Model Output Discussion

[grab my graupel]

A new Model Output Discussion thread

For those who would like to discuss the Media/Meto forecast etc. there is a designated area

http://forum.netweather.tv/forum/12-weather-in-the-media-on-the-internet/

And for Cold weather discussion, there's a seperate thread available

Also, the various Regional threads are still available, but they're now in their own seperate subforum

http://forum.netweather.tv/forum/142-regional-discussions/

All the latest Model Output, plus much more, can be found in the Netweather Data Centre

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

Please continue

[Mikel Nimbus]

GFS 18z ensembles are very interesting tonight, as picked up by TWS in the previous thread. At least 15 of the runs have some sort of mid Atlantic block linking up with a Greenland high out at +252.

That is surprisingly good agreement for GFS at that time range. I'd like to see it on a few more consecutive runs before beginning to proclaim GFS as the saviour

Could we be seeing the effects of the predicted MMW splitting the PV? I'll leave that to Chionomaniac to comment.

[Eugene]

After all the talk of the atlantic onslaught there is one front moving through the country this week, yes i kid you not one front on thursday, hardly a washout like some claimed is it, the wednesday front looks like fizzling out now due to the block out east, temps average to cool.

[bluearmy]

ecm in its latter stages shows the consequences of the remnants of the siberian block being supported by an arctic ridge and reasserting to our northeast. the trough tumbling over the top of the retrogressing azores ridge has nowhere to head but across us. could be an ineteresting spell and blast has said for ages that we were due a storm in that period.

Edited January 17, 2010 by bluearmy

[tinybill]

morning all is the gfs fantasy world saying the big freeze is coming back at the end of Jan for Feb, the first signs it could be

[Frosty.]

The ECM 00z is screaming snow potential from next wednesday through to T+240 in northeast britain at least with the cold scandi block far more reluctant to give ground and with break away troughs from the main atlantic lows just feeding into the cold continental flow and becoming absorbed giving a snowfest to many parts of northeast england and scotland with blizzard conditions & drifting. The downside is that the ukmo and gfs are rather more progressive but even the gfs has very cold air just to the east a week from now! AND FI still has a wintry spell from the arctic so not much indication of a mild spell becoming established any time soon.

Edited January 17, 2010 by Frosty039

[KTtom]

After all the talk of the atlantic onslaught there is one front moving through the country this week, yes i kid you not one front on thursday, hardly a washout like some claimed is it, the wednesday front looks like fizzling out now due to the block out east, temps average to cool.

There is a window of opportunity after nextweekend for the high to move westwards as the Atlantic lows take a short break, unfortunately the forementioned trough sits to the west of Norway preventing it doing so.....different run mid term as the high sinks to mid-europe.

[tinybill]

The ECM 00z is screaming snow potential from next wednesday through to T+240 in northeast britain at least with the cold scandi block far more reluctant to give ground and with break away troughs from the main atlantic lows just feeding into the cold continental flow and becoming absorbed giving a snowfest to many parts of northeast england and scotland with blizzard conditions & drifting. The downside is that the ukmo and gfs are rather more progressive but even the gfs has very cold air just to the east a week from now! AND FI still has a wintry spell from the arctic so not much indication of a mild spell becoming established any time soon.

interesting time ahead someting nice to wake up to!!!

[West is Best]

The ECM 00z is screaming snow potential from next wednesday through to T+240 in northeast britain

There's no snow potential really, let alone 'screaming' snow potential Karl on the ECM until T240, Wednesday week. Up until then all three major models have a Bartlett scenario high pressure to the south. The Siberian high is there (it's not a Scandinavian high) but it stands little chance of advecting cold air east.

The best hope for cold are the GFS ensembles, which give rise to some hope. Otherwise it's a relatively mild scenario for a week.

[Frosty.]

There's no snow potential really, let alone 'screaming' snow potential Karl on the ECM until T240, Wednesday week. Up until then all three major models have a Bartlett scenario high pressure to the south. The Siberian high is there (it's not a Scandinavian high) but it stands little chance of advecting cold air east.

The best hope for cold are the GFS ensembles, which give rise to some hope. Otherwise it's a relatively mild scenario for a week.

Relatively mild where? The cold continental flow returns by late tuesday and wednesday has a very good chance of a snow event in central and eastern britain, the ecm shows the scandi high closer to the uk until sunday with lows and fronts bumping into cold air in the north and east giving a risk of further snow although northern hills are probably most at risk and then we have the gfs in FI still showing an arctic outbreak which it has done on most recent runs.

[cold snap]

The ECM 00z is screaming snow potential from next wednesday through to T+240 in northeast britain at least with the cold scandi block far more reluctant to give ground and with break away troughs from the main atlantic lows just feeding into the cold continental flow and becoming absorbed giving a snowfest to many parts of northeast england and scotland with blizzard conditions & drifting. The downside is that the ukmo and gfs are rather more progressive but even the gfs has very cold air just to the east a week from now! AND FI still has a wintry spell from the arctic so not much indication of a mild spell becoming established any time soon.

http://www.wetterzentrale.de/pics/Recmnh2401.gif

Blizzards North east England

morning all is the gfs fantasy world saying the big freeze is coming back at the end of Jan for Feb, the first signs it could be

Morning what i can see this morning is both GFS and ECM both want the big freeze back.however its in f1.

