Model Output Discussion

[The PIT]

Looking like it will be windy on Tuesday evening/night.

http://gfs.netweather.tv/gfs.20090227/12/102/ukwind.png

Yes it needs keeping an eye on but will down grade closer to time. Certainly looks like becoming windy with some proper rain around ending the long dryish period we've had. Really cold air stays away from us again but it'll be interesting to see what -5 translates to on the ground when the time comes if it does arrive as suggested.

[Frosty.]

I wouldn't say it was completely different next week at all - yes there are subtle changes but nothing unexpected in that, particularly when we're talking about the tracking of a fairly large atlantic depression.

It's beyond 144 where there is some divergence from the 06z, but again at that range it's pretty typical and you can see the points at which it's happening.

You can follow the runs alongside eachother on the viewer (click prev on the right hand side of one of the drop downs to show the 06z), and you can see the slight variances up to 144, then the more defined differences appear, particularly in the modelling of the low pressure.

http://www.netweather.tv/index.cgi?action=nwdc;sess=

Hi Paul,

I notice the GFS Northerly which it was showing on some deep FI charts since last weekend has almost made it into the reliable timeframe but the ecm is rather different and crucially different with the track of the large atlantic depression, i'm hoping the ecm looks more like the gfs 12z tonight but also hoping for the Northerly (if it happens) will last longer than shown currently.

[J10]

Definite chance of some overnight snowfalls in many areas for the mid part of next week, going by recent output, by day it will be restricted to higher ground.

[Geordiesnow]

Unsettled wet and chilly period coming up but certainly an interesting spell weather is on the way, not sure how much snowfall there will be but i do think higher ground will get quite a dumping. Chance at lower levels at times aswell whenever showers will fall during the nighttime hours.

[PB22]

UKMO 12z:

http://www.wzkarten.de/pics/Rukm961.html

http://www.wzkarten.de/pics/Rukm1201.html

http://www.wzkarten.de/pics/Rukm1441.html

Subtle differences, but interesting nonetheless. However, that high over the Azores looks like sitting there for some time, and this could, not for the first time, scupper our hopes of something colder in the medium to longer term.

On the face of it, the ensembles from GFS aren't particularly cold and aren't supportive of much more than cold rain for many lowland areas - i.e. Suffolk:

http://91.121.94.83/modeles/gens/graphe_en...=100&run=12

Better for the northern hills though:

http://91.121.94.83/modeles/gens/graphe_en...150943396226413

Although many runs manage to stay just above -5C at 850hPa for much of the time.

And there are still signs of something milder developing by the second week of March, as per:

http://91.121.94.83/modeles/gens/run/gens-12-1-192.png?12

Or something colder:

http://91.121.94.83/modeles/gens/run/gens-5-1-192.png?12

The mean sums it up really:

http://91.121.94.83/modeles/gens/run/gens-21-1-192.png?12

It could go either way. Worrying for coldies is that the operational and control runs both go milder again in FI. All a long way of course and will change, thats just how things look at the moment.

Ensembles: http://www.meteociel.fr/modeles/gefs.php?carte=1

[Cecil Hogmanay Melchett]

UKMO 12z:

http://www.wzkarten.de/pics/Rukm961.html

http://www.wzkarten.de/pics/Rukm1201.html

http://www.wzkarten.de/pics/Rukm1441.html

Subtle differences, but interesting nonetheless. However, that high over the Azores looks like sitting there for some time, and this could, not for the first time, scupper our hopes of something colder in the medium to longer term.

Nice charts for dec or jan Paul but for the first 10 days of march transitory snow for hills only IMO.

As you say that azores high has come back into play for the last few weeks and its no coincidence that the cold has vanished for about the last 2 weeks as well.

Still,clocks go forward in 4 weeks and the long evenings will be back !!

[PB22]

Nice charts for dec or jan Paul but for the first 10 days of march transitory snow for hills only IMO.

As you say that azores high has come back into play for the last few weeks and its no coincidence that the cold has vanished for about the last 2 weeks as well.

Still,clocks go forward in 4 weeks and the long evenings will be back !!

As your name goes, happy days!

Agree about snow mainly for high ground though, although some may fall to lower levels in heavier showers. Lets see what ECM shows in a bit and what route it takes tonight.

Edited February 27, 2009 by Paul B

[bluearmy]

As your name goes, happy days!

Agree about snow mainly for high ground though, although some may fall to lower levels in heavier showers. Lets see what ECM shows in a bit and what route it takes tonight.

The ecm 00z run really was a 70's/80's classic as it evolved with the blocking to the north extensive and the continental trough in the right place combined with the AH not interfering. problem now is that the cold pooling to our east is disappearing fast and if this pattern were to verify, its just getting that bit too late to take advantage of such superb sypnotics. there is nothing i dislike more than a wet wintry mix in march or april.

[Cheese Rice]

Definite chance of some overnight snowfalls in many areas for the mid part of next week, going by recent output, by day it will be restricted to higher ground.

Agree, GFS shows snow on charts for next week, and if it came of everywhere would see some snow, GFS shows -2-5 upper air is over the uK for quite some time which should amount to something, definatley some intresting weather coming up, strong winds, sleet,snow,hail,rain,sunshine,showers everything.

Its good to see wintry weather back on the bbc five day forecast http://news.bbc.co.uk/weather/forecast/18 and this is for leeds center (probs wont happen but still)

[Frosty.]

