Model Output Discussion:

[Eugene]

yet again they seem to be disregarding the GFS, which is understandable with its wild swings

Lets be fair nick ECM and UKMO have both swung wildly too, both models going for cold easterlies on monday before dropping the idea yesterday, UKMO not until 12Z.

http://www.ecmwf.int/products/forecasts/d/getchart/catalog/products/forecasts/medium/deterministic/msl_uv850_z500!Wind%20850%20and%20mslp!216!Europe!pop!od!oper!public_plots!2010020112!!chart.gif

http://www.ecmwf.int/products/forecasts/d/getchart/catalog/products/forecasts/medium/deterministic/msl_uv850_z500!Wind%20850%20and%20mslp!216!Europe!pop!od!oper!public_plots!2010020100!!chart.gif

[Frosty.]

im going to just sit on the fence and expect these wild wings to continue.

Do you think the seagulls will help us this time teits B)

No doubt the gem is the best output this morning but there are such huge differences between all the models that we could still get anything from very mild to very cold and everything in-between too. With the ukmo looking so averagy again, probably best not to get too excited.

[TEITS]

im going to just sit on the fence and expect these wild wings to continue.

Do you think the seagulls will help us this time teits B)

No doubt the gem is the best output this morning but there are such huge differences between all the models that we could still get anything from very mild to very cold and everything in-between too. With the ukmo looking so averagy again, probably best not to get too excited.

At the moment its difficult to put your trust in any model. Remember mondays excellent 12Z UKMO/ECM was followed by a dreadful 18Z GFS/GEFS members and this proved correct at the time and the following mornings 0Zs trended towards the 18Z!

[Frosty.]

Dunno, but it must be stressed they're regularly changing the prospects / making tweaks to the GM based on other models .... as you'd rightly expect. I've stressed this before. Fairly often I see briefings explaining tweaks based on better continuity in Arpege, GFS, etc etc (other nations doing likewise based on UKMO; it's all swings and roundabouts). I've never really seen the folks at Ops Centre locked slavishly into some quasi-religious following of their own (longer range) modelling at the expense of sound scientific analysis and due flexibility. They've remained largely bullish about the likelihood of something colder appearing into the 10-15 day period for a while now..... anyway, we'll see further mid-range briefing details after 12Z so I'll await with interest.

Thanks for the reply Ian, always great reading your expert views. B)

ame='Frosty039' date='03 February 2010 - 10:25 ' timestamp='1265189148' post='1762578']

At the moment its difficult to put your trust in any model. Remember mondays excellent 12Z UKMO/ECM was followed by a dreadful 18Z GFS/GEFS members and this proved correct at the time and the following mornings 0Zs trended towards the 18Z!

I honesty don't know what to think dave, the models have improved since sunday though but the ukmo is a concern yet again with its nothing to write home about 00z output.

[Glacier Point]

http://www.knmi.nl/e...agse/index.html

The day 5 ECM ensembles are starting to show what would reasonably be expected given what's going on with momentum transports across the Pacific Ocean in particular with signals for a mean ridge to develop across Canada and western Greenland and, a probable transient eastern extension of the ridge towards Iceland helping to draw colder air situated over Scandinavia towards the UK mid month.

Edited February 3, 2010 by Glacier Point

[snowmadchrisuk]

Massive Improvement from the GFS / NAE regarding Current events :

[Eugene]

http://www.wetterzentrale.de/pics/Rtavn841.png B)

[Iceberg]

GFS 06Z better at T72 as well. !

[Matty M]

6z is interesing

Note the total change in the shortwave over northwest Scandy.

High pressure cell forming.

Force jet further south.

[snowmadchrisuk]

http://www.wetterzentrale.de/pics/Rtavn841.png B)

Easterly brought back at 72 hours I wondered why the METO have sleet and Snow showers for the East midlands over the weekend .

[Polar Continental]

I have missed a lot of runs this week as I was hoping that if I left it a few days everything would settle down and become clearer , this is obviously not the case , I don't know if this is an example of how bad the models are preforming at the moment , but the models this morning show rain for today but the Met office / BBC are Insisting it will be Heavy Snow across the Midlands and Wales. Even the NAE model only Shows Snow for the far East . Basically what seems to be happening is every time the warm air looks like it will make inroads it can not make it across the whole country and the Cold air wins. This is what I think will prove to be a big turn around from the Models back towards Cold next week. +96 on the UKMO still gives us hope by the way IMO .

