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

[Andy hoyland]

im surprised there so much optimism this morning. i cant see anything now other then a cold snap which gradually loses its grip as the week goes on. all models now suggest average returning by later next week when once there was continued cold, re-loads, and no sign of anything milder. ok, this could change, but a warm up WILL happen at sometime, so its not unrealistic to supose that this mornings runs actually show one.

what was first seen as a possible record breaking cold spell for mid march, is now little more then a few pesky days of rawness which isnt likely to deliver settling snow for most of the country although i expect many will see snow. im not expecting it to beat the snowfall of march 79 here, and certainly not march 1970.

on the down side the outlook does look wetter as a moblie atlantic is suggested when temps rise later next week.

...oh and i dare say we arent out of the woods yet, more cold/below average will be a real pain imho this spring, abit like 83 or 79.

From an observers point of view, every post you make in this forum makes this place just that little but more depressing.

[John Badrick]

From an observers point of view, every post you make in this forum makes this place just that little but more depressing.

I know why does he do that? so annoying

[Man With Beard]

Virtually the whole country under -12C uppers - a collector's item

[Yorkshiresnows]

im surprised there so much optimism this morning. i cant see anything now other then a cold snap which gradually loses its grip as the week goes on. all models now suggest average returning by later next week when once there was continued cold, re-loads, and no sign of anything milder. ok, this could change, but a warm up WILL happen at sometime, so its not unrealistic to supose that this mornings runs actually show one.

what was first seen as a possible record breaking cold spell for mid march, is now little more then a few pesky days of rawness which isnt likely to deliver settling snow for most of the country although i expect many will see snow. im not expecting it to beat the snowfall of march 79 here, and certainly not march 1970.

on the down side the outlook does look wetter as a moblie atlantic is suggested when temps rise later next week.

...oh and i dare say we arent out of the woods yet, more cold/below average will be a real pain imho this spring, abit like 83 or 79.

Can't help feeling you've got out of bed the wrong side ....... which charts are you looking at. This was always going to be a 2-3 day very cold blast ........ nothing has changed .... apart from a change to a forecast for more widespread convective snow showers than frontal snow in the South.

Looks great and notable .... after that, who cares, it is spring and eventually it will get warm. Hopefully you can then cheer up a bit !

Y.S

[shaky]

The degree of model disparity from the midnight runs is proving a headache now for Exeter, not least with GFS moving to the UKMO-GM solution re Sun-Mon developments to south. However, re the N Sea showers, there is at least some better continuity. These could well prove to be a significant event. Note how the upper trough digs-in across the North Sea before then disrupting... the net result, as evidenced by profiles at 12Z Monday for E coastal areas, is that when synthesized across SST's of 4C, tops go up to below -20C. Clearly, this could generate wintertime low-topped CB's and consequently some locally heavy snow showers. Thereafter, by 12Z Tuesday, a repeat exercise with profiles across SST's of 4C could generate CUSC with tops below -10C. These would be high-based, but local convergence - such as in the Dover Straits - could generate some snow showers in places. Anyway, Exeter re-visiting the warnings in discussions this morning, so anticipate some changes in various respects are likely.

Nice one ian!fingers crossed for some heavy snow showers then!!

[Summer Sun]

After a bitter start to the week we finally see temperatures lift towards the end of the week with winds turning north westerly then swinging to the southwest

The full ECM ensemble is trending milder from half way

Edited March 9, 2013 by Gavin.

[fergieweather]

Latest high-res snow depth output has arrived.... for Monday event in south. Broadly supports current yellow warning area albeit crucially, EC snow accumulations (00z, just received) are much more muted in areal sense (effectively SW peninsula and Lyme Bay area). Notably, the only part of S'rn England where both sets of output have absolute agreement on quite significant snow (by 12z Monday) is Dartmoor. Amounts elsewhere in EC much less striking (and for most of the S, absent altogether!), whereas UK4 has broader area south of M4 with trace/small/1-2cm settling and peak amounts Dartmoor and Essex coast of Thames Estuary. It's going to be later tomorrow before we can adequately make a call on the prognosis in the S for Monday's event.

[Bottesford]

Few posts gone this morning - lets keep it model related peeps!

[IDO]

Even the latest GFS runs for Monday's Low show high variance with snow depth:

0z: 06z:

Difficult to know where the highest risk will be when inter model there is so many changes.

