Winter Model Output Discussion - 06Z 09/02/13 onwards

[shotski]

Of all the GFS runs to show a great evolution, it had to be the 06z didn't it!

I do hope this is the start of a new trend but my head says its just the worst verifying GFS run of all having a wibble. However, as Ryan says, it does have some minor model support and NOGAPS (the rapidly becoming ex-cannon fodder model!) has had this setup on one or two of its recent runs too.

mate it has big support and should be taken seriously. sorry can't post any charts but on my phone.

[BLAST FROM THE PAST]

The 06z GFS shows a way where we could bring that cold back west later next week.

It shows the energy attacking at a better angle SE which allows the ridging Azores High to build around the top of the low sinking across the UK thus linking with the Scandi High at a more northerly latitude.

http://modeles.meteo...gfs-0-150.png?6

In this marginal setup it shows just a minor difference on the angle of that sliding low allows the block to the NE to regress west which brings the easterly in.

Of course it`s only one run and we need to see more support but there is a signal for a build of height anomalies towards Greenland the week after next and this is a way that this could happen-ie easterly to a northerly.

http://176.31.229.22...-0-0-204.png?12

It would be a decent finish to Winter if this evolved.

Indeed Phil, probably the only 'likely' way to get there in time for any meaningful snow to be lyting without thaw.

BFTP

[Timmytour]

Regarding tomorrow and the Met Office....for me they have been the most cautious about what may or may not transpire and build in the caveat of "stay tuned" to every forecast.

A hell of a lot better perspective than some on here have had We can all see the models have been erratic in their approach to what they think will happen.....understandably so because there are only events on a relatively local scale. No one's pointing at a little strip of land anywhere else in the Atlantic and measuring their performance against how it models things there.

The Meto rely on models as well, and these may be more powerful, but no less vulnerable to local variation.

Edited February 9, 2013 by reef
Stick to the models

[bluearmy]

with all the emphasis on the near timeframe, i hadnt actually noticed that the 06z high res is very similar to the ecm op in its overall pattern. the ecm op was at the top of its ens 14/15th so maybe that disruption does need to be backed west somewhat. interesting.

Edited February 9, 2013 by bluearmy
Models only please

[Cloud 10]

Ensemble mean from gfs 06z at 168 versus the operational shows the op run to be a bit

over enthusiastic,but a nice run anyway with lots of retrogression!

mean.. op run..

Please lets not start the sniping that was evident in the last thread.

[Froze were the Days]

I cannot recall a run like this.Could you elaborate a little.Ta

Not quite sure what you mean about elaborate a little but just saying the GFS has been particularly poor this winter in both the fairly short and medium term, some people say that the GFS can pick up trends in FI but I haven't seen it pick up any regarding 'slack' heights to the north east as has happened on a few occasions this winter have you? Just because the 06z has flipped and shows heights to the NE and then to Greenland it shouldn't be taken seriously the model has been well off course this winter, the only slight crumb of comfort is that the CFS has been consistent showing a very blocked late February and March with a very -NAO. Be interesting to see the GFS output in the next day but It has been coming out with all sorts of solutions.

[Long haul to mild]

mate it has big support and should be taken seriously. sorry can't post any charts but on my phone.

I certainly hope it's right, but I have seen too many variable model outputs in the last few days to get on board yet!

However, as you say, there is support for it elsewhere. If that support came from somewhere like the UKMO then I would certainly be very interested.

[phil nw.]

Indeed Phil, probably the only 'likely' way to get there in time for any meaningful snow to be lyting without thaw.

BFTP

Yes to get the deep cold something from the North/North East would be the best way forward now Fred.

We really need to see some of the vortex dropping down through Scandinavia for the best scenario as you would know i am sure.

At present there`s no real indications of that-just a persistence of low hts around W.Europe but if those heights do regress away from Scandinavia then it will leave the gap for that-but it`s then down to the vortex to play ball.

[Frosty.]

Ensemble mean from gfs 06z at 168 versus the operational shows the op run to be a bit

over enthusiastic,but a nice run anyway with lots of retrogression!

mean.. op run..

The retrogression was so good that it was almost as if BFTP was at the controls of the 6z, moving that high westwards

[NickR]

I think maybe the East will get more accumulations with the heavy showers coming from the Easterly. The forecast is certainly had a change for Yorkshire, higher ground now from 20cm to 10cm with lower levels seeing sleety conditions.

Uppers on GFS aren't good: -5°C to -7°C for EA up to the NE. I wouldn't expect too much convection from that.

[Cheshire Freeze]

Yes to get the deep cold something from the North/North East would be the best way forward now Fred.

We really need to see some of the vortex dropping down through Scandinavia for the best scenario as you would know i am sure.

At present there`s no real indications of that-just a persistence of low hts around W.Europe but if those heights do regress away from Scandinavia then it will leave the gap for that-but it`s then down to the vortex to play ball.

It's exactly what we need to see. I've been banging on that drum for a while. I dislike these height rises to the east with a passion as we're always reliant on conditions on the continent and strength/amplitude of jet.

Greenland height rises are less stressful to model and more stable. Plus usually deeper cold and unstable air is advected from the N and E.

I certainly wouldn't be sad if we never saw a Scandi high again TBH. One hasn't truly cut the mustard for years. A Greenland-Scandi combo is a different matter.

