Model Output Discussion

[Altostratus]

I was nervous before - I'm even more nervous after that ECM run! Worryingly, it seems to fit well with the METO forecast. Let's hope that was an outlier.

[Iceberg]

Changes, yes, I think the ECM has frankly got lost at the 96Z mark, UKMET is halfway between ECM and GFS, GFS is very good but a bit OT with the low, the GFS Ensembles are frankly very good.

UKMET and GFS agree on Snow as early as Monday next week.

ECM and GFS ENS seem to be hinting at something quite prolonged.

Something between GFS and METO would be good for next week.

Edited December 10, 2009 by Iceberg

[Polar Gael]

This morning's ECM appears less favourable, but crucially, only once it gets into FI. Am not completely convinced by its evolution, so now I guess we wait and see if the others will jump on board or if this is a rogue run.

Edited December 10, 2009 by Polar Gael

[mountain shadow]

ECM looks like it has jumped ship for the deep cold this morning. Hopefully its Ensembles

show a different picture later. Bit if a stinker or should i say sinker.

[liltbrockie]

Hi guys!

I'm not too happy with the GFS this morning. The high pressure that wants to form over greenland is linking back up too readily with the high pressure from whence it came and pushing any cold air back further east. This operational run was a warm outlier though, I believe, so there's still hope it might be a wobble.

However, I have seen the GFS get our hopes up before in a situation like this...we are teased with high pressure staying north but it nearly always sinks back down very quickly when things get into the reliable time frame..

Here's hoping though...

PS..Whats going on with the ensembles update on this site... the graphs are still on the 06hrs run from yesterday!?

Matt

[carinthian]

NO, these are great charts for winter wonderland. You would have given your right arm for these 10 days ago.

The building blocks are all now all in the right place. Block to the NW. Great pool of cold upper air in the right position ( White Sea). Troughs or short waves fed out from the cold pool pushed into Western Europe. Snow will come, whether from the East. northeast or north. Great charts for all of next week and a chance for the UK to dry out over the weekend.

C

[Iceberg]

Just a reminder, there is a reason why ECM does not go below 72hrs, it is a medium range forecasting model used for trend forecasting, not specifics like will it snow.!

Due to this is does not forecast SW for small lows very well, in the north, it was never designed to. (although for some reason it is very good at picking up Hurricanes forming).

I am sticking with GFS and METO and a blend between the two.

[TEITS]

A right mixed bag of models this morning.

Whilst there remains some uncertainity between +96 & +120 between +144 & +192 and all sorts of possibilities are showing themselves. Based on the models we could have cold ENE,lys as the SW tracks S, Cold N,lys, or even a LP tracking along the S coast giving a snow event for those from the M4 Northwards.

If I was honest I remain clueless in what will happen towards the end of next week and so are the models. Im just going to sit back and let it all unfold and enjoy the colder weather early next week.

I will add that looking at the ECM at +144 and comparing to the other models and to be honest it doesn't look right. I haven't been that impressed with the consistency of the ECM of late.

[Frosty.]

The ECM 00z keeps high pressure in control for the whole of next week so at least it should be on the cold side with overnight frosts and some fog and some areas will have sunshine, not really what I was hoping to see after the wintry blast on the ecm 12z yesterday but par for the course in the uk. Even the Northerly which follows looks rather feeble and would just bring a few wintry showers to eastern coasts. I expect the meto update today to reflect this major downgrade despite what the gfs keeps showing..I think we have been duped again but won't know for sure until the 12z runs are complete.

[Duane S.]

Interesting charts this morning. Would I take a GFS solution right now? Well I would certainly take exactly what the 00z has predicted in a shot but if it is going to be like that then it becomes a lot riskier and potentially a lot more marginal, especially living on the south coast. HOWEVER, the potential would be there for a massive massive battleground snow event for the south.

As for the ECM, I'm not saying it just because it doesn't show what we want but I don't buy it, it just looks wrong.

[TEITS]

I expect the meto update today to reflect this major downgrade despite what the gfs keeps showing..I think we have been duped again but won't know for sure until the 12z runs are complete.

The Met O will not base its forecast on the 0Z ECM because like yesterday they disregarded this. They will look at their own model and the ECM ensembles and look to see which is plausible.

[VillagePlank]

0z in the (semi) reliable timeframe looks like snow starting Monday evening and continuing through to Friday. Not too sad, if you ask me - especially as I was expecting a mild Decemeber! A week+ of coldness should be very nice, and, hopefully, with some crunching frost, should set the mood for Christmas quite nicely. Personally, I only really analyse the 6z since the 0z, for me, tends to be the hangover run ...

Edited December 10, 2009 by VillagePlank

[Eugene]

http://www.wetterzentrale.de/pics/Rtavn2281.png

OMG severe blizzards if that came off though it must be said both a wet and warm outlier in IOW cough London :o

[J07]

Just a reminder, there is a reason why ECM does not go below 72hrs, it is a medium range forecasting model used for trend forecasting, not specifics like will it snow.!

Due to this is does not forecast SW for small lows very well, in the north, it was never designed to. (although for some reason it is very good at picking up Hurricanes forming).

It does go below 72 hours. 3 hourly time steps from 00 out to I think 72, and then 6 hourly beyond that. It's fine for forecasting in short term.

[West is Best]

There's no real doubt that there's a downgrade on the 0z. The question is whether it really will matter in the long run. I think we characterise the following overnight trends:

1. The high pressure is further east

2. The high is less strong

3. The high does not link as successfully nor as sustainably with the Greenland high

We need to have some nerves of steel today with the runs, to check the ensembles, and see whether this is a major downgrade trend that will get worse, a blip which will reverse, or nothing more than a 48 hour delay to the onset of the more intense synoptics that were showing yesterday.