[bradymk]

The full ECM ensemble is trending milder from half way

Yes but as you would expect. We are now mid-march and we are not going to get several consecutive days of ice days so the ens are always going to trend milder as the temps next monday are as you say bitterly cold. However they only go to 5c, 5c mid to late March is certainly not mild and springlike. From a personal point of view, I would like to see a few days of cold/snow but then a warmup but I think we will stay cold and below avg for the whole of March. And by the way, for some people (cold and below avg does not mean blizzards)

[bluearmy]

The extended ens not looking as mild as they were. Besides,if the trough does park itself over the uk, holland will be less cold. Away from scotland, wouldn't expect anything too wintry in week 2.

As far as this week being a downgrade? Uppers of -14c at T72 and possible mid march ice days- come on rob. Just as feb was notable for 84 hours of sub -10c uppers, so this march will maybe be referenced in years to come for delivering an ice day post the 10th and such low uppers.

[Welsh_Weather]

I really can't see anywhere away from the far south west getting anything significant as these depressions are always modelled too deep and the weaker the depression is the further south it will be. There may be a few outbreaks of light snow overnight into Monday morning in some other areas from anything that breaks off the main front. All I can see from this is local dustings for some. Hope I'm wrong though, but past experiences tell me I won't be.

This does not include the convective sometimes heavy snow showers the east coast ad south east will get anytime from Sunday night through to Tuesday IMO

Edited March 9, 2013 by Welsh_Weather

[Methuselah]

Please peeps, can we show a wee bit more respect, to those whose opinions do not tally with our own?

[SMU]

http://modeles.meteo.../gfs-0-72.png?6

9999 Posts!!!

The GFs seems to be wanting to push the low up into the SE moreso than the Euros- this is still a developing event-

My own personal opinion is the UKMO model suite for muted PPN is still a little out of kilter, but the models do struggle with dynamic PPN so I guess its to be expected-

For example- the perfect windflow & allignment for a Streamer will deliver endless snow showers but the depth signal is always to low in the models-

I note the NAE starts to drive the shower train 06z T 48...

the rather crude GFs PPn rates has moved the core of the depth from the South central zone east along to Sussex & Kent & Outer london south-

30 mm totals-

http://91.121.16.5/modeles_gfs/runs/2013030906/84-777.GIF?09-6

S

Edited March 9, 2013 by Steve Murr

[Staffordshire]

R.e convection chances further north, mention of cbs so will these be forming overland then instead of just from moisture picked up from north sea and only effecting east coasts? I see the gfs models them getting well into wales but will these of been from the north sea and weakend by then? sorry my convection knowledge is poor

Edited March 9, 2013 by Staffordshire

[mushymanrob]

Can't help feeling you've got out of bed the wrong side ....... which charts are you looking at. This was always going to be a 2-3 day very cold blast ........ nothing has changed .... apart from a change to a forecast for more widespread convective snow showers than frontal snow in the South.

Looks great and notable .... after that, who cares, it is spring and eventually it will get warm. Hopefully you can then cheer up a bit !

Y.S

erm, the charts that have been posted several times a day for the last ten days . yes there was an initial very cold noteable blast that was expected to last a day or two...thats not changed except that its looking like it wont be as severe as previously suggested.... some predicted a daytime max on -4c , ok those might have been reached IF those sypotics became reality...but as usual they didnt.

several of the recent runs predicted re-loads of he cold, predicting a protracted cold spell lasting over a week, very few have suggested a shorter cold spell. so as i see it, the cold chances going on this mornings runs have been significantly shortened.

my post wasnt miserable, it was realistic, most here are looking for either snow (as in a decent dumping) or warm spring sunshine, i dont think either 'side' will be happy with what is a rather gloomy, raw, wet, week ahead, with little in the way of settling snow for most, and precious little warm sunshine.

[bluearmy]

Incidentally, I haven't been paying attention to the hemispheric pattern enough. Nw russia/eastern finland progged to see sub 492 dam thickness later in the week. is that unusual? Remember that arctic ridge on the models a couple weeks back? At the time I posted that would mean frigid for either the eastern seaboard or nw europe. At the time, the models went for the form horse but as reality approaches we see its us !!

[fergieweather]

My own personal opinion is the UKMO model suite for muted PPN is still a little out of kilter, but the models do struggle with dynamic PPN so I guess its to be expected-

Hi Steve, I think if anything, it's the convective PPN element they struggle with - especially adequately advecting showers inland (a known model deficiency, not just with UKMO products) - rather than handling dynamic PPN features (such as warm fronts).

[Frosty.]

