SMU

@chris55 If you really really really simplified it & made all the pressures equal & had 3 fixed points 1) Greenland high for 17 2 ) Atlantic ridge for 17 3 ) Flat pattern for 17 then of course the mean would show an atlantic ridge. At the moment the 216 > 240 Means show the 552 contour level with ireland. That means the significant weighting is for 2-3 & a minor cluster for 1. My next port of call then would be compare the 192 Mean 12z tomorrow with the 216 12z mean from today to see if there is any backtrack to a more amplified pattern. The reality will be somewhere in the midpoint ....

Somewhere between 2-3 - Maybe we can prop a wedge that sinks East slightly....

0 Greenland highs....

No thats 15% for a true GH Also see above post...

Possibly > Thats included in my 15% though > also inc is the GFS op. Thats all your getting... I think really its just a matter of differentiation between an atlantic ridge & a true GH as remember there may be newer members that cant quite tell the difference yet - Some may see Greenland heights & think its the same as a true GH... Also a GH would certainly guarentee the jet track in the atlantic being steered south now we are 'hoping' it stays south... I would say 'moderate' optimism tonight for cold weather in the 7-10 window but maybe not deep cold. Rain turning to snow thurs could be another curtain twiching moment this week...

A slow toppler > yes thats in the Mix....

Yes ... 1) High pressure enhances the advection process - Weaker high = slower / weaker CAA 2) High pressure stops / steers the movement East of the atlantic > without it cold will never last... So the PV dropping into Scandi / Central Europe alone cannot drive the cold air west alone - it needs help..

I will give you 15% > that includes some goodwill

Just looked at the 12z EPS. Chances of a GH. 0% with 99% confidence. 552 Contour at 12z 216 EPS - 168 Jet to much positive tilt. GH will come from a northward vertical ridge not a ridge out of Canada. A proper Greenland high A lot of confusing wording on here being posted that should be made clearer for some of the newbies.... The *Best* case scenario is as @Kasim Awanmentioned a block in the atlantic that holds in situ long enough to deflect the atlantic track further south whilst the trough to the forces cold air south..

Look at the mean here. ( & others ) The 552 Contour is what we use to distinguish the wave height & whether thats a GH or an atlantic ridge. The ECM 00z 240 mean has that contour adjacent to Ireland. That means the GH cluster could be scrapped essentially. When there is going to be a cut off GH that contour will be way up there over Greenland even at day 9/10.

You keep saying theres a GH on the means. There isnt. Theres no GH on the GEFS means either. So what your posting is totally wrong. GEFS 12z Mean 192. No GH. EPS 00z Mean No GH 12Z GEM Means The only model is the GFS operational. Which means its 99% going to be wrong.

The American pro mets rarely blend the GFS. Its always EPS & ECM & Occasionally GEM driven. @nick sussex watched them most of the time. He will 100% say the same thing. Euro blend > GFS always. Also can you show the GH on EPS as it doesnt exist.

They didnt mate. There may have been a cluster however dont confuse a ridge & a GH on the anomalies 00z 216 Mean. No GH

GFS will never be ahead of any euro for a greenland high. The chances of a GH here are near 5% if not below. Why? Because the models have to much positive tilt on the jet to develop anything other than a blocking atlantic ridge which may stay in situ long enough like the GEM to bring the cold air south more so than the ECM. The solution lies probably somewhere in the middle. It looked great intially with the vortex apparently dropping into Europe however that position is morphing North westwards towards Norway & this means it has to come round the back of a low pressure rather than direct NE > SW like before. As a result its modified warmer & not as good.

No > it is terrible. Flat as a witches...

The 216 is even worse... As Said 2 days ago ..... Need to keep firmly grounded here. No booms or anything else until Euros on board.

Not really - No sub -4c air makes it a pretty poor effort

Mixed emotions tonight Excellent 12z GFS but another very poor ECM ... Another day of waiting .... The ECM OP continually being the odd one out - it has a history of being volatile - but we do need the euros on board...

Day 5 swing back to cold for the SE -5c the midpoint & -8c the top out > could be some snow

I didnt see it - have you got an image - S

No it wasnt. It was just time to take a break - chasing the charts in early December rarely bares fruit so good to take a 2 week or so break

Evening My comments earlier were directly aimed at the slighter poorer medium term trend from UKMO today as it didnt follow yesterdays move to the wedge > infact it moved away from it. The spirits have been somewhat lifted by the ECM Mean though > lets hope those crazy values are still there come day 3/4

A pretty poor day model watching. UKMO has trended flatter, ECM also poor all the way out past 192. We are pinning hopes on outputs past 200 again which is always dicey at best. Shame really just as the deep cold was getting going like the good old days...

-2.1 / -2.3c at home already !!

GFS 06z looks improved through 66 sending more energy SE