1220 replies to this topic

[Barb-]

Imagine if everything was a few hundred miles further south in the GFS 18z FI... epic, rerun of 1947 stuff

[mountain shadow]

If we similar charts tomorrow morning I expect the Meto daily update will be interesting. Certainly shades of some classic winter charts. Bitter easterlies coming up against distrubted atlantic low pressures systems.

[BLAST FROM THE PAST]

This is a Jan 87 event......if only eh?

BFTP

[kold weather]

A good run from the 18z but obviously room for improvement with regards to what happens around 240hrs, a weaker jet with some sort of under-cut would put the forum into mass hysteria!

[bluearmy]

i keep thinking - that'll be my last post of the day' and then another crazy chart pops up. fi gfs is full of diving troughs as many gefs members have been all day. the end of the run is as good as you'd want to see from a snow perspective, given where we've come from in 24 hours. low res is low res though and just as we would treat the zonal express with disdain, i;m afriad we must do the same with the polar one.

[TomSE20]

Looked very good for most of the run but became a "Kettley" easterly soon after.

No point in getting hooked up on detail yet though. The background signals and trend are there for all to see, will be interesting to see the other ensemble members.

Certainly its been a fascinating days model watching. Lets hope we wake to find the trend still going in the right direction!

Regards,
Tom

[Jackone]

nick sussex, on 07 January 2012 - 22:44 , said:

A decent run from the GFS 18hrs in the higher resolution, the trigger shortwave is too far east but at least the trends been maintained from the earlier output.

Indeed this is much better in the lower resolution upto 240hrs than the ECM, note here your more likely to see further trough disruption and the PV is unlikely to sink the high, you don't get the quick easterly here but the PV is likely to give up the ghost and head off much further to the west!

Anyway this is well into FI and I'm not a great advocate of the GFS lower resolution but a good end to the day.

I expect there will be a good turn out tomorrow morning for those who can cope with the stress!

I tend to agree the heights from Svalbard to Greenland are far better on this run, compared to ECM 12Hz, and IMO if the low pressure came in a slightly different angle further south, we would be on the cold side.

With this better blocking there would be better potential down the line.


The above chart shows the 500HPa profile at T+288 for the GFS 12Hz run to the 18Hz, completely different.

[kold weather]

Actually if your looking at the pure weather, its probably not that great of a run...temps broadly average throughout, Europe isn't even that cold after the intial Arctic burst around 192hrs.

An OK run but I'd not say anything more...the potenial is clearly there though!

Shift everything 200 miles SW and things would become very interesting!

[nick sussex]

I know people might be thinking how can this GFS be better than the ECM even though the latter did bring in that easterly flow, if you put aside the GFS blowing up that low near the UK the NH pattern is far better at 240hrs.

If you want a cold spell that delivers we must see the PV edged away, and the block further north, the ECM was great at 168hrs but then the PV was eventually going to sink the high.

I'd certainly take the ECM 168hrs and the GFS NH pattern at 240hrs, not too much to ask is it!

[kold weather]

nick sussex, on 07 January 2012 - 22:52 , said:

I know people might be thinking how can this GFS be better than the ECM even though the latter did bring in that easterly flow, if you put aside the GFS blowing up that low near the UK the NH pattern is far better at 240hrs.

If you want a cold spell that delivers we must see the PV edged away, and the block further north, the ECM was great at 168hrs but then the PV was eventually going to sink the high.

I'd certainly take the ECM 168hrs and the GFS NH pattern at 240hrs, not too much to ask is it!

My problem is we effectivly still don't have anything that cold till maybe 360hrs out...it might be borderline cold enough for some sleet/snow at 216-240hrs but other then that we are once again controlled by the Atlantic.

However if we use our heads and think that FI does tend to overdo low pressure systems....certainly lots of chances from the 18z run. If only that jet didn't come on so strong.

However the 18z really is NOT that cold...as surprising as that may be to some!

[Howey]

Steve Murr, on 07 January 2012 - 21:14 , said:

I will have a C please bob...

Q: what C has a 7 day cold spell with maxes of -4c...?

S

Could I have another letter please, Bob? Can't find any ensembles for C's other than Copenhagen. I'm thinking somewhere in Eastern Europe, but hoping for Cromer or Chelmsford.