Cold fans need to treasure the coming days as these extremely cold feeling scandinavian winds blow in, really impressive for this time of year and putting the winter to shame, there was nothing like this cold rush throughout the winter months, just imagine if there had? It looks like the south of england could have significant snow late sunday and during early next week but then conditions would appear to ease from midweek but remain cold with frosty nights, there is a spoiler low modelled to the nw of the uk after midweek which currently looks like mixing out the cold uppers with at least a possible return to more seasonal weather from next weekend onwards, the models looked more wintry, longer term yesterday but not on today's gfs and ecm 00z.

[Tamara]

Maybe just got out of bed on the wrong side here, so please allow a bit of Imbyism from me on what i agree is a fantastic March set up from a cold/snow perspective.

This Channel low,am i alone in wishing it would just take a massive hike South? Why?because i would have much rather had the possibility ( as they still do further North of convective and perhaps prolonged and heavy snow showers).For the South now we have an all or nothing scenario playing out here imo,The all being a decent dumping from the channel low,or the more likely scenario now of a cloud sheet from the low killing convection in the South,some light snow at best and a bitter wind.I would of rathered a 'clean' solution of sunshine and heavy snow showers as was originally on the menu for all.

As hopeful (and wanting to be excited) as I am I think you have made a good post on an IMBY basis. The general synoptics though are stunning for the time of year and if I was in the south west atm and especially the Channel Islands I would definitely be excited. Eastern and North Eastern parts and areas of the East Midlands maybe have good reason also to be pleased with snow shower potential.

I do agree that other than these fringes and the snow possibility that the penetration of the cold through windchill is going to be something else!

[The Giant Daddy Jackpot]

http://modeles.meteo.../gfs-0-72.png?6

9999 Posts!!!

The GFs seems to be wanting to push the low up into the SE moreso than the Euros- this is still a developing event-

My own personal opinion is the UKMO model suite for muted PPN is still a little out of kilter, but the models do struggle with dynamic PPN so I guess its to be expected-

For example- the perfect windflow & allignment for a Streamer will deliver endless snow showers but the depth signal is always to low in the models-

I note the NAE starts to drive the shower train 06z T 48...

the rather crude GFs PPn rates has moved the core of the depth from the South central zone east along to Sussex & Kent & Outer london south-

30 mm totals-

http://91.121.16.5/m...84-777.GIF?09-6

S

And just look at those totals for the Normandy area - they will be absolutely deluged!

[TEITS]

PS: based on high-res (UK4 / UKV) output UKMO are especially looking at Wash/Lincolnshire/Norfolk/N Cambs area for warning re snow later today/tonight. 2-5cm, locally 10cm. Intensity-dependent re settling given higher depth temperatures and RST's.

Very exciting to hear.

I shall certainly be keeping a close eye on the radar later on because like you say the intensity will be a big factor with regards to snow depth.

Have to say the chart below really is one of the most impressive charts I have seen in my whole time on this forum.

http://expert-images.weatheronline.co.uk/daten/proficharts/en/nae/2013/03/09/basis06/ukuk/t850/13031106_0906.gif

May have to wait many years to see similar 850s being predicted at this time of year.

[Cloud 10]

Greenland high notched up to 1060mb on the 06z gfs.

[TEITS]

Maybe just got out of bed on the wrong side here, so please allow a bit of Imbyism from me on what i agree is a fantastic March set up from a cold/snow perspective.

This Channel low,am i alone in wishing it would just take a massive hike South? Why?because i would have much rather had the possibility ( as they still do further North of convective and perhaps prolonged and heavy snow showers).For the South now we have an all or nothing scenario playing out here imo,The all being a decent dumping from the channel low,or the more likely scenario now of a cloud sheet from the low killing convection in the South,some light snow at best and a bitter wind.I would of rathered a 'clean' solution of sunshine and heavy snow showers as was originally on the menu for all.

This is a very good post and should be taken on board by those in the S/SE. What you say is perfectly plausible and I have seen such a scenario occur in my location, so I know full well how frustrating it could be. At the moment its 50/50 whether the far S/SE is in the ideal position or worst for heavy disruptive snow.

Anyone else like me delighted to see mild temps being predicted.

http://www.wetterzentrale.de/pics/Rtavn22817.png

I might be delighted with the potential this weekend/next week but even I have had enough of cold weather!

Edited March 9, 2013 by THE EYE IN THE SKY

[snowmadchrisuk]

From what I can see r.e. Sunday night/Monday is that the Models have shifted Higher totals away from the SW and changed this to the SE, Kent looks in a good position on both GFS and ECM precipitation charts .