Model Output Discussion:

[Iceberg]

UAE shows the colder undercut nicely

The T48 chart has sub 130 thickness in the east counties, 950 temps of 0 to -1, but 850s at only 0 to -1, showing the colder air at surface as well.

It also has 2M temps widely at 2C or 3C we don't have long to wait for the colder air to kick in now.

[kold weather]

Yep so far some very neat 12z runs thats for sure, will be interesting to see just what the ensembles show and whether they are also cold...

Can't quite believe how quiet this thread is today, esp compared with yesterday, I guess many people thought it was already game over based on the 0z!

One word to describe tonights GFS...mental.

Shades of Feb 47' there surely?

Its certainly a very interesting pattern, even without much of an upper high at all over Iceland we still look likely to hold onto at the very least a cold surface high, but I think at some point with the set-up quite possibly becoming stagnant we could see an easterly.

Iceberg, yep the 12z GFS shows this nicely as well, monday seems likely to be one of those cold and dull days I think.

[sandstorm2]

The models are showing it becomimg slightly milder at +384, sorry couldn't resist.

SS2

Edited February 5, 2010 by sandstorm2

[karyo]

Very pleasing 12z output so far. Not just cold but some snow too for many areas!

The GFS FI is sensational. If it was to come off, the Baltic sea would be complete frozen!

Karyo

[morfius]

That cold pool is insane, imagine if that shifted our way! Ashame it's the last one of FI...

[cooling climate]

I for one enjoyed every minute of that run, how often are we likely to see runs like that.

If the 12z GFS operational run verified many places would still be clearing snow drifts

come may lol.

Excellent UKMO run as well which leaves the ECM 12z and I am positive it will not

disappoint.

Hey nick even with all that cloud and snow my CET guesstimate would still be on track

I think lol especially with what looks to be on the way for the last third of the month.

[chionomaniac]

That cold pool is insane, imagine if that shifted our way! Ashame it's the last one of FI...

Yes, that is insane. I know it is FI and therefore very unlikely but the reasoning behind these charts can be valid. With above average Eurasion snow cover and a relaxed polar vortex releasing cold to latitudes further south, whereas we may never see cold scenarios modeled like this in the reliable timeframe, it is great to see a winter when factors come together to even have a chance of modeling these cold pools.

[TEITS]

So based on the UKMO/GFS the outlook so far is.

+72 Cold E,ly flow with upper temps around -7C/-8C. This bringing cloudy conditions in E areas with a mix of light rain/sleet/snow in places.

http://www.wetterzentrale.de/pics/Rmgfs722.gif

+96 Cold NNE,ly with upper temps around -8/-9C. This bringing scattered/occasional snow showers in E areas.

http://www.wetterzentrale.de/pics/Rmgfs962.gif

+120. Same as +96 but probably an increase in snow showers, possibly an area of more prolonged snow affecting more inland locations.

+144. Winds veering to a ENE,ly with upper temps around -11C and more snow showers.

http://www.wetterzentrale.de/pics/Rmgfs1442.gif

Edited February 5, 2010 by THE EYE IN THE SKY

[LomondSnowstorm]

One thing I've noticed is that the GEM is much more keen on an undercut than any other model http://91.121.94.83/...un/gem-0-84.png

http://www.meteociel...96-21.GIF?05-17 http://www.meteociel...M1-96.GIF?05-12

And yet it has been showing this consistently for about three days now.

Not sure if the GEM is just completely on the wrong track or whether the other models are failing to pick up on this.

LS

[Ben_Cambs]

I for one enjoyed every minute of that run, how often are we likely to see runs like that.

If the 12z GFS operational run verified many places would still be clearing snow drifts

come may lol.

Excellent UKMO run as well which leaves the ECM 12z and I am positive it will not

disappoint.

Hey nick even with all that cloud and snow my CET guesstimate would still be on track

I think lol especially with what looks to be on the way for the last third of the month.

ECM tonight will be very important regarding the positioning of the high, of course the further NW the better. Totally amazing output from GFS 12z..... Regarding your CET guess of a negative CET, that is a very brave call from you!

[Freezing-Point]

Over the past 7-10 days most on here have been completley caught out by the forthcoming cold period. Led completely by the daily main model runs with it seems little respect to any of the other signals.

Well done to the few on here who have stuck their necks out, used instinct, historical data, cyclic patterns and whatever other means to predict the cold spell.

