Spring Model Discussion 18Z 6/3/13 onwards....

[Summer Sun]

No it looks like a cloudy high, pass

At least it would be a warm high though and given the stronger sunshine now any breaks in the cloud would make it feel very pleasant the south east would be best favoured at this very early stage going by the chart below

Its deepest FI so who knows it could drift east wards and allow a southerly to develop plenty to play for I feel for the final 3rd of the month

Edited March 9, 2013 by Gavin.

[Frosty.]

Cloudy or not, its still a pleasantly warm one. And its not looking that cloudy either until the far reaches of FI.

Well high pressure centred to the southwest of the uk with a moist nwly breeze bringing overcast and probably drizzly conditions don't float my boat, if the high was to the southeast or east with low pressure to the west we would have a warm Sly breeze and probably a lot of sunshine but the depths of FI could just as easily be cold and unsettled.

[Frosty.]

At least it would be a warm high though and given the stronger sunshine now any breaks in the cloud would make it feel very pleasant the south east would be best favoured at this very early stage going by the chart below

I will believe it when the meto change from the current cold, showery outlook with widespread frosts.

[Summer Sun]

Re for the potential snow in the south Ian Fergusson tweeted this a few minutes ago

@Rosswsm NAE worries me, pushes it all (snow) back into the channel, whats the thinking from the expert charts there? Thanks.

@fergieweather yes Ross, the trend continues a southward rather than northern bias; hopefully worst will miss entirely. Will see.

Edited March 9, 2013 by Gavin.

[Cheshire Freeze]

Plenty of colder options in the GEFS. All up in the air really.

[J10]

No it looks like a cloudy high, pass

Indeed I wouldn't be happy with that , however if the high was a bit further north and east , I'd be much happier.

[Rammie]

Apologies for posting in here, but would like to clarify something.

What is the model output showing now for England, Sunday to Tuesday? Judging from the slow post rate in here, I'm guessing the ppn possibility is lower than was thought a day or two ago. But what about the cold? That talk of -10 uppers, even -12 or 14. Is all that off now as well?

[nick sussex]

Apologies for posting in here, but would like to clarify something.

What is the model output showing now for England, Sunday to Tuesday? Judging from the slow post rate in here, I'm guessing the ppn possibility is lower than was thought a day or two ago. But what about the cold? That talk of -10 uppers, even -12 or 14. Is all that off now as well?

No those values are still on, its the snow potential which is more uncertain especially for southern areas.

[AWD]

Apologies for posting in here, but would like to clarify something.

What is the model output showing now for England, Sunday to Tuesday? Judging from the slow post rate in here, I'm guessing the ppn possibility is lower than was thought a day or two ago. But what about the cold? That talk of -10 uppers, even -12 or 14. Is all that off now as well?

Still got the very cold upper air temperatures forecast for the beginning of the week;

Uncertainty on snow distribution although nothing major currently being shown with confidence.

[lord stratus]

Apologies for posting in here, but would like to clarify something.

What is the model output showing now for England, Sunday to Tuesday? Judging from the slow post rate in here, I'm guessing the ppn possibility is lower than was thought a day or two ago. But what about the cold? That talk of -10 uppers, even -12 or 14. Is all that off now as well?

A couple of chilly mainly dry days out to Tuesday then a warming trend. A little snow is possible tonight and tomorrow but not much to speak of really.

[Thundery wintry showers]

The cold 850hPa temperatures are still there, generally between -11 and -13, and -14 locally.

The precipitation projections have shifted the main frontal zone away from the south of England for Monday. On the other hand, moderate snow showers are forecast quite widely for eastern areas on Sunday (a slight cap above the 800hPa level will restrict convection but will not come close to preventing it altogether). These are likely to continue through until around Monday lunchtime but the weather is likely to turn increasingly dry and cloudy as Monday progresses, due to a more extensive cap on convection over the North Sea. I think Tuesday and Wednesday are looking brighter and less cold with scattered wintry showes.

