Model Output Discussion:

[SMU]

touché young Steve

As to the models then the input from Ian F and the data available from NOAA as well as the overall output that we see from UK Met all support the view of cold not mild getting the upper hand by early next week. I also agree with GP's view that it is probably not going to be anywhere near as long lasting as the previous spell but then it would take something pretty unusual to repeat that if we are honest-so a minimum of 3-4 days and a maximum of about a week perhaps a shade over.

BUT the actual outcome is certainly not set in stone which the posts from UK Met that Ian drops in make very clear.

Agree John, although my point in reference was taking the 18z in isolation-

We have seen a model swing today, something akin to what we usually see on the eve of a bitter Cold spell- IE a total collapse to mild in 3 runs- today has been the same in reverse-

The GFS + ensemble suite, the UKMO from 00z>>12z & the ECM -all be it in a moderated swing-

Whilst that doesnt guarentee anything & certainly doesnt present a sustainabilty in the protracted cold spell, it does at least inspire me with 'some' confidence that we are on the right track-

I think maybe the 00z of the Early hours Friday Morning- Where Monday is in the 60ish Timeframe should we really start feeling confident as the trigger low is backed up by a small shortwave digging South & these are hard to forecast-

Steve

[John Cox]

The strange thing is Steve is that the 8th Feb has been highlighted by GFS for the past 10 days as the beginning of an easterly, It has appeared and then disappeared for a while and now is back again and by other models.

I think we may be on the cusp of something special.

Fingers crossed.

[The Eagle]

The strange thing is Steve is that the 8th Feb has been highlighted by GFS for the past 10 days as the beginning of an easterly, It has appeared and then disappeared for a while and now is back again and by other models.

I think we may be on the cusp of something special.

Fingers crossed.

Quite a number of the ensembles want to sink the high pressure to the North very quickly. Far from ideal. Not as good as the 12z ensembles IMO. But still it's only one run and clearly a positive trend today.

[John Cox]

Hi The Eagle,

I have been watching every 6 hourly run and the easterly keeps appearing, if not on every run , but it fails to go away.

Quite a number of the ensembles want to sink the high pressure to the North very quickly. Far from ideal. Not as good as the 12z ensembles IMO. But still it's only one run and clearly a positive trend today.

[Guest North Sea Snow Convection]

Taking t144 as a trial ballpark point on the 18z ensemble maps - I can see only one member remaining that shows any sort of south westerly and the atlantic low coming in . The rest are mainly cold easterly with also a few fairly cold anticyclonic.

Quite a change from yesterday.

What will tomorrow bring?

Edited February 3, 2010 by North Sea Snow Convection

[Tom D]

I've just had a look at the models this evening, not seen the other runs today, but nice agreement for a another very cold spell coming up. I'd still be cautious to get too caught onto the exact developments after +120 but definite potential for snow lovers.

Interesting to see that the Scandinavian trough actually brings us another cold spell as it revolves around the Greenland high as it grows, having been a bit of an annoyance over the last few days for preventing the easterly so many have wanted!

[TEITS]

Some exciting members from the GEFS.

http://91.121.94.83/modeles/gens/run/gens-19-1-150.png?18

http://91.121.94.83/modeles/gens/run/gens-18-1-150.png?18

For me personally im not bothered about the details just yet. All I hope for from the 0Zs is the general trend to continue. Some of the GEFS membera are similiar to the ECM whilst some are like the UKMO. For longer term prospects I prefer the UKMO output.

GEFS Parallel run is looking very nice so far.

http://91.121.94.83/modeles/gensp/run/gens-0-1-132.png?18

P.S John H I can't be bothered to explain further. The gist of what im saying is their has been other members who have been successful this winter. These also deserve some credit even though their techniques may differ to GP and may not be as technical. I have noticed you seem very quick to praise GP but less so towards others.

[Guest North Sea Snow Convection]

Quite a number of the ensembles want to sink the high pressure to the North very quickly. Far from ideal. Not as good as the 12z ensembles IMO. But still it's only one run and clearly a positive trend today.

I'm happy with them - the atlantic is taken virtually out of the picture and the presence of a few anticyclonic charts is nothing to worry about. I suspect the ensembles would be quick to place the high slightly further south anyway.