Once again this morning there is no retreat from the siberian high,its there waiting in the wings.for any slip up from the atlantic.

[bluearmy]

not that it makes any difference what peeps on here want or dont want but the block holding up the trough will not deliver another freeze to the UK.

we need the trough thru to get the greeny ridge established again. the stand off just wastes a few more days of lower solar input winter with few benefits for coldies.

[Iceberg]

There are good signs that a return to colder weather is due around the turn of the month. Very good verification of Arctic blocking on the ECM longer ensembles and GFS ensembles and this has complete support from the teleconnections. AO forecasts are fully support this, as does the GFS 10-15 day composits. Buggermy return key has stopped working.

[Weather-history]

Not sure where all 3 models showing a Bartlett scenario comes from because you need the main high pressure cell to be over France or that region to be a true Bartlett with no low pressures running into central or southern Europe.

The GFS 0z mean chart is not Bartlett

http://www.wetterzentrale.de/pics/Rz500m5.gif

The ECM is not Bartlett neither

http://www.ecmwf.int/products/forecasts/d/getchart/catalog/products/forecasts/medium/deterministic/msl_uv850_z500!Geopotential%20500%20hPa!144!Europe!12!pop!od!oper!public_plots!latest!chart.gif

UKMO looks closest to Bartlett but the main high pressure is over Russia

www.wetterzentrale.de/pics/Rukm1441.gif

This is true Bartlett

http://www.wetterzentrale.de/pics/archive/ra/1998/Rrea00119980212.gif

Edited January 17, 2010 by Mr_Data

[john mac]

Not sure where all 3 models showing a Bartlett scenario comes from because you need the main high pressure cell to be over France or that region to be a true Bartlett with no low pressures running into central or southern Europe.

The GFS 0z mean chart is not Bartlett

http://www.wetterzentrale.de/pics/Rz500m5.gif

The ECM is not Bartlett neither

http://www.ecmwf.int/products/forecasts/d/getchart/catalog/products/forecasts/medium/deterministic/msl_uv850_z500!Geopotential%20500%20hPa!144!Europe!12!pop!od!oper!public_plots!latest!chart.gif

UKMO looks closest to Bartlett but the main high pressure is over Russia

www.wetterzentrale.de/pics/Rukm1441.gif

This is true Bartlett

http://www.wetterzentrale.de/pics/archive/ra/1998/Rrea00119980212.gif

Thanks Mr Data, WIB you seem to be obsesed with bartlett's in the last couple of days, i cant really see any bartlett in the charts atm :unsure:

[West is Best]

Thanks Mr Data, WIB you seem to be obsesed with bartlett's in the last couple of days, i cant really see any bartlett in the charts atm :unsure:

Because the rise in high pressure to our south is continually appearing on the models. Discussion of 'true' Bartletts as opposed to proto-Bartlett's (a Bartlett which is forming) is an indication to me of the territory we are in here.

What we need for cold is the Siberian high (I repeat it is not a Scandinavian high - check your atlases) to clear out the way. Without a block to the west there is little or no hope that cold to the east will advect westwards from a Siberian high. It will continue to tantalise and whittle away precious winter days. This is accentuated by this trend of high pressure rise to our south (Bartlett territory) because with those two setups we will continue to have a relatively mild southerly to south-westerly feed. The term 'relatively' refers to genuine cold.

As for the fleeting ECM scenario for the north-east mid next week, it's true that for a brief 24 hour period some colder upper feed comes in. That might produce something sleety or snowy, but without the deep surface cold I fear that any precipation off low levels will be heavily influenced by the long draw off the north Sea and will, therefore, be rain. Cold rain, for sure, but still rain.

At the moment the models are going nowhere in terms of a return to cold.

Edited January 17, 2010 by West is Best

[john mac]

Well eyes down for the 6z, i have a feeling that its going to be an upgrade compared to yesterday. :unsure:

[bluearmy]

http://www.meteociel.fr/modeles/naefs_cartes.php?ech=192&code=1&mode=0&map=1

this is a good game - see if you can find an omega block showing on an ens mean of 50 runs at a timescale of 2 weeks? surely not possible? think again ...........

[Ben_Cambs]

Over the past few days there has been agreement especially in GFS that we will enter a another cold spell towards the end of the month into Feb.

By the way I am very interested in this ECM chart at T+240:

Does anyone have any ideas in what would happen with this chart?

[Guest North Sea Snow Convection]

A lot of pointing towards FI this morning in terms of another cold spell possibility. Nothing especially mild is suggested, but other than the proximity of some surface cold initially in the east then temps wise things look fairly average.

I may be wrong, but I do think that the coldest weather of the winter has passed us by and although there is plenty of time for further cold weather with signs of pressure build over the arctic it could be the case that some are over assuming that we in the UK are going to automatically reload into another very cold spell towards the end of the month. Whilst the possibility is there, I do think the overall signals are fading in terms of whether the UK is going to see any renewed surge.