I need to keep a close eye on all the major models, as the weather forecasts on my web-site are based around as such. I normally go out around a week, but have been unable to do this for some time. Having to stick to 96 hours for the outlook, but I have stuck my neck out today and gone with the GFS beyond the weekend, so colder after the weekend.

Is it not correct that even though GSF at T96 swings to the east, the feed off the continent is not particularly cold by this point anyway as the block c/w cold air has been pushed north?

Yes, the GFS projects upper air temperatures around 5c, but if thee easterly wind digs in as suggested, these will fall as colder uppers are dragged off the continent. Having said that, surface temperatures will be colder than the uppers.

[Eugene]

Crazy to think 16C/17C was being bandied about just a few days ago for sunday and now temps look like this at this rate sunday will be an ice day B)

http://www.wetterzentrale.de/pics/Rtavn10217.png

[Matty M]

As they say in Darts, GAME on!

[cooling climate]

At t102 the 06z GFS run has the makings of turning into a cracking run with heights

extending up towards Spitzbergen (Svalbard) and the low in the Atlantic to undercut

the block with CAA moving southwestwards.

[nick sussex]

Oh I hope this isn't another GFS wild goose chase! Remember unless the UKMO comes on board then anything the GFS shows is very suspect, that still has to perform a big backtrack to get close to this.

[Ian Fergusson]

Massive Improvement from the GFS / NAE regarding Current events :

NB: NAE was tweaked overnight (as always) by the UKMO Chief Forecaster to account for more bullish, but transient lowering of WBFL's this morning into more southerly parts of the Midlands; plus enhancing the snow signal more generally on the raw PPN fields. It proved the correct call (e.g., snow fell readily this morning, albeit without significant settling, over uplands of Gloucestershire, parts of North Wilts etc - - so further south than yesterday's runs catered for but correctly reflected by the 00Z modified run).

[Matty M]

The 144hr and 168hr charts of GFS mayyyyyy be tasty!

[Iceberg]

And at T114 we have classic closed low near northern spain, sending the energy away. Good High orintation and the cold spell is definately on.

It's unbelievable different to METO though even at 72 or 96.

[TEITS]

B) Easterly brought back at 72 hours I wondered why the METO have sleet and Snow showers for the East midlands over the weekend .

Only just noticed that and im amazed.

Something is seriously a miss here. Look at last nights +120 fax chart and remember last nights UKMO/ECM.

http://www.wetterzentrale.de/pics/brack4.gif

Now considering the forecast was written at 3.34am there was nothing in the output that suggested that forecast!

[Matty M]

This run could be dangerously good, i hope people will keep a level head and remember its just a run of the 6z GFS.

[dinger]

The 144hr and 168hr charts of GFS mayyyyyy be tasty!

It certainly looks like the ridge has linked with the Siberian High at T120. Hopefully we'll see the high flatten out in the rest of the run and bring in the bitter cold pooling up in the east. Only the one run mind you. Could and will change again

[nick sussex]

As that line out of poltergeist goes, don't go into the light, the light is evil, it's pretending to be your friend! B) An unbelievable change in the model output from the GFS especially.

[Iceberg]

The good 06Z is very partly due to the upper and lower WAA through up by the monster LP in the eastern Atlantic. Without the distruption to the WAA through SW's or secondary LP's it really helps to reinforce the ridging to our north. From there the 144Z chart is very likely to be good.

Guess the date that the cold air first starts to hit the UK.....8th 9th of Feb.

Edited February 3, 2010 by Iceberg

[TEITS]

This is now just getting silly.

http://www.wetterzentrale.de/pics/Rtavn1321.png

Going back to my earlier post and it seems the Met O know the models have been wrong which is why the forecasts differ so much. However this doesn't explain the discrepancy between the Fax and the forecast.

[Matty M]

I think the 6z just decided to draw up the perfect coldies run for Britain to have a larf at us because its models been so useless of late!