[Steve Murr]

I think given the Choice most people would take the 18z , with an 'almost' perfect Straddled easterly at 192 then many more snow events out to 384-

Also for those who wonder why its never easy modelling Easterlies as opposed to nice sinuous Westerlies heres you answer-

When we had the mild weather in december-

Xmas day Jet-
http://176.31.229.22...18-5-114.png?18

Very easy to model,lots of consistency-

T 192 18z TODAY
http://176.31.229.22...18-5-192.png?18

Look at the jet - its been ripped to peices with fragments all over the place across the pole- far from easy to model that-

One final thing- Its been a long journey over the last 3 weeks, from the onset of the drip feed fed down from the stratosphere, to the Aleution high modelling, now onto the scandi high- its all fed along nicely- around the 15th- all be it with minimal acceptance from the operational GFS-

What comes after the POSSIBLE scandi high easterly when the stratosphere ramps up another level of warmth-

The zonal winds could go mega Negative & a 4 wave standing pattern with a tanked negative AO is in the mix, months like Feb 47, 63, Jan 85 & feb 56, Feb 86 all spring to mind-

Its all balanced on the mean zonal flow easing off enough to get the heights in the right place at the second bite!

Remember people the Easterly ensembles tracker-

Warsaw, Berlin, Debilt / amsterdam then London - thats how they Crash-

S

[Cloud 10]

Things still cooking very nicely in the stratosphere as well.




Surely some epic runs amongst the gefs ensembles.

[BLAST FROM THE PAST]

Ian Brown, on 07 January 2012 - 22:50 , said:

I would just advise people to remember similar set-ups involving the Arctic High from years gone by, and what we should expect is failure of the cold air to reach the UK. Thats the bottom line situation from these synoptics and likely going forward evolution.

That is not to say there would not be another shot at something similar later on, but fully expect this one to go the way of the pear. The PV will not yield at this point.

Previous 3 years have put that to bed, its a very much enhanced chance now Ian.

BFTP

[Jason M]

Its all nonsense after 200 hours anyway, but if we ended up with a pattern as shown at the end of FI, I for one would be saying 'deal' every time

I'd actually be more worried if GFS was showing the perfect synoptics for a cold spell in FI because the odds of the model nailing something like that this far out are tiny. Even if we revert to the 1988/89 retro charts of the last couple of weeks tommorow, its just nice to have some interest.

Overall, i'm pleased with the pub run and the fact that were seeing variations on a theme accross a number of different models. Very interesting that GEM picked it up first though (and not for the first time either).

Jason

[Matty M]

Just for any newbies that dont realise. The chance of an easterly for the UK for 5days or more at point stand at about 10-20%. This is what we are excited about, so please do not go telling your relatives and the likes!

[kold weather]

Steve Murr, on 07 January 2012 - 22:56 , said:

What comes after the POSSIBLE scandi high easterly when the stratosphere ramps up another level of warmth-

The zonal winds could go mega Negative & a 4 wave standing pattern with a tanked negative AO is in the mix, months like Feb 47, 63, Jan 85 & feb 56, Feb 86 all spring to mind-

Its all balanced on the mean zonal flow easing off enough to get the heights in the right place at the second bite!

Yeah, my gut is the 18z GFS is right and there will be a little too much energy for the first bite of the cake. My gut though is you are getting another several warming events going on, so expect some major northern blocking at some point, probably just outside the model's range at the moment.

There is only one way deep FI is going...though 384hrs is probably a rain-snow event for most

I just wished that low at 240hrs wasn't as large and as strong, W/C Europe back upto 6-9C because of that, sorta defeats the point of the intial cold wave in some ways.

[nick sussex]

kold weather, on 07 January 2012 - 22:55 , said:

My problem is we effectivly still don't have anything that cold till maybe 360hrs out...it might be borderline cold enough for some sleet/snow at 216-240hrs but other then that we are once again controlled by the Atlantic.

However if we use our heads and think that FI does tend to overdo low pressure systems....certainly lots of chances from the 18z run. If only that jet didn't come on so strong.

However the 18z really is NOT that cold...as surprising as that may be to some!

Yes I understand your point but getting a correction of a few hundred miles is nothing in global terms, the only reason the GFS didn't send the thread into meltdown was that overblown low, we know from experience that models aren't good at resolving shortwaves and trough disruption in later timeframes.

Given the winter so far who needs a two day easterly which then gets sunk by the PV, I know we have the other warming which could give another attempt but I think we need to see the block further north and the PV edged further west.

We may well see that tomorrow, certainly the ECM 168hrs holds the most potential at that timeframe, given the changes so far who knows what will happen.

[BLAST FROM THE PAST]

Matty M, on 07 January 2012 - 23:00 , said:

Just for any newbies that dont realise. The chance of an easterly for the UK for 5days or more at point stand at about 10-20%. This is what we are excited about, so please do not go telling your relatives and the likes!

And 5 days ago 0% for weeks and weeks and weeks according to the models?

BFTP

[kold weather]

A VERY different 18z control run, thats for sure, shortwaves flattens the pattern totally out by 180hrs...would probably have to get a northerly from that run to get anything cold.

Also little support for the OP, nearly all runs have the jet flattening out the pattern...not a great set of ensembles out to 216hrs...