Model Output Discussion

[kold weather]

Well i think its unlikely the PV will limpet itself to Greenland and this would go against the expected pattern by NOAA on last nights discussions. I can't see that much has changed overnight and it would tie in with the EPO forecast west USA ridge, trough over east USA and North Atlantic high, this is what they're going with.

Considering what the model output showed a few days ago I'm feeling quite positive about things for the next 10 days, to be honest if we can end January on a cold note and start February the same then if lets say it does turn milder, then its still been a good winter.

Well in theory at least some sort of northerly flow should occur given the power of the LP sliding towards Scandinavia, the big differences on the models is the source of the flow, the 06z GFS had a cloudy mucky high pressure dominated flow, whilst the ECM is a colder northerly flow...I suspect the ECM is closer to the mark.

[cooling climate]

The GFS finally coming round to the heights to the north and subsequent northerly. The GFS

was the first model to show this three or four days ago but then like the GFS model does it

decided to ditch the idea.

Northern hemisphere charts were showing the possible trend to a -AO several days ago when

I said expect the models to flip from the zonal pattern they were showing. Unfortunately the

GFS is now playing catch up.

[nick sussex]

The 12z hasn't come on board , Infact it is milder than the 6z was for next week , Tuesday has +5 850's and high pressure splap bang on top of us . Surface flow looks like it may be cooler but nothing wintry from the 12z really at all out to the middle of next week.

The UKMO still brings in the easterly and is more amplified upstream, the GFS IMO is wrong here and will backtrack later, i expect the ECM to back the UKMO.

[sandstorm2]

Quite a big difference on the 1200 GFS, at +144 the small low sitting on the NW coast of Scotland has disappeared and the blocking high is ridging north leaving us in a weak northerly flow, not to cold but not mild either.

One of the models is seriously barking up the wrong tree!

SS2

Edited January 22, 2010 by sandstorm2

[Guest North Sea Snow Convection]

The UKMO still has an easterly (although a dry one) on Tuesday but then sends the northerly later in the week into Europe

[sandstorm2]

Have just looked at the UKMO 1200 and it is actually very similar to the GFS at +120, 144, though as Tamara says UKMO sends the Northerly into Europe.

SS2

[nick sussex]

The UKMO still has an easterly (although a dry one) on Tuesday but then sends the northerly later in the week into Europe

Yes but it still looks better than the GFS in terms of the upstream pattern, i think the curve back in the jet over Europe could still develop to bring the northerly in whilst the GFS looks desperate to sink the high. I have a good feeling about the ECM this evening and think it might push the Scandi trough further west with the block further north.

[snowmadchrisuk]

The UKMO still brings in the easterly and is more amplified upstream, the GFS IMO is wrong here and will backtrack later, i expect the ECM to back the UKMO.

I agree it is still there , although it doesn't look as good as it has done and looks like Showers would be limited. As for the Northerly into Europe that Tamara pointed out i'm not sure but GFS only gives us a very week Northerly and then flattens the patten with heights failing to rise. Other factors are pointing to Northern blocking becoming established so I wouldn't go with GFS on this one.

[PB22]

No doubts in my mind that the UKMO 12z run this evening has come towards the GFS slightly in that the easterly around the T+72 mark isn't as potent (for want of a better word as it was never that potent to start with). It's gone by T+120 (whereas it was still going on this morning's run):

And then by T+144 we are under milder and cloudy north-westerlies with a lot of Atlantic murk probably being pulled in around the top of that Atlantic high:

The GFS 12z is a little bit better with regards to any potential northerly later next week:

http://www.wzkarten.de/pics/Rtavn1681.html

http://www.wzkarten.de/pics/Rtavn1682.html

But even this tends to just flirt with the north and east.

Overall so far the model output this evening is rather mediocre IMO to be honest. Let's hope the ECM can give us something a little more exciting but I wouldn't hold my breath.

[kold weather]

The GFS evolution once again turns rather sour for the start of Feb, +ve AO kicks in and a nice big PV develops...

The thing to note is the development of the strong upper vortex over Scandinavia ends up rotating another developing upper vortex right over Greenland, its quite a plauseable solution BUT I suspect the GFS is rather on the quick side of bringing it in and as Iceberg said may well be a little too far west compared to what will really happen, and also given the state of the PV thus far this winter its probably rather overdoing that side of things, however I can see a +ve AO phase to be honest occuring for feb.

[Guest North Sea Snow Convection]

Yes but it still looks better than the GFS in terms of the upstream pattern, i think the curve back in the jet over Europe could still develop to bring the northerly in whilst the GFS looks desperate to sink the high. I have a good feeling about the ECM this evening and think it might push the Scandi trough further west with the block further north.

Nick, I think that overall the 12z output so far is less wintry than earlier. The potential for snow showers has dwindled early in the week for south eastern areas, and the UKMO seems to me to have moved towards the GFS a little. The high transfers westwards across the UK rather further south and then like the GFS (albeit slightly better) doesn't amplify things enough to pull the northerly down across the UK.

Hopefully you are right about the ECM later.

I think that the wintry suggestions by the UKMO for next week might be revised by tomorrow in terms of snow potential. Much as TEITS suggested this morning.

Of course next week does still look fairly cold - but essentially dry I think till later in the week when the front comes down from the north.

