Spring Model Discussion 25th March 2013 012z onwards

[cheeky_monkey]

A look at summer curtsey of CFS

Uppers

June

July

August

Average pressure for the same time

June

July

August

And the 2m temperatures

June

July

August

PS these CFS charts got this cold spell in advance so its going to be a case of seeing what it shows over the coming weeks

If I understand the 2m temperature correctly that would bring average temperatures in the high teens?

A look at the remainder of spring can be found here - http://forum.netweat...80#entry2667888

Judging by those charts looks like July best chance of decent summer weather..June and August dont look great away from the south west.

[mushymanrob]

Thats average not mild (nice in the sun though if we manage to get any.

erm, average is mild sir at this time of the year...

[Purga]

Some serious straw clutching going on looking at charts 3-5 months ahead - LOL

Still the days will be getting shorter by then.

[stodge]

Afternoon all

More extraordinary synoptics on offer and as I'm unable to examine the charts on a daily let alone a six-hourly basis, perhaps the wonderment of them is still with me. Maybe one or two on here should step away for a couple of days and obtain a small dose of perspective. So, where are we going forward ?

http://www.meteociel.fr/modeles/ecmwf/runs/2013032700/ECM1-144.GIF

Out at the fringes of reliable on the 00Z output and the cold airflow (though perhaps more SE'ly than E'ly) is with us. This might well be a clearer and drier airflow with less fetch across the North Sea so the possibility of sun by day but very low night time temperatures especially over lying snow and with that airflow sourced from a snowy Europe, you'd have to say cold. The HP from Greenland is an option that has been toyed with on a few runs and it offers a clear way out of the cold pattern IF it migrates SE into Europe as it would lower heights to the NW in tandem with a northward push of the jet but it's early days on that.

http://www.meteociel.fr/ukmo/runs/2013032700/UW144-21.GIF?27-06

The 00Z from UKMO goes down a slightly different path. Yes, cold, but the HP is more of a ridge than a cut-off or discrete feature. However, the strong NW/SE orientation of the LP systems keeps the UK on the cold side of the street. That said, you could envisage an evolution to a Scandinavian HP which might offer some opportunities for lowering heights to Greenland but again all very tentative and cold very much in charge. As with ECM, not a lot of precipitation on offer especially away from the SW though showers to onshoe E and NE coasts remain on offer.

http://modeles.meteociel.fr/modeles/gfs/runs/2013032706/gfs-0-144.png?6

Off to the 06Z for the GFS output and something of more interest for snow/cold rain fans. The LP is much closer to the south and while I'm not sure I'd be screaming "Channel Low", it certainly offers something of interest to southern counties though I suspect any snow would be for the Cotswolds and the Home Counties rather than right on the coast. The HP is the ECM model of the discrete feature sliding SE past the NE of the British Isles into Europe which would offer possibilties for mild fans. There are hints of pressure rising to the far SW which might disrupt the Atlantic LP trough and re-configure the pattern with HP to the NE and SW and a more typical battleground environment but again that's outside the reliable timeframe.

http://modeles.meteociel.fr/modeles/navgem/runs/2013032706/navgem-0-144.png

http://modeles.meteociel.fr/modeles/gem/runs/2013032700/gem-0-144.png?00

http://www.meteociel.fr/modeles/jma/runs/2013032612/J144-21.GIF?26-0

A selection of the other models. GEM is interesting as it develops the cut-off from the Greenland HP re-positioning toward Scandinavia which is one of the clues toward a slight reset of the pattern toward something more conventional.

So, cold in charge for the foreseeable. All models offer hints and teases of some kind of slight shift in the pattern - we're a long way from an outright pattern change. The focus of blocking might shift to Scandinavia or it might not. I think the clue is not to look at where the HP is but where the LP is or isn't. The stagnant Atlantic trough and its NW/SE orientation aligning with the block keeps us on Cold Street and fans of mild will be looking to change that and there are some hints but only hints and it's hard to be confident about anything approaching even average over the next seven days.