The falling angular momentum and the rather diminished prospects for an MMW are not going to help. Also there is a rise of pressure over Iberia also progged in FI that could easily also keep the cold air to our NE. That could easily be a first step towards the Feb scenario that GP has repeatedly pointed to.

Understandable hopes being expressed within the context of the remarkable first half of the winter - but expectations about the second half of the winter might be rather too high imo. I am less convinced now than previously about a further very cold spell.

[Frosty.]

A lot of pointing towards FI this morning in terms of another cold spell possibility. Nothing especially mild is suggested, but other than the proximity of some surface cold initially in the east then temps wise things look fairly average.

I may be wrong, but I do think that the coldest weather of the winter has passed us by and although there is plenty of time for further cold weather with signs of pressure build over the arctic it could be the case that some are over assuming that we in the UK are going to automatically reload into another very cold spell towards the end of the month. Whilst the possibility is there, I do think the overall signals are fading in terms of whether the UK is going to see any renewed surge.

The falling angular momentum and the rather diminished prospects for an MMW are not going to help. Also there is a rise of pressure over Iberia also progged in FI that could easily also keep the cold air to our NE. That could easily be a first step towards the Feb scenario that GP has repeatedly pointed to.

Understandable hopes being expressed within the context of the remarkable first half of the winter - but expectations about the second half of the winter might be rather too high imo. I am less convinced now than previously about a further very cold spell.

A lot depends on your location, I know i'm no expert but the ECM 00z surely has at least some potential for snow in the north and east (and northern hills especially) although not much joy for the south and west but the block seems reluctant to move away and does move closer around midweek so does FI start next wednesday I wonder? The gfs 00z still shows a fairly cold mid-late FI with N'ly winds.

Edited January 17, 2010 by Frosty039

[MR EXTREMES]

not that it makes any difference what peeps on here want or dont want but the block holding up the trough will not deliver another freeze to the UK.

we need the trough thru to get the greeny ridge established again. the stand off just wastes a few more days of lower solar input winter with few benefits for coldies.

being a coldie myself im always intrested in cold runs.

this week has been dominated by trends towards mild even weather online are sure mild will win im sure aswell.

not so sure about uncle barty though infact im cert of no uncle barty but blocking in the alantic seems likely and my view has not change this morning in regards to the meto warning for snow event futher north and east you are and higher up you are the better the chances for a snow event.

although cooler air its not deep cold and is likely to be marginal,

except for northern areas above 600 to 800meters.

ofcoarse a arctic outbreak is something im looking at,

and is most likely outcome at some point.

but dont be deluded by the models alantic will win and cold from the nw and north is possible as systems push futher east bumping into heights then push this feature futher away east.

then a more mobile alantic will be the dominating feature.:unsure:

[Guest North Sea Snow Convection]

A lot depends on your location, I know i'm no expert but the ECM 00z surely has at least some potential for snow in the north and east (and northern hills especially) although not much joy for the south and west but the block seems reluctant to move away and does move closer around midweek so does FI start next wednesday I wonder? The gfs still shows a fairly cold mid-late FI with N'ly winds.

I'm talking within the context of a reload of another countrywide cold spell such as we have seen in the last month or so. Yes undoubtably there is potential for some snow in a few parts of the country over the coming days, but overall there is no reliable sign of a return to the significant upper cold conditions that have dominated the first half of winter. More importantly, in my opinion, the chances of the UK being influenced by any further upper cold surge are less than they have been

[cooling climate]

From what I can see of the stratospheric charts a MMW is still a real possibility but as I said in a

post yesterday its not the b all and end all as I think some are now over fixated with this

Atmospheric response.

In my opinion it is more important to look at the mjo and possible rosby wave dispersal into the

Arctic, afterall this is what led to the tanked AO that we have seen so far this winter.

Plus lets not forget the increased ozone in the lower stratosphere which aided in blocking over the

Arctic.

I really can not see this suddenly switching off and fully expect a cold pattern to return as the models

are starting to trend to in FI.

[PB22]

Prospects for snow potential around the middle of this coming week have been reduced even further on the 06Z GFS run. We stil have the weak undercutting low:

http://www.wzkarten3...s/Rtavn781.html

But the cold air is even further to the east now:

http://www.wzkarten3...s/Rtavn782.html

And dewpoints above 0C everywhere, even over Scotland:

http://www.wzkarten3.../Rtavn7810.html

Surface temperatures are still chilly, but not cold enough:

http://www.wzkarten..../Rtavn7817.html

What people could well see, especially across central and western Britain, is plenty of cold rain:

http://www.wzkarten....mgfs120sum.html

The FAX chart isn't quite as good as last night's either, with everything slightly further east, including the cold air:

http://www.wzkarten....cs/brack2a.html

However, the ECM 00Z run is a little more promising, with more in the way of cold air across the north and east:

http://en.vedur.is/photos/atlant_evr_hitaspa/100117_0000_90.png

But there's not much precipitation around:

http://en.vedur.is/photos/atlant_evr_urkomuspa/100117_0000_90.png

Longer term is anyone's guess really. There are signs of colder conditions returning once again, but they are deep into FI.

Edited January 17, 2010 by Paul B