Model Output Discussion

[snowmadchrisuk]

Looking at the models, the METO convergency zone and the lows that stall over the channel latter in the week, not to mention the NMM on Monday, Southampton and the IofW would be a good call for something IMO.

UKMO has the high to southerly for my liking, it is charts like that what can end up causing downgrades. Yesterday it had it over Greenland , today it doesn't even have it over Iceland . Apart from that though , GFS / ECM looking perfect . ECM probably the best this morning.

[Geordiesnow]

Not such as good runs this morning as there is less cold air around and pressure rises pretty quickly so killing off any showers pretty quickly.

To me this easterly looks like the equivalent of a Northerly topoller. It must be said, even the potential Northerly that might follow it may not happen so this run is not really going to get me out of my seat in excitment.

Heres hoping for a better 06Z run.

[Just Before Dawn]

Yep I think the Meto forecasts for Wed are purely UK Met model auto generated. We really need to wait ofr the manual updates, BBC forecasts etc.

Tomorrow will be the key day for the METO site watching as Thursday comes into play and the advance warnings start to appear.

Agree with the first part - the Met outputs will get moderated and issued in a refined form and so it's going to be interesting to see what happens. I suspect a few people will be watching Countryfile tomorrow - I wonder which unfortunate broadcast meteorologist will have that 'pleasure'.

I doubt the MetO will issue any advanced warnings until Monday night or Tuesday Morning, That'll be about as late as they could leave it given they have commercial responsibilities to a whole range of weather-reliant customers who are working to a clock in these circumstances. I can't see them going much earlier than that because of the existing geographical uncertainties. Unless, of course we get 48 hours of total model agreement on the nature, duration and severity of the Wednesday-Friday event. Come Tuesday AM, they'll have to make a call one way or the other, at least for their commercial clients, who have equipment to prepare, rosters to organise and, potentially, overtime to pay.

Edited December 12, 2009 by Just Before Dawn

[Lewis]

Good morning,

I just woke up and missed the 00z GFS would anyone be willing to fill me in in terms of its output.

06Z coming out now.

Lewis

[John Snow]

Not a bad set of charts this morning, not going to need the army delivering emergency supplies by helicopter between the Wash and Fife as would have been the case with yesterday evening's ECM but nice charts for a sustained period of snow with a few reloads, positive charts this morning

[Neilsouth]

http://www.wetterzentrale.de/pics/Rtavn7817.png

A colder day for the SE , very raw and cold.

[frostyjoe]

http://www.wetterzen...s/Rtavn7817.png

A colder day for the SE , very raw and cold.

reallyy a 6c max i thought we were getting 3c maxes.... it looks like this cold spell is constantly downgrading...

[TEITS]

What some need to take into account is changes will always occur at this timeframe. The key period is between +96 & +120 and as we all know this is subject to change. For example when we have N,lys progged it isn't until +72 that the models start shifting this E wards.

Remember small changes can mean the difference between isolated wintry showers and prolonged heavy snow.

[PB22]

How long have we been waiting to see charts loaded with potential at T+96? Like this one:

http://www.wzkarten.de/pics/Rtavn961.html

http://www.wzkarten.de/pics/Rtavn962.html

[Neilsouth]

http://www.wetterzentrale.de/pics/Rtavn841.png

http://www.wetterzentrale.de/pics/Rtavn842.png

http://www.wetterzentrale.de/pics/Rtavn843.png

http://www.wetterzentrale.de/pics/Rtavn844.png

http://www.wetterzentrale.de/pics/Rtavn8417.png

South east might see some sleet , 528 only just making inroads into the north sea tuesday 18z

[weather eater]

Well I know there`ll be snow from this thats a fact with the way these models are showing now.

This was IMO the last really lively easterly with a low not pick up on this gave for windspeed 2 inches and strong winds,blizzards for a time and even a gale,winds swung from E/NE to E/SE that day.

http://www.wetterzentrale.de/archive/ra/2006/Rrea00120060224.gif

http://91.121.93.17/pics/Rtavn1201.png

Just read Steve`s post.

I missed this from yesterday, you mistake what I am saying, It will obviously snow but where and when are will change a few times before we get there, so it’s a bit pointless discussing now. With so much going on with the models at the moment where it will snow posts just clutter the whole thin up.

The chopping and changing of the fine detail in regards of how this easterly will affect us shows this nicely, we have more excellent runs this mornings, but they do show how things can alter almost down to the wire.

