Model Output Discussion 1200 hrs 30/09/14

[Barry12]

ECM looks like its on UKMO and GFS P side at 120

 

ECM;

 

 

UKMO

 

 

GFS P

 

[Captain Shortwave]

Really not much to say

High builds over Scandi and gets sucked into the Euro ridge, a westerly pattern restored for the UK

As big a difference between the Euros and GFS with respect to the Atlantic ridge earlier, the charts for the start of week 2 are not miles apart. The cool spell could bring wintry precipitation to the highest ground in Scotland, but otherwise not much apart from maybe a frost on Wednesday night.

 

On a more positive note

Cross polar flow developing, the ECM would probably build a deep Atlantic trough/Euro high pattern.

Edited October 30, 2014 by Captain shortwave

[MR EXTREMES]

ecm has a problem heights trying to build up into scandi low coming in from the west lower heights to the south of the uk and azores heights trying to build in.

the low to our west dont look likely getting to far to quick but if heights in scandi can get far enough north then could be interesting futher on.

 

and then the next frame can the azores be our friend.

the heights into scandi are trying to push futher north interesting charts nothing extreme by far but different from last november.

 

frost and fog much more seasonal good about time.

Edited October 30, 2014 by emotional rollercoaster

[IDO]

Touch and go from the ECM, but by D8 its closer to the GEFS take on things:

 

GEFS mean at D8:  ECM: 

 

Not convinced either way yet so a couple more runs probably needed. 

 

The Northerly on the ECM is a tame affair, maybe 24-48 hours:  

 

So run of the mill from most models for the mid-week cool "snip". No point looking at D9 onwards from ECM as it is bound to push heights north; its MO lately.

[nick sussex]

Some disagreements this evening with the GFS/GEM/JMA not doing much with the ridge to the nw, where as the GFS P/UKMO/ECM topple this towards Scandi.

 

The longer term models do agree however that the PV will remain split, there looked like an opportunity with the PV splitting near Svalbard that some ridging might extend there and theres still a small chance we might see more forcing on the Atlantic troughing around T192hrs.

 

The problem however is the flattish upstream pattern after this initial amplification, we really need to see more sharpness on that Atlantic troughing, it may still happen we'll see.

 

I don't think the cold snap will amount to much but at least the PV is still reluctant to morph into one over Greenland so that's a positive.

[SMU]

Splendid ECM tonight, we see the polar height field split in half like a kipling cake!

Remember it isnt about UK cold for the first 2/3 of the month - however as we enter week 3 we want to start seeing signs of the polar heights shifting towards greenland & svalbard inline with the weak pv & continued frequent wave 1 activity...

Patience......

[IDO]

Yes NOAA are saying good confidence amongst the models for a flat zonal flow heading out of the Conus in the 8-14 day range. Their anomaly:

 

 

High heights to the east and lower heights to the west. The UK on the periphery of these two anomalies. Mind you they are ignoring the ECM op (used 30% GFS OP) for this output and do mention that they have made corrections to the ECM temp mean. Model of the day, the GEFS SUPERENSEMBLE Mean (an oxymoron to some on here!).

 

I am not surprised they are giving the ECM a wide birth at the moment, as the NH height bias shows for the last 10 days:

 

 

 

GFS very consistently good, whilst ECM continuing with its bias at overdoing heights in the NH. So until we see GFS prog height rises towards Greenland I will pass on the ECM.

[Man With Beard]

I'm deeply aware that an amateur like me can go off on one either because 1) of preference for a particular weather type or 2) the feeling you have spotted a trend - the danger is that you then only look for what you want to see and ignore all the other evidence around you.

 

My hunch at the moment is that no part of the PV is going settle over Greenland for any particular amount of time in November, and that the whole PV itself is never going to get completely organised. Why? Because the the trend of the models over the past weeks has been to backtrack on these issues - PV looking like establishing on some runs by T192+ ish, but by T120 is isn't there.

 

ECM T240 tonight - the PV still in trouble, but a large lobe over Greenland/Canada - keeps it flat nearer to us and the cold looked up to the north (outside chance of an easterly?):

 

 

GFS (P) at T240; PV slightly better formed, same situation as ECM (though this model had been splitting the PV further out the previous two days):

 

 

 

T120 though -

 

the PV looks more like an octopus, no guarantee where it will go:

 

 

 

 

So though I have a hunch, I can't shut my eyes to the longer range evidence telling me the PV might be established more by mid-month. But ... it hasn't actually happened ... yet. 

[ANYWEATHER]

The weekend will see a dramatic cool down in temperatures as it sweeps this horribly warm air away and leaves us into some normal weather. Next week still will see a significant change in our weather. Gone is the  tropical air mass and we swap that with some polar maritime air sourced from the Greenland area.    

[bluearmy]

Still waiting to see the fi modelled relocation of the vortex (or at least part of it ) to the Canadian side of the arctic.

