Spring Model Discussion 18Z 9/3/13 onwards....

[Blake]

You shouldnt be using the GFS accumulation charts they are very unreliable! You would find that by today's runs that it would change quite dramatically!

It wasn't the amounts or locations as such as I am more than aware that it means little when in FI but moreso the return of cold again with ppn over parts of the UK as mentioned by a few that suggests this may be one of many more chances to see the white stuff before winter leaves us.

I think winter is playing catch up after the SSW. Are spring months usually cooler when SSW takes place around the turn of the year?

[stratty]

Morning All

My 10000th Post from being here ~ 8 Years-

Only usually posting in the winter threads thats 12 posts a day where has all the time gone!

Its been a fantastic 8 years posting on net weather- thanks to everyone for making it a great forum ( even with the rollercoaster ups & downs)

best regards

Steve

Happy 10000th Steve thanks for your continued input!!!!!!!!!!

[SLEETY]

Here is something I wasn't expecting to see a slight shift N of the LP according to the 06Z NAE.

http://expert-images...031109_1006.gif

See what I mean teits this isnt over yet,a nowcast situation is what is needed for this.

[SMU]

nae 06z t36

http://expert-images.weatheronline.co.uk/daten/proficharts/en/nae/2013/03/10/basis06/ukuk/prty/13031118_1006.gif

Moving north into the mix

S

[mushymanrob]

I'm sure virtually everyone on here is a pretty reasonable type of person in their daily lives (the majority of people are), so please have a step back before posting and ask yourself whether you would speak to someone face to face in the way your post may be worded and the tone you're using too. We're talking about weather, it's a shared hobby/interest for all of us so there's no need to be aggressive or disrespectful when you're putting your opinions on here

mate, id say things to your face alot stronger then what i post on here! :lol: cos to the face you can pick up on the nuances, the expressions, that cant on type.

Interesting to see the ECM trying to develop colder conditions later after a milder interlude.

yep, pretty much what i expect based on experience, no quick return to average/above average. things have been below av for a while now, i expect a spring on the cool side, at least for another month if not longer.

gibby called this cloud right, along with others i expected a sunnier possible showery spell after yesterdays frontal rain had sunk south. it will come, but not as quick as it first appeared. im still not sure on the distribution of north sea showers, coastal counties look favoured, but the could be a 'wash streamer', where a concentration of more persistent showers could get quite far inland to areas downwind of the wash.

it looks like we might be spared the severest of temps, below -10 uppers indicate quite low daytime maxima, but its mid march, in jan temps would have been much lower.

cool and showery looks like taking over as winds swing around to the north then northwest, west and southwest as the week goes on. it might get milder but cool is never far away. this pattern is i believe likely to last, like spring 83 a cool showery (or periods of rain) outlook with no tangible sign until deep fi of anything much warmer or sunnier.

[Cloud 10]

The ECM 00z ensemble mean is even more bullish than yesterday's 12z for prolonging

the cold spell with -4 uppers covering all of the UK and more at day 10.

Also an "interesting" chart from the operational at 216hrs.

[nick sussex]

the ecm ens mean in fi continues to promise winter nirvana charts with a cold trough sunk across the uk rather than eastern europe. apart from upland areas n half of the uk and many parts of scotland, thats unlikely to deliver too much white stuff that will settle. a few weeks too late. no guarantee that the mean will verify, especially as its unlikely to have naefs support for being quite as amplified (judging be the gefs mean). however, the ultimate in 'sods law' to see this output when its too late for coldies to benefit. no one want to see cold and damp/wet. lets hope history repeats this year when over the past decade, cold march's were followed by decent summers.

EDIT: naefs update isnt too far away - not quite as amplified/deep but pretty good as a wintry set up (if it were winter)

Yes its a bit if only with that set up but certainly I think for those wanting a decent summer it is better to have a colder March, have that northerly blocking now than it appearing early summer and causing another washout.