[Paul]

For those of you with Netweather extra subscriptions (full), we just launched beta versions of our new NMM models. The NMM-18 is a medium range model running out to 168 hours, with a resolution of 18km. The NNM-6 is an upgraded version of our existing NMM 8km model, running at 6km out to 48 hours. The two new model viewers can be found here:

NMM-6

http://www.netweather.tv/secure/cgi-bin/premium.pl?action=nmm6;sess=

NMM-18

http://www.netweather.tv/secure/cgi-bin/premium.pl?action=nmm18;sess=

[Radiating Dendrite]

For those of you with Netweather extra subscriptions (full), we just launched beta versions of our new NMM models. The NMM-18 is a medium range model running out to 168 hours, with a resolution of 18km. The NNM-6 is an upgraded version of our existing NMM 8km model, running at 6km out to 48 hours. The two new model viewers can be found here:

NMM-6

http://www.netweathe...tion=nmm6;sess=

NMM-18

http://www.netweathe...ion=nmm18;sess=

Hi Paul,

How does the medium range NMM compare to the other models in terms of resolution etc?

This may be a question for another thread, but am I right in thinking the NMM is your own model? How do you get the data etc if that is the case?

Edited March 27, 2013 by Radiating Dendrite

[Paul]

The NMM-18 is quite a lot higher resolution than most other medium range models - particularly the publicly available ones - it's at 18km, the likes of the GFS, ECM, UKMO etc are all run at around 25-50km, although the output made available is sometimes at a lower resolution depending on the source.

[Snowman.]

A look at summer curtsey of CFS

Uppers

June

July

August

Average pressure for the same time

June

July

August

And the 2m temperatures

June

July

August

PS these CFS charts got this cold spell in advance so its going to be a case of seeing what it shows over the coming weeks

If I understand the 2m temperature correctly that would bring average temperatures in the high teens?

A look at the remainder of spring can be found here - http://forum.netweat...80#entry2667888

Gav they got last summer down well also.

I actually put faith in this model.

[Summer Sun]

Easter Sunday see's the last of the -8 uppers clearing away

The south hits the dizzy heights of 7c

Easter Monday starts with a widespread frost

[swilliam]

erm, average is mild sir at this time of the year...

erm no - these terms (mild, cold warm etc.) refer to the difference from the average not to actual values - hence why the current Meto foracst for the next few days refers to very cold even though temps are around 5C which would certainly not be very cold in January - it would be rather ciold..

[Suburban Streamer]

The NMM-18 is quite a lot higher resolution than most other medium range models - particularly the publicly available ones - it's at 18km, the likes of the GFS, ECM, UKMO etc are all run at around 25-50km, although the output made available is sometimes at a lower resolution depending on the source.

hi Paul

If i recall correctly, the nmm on meteociel is run at 5km, albeit, it only shows roughly half of the UK

[KTtom]

Just some tentative signs of the easterly flow being cut off by the middle of next week with temps edging towards double figures in the south......spring may finally be around the corner..

Edited March 27, 2013 by KTtom

[summer blizzard]

Consensus at day 8 that high pressure will be to the north east of the UK, cold but dry.

[Paul]

hi Paul

If i recall correctly, the nmm on meteociel is run at 5km, albeit, it only shows roughly half of the UK

That's a short range model (eg similar to our 6km version), it's also not the same model - their nmm is run on their servers in house (I assume). We run our own version of the model with (probably) different physics etc within it as there are countless different ways to run it.

[Cheshire Freeze]

I think a warm up then a northerly would be more of a kick in the plums than if it just stayed cold.

But with the AO looking to remain negative, it's more than a possibility.

Anyway, FI conjecture aside, uppers look to moderate next week. However on the flipside I'm unconvinced of how much sun there will be with a cool, cloudy E'ly flow. Could feel just as cold even with warmer air temps.

Edited March 27, 2013 by CreweCold

[mushymanrob]

erm no - these terms (mild, cold warm etc.) refer to the difference from the average not to actual values - hence why the current Meto foracst for the next few days refers to very cold even though temps are around 5C which would certainly not be very cold in January - it would be rather ciold..

i understand that 'cold' and 'warm' are terms to discribe the difference from the norm...but mild? can it be 'mild' in july? wouldnt that be below average? i thought 'mild' was the term to discribe gently warm air, 8-14c . i dont think ive ever known weather be discribed as 'mild' outside nov-april....