Edited February 9, 2013 by CreweCold

[shotski]

I certainly hope it's right, but I have seen too many variable model outputs in the last few days to get on board yet!

However, as you say, there is support for it elsewhere. If that support came from somewhere like the UKMO then I would certainly be very interested.

blocking to the north and west of the uk is almost a cert mid month imo. but the evolution to anything cold

may well see a temporary warm up.

[lorenzo]

That removal of westerly inertia mentioned by GP seems to have immediately removed, the tendency and mountain torque charts show a whole bunch of blue ans scrubbing of westerlies and this appears to overnight have manifested itself in the Jet. Fascinating 06z.. With the ECM at the mid-range tending on the mild side tonights 12z will again be worth scrutiny. Will it back track to similar output from 48 hrs earlier.

Looking at the postage stamps last night the ECM Easterly solutions where diluted from Thursday 12z approx 50% of the suite, perhaps this was the model doing the pick up a theme drop it for a couple of runs then get back on line with it routine.

One thing about the 06z GFS is that the progress through the slider to the building of heights looks like a completely steady evolution, almost effortless, the pivotal point appearing to be where things go at around 120hrs. A well aligned and very lazy looking jet.

Couple of pressure ensembles.. First just North of Scotland and the other Greenland. Op on its own with the height rises, geographically the retrogression is evident, so two trends to keep a watch on, will the ensembles follow the op, and will they travel.

[Snowman.]

Uppers on GFS aren't good: -5°C to -7°C for EA up to the NE. I wouldn't expect too much convection from that.

Because it hadn't had time let that run on that would drop to about -10 in the north.

[NickR]

Because it hadn't had time let that run on that would drop to about -10 in the north.

True - Mon night/Tues am is better....

BTW - what is the rule about wind direction compared to the isobars? I seem to remember reading that the wind doesn't follow the direction of the isobars but is offset by about 30°.. can't remember in which direction though!

[phil nw.]

In order to keep the thread on topic please use the report function for posts anyone is unhappy about.

Better than clogging the thread up with complaining posts which in themselves encourage reactions.

OK thanks folks-back to the models.

[Manchester_Sunset]

Uppers on GFS aren't good: -5°C to -7°C for EA up to the NE. I wouldn't expect too much convection from that.

It showed on Sky/Calendar it goes east then swivel round and goes southwards and sorts of fizzles out here. I'm not expecting a lot from this.

[johnholmes]

True - Mon night/Tues am is better....

BTW - what is the rule about wind direction compared to the isobars? I seem to remember reading that the wind doesn't follow the direction of the isobars but is offset by about 30°.. can't remember in which direction though!

In most situations you will find the surface wind is backed, ie anti clockwise from the isobars

How much is dependent on many factors but a rule of thumb of 30 degrees would be okay for most inland stations, more than that at night/under an inversion

[lorenzo]

True - Mon night/Tues am is better....

BTW - what is the rule about wind direction compared to the isobars? I seem to remember reading that the wind doesn't follow the direction of the isobars but is offset by about 30°.. can't remember in which direction though!

try this page details all the different factors well. http://www.aos.wisc.edu/~aalopez/aos101/wk11.html

[Snowman.]

True - Mon night/Tues am is better....

BTW - what is the rule about wind direction compared to the isobars? I seem to remember reading that the wind doesn't follow the direction of the isobars but is offset by about 30°.. can't remember in which direction though!

Seems about right

[Ryan Dutch Weatherman]

End for the 16e or 17e run at a row , here he is CFS latest again.00z.

March 2013 , winter start in UK.

Lets walk with en hope for the CFS.

[NickR]

Many thanks all!

[bradymk]

End for the 16e or 17e run at a row , here he is CFS latest again.00z.

March 2013 , winter start in UK.

Lets walk with en hope for the CFS.

Only problem is that if we had believed the CFS daily this Winter, we should of had a very cold winter one day and a very mild the next, it seems to have been showing different eye candy charts every run and none have really come off. It changes more than the GFS and that is saying something GFS 6z much better however its so frustrating knowing that it will probably be showing a completely different outcome come half 4. Not that the GFS is alone with constant changes at the moment.

[Isabellesnanny]

Sorry if this is off topic - not sure where else to post. As a real amateur just wondered what the Netweather forecasts ( 7 day/10 day) are based on - they seem to change so dramatically with each 6 hour whereas with the Metoffice forecast you can generally think that the next 24 hours is pretty much correct - for example hardly any snow for my region on the 4am run whereas by 10.00am snow everyday for almost the next 10 days.

I am still struggling with the models so rely on the forecast to know what is going on but I am just confused as to why such drastic changes occur on this particular forecast which are not showing on others.

Again sorry if off topic but would be grateful for your thoughts.

[bradymk]

Sorry if this is off topic - not sure where else to post. As a real amateur just wondered what the Netweather forecasts ( 7 day/10 day) are based on - they seem to change so dramatically with each 6 hour whereas with the Metoffice forecast you can generally think that the next 24 hours is pretty much correct - for example hardly any snow for my region on the 4am run whereas by 10.00am snow everyday for almost the next 10 days.

I am still struggling with the models so rely on the forecast to know what is going on but I am just confused as to why such drastic changes occur on this particular forecast which are not showing on others.

Again sorry if off topic but would be grateful for your thoughts.

Someone will have to confirm this but I think they are based on the GFS model which currently is changing drastically each run (every 6 hours) so that would explain the dramatic changes.