I have noted that the meto have also maintained that we will get this easterly flow since the last cold spell (although its a little delayed). Well done to them also.

[kold weather]

With regards to the positioning of the high its going to be 50-50 IMO as to whether its good enough or not, however I suspect for a time at least we will see a reduction in the showery flow as the upper high builds. whether or not it cuts off the easterly totally I've not got a clue right now though!

[snowking]

Not really agreeing or disagreeing with that but I do find it very funny and ironic that that post has just disappeared!

One thing I've noticed is that the GEM is much more keen on an undercut than any other model http://91.121.94.83/modeles/gem/run/gem-0-84.png

http://www.meteociel.fr/ukmo/run/UW96-21.GIF?05-17 http://www.meteociel.fr/modeles/ecmwf/run/ECM1-96.GIF?05-12

And yet it has been showing this consistently for about three days now.

Not sure if the GEM is just completely on the wrong track or whether the other models are failing to pick up on this.

LS

I was expecting to be able to shoot you down in flames with the chart correlation, but actually at day 5 currently the GEM verifying the best

http://www.emc.ncep.noaa.gov/gmb/STATS/html/graphics/acz5.gif

Of course that doesnt necessarily mean this chart will verify, but if as you say this has been a consistent output for a few days its worth taking a look at

SK

[TEITS]

After some were disappointed with last nights 18Z GFS/ensembles im pleased to say the 12Z GEFS mean is much better.

Here is the mean at +96/+120/+144.

http://91.121.94.83/modeles/gens/run/gens-21-1-96.png?12

http://91.121.94.83/modeles/gens/run/gens-21-1-120.png?12

http://91.121.94.83/modeles/gens/run/gens-21-1-144.png?12

Don't forget the mean is made up from all 20 members. So you might find some members even better than the 12Z GFS OP and some less so. These days I don't tend to look at each member but I would appreciate anyone finding a better member than the GFS OP.

[snowking]

Should also add with regards to the GFS the 12z has the best verification stats for heights and temperatures over the last month, with current standings over the last 3 days or so not really giving a bias either way

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/gfs4cyc/daily/cor/cor_day5_gfs_HGT_P500_G2NHX.gif

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/gfs4cyc/daily/cor/cor_day5_gfs_T_P500_G2NHX.gif

SK

[Freezing-Point]

After some were disappointed with last nights 18Z GFS/ensembles im pleased to say the 12Z GEFS mean is much better.

Here is the mean at +96/+120/+144.

http://91.121.94.83/modeles/gens/run/gens-21-1-96.png?12

http://91.121.94.83/modeles/gens/run/gens-21-1-120.png?12

http://91.121.94.83/modeles/gens/run/gens-21-1-144.png?12

Don't forget the mean is made up from all 20 members. So you might find some members even better than the 12Z GFS OP and some less so. These days I don't tend to look at each member but I would appreciate anyone finding a better member than the GFS OP.

Going off those charts I think you will be needing to take some new pictures soon!!!

Edited February 5, 2010 by Freezing-Point

[kold weather]

One thing I've noticed is that the GEM is much more keen on an undercut than any other model http://91.121.94.83/...un/gem-0-84.png

http://www.meteociel...96-21.GIF?05-17 http://www.meteociel...M1-96.GIF?05-12

And yet it has been showing this consistently for about three days now.

Not sure if the GEM is just completely on the wrong track or whether the other models are failing to pick up on this.

LS

I suspect given its at 84hrs and the models plus ensembles don't really agree with it I think you can throw it in the bin so to speak, its WAY too quick in destroying the heights to the north from the looks of things...

The 12z control run tonight goes with the high building a little too close and eventually sinking slowly around 240hrs, a very cold outlook though less snowy then the op run probably...

[LomondSnowstorm]

I suspect given its at 84hrs and the models plus ensembles don't really agree with it I think you can throw it in the bin so to speak, its WAY too quick in destroying the heights to the north from the looks of things...

I thought that, just a bit odd how a supposedly reputable model can go off on one like that! That is a better mean than last night's one, showing that perhaps the ensembles are every bit as prone to change as the operationals!

LS

[J10]

It is good to see an apparent upgrade in the models today, after what now appears to be a blip in last night's 18Hz run ,and it does appear that a cold spell (and quite possibly another severe one) is extremely likely.