[snowspotter]

Big changes in the bigger picture - the low southwest of Greenland evident on the 00z has vanished on this runat 96hrs. low southern scandi look more active as well

[PB22]

http://www.wetterzen...cs/Rtavn841.png

http://www.wetterzen...cs/Rtavn842.png

http://www.wetterzen...cs/Rtavn843.png

http://www.wetterzen...cs/Rtavn844.png

http://www.wetterzen...s/Rtavn8417.png

South east might see some sleet , 528 only just making inroads into the north sea tuesday 18z

Do you always copy the posts over from TWO?

Deep cold air coming across the North Sea by T+108:

http://www.wzkarten.de/pics/Rtavn1082.html

[TEITS]

Lets cut out this SE bias nonsense.

Pretty obvious everyone is going to concentrate on their own location. Furthermore Neil did clearly state the SE in his post!

Based on the GFS so far Lincs/Humberside seem most at risk.

[Neilsouth]

http://www.wzkarten.de/pics/Rtavn1082.png

Cold air making inroads now! , lets hope it gives us all a good snow event

[Matt12345]

It's not, but NeilSouth always looks at his part of the world, not the gernal chart/run/model it's self. He's bias.

lewis

After all the fantastic charts the models have been producing really (including all the very cold potential) if the we see day time temps of around 2-5 over the next week or so, i would not call it a 'cold spell'. Cold to to me is day time temps below 0.

[cooling climate]

Excellent charts again this morning, although given the synoptics on offer some of the comments again this

morning are baffling to say the least.

Quite a few members used to question if synoptics like the ones being shown were still possible or if they

were forever to be consigned to the archives.

Well here we are on the cusb of a winter weather pattern (prolonged cold and wintry weather) not seen for

for years and years.

As for the models it looks as though they are just juggling around slightly with the orientation of the high and

low pressures which will strengthen the easterly one run and then down grade it slightly the next.This is where

I think the ensembles come into play and give a better idea of the pressure pattern and 850 temperatures

rather than pinning it all on just the operational run.

Wednesday onwards still looks to be the time frame when we start to see the real cold and wintry weather take

hold.

[snowmadchrisuk]

http://www.wetterzentrale.de/pics/Rtavn841.png

http://www.wetterzentrale.de/pics/Rtavn842.png

http://www.wetterzentrale.de/pics/Rtavn843.png

http://www.wetterzentrale.de/pics/Rtavn844.png

http://www.wetterzentrale.de/pics/Rtavn8417.png

South east might see some sleet , 528 only just making inroads into the north sea tuesday 18z

The 528 is delayed slightly on this run compared to 00z , the 6z also makes more of the warm sector on Tuesday. Never the less the 528 is in by Wednesday evening . Nice to also see more and more runs extending the patten into Christmas.

[Duncan McAlister]

Is it just me or is this cold plunge being moved further and further south?

[Lincs Observation]

Lets cut out this SE bias nonsense.

Pretty obvious everyone is going to concentrate on their own location. Furthermore Neil did clearly state the SE in his post!

Based on the GFS so far Lincs/Humberside seem most at risk.

You beat me to that post Dave, yes we be on the end looking down the barrel, and been on the coast should be first to react to conditions when the radar watch starts next week.

LO

[Nick L]

Much deeper cold making it's way in earlier compared to the 00z, great news:

00z:

http://212.100.247.145/viewimage.pbx?type=gfs;date=20091212;time=00;ext=120;file=tmp850;sess=8f9c13e73c795cb0b5103476b58e78df;

06z:

http://212.100.247.145/viewimage.pbx?type=gfs;date=20091212;time=06;ext=114;file=tmp850;sess=8f9c13e73c795cb0b5103476b58e78df;

[PB22]

Is it just me or is this cold plunge being moved further and further south?

It's you, its further northwest on this run:

http://www.wzkarten.de/pics/Rtavn1201.html

http://www.wzkarten.de/pics/Rtavn1202.html

Incidentally, here's the ECM ensembles for De Bilt - something of a split for later next week between cool and cold:

http://www.knmi.nl/exp/pluim/vijftiendaagse/index.html

[MKN]

High pressure isnt centred over greenland aswell as was being shown, doesnt look to good.

[Neilsouth]

Do you always copy the posts over from TWO?

Deep cold air coming across the North Sea by T+108:

http://www.wzkarten.de/pics/Rtavn1082.html

Sometimes i do , sometimes i don't... Aren't we all looking at the same run anyway?

Gfs does seem to be pushing the cold further south , lets hope it doesn't go any further and avoid the uk altogether. Still plenty of runs to get through yet

[glasgow-guy]

Much deeper cold making it's way in earlier compared to the 00z, great news:

00z:

http://212.100.247.1...5103476b58e78df;

06z:

http://212.100.247.1...5103476b58e78df;

Thursday still looking like a good one lets hope it lasts