It does however look potentially very good for the Scottish ski resorts and higher ground in the north might see a bit more fun but I think we'd need to see the troughing getting much further se to deliver more widely.

[bluearmy]

nae 06z shows -15c upper over the midlands tomorrow night !!!!!

only a small area moving in from the wash but hopefully, even if it doesnt make it as far as the midlands, it can verify near the coast.

in my own little world, thats more significant than any transient snowfall we might see. i would exchange that for a proper southern county blizzard (though i appreciate the concerns some have for disruption, most on here are indulging in a hobby where the extremes are what interests them).

[Frosty.]

Still the trend on the GFS 00z and ECM 00z for things to turn less cold next week. How ever It's not going to be particularly mild or cold.

come the end of the week / start of next weekend both the ECM and GFS 00z show a LP centred over or near to the UK that has originated from the NW and subsequently it brings with it much more unsettled weather.

Yes, it would probably still be cold enough for snow on northern hills later in the week and then possibly much colder again soon after. It will be interesting how the met office word this today in their update, since yesterday's update indicated a continuation of the cold theme for the next few weeks with no milder blips inbetween.

[nicknacknoo]

Slighty further North and looks like more of a squeeze on at T39

[SLEETY]

..........the storm that made me fall in love with extreme weather! the 12th or thereabouts, living in Gloucester then. Was but a mere child and had a nightmare in the middle of the night. My mum (Happy Mother Day!) got up with me to get a drink from the kitchen and the first signs of snow were blowing around. Waking up the next morning to see my dad trying to clear the drive with the neighbours, blizzard absolutely chucking it down and snow drifts of already a metre around. The schools were closed right up to Christmas because of temperatures freezing up the pipes....around the minus teens? Father Christmas bought me a weather station (not quite like todays technology! lol) that year and from that day on i took the temperature every day. Happy days. Sorry but the current charts do not show any such thing unfortunately for us! I'm not sure i'll ever see such an event in this country again..............i live in hope!!!!!!!

I'm not the only older one in here then.!

13th December 1981 was the date I think.Started snowing in Sussex around early afternoon by early evening their was close to a foot of snow with 10ft drifts over the downs with people trapped in their cars.However its then that the forecast went dramatically wrong as the centre of the low pressure system which was forecast to run along the channel suddenly veered North and the Snow turned to rain South of the centre of the low pressure system and by morning most of the snow had melted.

So a taste of what things could turn out like with Northern France getting Snow turning to rain and Southern Counties heavy snow if the centre of the low moves North!

[nick sussex]

A small northwards shift in the low which is unusual given the past history of these set ups. It's still on a knife edge though so I think its going to come down to nowcasting.

Later the interest grows somewhat in that the models seem to be slowly edging the pattern a little further east, in this case the surface high over Scandi is a nuisance because it acts to slow that process down.

[jethro]

If this was to swing further North, what are the conditions which would cause this to happen and what should we all be looking for? Can a last minute swing North be predicted or is it a case of just waiting and watching?

[Methuselah]

If this was to swing further North, what are the conditions which would cause this to happen and what should we all be looking for? Can a last minute swing North be predicted or is it a case of just waiting and watching?

Sudden, unexpected deepening is what I'd look for, J. It wouldn't take all that much change in trajectory, for the whole of Southern England to take a pasting...The best course-of-action, IMO, is to take notice of what IF's updates have to say...

[SLEETY]

Tomasz Schafernaker â€@Schafernaker

@fergieweather @carlharlott latest computer model shifts snow slightly north. Could be further north still in reality. watching this space.

[Captain Shortwave]

With this set up given over the pole later on, it would not take much for conditions here to turn very cold again. Impressive arctic high engulfing North East Canada, Greenland, looping over us into Finland and Russia.

Just looked at the ECM this morning. Seems west based -NAO is looking less likely again.

Edited March 10, 2013 by Captain shortwave

[VillagePlank]

Sudden, unexpected deepening is what I'd look for, J. It wouldn't take all that much change in trajectory, for the whole of Southern England to take a pasting...The best course-of-action, IMO, is to take notice of what IF's updates have to say...

