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

[Froze were the Days]

Be very wary again folks we're not going down the 'same route' as a few weeks ago - Fax charts unchanged from UKMO raw output and following a drier pattern although still very cold.

[damianslaw]

Busy in here this evening - must be snow on the way! Its a very cold outlook for the time of year - some truly cold synoptics are on the cards..

All models show the atlantic trough stalling against a very cold pool of air over scandi, forcing frontal systems to retreat back southwards as the bitterly cold uppers move in from the east accompanied by what will be a very raw east wind.

BBC showing maxima of 1 degrees only for many eastern parts come Monday and there will be a return of sharp nightime frosts for many.

The high is projected to anchor to the NW over Greenland and with the PV locked in place over NW Russia/N Scandi and a very southerly tracking jet all the ingredients are there for a sustained very cold spell of weather with snow very likely for many.

We've had cold snowy periods in March on a number of occasions, and there is now a very strong likelihood we will be seeing another one from this weekend onwards.

These are the king of synoptics snow cold lovers long for in the height if winter - better late than never..

[Panayiotis]

CMA looking juicy with cold all the way starting from 96hrs!

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

Also starting at 96hrs the CFS is cold all the way to 540hrs!

http://www.meteociel...&carte=0&run=10

And to end this post, the NASA high res models brings -15C uppers to Scotland with those uppers knocking on the door in the east at 111hrs!

Edited March 6, 2013 by Panayiotis

[nick sussex]

I think before hysteria breaks out in here in terms of what can be expected its essential to view this in its proper context.

The coldest uppers, lowest dew points are likely to last for around 48hrs max, if the GFS/ECM verify then yes that's condusive to generally snow.

Thereafter those low uppers moderate, that's where more marginality comes into the equation, the flow moves round to more n/nw. In mid winter this wouldn't be a problem but I don't think people should view the entire higher resolution GFS as one long snowfest, this will be just raising expectations to levels not achievable.

It might be a case of snow, drier frosty for a day, then a wintry mix before a reload if you go by the ECM,that also has that Channel Low later but far too into the future to put too much faith in.

There are certain things the models can do but they can't stop the increase in solar energy, at this time of year its a bit more uncertain unless you have those very low uppers, time of day when snow falls makes a difference etc.

I think if people view the upcoming pattern in its proper context and the GFS/ECM verify then they won't be too disappointed, very rarely can March just produce one long spell with just snow, you're bound to get a mix of things thrown in.

[ITSY]

CMA looking juicy with cold all the way starting from 96hrs!

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

Also starting at 96hrs the CFS is cold all the way to 540hrs!

http://www.meteociel...&carte=0&run=10

And to end this post, the NASA high res models brings -15C uppers to Scotland with those uppers knocking on the door in the east at 111hrs!

Now THAT would bring convection!

[Yarmy]

Ferocious cold on the NASA GEOS thingy. Never really looked at it before: is it new, and are there any verification stats for it?

[Captain Shortwave]

Ferocious cold on the NASA GEOS thingy. Never really looked at it before: is it new, and are there any verification stats for it?

Yeah, -14 uppers lapping into the UK

[Tom Jarvis]

Ferocious cold on the NASA GEOS thingy. Never really looked at it before: is it new, and are there any verification stats for it?

From what I have heard it is the highest resolution model available on the Internet so. Even higher than the ukmo

[be cause]

CMA looking juicy with cold all the way starting from 96hrs!

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

Also starting at 96hrs the CFS is cold all the way to 540hrs!

http://www.meteociel...&carte=0&run=10

And to end this post, the NASA high res models brings -15C uppers to Scotland with those uppers knocking on the door in the east at 111hrs!

no sign of spring here .. -8 and lower uppers for all up to and beyond the Equinox ...!

[SMU]

I think perhaps some of those lower models are the same as the ECM & GFS but overcook the depth of the cold pool-

However it could be that the big models - like the last cold spell underestimate the cold...

Could we.... Could we get the -16c line get into the UK...

we have 2 chances- 1 monday & perhaps one again weds/ thurs on the second wave....

Last very cold upper day @-15c...

http://modeles.meteociel.fr/modeles/reana/2005/archives-2005-2-28-0-2.png 28th Feb 2005- some 8 years ago, that was just scraping -15c but was a glancing blow from the east... ( was after 10 days of snow though)

Currently this is as close as the 510 line gets

http://modeles.meteociel.fr/modeles/gfs/runs/2013030618/gfs-3-96.png?18

S

PS I am limiting my posts to 7 a day until sunday- I would like my 10,000 th post to say HEAVY SNOW¬¬¬

[Timmytour]

Well it continues to look good for cold lovers....and the hopes of accompanying snow are high enough to get excited.

Excited wasn't the word I'd use to describe whoever delivered the London and SE forecast thisevening at 10.30pm..."and little change for the weekend". Immediately followed by John Hammond on about as big a ramp as I've seen from a BBC forecaster from 5 days out! And a 5C difference in the temps they showed for London on sunday!

[peterf]

From what I have heard it is the highest resolution model available on the Internet so. Even higher than the ukmo

time will show if it's any good.