Today's charts are also better for potential snow with the High Pressure being ever so slightly further north than was the case on earlier runs, and certainly better for Ireland, as the cold weather extends further west much sooner. As said a few posts above, ECM is important tonight, to see the exact positioning of the high and to see how far north the instability can get.

All in all though, very good models today.

[billy]

Very nice 12z GFS and UKMO tonight. Just saw Darren Bett on news 24 saying colder next week but nothing like what weve seen so far this winter. I know hes a mild ramper but i thought looking at these charts it could be just as bad across Southern Uk at least.

[kold weather]

If there is one fault with the GEM I have to admit its probably the fact it can be very progressive at times, it ensembles are even more amazing in that respect, I've seen them go for a huge Greenland high, to Bartlett then back again in the space of 7 days on quite a few times, its insane really!

Anyway from what I've seen of the ensembles, looks cold for quite some time yet, but the ins and outs seem to be uncertain still as per normal. At least we should get cold down within the next 48-60hrs, thats always a good starting point.

[Weathizard]

It is good to see an apparent upgrade in the models today, after what now appears to be a blip in last night's 18Hz run ,and it does appear that a cold spell (and quite possibly another severe one) is extremely likely.

Today's charts are also better for potential snow with the High Pressure being ever so slightly further north than was the case on earlier runs, and certainly better for Ireland, as the cold weather extends further west much sooner. As said a few posts above, ECM is important tonight, to see the exact positioning of the high and to see how far north the instability can get.

All in all though, very good models today.

Question from relative novice, would this high pressure effect weather conditions for the entire country? sorry I'm just a bit new to this all.

[Paul]

I'm not looking to start a full scale discussion of this on here, so if you want to reply feel free to do it via pm rather than publicly, but I think something needs to be said on here...

When you consider the team freely give up their time to moderate on here, and bearing in mind that when we asked the membership for their views at the beginning of winter one key request was that the model discussion threads were actually kept to discussing models, it's disappointing when there are so many posts having to be removed/moved, and even more disappointing that people think it's ok to start 'team bashing' within the thread because of this.

There are 3 main model threads - all pretty clear in their definitions and all available at all times..

Technical model discussion - For the much more in depth looks at the models/teleconnections etc in a slower paced thread.

Model output discussion (this thread) - For model based discussions - with the emphasis on fact based opinion and thoughts on the actual output

Model chat and moods - A chattier thread for less factual discussion - eg 'Woohoo this run's great it's upgraded the cold'

Now of course there's some crossover, particularly between the chat and discussion threads, and sometimes it may be hard to know where to post something. But 99% of posts which are being removed/moved from here aren't in this category, they're just way off the scale - often not even anything to do with the models!!

To get to the point though, the team are volunteers and they're all spending huge amounts of time trying to keep this place on the straight and narrow, sometimes (as all of us do) they will make mistakes, may act on a post which perhaps could have been left as is, may miss a post which is crying out to be removed and so on, but everyone is doing their best to do what is right for the forum and it's membership.

So next time you have a post removed/moved, please don't moan at the team (particularly not publicly within a weather related thread), perhaps consider why it may have been removed first, and try to post into the correct thread next time. If you're still unsure as to why it was removed/or moved and haven't heard from the team member who did the moderating (unfortunately in such busy times it's just not possible to contact everyone), then please feel free pm a team member and ask - we'll be glad to check for you and let you know.

This is a community, with several thousand members now and for it to work properly everyone has to take a bit of responsibility and help out - so please try to post into the correct threads, and report posts you think are an issue.

Thanks

Paul

[J10]

Question from relative novice, would this high pressure effect weather conditions for the entire country? sorry I'm just a bit new to this all.

Basically the higher the pressure the lower the potential for showers, as the showers are not given the energy they need to form, and the High pressure acts as a cap stopping the air rising to from the shwoers.

So the further north the high pressure, the greater the chance of convective activity, i.e showers across the UK (especially in eastern areas).

[The Weather Dragon]

What a Winter - having already experienced some excellent synoptics this winter how fortunate are we to have another potentialy exciting cold spell developing in a realistic timeframe. Models are firming up on the evolution now. I am looking no futher than T96 at the moment - and am delighted at the cross model agreement up to that stage. Once again a truly absorbing winter.

Edited February 5, 2010 by Jonathan Evans