[Paul]

i understand that 'cold' and 'warm' are terms to discribe the difference from the norm...but mild? can it be 'mild' in july? wouldnt that be below average? i thought 'mild' was the term to discribe gently warm air, 8-14c . i dont think ive ever known weather be discribed as 'mild' outside nov-april....

This is all getting way off of the topic of the models though, so please if you want to continue take it to a new thread or pm. Fwiw though, John posted up a guide with the Met Office temperature definitions a few years back

http://forum.netweat...re-definitions/

[Tim Bland]

Still no signs of a decent low undercutting so snow fans can have one last horah, It seems like a waste of the cold not to get any snow in the next week. If it's just going to be cold with grey slate sky's id rather have some warmth and I'm about as hard core cold fan as you will get!

[Suburban Streamer]

That's a short range model (eg similar to our 6km version), it's also not the same model - their nmm is run on their servers in house (I assume). We run our own version of the model with (probably) different physics etc within it as there are countless different ways to run it.

ah ok thanks paul, i had often wondered why the nmm output on meteociel is often very different to the output on netweather

[mushymanrob]

i see the 12z continues to suggest the high east of north next week, thats about as good as we can expect i guess assuming there has to be one close by! certainly better for less cold uppers, but the price to pay will probably be alot of stratus. wont be bad though in any breaks in the cloud, so western areas atm could get some decent days.

[rory o gorman]

good end to the gfs , AZ high building vortex back intact . we might get a summer yet

[Summer Sun]

As has been consistent now for a number of days temperatures next week now look like they will moderate somewhat still below average but higher than of late

Tuesday see's highs of 7c to 9c for England and wales

24 hours later we see a tropical 11c in the south west and parts of the south coast with 7c to 9c widely for England and wales

Thursday only goes to 12 noon but looking at those temperature double figures would be reached in the south west and parts of the south coast again with 7c to 9c again widely England and wales

Other than a bit of rain in the west early next week the bulk of the country will be bone dry

Next weeks cloud cover to Friday

Given some sunshine and if the wind was light along with longer days it would feel spring like if nothing else

Edited March 27, 2013 by Gavin.

[swilliam]

i understand that 'cold' and 'warm' are terms to discribe the difference from the norm...but mild? can it be 'mild' in july? wouldnt that be below average? i thought 'mild' was the term to discribe gently warm air, 8-14c . i dont think ive ever known weather be discribed as 'mild' outside nov-april....

I think mild (and rather mild) is normaly used in late autumn, winter and early spring and means about 2-3C above average. In spring and summer they (MeTO) they use warm (and rather warm) as presumably they think Joe public would get confused if they described 10C as warm..I am not sure when they officially switch - maybe JH or IF can clarify. Whatever the actualities are it is clear that there is not going to be anything significantly above average for the next couple of weeks.

Back on topic it seems that the GFS 12Z has continued the idea from the -06Z of the next depression not undercutting at 120.

This leads to the high orienting itself on a SE/NW axis and therefore we end up with a less cold SE flow.

In contrast the UKMO does undercut the depression

And we end up back in a cold NE flow

0Z ECM went with the UKMO - are we heading for another stand off I wonder

[PB22]

I do feel sorry for those who live along the east coast this spring and early summer following this extended cold spell.. When, eventually, conditions do warm up, there will be a horrendous amount of sea mist/fog and low cloud plaguing eastern areas everytime the wind is from an easterly direction thanks to those North Sea temperatures being so subdued. Given synoptic patterns that could be a very frequent occurrence indeed, more so than normal.

[Harsh Climate]

I agree things look like gradually becoming less cold gavin with the chance of any snowfall accumulations becoming less and less. I have officially had enough of this cold spell now and want some warmth!

We have had almost constant snow showers today under -10 uppers, but with absolutely no accumulations. Too late in the season just to be happy with the sight of falling snow lol.