stay long as it was a breakdown event but was good while it lasted.

The only snow to fall that year and a lot too just wasn't sustained and was a very dry easterly as it build over us leaving the northern half exposed to mild temps.

Just been looking through last years pics and tweets etc...

Was an all snow event here and lasted a few days with a further snowfall 3 days later which the led to the breakdown.

Steve has been very fair in pointing out snow opportunities for any uk region as and when he sees them. I don't understand why he and TEITS get so much flack on he when they mention their own regions. They are valued posters IMO and should be respected for their input.

Back on subject and looking at the bigger picture the cold spell next week seems to be gradually upgrading day by day, which is great because its normal to see it downgrade. Hopefully a NW followed by N followed by NE flow then there's something for everyone! No deep freeze but plenty of falling snow likely in the next week or so

[lorenzo]

http://www.meteociel...H1-168.GIF?31-0

Not bad with that shaft of high pressure & an elonged trough due to trough disruption heading over the UK- again promising some snow on its eastern flank-

Cold with maximas ~ 3c for the MEAN.

The 192 could look very good.....

S

Looking at this stage of the ECM run what would you be looking out for within the ECM postage stamps Steve to improve the 192 position to very good vs Hum.. between this point and the end of the run well beyond my ability to compute different solutions ! Any pointers..

[Gibby]

Good evening. Here is the evening report on the 12z output from GFS, UKMO and ECM for today Thursday January 31st 2013.

All models are fairly agreed on the pattern between now and the middle of next week. The current Westerly flow turns Northerly tomorrow as a developing frontal system crosses and exits Southern Britain later tonight and tomorrow morning. Rain will spread East over Southern Britain tonight, clearing away East through the morning as cold Northerly winds usher wintry showers down Eastern Coasts and rain showers down the Western side of Britain through tomorrow afternoon and evening. Clearer weather follows with a cold and bright day likely for all on Saturday with the few snow showers near Eastern coasts early in the day dying out later. A frosty Saturday night looks likely as a ridge crosses down from the NW followed by a warm front which brings a windy and wet day on Sunday in temperatures returning to near normal. The first few days of next week sees a strong WNW flow over the UK with innitial rain clearing SE with increasingly wintry showers penetrating SE over the UK towards the middle of the week when thing could become quite wintry at times with frequent snow showers in a biting Northerly wind, especially towards the East.

GFS then shows the isobars opening out later next week as milder air tries to drift in from the West with High pressure inching close to Western Britain. A light Northerly still predominates at the start of the weekend before milder winds infiltrate into the UK from the NW. The rest of FI shows changeable weather for most with the trend to rather milder conditions later in FI.

The GFS Ensembles show a rather cold picture for the best part of the run before an improvement in temperatures to near normal levels occurs late in the run. Occasional rainfall occurs nationwide at various points throughout the run indicating a persistence of Low pressure close to our shores.

The Jet Stream shows a continuation of the flow over the UK from the NW on the Eastern flank of the ridging over the Atlantic of the Atlantic High pressure area.

UKMO shows Low pressure over Scandinavia with cold North or NNW flow with wintry showers over the UK, heaviest in the North and East and around coastal exposure in the West too.

ECM tonight shows a rather cold second half to next week with a flow from the NW or North with wintry showers at times, especially once more in the North and East. By the weekend a ridge is collapsing SE over the Uk with a cold day for the South and East on Saturday with wintry showers in the SE with a mild SW flow developing over the NW with wind and rain approaching.

In Summary tonight there is a real mish mash of synoptics tonight all of which point to the same general pattern created by High pressure to the SW and West and Low pressure to the North and East with attendant spells of rather cold and showery conditions with some snow over the hills. Sandwiched within these lengthy rather chilly spells are some short milder interludes with some rain. There seems little evidence of any slide into anything very wintry tonight.

[Richie V]

Good evening. Here is the evening report on the 12z output from GFS, UKMO and ECM for today Thursday January 31st 2013.

All models are fairly agreed on the pattern between now and the middle of next week. The current Westerly flow turns Northerly tomorrow as a developing frontal system crosses and exits Southern Britain later tonight and tomorrow morning. Rain will spread East over Southern Britain tonight, clearing away East through the morning as cold Northerly winds usher wintry showers down Eastern Coasts and rain showers down the Western side of Britain through tomorrow afternoon and evening. Clearer weather follows with a cold and bright day likely for all on Saturday with the few snow showers near Eastern coasts early in the day dying out later. A frosty Saturday night looks likely as a ridge crosses down from the NW followed by a warm front which brings a windy and wet day on Sunday in temperatures returning to near normal. The first few days of next week sees a strong WNW flow over the UK with innitial rain clearing SE with increasingly wintry showers penetrating SE over the UK towards the middle of the week when thing could become quite wintry at times with frequent snow showers in a biting Northerly wind, especially towards the East.