I am in agreement with Jackone about the GFS FI- I think the high is a bit too far south and west for much in the way of sunshine, and the moist westerly flow could well bring some drizzle to western and northern Britain, but a bit further north and east and we'd be talking a spell of warm sunshine. However the scenario with the most support seems to be changeable with temperatures slowly recovering close to average.

Edited March 9, 2013 by Thundery wintry showers

[Cheshire Freeze]

Seeing as it looks like we'll quickly lose the cold (based on current trend of modelling), it'd be nice to get some convective showery weather.....alas it doesn't even look (at present) like there's much chance of this.

It's quite sad IMO how this cold blip is to manifest itself. Earlier in the week it looked like an unstable, bitter NE'ly flow with the high liklihood of embedded trough features. Now it looks like a 2 day cold spell with the main low going too far south and nothing special in terms of convection elsewhere. Story of this winter repeated.

[LomondSnowstorm]

I'd be wary of writing anything off in terms of snowfall amounts, certainly with the hard to predict convective element in play. All it takes is one prolonged streamer tomorrow evening to give a good dumping to a given location in the eastern half of the country, and with the upper air profile you could be looking at powder snow and rain to snowfall ratios well in excess of 10:1.

[Rammie]

Thanks for the responses guys. Al least it should feel cold with uppers like that. Just hope the wind picks up too.

[AWD]

Thanks for the responses guys. Al least it should feel cold with uppers like that. Just hope the wind picks up too.

Windchill also looking rather chilly too;

[nick sussex]

The ECM has a deeper low further north at T48hrs compared to the UKMO.

The fax charts better than expected given the UKMO raw output, the key is the T72hrs to see what the ECM does with the track of the low.

Actually we really need the in between parts and we only get a 24hrs jump with the ECM which is a shame.

Edited March 9, 2013 by nick sussex

[bluearmy]

isnt it funny that exeter modified the raw gm yesterday evening at day 4 to place the depression over brittany as per ecm (and gfs). 24 hours later and we see that the ukmo gm was right and they should have gone with it !

[nick sussex]

The T60hrs fax chart shows the low heading more ne, it does get close to the se quarter:

This would tie in with the trend to have an arc of precip extending out of France but I really wouldn't trust the output in terms of detail because theres not a big margin for error.

At this point theres still time for changes.

[A.J]

The ECM has a deeper low further north at T48hrs compared to the UKMO.

The fax charts better than expected given the UKMO raw output, the key is the T72hrs to see what the ECM does with the track of the low.

Actually we really need the in between parts and we only get a 24hrs jump with the ECM which is a shame.

good spot Nick, ECM has LP centre definitely further north at T48 compared with UKMO & GFS 12z outputs....LP centre deeper on the ECM output than UKMO.....I would imagine if verified this would throw ppn further north and north east as well as strengthening ppn signal?

comparison charts from meteociel, GFS/UKMO/ECM 12z outputs at T48

[IDO]

Another mild GFS op compared to the mean (2m temps):

Still some ensemble members keeping it cold, but dwindling (850s):

So it is possible the recent milder op runs are onto something and will pull the mean up up in due course.

Edited March 9, 2013 by i'm dreaming of...

[Cloud 10]

Convection heaven for Northern and Eastern areas of the UK at 96hrs on this evening's ECM,

with uppers between -8 and -11.

Lovely cross polar flow.

[Summer Sun]

Pleased to see GFS FI is onto something once more the ensembles are going in the right direction the final 3rd could be the best part of the month if your a mildie like me

All in all we are heading in the right direction again tonight

[Summer Sun]

ECM is slowly but surely shifting the flow to a south westerly cool at first but milder air should follow on

[Dave Kightley]

Won't be in a South West flow once it clears south and east.... Whenever that is...

[Stuie]

Pleased to see GFS FI is onto something once more the ensembles are going in the right direction the final 3rd could be the best part of the month if your a mildie like me

All in all we are heading in the right direction again tonight

I suppose Gavin you are in a no lose situation, it can only go 1 way temp wise. Could you imagine anything lower? The scatter doesn`t even fill you with confidence that anything springlike is in a reliable time frame.