[Frosty.]

The Met O will not base its forecast on the 0Z ECM because like yesterday they disregarded this. They will look at their own model and the ECM ensembles and look to see which is plausible.

Fair enough TEITS, I just wasn't expecting such a poor ecm run relative to the stunning 12z yesterday, that's why I am giving the 12z run a chance to salvage the situation but i'm sure this 00z will have raised an eyebrow or two at the met office with all the talk yesterday of faxes being sent to council depots about severe wintry weather ahead.

[LomondSnowstorm]

GFS Parallel looks ok, with a bit of a better easterly on Sunday night and the northeasterly coming in by Wednesday evening

[Eugene]

The ECM 00z keeps high pressure in control for the whole of next week so at least it should be on the cold side with overnight frosts and some fog and some areas will have sunshine, not really what I was hoping to see after the wintry blast on the ecm 12z yesterday but par for the course in the uk. Even the Northerly which follows looks rather feeble and would just bring a few wintry showers to eastern coasts. I expect the meto update today to reflect this major downgrade despite what the gfs keeps showing..I think we have been duped again but won't know for sure until the 12z runs are complete.

I dont agree with this, i think UKMO will be putting more hinters out that we could be in for a severe spell of weather, GFS ensembles are showing prolonged cold and so will be ECM.

Why are you writing it off purely because of just one run before it has even happened.

http://www.wetterzentrale.de/pics/MT8_London_ens.png

[TEITS]

Fair enough TEITS, I just wasn't expecting such a poor ecm run relative to the stunning 12z yesterday,

Neither was I to be honest although the ECM has been responsible for many mood swings these past few days!

Going back to the GFS and I don't agree with some members saying its a downgrade. We are nearly at the stage where what may be an upgrade for some could be a downgrade for others based on your location.

The 0Z GFS has certainly upgraded the E,ly for early next week but towards the end of the week it isn't an upgrade or downgrade, just a different evolution. I would say the models seem to have backed off the idea of a bitter ENE,ly with the SW sinking S. However on a positive note the 0Z GFS suggests LP tracking along the S which will give a massive snow event for some.

late next week I don't know if we're going to have a N,ly/NE,ly/ENE,ly/E,ly, such is the confusion. However im fairly confident the flow will come from one of those directions!

Edited December 10, 2009 by THE EYE IN THE SKY

[phil nw.]

I can`t see how anyone who likes cold can complain about these charts from00z at T96hrs.

GFS http://www.wetterzentrale.de/pics/Rtavn961.png

UKMO http://www.wetterzentrale.de/pics/Rukm961.gif

ECM http://www.wetterzentrale.de/pics/Rtavn961.png

GEM http://www.wetterzentrale.de/pics/Rgem961.gif

Solid agreement there.Cold uppers arriving Sun/Mon from the East.A solid block right up to Greenland.

A good pool of cold air to the NE.

Sypnotic details beyond still to be firmed up but these are wonderfull charts for a good Cold spell which we rarely see in the UK.

[Frosty.]

I dont agree with this, i think UKMO will be putting more hinters out that we could be in for a severe spell of weather, GFS ensembles are showing prolonged cold and so will be ECM.

Why are you writing it off purely because of just one run before it has even happened.

http://www.wetterzentrale.de/pics/MT8_London_ens.png

It's just my over reaction to a poor ecm run, i'm sure a few others felt the same but hopefully it's just a late wobble and I haven't checked the ensembles yet. :o

[Nick F]

Slight upgrade by GFS with the depth of the cold in the initial easterly which develops over the weekend - with T850s approaching -10C across the SE and E by early Tues - this would likely be accompanied by snow across the south if it evolves like GFS as a trough moves west in the flow.

Beyond that, differences in how to handle the shortwave dropping down across Scandinavia and the orientation of the high to our NW are making it difficult to say where we go on from there and whether that really frigid air over NE Europe/NW Russia will come towards us. ECM has been a little more unstable with its output in this regard, so more runs needed to firm up where we may go from early-mid next week after the initial easterly.

[liltbrockie]

I think it's worth mentioning again that the GFS charts you see was from a major warm outlier.. The majority of the runs showed a good -5 degrees on the 850 temps

[Paul Sherman]

The Met O will not base its forecast on the 0Z ECM because like yesterday they disregarded this. They will look at their own model and the ECM ensembles and look to see which is plausible.

Dave I alluded to this in the Cold Spell Discussion yesterday and was jumped upon straight away, from yesterdays Meto Update and the way they worded it, it looked like they were happy with the Ukmo up to T96 & Then a halfway house with more of a Northerly.

We will only know from Sat or Sun onwards though

[phil nw.]

There's no real doubt that there's a downgrade on the 0z. The question is whether it really will matter in the long run. I think we characterise the following overnight trends:

1. The high pressure is further east

2. The high is less strong

3. The high does not link as successfully nor as sustainably with the Greenland high

We need to have some nerves of steel today with the runs, to check the ensembles, and see whether this is a major downgrade trend that will get worse, a blip which will reverse, or nothing more than a 48 hour delay to the onset of the more intense synoptics that were showing yesterday.

Really Richard.I can`t see downgrades,See my post above.There`s nothing different with the general setup.

It`s going to get cold.We have the Greenland block and the cold pool to the NE.Nothing is different.The weather will be the same.

Too many are picking holes in small details yet to be firmed up.