[knocker]

Wow. Impressive Unprecedented for S. Carolina in late October? And a split vortex but..........

Edited October 30, 2014 by knocker

[Mucka]

Yes NOAA are saying good confidence amongst the models for a flat zonal flow heading out of the Conus in the 8-14 day range. Their anomaly:

 

814day.03 (19).gif

 

High heights to the east and lower heights to the west. The UK on the periphery of these two anomalies. Mind you they are ignoring the ECM op (used 30% GFS OP) for this output and do mention that they have made corrections to the ECM temp mean. Model of the day, the GEFS SUPERENSEMBLE Mean (an oxymoron to some on here!).

 

I am not surprised they are giving the ECM a wide birth at the moment, as the NH height bias shows for the last 10 days:

 

bias_day10_HGT_P500_G2NHX (4).png  bias_day10_HGT_P500_G2NHX (5).png

 

GFS very consistently good, whilst ECM continuing with its bias at overdoing heights in the NH. So until we see GFS prog height rises towards Greenland I will pass on the ECM.

 

If the 0 line is no bias and below negative bias and above positive bias then that is not really what those charts show.

They show ECM has recently been more accurate than GFS and while it does have a positive bias at times it is no worse than GFS negative bias?

Edited October 30, 2014 by Mucka

[Cloud 10]

Interesting looking at the day 10 ensemble mean verification stats which shows them falling through the floor in the last few days.

 

Not sure why the ECM isn't included on those graphs anymore?

 

[Jo Farrow]

Jonnie Hammond throwing in the low prob outlier of Monday/Tues's low from BAy of Biscay coming into the cold air and producing some hill snow over southern Britain. Cheeky on News 24's Week ahead

[johnholmes]

Jonnie Hammond throwing in the low prob outlier of Monday/Tues's low from BAy of Biscay coming into the cold air and producing some hill snow over southern Britain. Cheeky on News 24's Week ahead

 

as you say Jo, 'cheeky' but a possibility perhaps?

[Jo Farrow]

as you say Jo, 'cheeky' but a possibility perhaps?

think he's having fun on a night shift

[johnholmes]

Interesting looking at the day 10 ensemble mean verification stats which shows them falling through the floor in the last few days.

 

Not sure why the ECM isn't included on those graphs anymore?

 

cor_day10_HGT_P500_G2NHX.png

 

If we look at day 6 for all models then all show a dip recently and the latest 6 days are missing UK Met, and others, so not sure why the models are missing

 

http://www.emc.ncep.noaa.gov/gmb/STATS/html/new_acz6.html

think he's having fun on a night shift

 

good to see and hope his bosses feel the same way!

Edited October 30, 2014 by johnholmes

[bluearmy]

this place could do without that kind of stuff! they need little encouragement at the best of times !

 

early november is not a time for snow - its for cold still frosty and foggy mornings. the best winters of the seventies and eighties had novembers that delivered thus. it appears that next week will at last see the current ridiculous autumn temps moderate.

[Jo Farrow]

If we at day 6 for all models then all show a dip recently and the latest 6 days are missing UK Met, and others, so not sure why the models are missing

 

http://www.emc.ncep.noaa.gov/gmb/STATS/html/new_acz6.html

 

good to see and hope is bosses feel the same way!

I suppose with the more lengthy broadcast space, why not take the time to explain some of the other solutions. Though it always runs the risk of ".......snow........" being the only word heard, which is a shame, when adding a spicy snippet

[johnholmes]

I suppose with the more lengthy broadcast space, why not take the time to explain some of the other solutions. Though it always runs the risk of ".......snow........" being the only word heard, which is a shame, when adding a spicy snippet

 

you know more about that pitfall than anyone on here Jo other than Michael

Edited October 30, 2014 by johnholmes

[Mucka]

Interesting that the 18z wants to flatten the ridge as with the 12z but this time the parallel goes the same way...

[Ali1977]

Best chart of the 2014/15 season for potential cold, shame it's at T384

[Cloud 10]

this place could do without that kind of stuff! they need little encouragement at the best of times !

 

early november is not a time for snow - its for cold still frosty and foggy mornings. the best winters of the seventies and eighties had novembers that delivered thus. it appears that next week will at last see the current ridiculous autumn temps moderate.

 

Shame on you BA....

 

Certainly some ridiculous autumn temps tomorrow with some last day of October temperature records set to be broken.

 

[knocker]

The 18z GFS back on a coastal track with the Nor'easter and Maine could have over two feet of snow by the 3rd.

[Frosty.]

Halloween temperature records are likely to be smashed tomorrow with a summery 19-21c for large areas of southern UK due to a combination of very warm 850's sourced from southern Europe and increasingly clear & sunny skies but during the weekend a few active cold fronts with bands of rain will sweep the warm air away eastwards and it will turn progressively cooler. I'm looking forward to the colder showery spell next week with an increasing risk of night frosts. :-)