Not a bad ukmo 12z run, not as good as the gfs 12z at T144 but it still has a chilly NW'ly showery airflow with wintry showers and night frosts, the gfs looks more dramatic and evolves into a N'ly, the ukmo looks like it would not support that idea if it went out further, all eyes on the ecm now.

[Yeti]

Very poor ECM unfortunately, the low fails to get far enough east and hill snow looks like being at more of a premium

http://www.wetterzentrale.de/pics/Recm1441.gif

[Guest North Sea Snow Convection]

Very poor ECM unfortunately, the low fails to get far enough east and hill snow looks like being at more of a premium

http://www.wetterzentrale.de/pics/Recm1441.gif

Nothing poor whatsoever about this Shades of some negative anomalies arriving??

[carinthian]

Very poor ECM unfortunately, the low fails to get far enough east and hill snow looks like being at more of a premium

http://www.wetterzentrale.de/pics/Recm1441.gif

Very Poor ? Nay.. Easterly on the way fed by an Arctic High ?

C

[nick sussex]

Its a case of the ecm dishing up some really interesting output a month too late with charts that would normally send the net weather server crashing! The ecm looks similar to its earlier 00hrs run but isn't really supported by the other models. Its a long shot but if the Arctic high could actually make it far enough sw wards then theres still a chance that any easterly could still be interesting. But the ecm has proved just as unreliable as the gfs FI output so although nice to look at the chances of it coming off are very slim.

[Eugene]

Very poor ECM unfortunately

lol is that some kind of joke ECM 12Z is the best run tonight for prolonged cold with the arctic high nudging down into northern scandinavia.

Edited February 27, 2009 by Eugene

[Cloud 10]

The elusive arctic high makes another appearance on the 12z ecm.

Plenty of northern blocking on offer on this run.

[Guest North Sea Snow Convection]

Its a case of the ecm dishing up some really interesting output a month too late with charts that would normally send the net weather server crashing! The ecm looks similar to its earlier 00hrs run but isn't really supported by the other models. Its a long shot but if the Arctic high could actually make it far enough sw wards then theres still a chance that any easterly could still be interesting. But the ecm has proved just as unreliable as the gfs FI output so although nice to look at the chances of it coming off are very slim.

Not neccessarily nick - the kickback from the MMW hasn't gone away. It has been only a matter of time before the final downwelling occurs. True we wanted it two/three weeks ago, but I will take this sort of thing anytime!

Is the ECM finally picking it up? Maybe this time it will happen?

Superb day 10 chart!

http://www.wetterzentrale.de/pics/Recm2401.gif

Edited February 27, 2009 by North Sea Snow Convection

[Polar Continental]

Well if the ECM verified and continued through the rest of March, then my CET guess of 3.3c wouldn’t be far out.

Actually the 0z GEM produced a similar evolution to the ECM, so it’s not quite out on its own with this projected blocking. We will see.

The GEM was the first model to pick out the February cold spell, but dropped it when the other models began to hint on it.

Paul

[Yeti]

lol is that some kind of joke ECM 12Z is the best run tonight for prolonged cold with the arctic high nudging down into northern scandinavia.

True in terms of the Easterly, but personally I would rather see the low tracking right across us with mega hill snow; unfortunately none of these easterlies have associated deep cold pools and so they are unlikely to produce much convection. But then again, that's personal preference of someone who lives near and regularly climbs high hills

[nick sussex]

Not neccessarily nick - the kickback from the MMW hasn't gone away. It has been only a matter of time before the final downwelling occurs. True we wanted it two/three weeks ago, but I will take this sort of thing anytime!

Is the ECM finally picking it up? Maybe this time it will happen?

Superb day 10 chart

http://www.wetterzentrale.de/pics/Recm2401.gif

I was talking more in terms of the sods law if some great synoptics appear too late in the season. Given that its early March if we can get the PV to drop into Russia and the easterly kick in then it would still deliver some snow, and come as quite a shock down here where its been like summer for the last week.

[bluearmy]

ecm spewing out 'carlsberg' fi charts on the bounce. lets hope we can trace that cold pool crossing the north sea at T240 on todays 12z in the same way as we did the one that gave us the early feb fun a month ago. (and theres another to follow)

[tundra]

With the ECM again predicting the zonal winds to go neutral to maybe negative between 70 and 90 degrees north in the lower troposphere, it will be interesting to see if the ECM nwp model agrees this time or as a couple of days ago rejects the idea again.

It looks like this time unlike two days ago the ECM nwp model is agreeing with its zonal wind forcasts for the tropasphere.

[bluearmy]

unfortunately none of these easterlies have associated deep cold pools and so they are unlikely to produce much convection.

ecm T240 has thickesses below 518dam over the north sea and a 515dam upstream. as nick says though, unlikely but pretty to look at.

[Snowaddict]

Superb day 10 chart!

http://www.wetterzentrale.de/pics/Recm2401.gif

Hi Tamara,

That's a stunning ECMWF Output this evening, 850mb temps almost always at -5 from T+120, getting much colder still on the latter frames:

T+216

T+240

SA.

[Cloud 10]

Not neccessarily nick - the kickback from the MMW hasn't gone away. It has been only a matter of time before the final downwelling occurs. True we wanted it two/three weeks ago, but I will take this sort of thing anytime!

Is the ECM finally picking it up? Maybe this time it will happen?

=