That's pretty much what GFS 6z is doing. Here's a comparison between yesterday's and today's 6z - primarily, as a cause, the PFJ tightens up and is less fragmented,

The low is making eastward progress less fast and is deepening, and swinging it the extra 50-100 miles further North. What a difference 1hPa/1Mb makes!

On a knife-edge, that's for sure - another 1hPa deeper and direct hit for London! Probably not, but I don't think the trajectory is completely set, yet. A complete nightmare for the professional forecasters, no doubt.

EDIT: of course, the changes, if you like snow, are for the low to deepen ever-so-slightly over Biscay. If it deepens over the Dover Straits you'd need a 90^o shift (which is never going to happen) Over Biscay, maybe a 10^o shift is enough.

Edited March 10, 2013 by Boar Wrinklestorm

[bluearmy]

Not really captain - that's what the chart you posted shows ??

The gfs op seems keenest and naefs shows the same in fi. Ecm suite just about keeps everything far enough east to keep us cold but at this time of year, that's unlikely to be quite good enough.

[Captain Shortwave]

Not really captain - that's what the chart you posted shows ??

The gfs op seems keenest and naefs shows the same in fi. Ecm suite just about keeps everything far enough east to keep us cold but at this time of year, that's unlikely to be quite good enough.

I was just commenting on the ECM there to be honest. Looking at the post again that might misleading. There are a lot of differences over the pole between the two ops, though probably less difference in the ensembles.

[mushymanrob]

Yes its a bit if only with that set up but certainly I think for those wanting a decent summer it is better to have a colder March, have that northerly blocking now than it appearing early summer and causing another washout.

but with respect nick, theres no corrolation between a cold march/spring and a decent summer , spring 75 cold - summer 75 hot, spring 76 nice - summer hot, spring 83 cold and wet - summer hot, spring 1990 nice - summer hot. of course id swap northern blocking now instead of june, but theres nothing to say we wouldnt get that anyway, its not either or.

[bluearmy]

the latest sat shows good convection north of the frontal cloud shield over the midlands south. One wonders how effectively this will clear, given th shortwave development over biscay. it may well be that the convection is sustained for longer east anglia northwards whilst the southern half midlands southwards, away from the south coast see little precip at all.

[nick sussex]

but with respect nick, theres no corrolation between a cold march/spring and a decent summer , spring 75 cold - summer 75 hot, spring 76 nice - summer hot, spring 83 cold and wet - summer hot, spring 1990 nice - summer hot. of course id swap northern blocking now instead of june, but theres nothing to say we wouldnt get that anyway, its not either or.

If you look at recent years early spring warmth has led to dire summers because the blocking signal arrived early summer. There are no guarantees of course but generally negative phases of both the NAO and AO come in clusters, so its better that we see a signal for northern blocking now, this might then give it time to wane by the summer.

[VillagePlank]

the latest sat shows good convection north of the frontal cloud shield over the midlands south. One wonders how effectively this will clear, given th shortwave development over biscay. it may well be that the convection is sustained for longer east anglia northwards whilst the southern half midlands southwards, away from the south coast see little precip at all.

Not due to be clear of South Coast until this evening,

[shedhead]

Latest guidance goes with my thoughts from yesterday that this event is getting squeezed ever closer to the south coast and that the best chance of any meaningful snow will be across parts of south Cornwall and Devon, particularly south Dartmoor, where some significant totals look possible locally. Think this part of the world looks prone to further upgrades too, but as is often the case we are talking fine, if not very fine lines here, with 20cms or 0cms still both on the table. Snow forecasting has always been notoriously and particularly difficult, so no reason why this situation should be any different.

[TonyH]

Weekly weather guide:

http://forum.netweather.tv/blog/309/entry-4579-weather-guide-monday-11th-to-sunday-17th-march-central-midlands-and-west-wales/