Edited January 22, 2010 by North Sea Snow Convection

[cooling climate]

GFS implodes again in FI but its slowly coming round to idea of a northerly.

The problem again is the modeling of the movement of the vortices which

will not be modeled correctly this far out.

The ECM should continue with the trend for northern blocking and a southerly

jet over the UK unless of course we get a rogue run.

[bluearmy]

the 00z ecm dragged the trough across us later in its run despite it not looking so promising at T144. the UKMO 12z run leaves us in the same kind of 'limbo'. i guess at this range, we could head in either the ECM/GEM direction from the 00z or the continuing GFS flatter pattern. (although i get the feeling that the 12z GFS was trying to move towards the ecm/gem scenario a little). forget low res GFS - the sudden change from T180 to T192 has become laughable.

[Geordiesnow]

The outlook does seem a bit of a knife-edge and its a one that could leave forecasters with egg on there faces as they are predicting cold air to head westwards.

UKMO has downgraded the slight easterly flow that was predicted for Sunday and it now has the low on top of us as the GFS been predicting for a few runs now. Although the UKMO is still keen on bringing a slightly stronger easterly flow than the GFS for next week.

Its an output that could either leave the most of the UK fairly cold or average or even slightly above in places especially the further west you are. Its a little bit of a forecasters nightmare at the moment.

Regarding the Northerly potential, its the same old problem really, we just can't get the high to retrogress westwards far enough and we don't get the Azores high ridging into Greenland properly hence we get a toppler or even no northerly at all.

An outlook that promises so much for cold lovers could end up into a dull cloudy spell for the most part. Saying that, even if the models did show a northerly, we would be cautious so it could easily change into our favour.

[Paceyboy]

JMA 12z is a fantastic run for cold. An easterly at first then a quick change to a northerly through thurs/fri with heights building over Greenland. The JMA has been consistently churning out very cold runs in the last few days...

[Wayneywoo]

JMA 12z is a fantastic run for cold. An easterly at first then a quick change to a northerly through thurs/fri with heights building over Greenland. The JMA has been consistently churning out very cold runs in the last few days...

Well spotted!

JMA +192hrs has to be the chart of the day, especially when you look at the NHem chart!

Oh if only!!

edit: Make that yesterdays chart of the day...

Edited January 22, 2010 by Wayneywoo

[PB22]

JMA 12z is a fantastic run for cold. An easterly at first then a quick change to a northerly through thurs/fri with heights building over Greenland. The JMA has been consistently churning out very cold runs in the last few days...

That's last night's JMA run that you are looking at. Tonight's will be out just after 7pm.

[john mac]

This thread can be so annoying sometimes, just because the UKMO goes slightly more towards the GFS then its all doom and gloom, lets be honest the models are really struggling atm and we should all be patient, like Nick said theECM may come up trumps and if it does then most peoples opinions will change once again. The models are going to continue changing from day to day so how about everyone trys stick to their opinon instead of changing it with every chart that comes out.

BTW i went out in to the forest today and all the ponds still had ice on them from the last cold spell. God its been so mild

[snowmadchrisuk]

There is a big dip in the 12z GFS Ensembles from the 28th Jan -1st Feb . There are also a lot of colder options after this. Only problem is I think I have lost most of the faith I ever had in them Ensembles lately.

[john mac]

There is a big dip in the 12z GFS Ensembles from the 28th Jan -1st Feb . There are also a lot of colder options after this. Only problem is I think I have lost most of the faith I ever had in them Ensembles lately.

Yes i know what you mean, i think its best to look at the ecm ensenbles and the fax charts atm as the models are struggling with things atm

[yamkin]

This thread can be so annoying sometimes, just because the UKMO goes slightly more towards the GFS then its all doom and gloom, lets be honest the models are really struggling atm and we should all be patient, like Nick said theECM may come up trumps and if it does then most peoples opinions will change once again. The models are going to continue changing from day to day so how about everyone trys stick to their opinon instead of changing it with every chart that comes out.

BTW i went out in to the forest today and all the ponds still had ice on them from the last cold spell. God its been so mild

Good post john mac Due to the models showing outputs here and there, the skillful MetO must be using their human input. I am really looking forward to the model runs and the MetO's updates.

[Guest North Sea Snow Convection]

The ECM joins the GFS in abandoning the easterly early next week. Not even a continental surface like the 12z UKMO. At this rate it will be a euro high! lol!

[Nick F]

Well, not much of an easterly on ECM either tonight, and doesn't really build the high as far north as UKMO, so UKMO looking on its own with the easterly by Tuesday ... be interesting to see the UKMet Fax interpretation later this evening.

[yamkin]

JMA 12z is a fantastic run for cold. An easterly at first then a quick change to a northerly through thurs/fri with heights building over Greenland. The JMA has been consistently churning out very cold runs in the last few days...

JMA 12Z is coming out

[Shunter]

The ECM joins the GFS in abandoning the easterly early next week. Not even a continental surface like the 12z UKMO. At this rate it will be a euro high! lol!

Yep....Seems to be the strongest signal is now for the displaced PV to drop into Scandi which causes the Siberian high to retreat gracefully. ECM seems to be heading towards the Northerly evolution at T120 so all not lost for cold lovers.

http://www.meteociel.fr/modeles/ecmwf.php?ech=120&mode=1&map=1