[TEITS]

Im not knocking the Met O but im utterly amazed at the latest fax charts. Why go with the UKMO raw output when the evidence strongly suggests its wrong.

John asked what should the fax look like and the answer is below.

http://www.meteociel...M1-120.GIF?06-0

I watched a Look East forecast earlier which suggested Max temps of 7C, min 4C on Sunday. Well the GFS certainly disagrees with this.

http://www.wetterzen...s/Rtavn9617.png

No doubt some will defend the BBC/Met O but in my opinion both the Fax charts and the BBC Look East forecast are dreadfully wrong. I have saved tonights fax charts onto my laptop such is my confidence that they will change.

Edited March 6, 2013 by THE EYE IN THE SKY

[nick sussex]

I think perhaps some of those lower models are the same as the ECM & GFS but overcook the depth of the cold pool-

However it could be that the big models - like the last cold spell underestimate the cold...

Could we.... Could we get the -16c line get into the UK...

we have 2 chances- 1 monday & perhaps one again weds/ thurs on the second wave....

Last very cold upper day @-15c...

http://modeles.meteociel.fr/modeles/reana/2005/archives-2005-2-28-0-2.png 28th Feb 2005- some 8 years ago, that was just scraping -15c but was a glancing blow from the east... ( was after 10 days of snow though)

Currently this is as close as the 510 line gets

http://modeles.meteociel.fr/modeles/gfs/runs/2013030618/gfs-3-96.png?18

S

PS I am limiting my posts to 7 a day until sunday- I would like my 10,000 th post to say HEAVY SNOW¬¬¬

Lol! How are you going to cope Steve if the output throws out some even colder solutions? 7 posts a day!

If the -16 hits in March that would be equivalent IMO to easily a sub -20 winter reading, even more noteworthy would be this coming later into the month.

[Purga]

What a cracker!

[Captain Shortwave]

Great ensembles from the gfs, keeping the extremely cold spike Sunday - Tuesday. The bbc website has london as +5 max on Sunday, just 2 degrees Monday which is a little more in line with output.

Hopefully we will wake up tomorrow morning with UKMO backing gfs/ecm to day 5.

[chris55]

At 120 we can not be confident of any outcome. We do have decent agreement of the broader pattern but the FAX and UKMO raw just highlights how at this range nothing is to be taken as gospel. A nudge south of the high and the instability would be reduced significantly.

Plenty more runs between now and Sunday, so plenty of time for changes.

If we take ECM and UKMO at 96, subtle changes can have a large impact on how good a flow it is for the UK and at 4 days out neither can be taken with 100% confidence.

[Duane S.]

Haven't posted for a while but have kept a watching brief on events unfolding over the past 7 days. I must say these are astonishing synoptics right here on the reliable timeframe doorstep. For me, the writing was on the wall when the GEFS ens started showing massive agreement for the upcoming cold spell run after run. Even if we don't end up with the more extreme offerings it could be a once in a xx year Mid-March cold spell for the south. For snow /ice days down here at that time of year we need the very best setup and that is pretty much what is on offer.

[Mucka]

GFS 00z much the same as recent runs, the high perhaps fractionally further SE while UKMO is an improvement but still not as good as GFS with the initial Easterly.

Very nice GEM 00z

Edited March 7, 2013 by Mucka

[winterof79]

Its a two/three day affair according to GFS

http://www.meteociel...?&ech=72&mode=0

http://www.wetterzen...chester_ens.png

UKMO no where near as good cold clipping s/e

http://www.meteociel...20-21.GIF?07-06

ECM one/two day but remaining cold.At the end of the run it looks like a small feature to our north is moving west towards Iceland.http://www.meteociel...map=1&archive=0 EDIT but it is yesterdays......

Edited March 7, 2013 by winterof79

[winterof79]

Note to ones self."must not grumble"

http://modeles.meteociel.fr/modeles/gens/graphe_ens3.php?x=283&ext=1&y=41&run=0&runpara=0

100%.......

[SMU]

Well a disapointing set of oveenight runs, the ECM is welcoming spring back in at day 9 and the easterly as usual is shunted away from the uk very quickly as more energy is coming south. I guess we cant moan to much as we still have a fantastic 24 hour window for snow, however its certainly been shortened and softened overnight...

S

[Luke Best]

I recall our Dutch friend banging on (and on and on) about a spell of March weather remarkably similar to the one we may be about to experience. Interesting that the CMA was doggedly progging similar synoptics so far out in advance. Does anybody know whether it stuck to its guns throughout the last few weeks?

[IDO]

GEFS now tightening up on the FI solution with more members jumping ship to a return to more average 850s. About six days of sub -5c uppers now based on the mean:

and by the end of FI mean 2m temp back to current measures:

Plenty of cold about but too far east:

The GFS op run is in the milder solutions this morning and is a bit of a downgrade from recent output (southern POV). About 48 hours of cold uppers then they are pushed east. Snow chances much reduced on this run for the south. But only one run so further output needed to firm up on longevity. Both the ECM and GFS have HP close to the west of the UK, so the UKMO updates are understandable, as this influence may be more dominant for most of the UK than the snow risk (east coast).

[Liam J]

Has the ECM even updated as both Meteociel and Netweather charts still have yesterdays 12z run?