I think that the signal for an initial high between Scandi and Iceland is, of the minute increasing - and against all the uncertainty we have been through that is all that matters. At least until early morning when the next session unfolds (for those that are around!)

Fingers crossed it is all still the same a few hours later when the rest of us are awake!

Edited February 3, 2010 by North Sea Snow Convection

[ScottSnow]

As others have pointed out the most important thing at the moment is maintaining the overall trend. Once the cold weather is here then we can discuss snow potential but thats a long way off yet.

However my opinion is that this winter has really been the joker in the pack, so if we do end up with high pressure to the north and entrenched cold I believe it may be harder to shift than people think. The cold has never really left Scotland since mid Dec and if we get this projected easterly I can see the cold weather hanging on for a good while yet.

[Duane S.]

General model agreement is what we have all wanted to see (although, admit it, we all enjoyed the drama ). We have it, well, sort of, so.. there are good reasons to be optimistic that the long awaited continental flow is just around the corner at last. Especially as the charts now tie in with the signals for Northerly blocking. The only word of caution would be that whilst I am sure that blocking will be the dominant force come this time next week and that there will be a CAA drive towards us, it COULD still end up in the wrong place for us and that would have to be my biggest fear right now.

Right! Now the last two times I went to bed after a cracking day of model upgrades in the past week or so, everything imploded the next day!! If it happens again (although I really don't think it will this time) I fear we will be both out of time and out of luck. Fingers crossed, the finishing line is in sight...

[PersianPaladin]

T96 on the 00z and although things look messy south of Greenland; the ridging is coming into place nicely.

Edited February 4, 2010 by PersianPaladin

[ScottSnow]

Yes the overall pattern is maintained by the 00z, another brick in place.

Although FI can only be taken with a pinch of salt, the cold weather is maintained throughout the run with high pressure entrenched to the north.

Backs up my hunch that IF we get the initial easterly then we may well see a prolonged cold spell again. This winter has been the joker in the pack and I wouldn't be suprised if we are dealt another ace.

Edited February 4, 2010 by Snow White

[David-kig]

GFS 00Z what a run! it bring the colder air soon sooner to. the upper look as cold as the last spell with maybe colder at times. blimey fun and games still on.

I dunno how to say because GFS 18Z weren't bad but this is an upgrade in short time frame is well.

[ScottSnow]

Just checked the UKMO 00z and although not a terrible run, the difference between it and the GFS at 96hrs is that the Atlantic low makes further inroads on the UKMO and the very cold weather is just kept out of reach by 144hrs.

Not terrible but not great lets just hope the ECMWF and GFS 06z the play ball.

Edited February 4, 2010 by Snow White

[NorthernRab]

Just checked the UKMO 00z and although not a terrible run, the difference between it and the GFS at 96hrs is massive. The Atlantic low makes much further inroads on the UKMO and the very cold weather is just kept out of reach by 144hrs.

Not terrible but not great lets just hope the ECMWF plays ball and theres consistency with the GFS 06z.

There really isn't a 'massive' difference between the UKMO 00z and GFS 00z at 96hrs, there are just lower heights to our north and not by much. It wouldn't take very much at all to bring in cold a lot sooner so we'll just have to watch.

[ScottSnow]

There really isn't a 'massive' difference between the UKMO 00z and GFS 00z at 96hrs, there are just lower heights to our north and not by much. It wouldn't take very much at all to bring in cold a lot sooner so we'll just have to watch.

Yes your correct and let's hope it gets here sooner. However in my opinion the UKMOs not as good as the GFS although the overall pattern is maintained which I suppose is the main thing at the moment.

[Iceberg]

ECM starts to bring the cold air in at T96, GFS T96 and UKMET GM T120.

Not much in it tbh, it's alot better than painfully watching it come in from 168 or even 240.

Still to early to talk about snow etc, except that there will be some somewhere.

Overall very good charts still.

[Bolton67]

Just checked the UKMO 00z and although not a terrible run, the difference between it and the GFS at 96hrs is that the Atlantic low makes further inroads on the UKMO and the very cold weather is just kept out of reach by 144hrs.

Not terrible but not great lets just hope the ECMWF and GFS 06z the play ball.