GFS then shows the isobars opening out later next week as milder air tries to drift in from the West with High pressure inching close to Western Britain. A light Northerly still predominates at the start of the weekend before milder winds infiltrate into the UK from the NW. The rest of FI shows changeable weather for most with the trend to rather milder conditions later in FI.

The GFS Ensembles show a rather cold picture for the best part of the run before an improvement in temperatures to near normal levels occurs late in the run. Occasional rainfall occurs nationwide at various points throughout the run indicating a persistence of Low pressure close to our shores.

The Jet Stream shows a continuation of the flow over the UK from the NW on the Eastern flank of the ridging over the Atlantic of the Atlantic High pressure area.

UKMO shows Low pressure over Scandinavia with cold North or NNW flow with wintry showers over the UK, heaviest in the North and East and around coastal exposure in the West too.

ECM tonight shows a rather cold second half to next week with a flow from the NW or North with wintry showers at times, especially once more in the North and East. By the weekend a ridge is collapsing SE over the Uk with a cold day for the South and East on Saturday with wintry showers in the SE with a mild SW flow developing over the NW with wind and rain approaching.

In Summary tonight there is a real mish mash of synoptics tonight all of which point to the same general pattern created by High pressure to the SW and West and Low pressure to the North and East with attendant spells of rather cold and showery conditions with some snow over the hills. Sandwiched within these lengthy rather chilly spells are some short milder interludes with some rain. There seems little evidence of any slide into anything very wintry tonight.

Brilliant as ever Gibby. I think some members need to take stock and read you in summary part over and over, this is true of some of the more expierienced also. Lots of ferreting around for the next ice age in mid FI going on today!

[Snowman.]

Just been looking through last years pics and tweets etc...

Was an all snow event here and lasted a few days with a further snowfall 3 days later which the led to the breakdown.

Steve has been very fair in pointing out snow opportunities for any uk region as and when he sees them. I don't understand why he and TEITS get so much flack on he when they mention their own regions. They are valued posters IMO and should be respected for their input.

Back on subject and looking at the bigger picture the cold spell next week seems to be gradually upgrading day by day, which is great because its normal to see it downgrade. Hopefully a NW followed by N followed by NE flow then there's something for everyone! No deep freeze but plenty of falling snow likely in the next week or so

Yes agreed here I do believe Feb could end with a BIGGER bang but every needs to be right heights in the NE need to be much higher than those in the South west, south and south east if we want some kind of holy grail easterly.

goes to show the MJO signals and other background signals show a different back story.

[Zenarcher]

Evening everyone it's been a while since I done a comparison between the models but today things are starting to look interesting again.

Next 72 Hours - High pressure sits to the South of the UK this will bring mainly cloudy weather with showers for Friday and the weekend, Saturday looks good for England clear and sunny through the afternoon. The wind will be strong at times over the next 3 days with gales likely at times mainly for those in the West and North. Minimum temperatures during the nights and early mornings look cold for inland areas.

Onto the models I see a slight disagreement over the Atlantic low here, most models show the low to exit the jet stream just off the South of Iceland and deepen the UKMO delays the exit of the jet stream and has the actual low placed slightly further South.

Here's the difference the GFS has good support here where the UKMO doesn't have much.

96 Hours - Two things to look at here,

Atlantic Ridge - All models seem keen on building one up at this point apart from GEM as the image below shows what most models show compared to GEM,

Atlantic Low - The UKMO didn't have too much support on it at 72 hours but gains a lot of support from the lesser known models they have placed it right to the far North of Scotland meanwhile the GFS and ECM have it further West close to Iceland as the image below shows the differences here between the two ideas,

One thing they do agree on is things do look very unsettled for the Northern half of the UK, very windy and wouldn't be surprised to see wintry weather there as well.

120 Hours - Things start looking better for cold weather here the models continue to build up an Atlantic ridging meanwhile the low to our North sinks South bringing a cold North Westerly wind across the UK again wintry weather would be likely especially for the North of the UK.

GEM is the only one that looks different here the Atlantic ridging is not too strong but with little support from earlier on I wouldn't read too much into it.

144 Hours - Model confidence at this stage is low but something like the UKMO and ECM look good with the Atlantic ridging still in place and over at the UK a cold NW'ly flow continues. However some models try to flatten things out here and send energy going over the ridging and make it sink.

Overall - Some disagreement in the early time range at 72 hours which leads to where the low ends up at 96 hours either right over the North of the UK or just to the East of Iceland. Later the models do agree on an Atlantic ridging building up while the low to the North sinks down South over the UK which could bring some wintry weather to some parts.

Edited January 31, 2013 by weathermaster

[J10]

With NW winds such as these western coastal districts can do very well, as luck would have it when the wind direction which suits us a best a NNW occurs early hours into Wednesday when the colder uppers and not there, saying that though some snow showers looking possible on Tuesday night.