Not terrible nor not great??

GFS18z T+96

UKMO 0z T+96

[Eugene]

Overall very good charts still.

Yes very good charts this morning as we are now seeing some kind of agreement on the atlantic not taking over our weather like some thought might happen just a few days ago, HP to our north and east remains the controlling factor and keeping the atlantic at bay, not much we can complain about this morning to be honest.

I wish people wouldnt always be disappointed if we dont see armageddon cold on every run, definate improvement this morning compared to the big uncertainty just yesterday morning.

[TEITS]

What a relief to see the E,ly trend continue this morning. Almost torture viewing these after recent escapades.

The detail remains uncertain especially wrt the SW over Scandi which can be notoriously difficult to model. The models all have slightly different ideas for the E,ly.

The ECM is slightly reluctant to move the SW S compared to the GFS as can be seen on the links below.

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

http://www.wetterzentrale.de/pics/Rtavn1441.png

The GEM/NOGAPS want to go the S,ly tracking LP route

http://91.121.94.83/modeles/gem/run/gem-0-144.png

http://91.121.94.83/modeles/nogaps/run/nogaps-0-168.png?04-06

So taking all of the above into account im quiet happy to accept the GEFS mean for the time being.

http://91.121.94.83/modeles/gens/run/gens-21-1-96.png?0

http://91.121.94.83/modeles/gens/run/gens-21-1-120.png?0

I will add that one observation I have made over the years is when an E,ly is modelled by the ECM/UKMO they tend to look slack affairs until this moves into +72 when all of a sudden the flow is strengthend. So whilst the outlook continues to trend towards cold there is still much uncertainity wrt to the details especially the SW over Scandi, exact positioning of block, atlantic LPs.

[LomondSnowstorm]

Nice to see a firming up of this pattern, and hopefully as TEITS says the flow will be a bit stronger come +72 hours than shown on the ECM. However, that ensemble mean looks pretty tasty I must say!

LS

[KTtom]

At last! We can sit back and take a breath beofe disecting the models in fine detail. Pretty much nailed on that the next 7-10 days won't be Atlantic dominated. There is still plenty of detail to iron out especially regarding the track of the Atlantic lows. I see that the channel low predicted by GFS and ECM for next Wednesday/Thursday has gone AWOL on the 00Z's.

I'm sure the detail for next week will change, definately looking cold but those who have their meter ruler propped up against the front door ready, may be a little dissapointed away from the NE.

Personally I'd prefer 3 days of cold, a big snow event followed by an early spring as opposed to 10 days of ice.

Edited February 4, 2010 by KTtom

[Frosty.]

Good model agreement this morning for much colder weather to hit the uk by early next week. The GFS 00z is a bitterly cold run full of snow potential and sub-zero temps, the ECM 00z is also a very cold run but mainly dry and higher pressure and no more than a few snow flurries, I would suggest the UKMO 00z is somewhere between the gfs and ecm, the NOGAPS 00z looks a mega wintry run with strong E'ly winds and snow in the north but less severe in the south, the GEM 00z also looks very cold with plenty of snow due to lower pressure.

[cooling climate]

One thing on the models yesterday afternoon that I found odd was the way they dropped

heights quickly to the north bring back a +AO. This to me does not fit at all with the signals

from the stratosphere (SSW) and downward propagating easterly winds etc.

This morning the ECM and GFS have completely switched showing a very negative -AO which

imo is more in line with atmospheric events and would fit with my beliefs of a prolonged very

cold February to come.

Excellent charts this morning with only detail to be sorted out over the next few days.

Edited February 4, 2010 by cooling climate

[Snowyowl9]

The atlantic looks like it will of failed again.

http://wzkarten.de/pics/brack2a.gif

Looks like temperatures won`t be getting back cold until the same day sunday in the south.

http://91.121.93.17/pics/Rtavn9017.png

As this slack low the temps looks abit high to me with a slack east flow.

http://91.121.93.17/pics/Rtavn601.png

http://91.121.93.17/pics/Rtavn6617.png

Considering the cold still be staying in N england.

http://91.121.93.17/pics/Rtavn4217.png

Edited February 4, 2010 by Snowyowl9