On ECM, pressure over northern Russia has risen from 1015 at T+72, to 1025 at T+96, to 1035 at T+120. It's starting to look very interesting.

The London GFS 850 mean has drifted down a degree or so and if the later cluster becomes dominant (and it is the only cluster) the mean will drop from it's already reasonable -6C. The mild blip has shrunk. There is a downward trend appearing again. And despite the rattle throwing it is snowing tonight in several relatively southern favoured locations and a week ago the 22/23 Jan had the highest snow row. (Yes, I know and I still don't put a lot of faith in them). So the GFS not been so bad and I see it is gaining some friends again 

Brighton Ensemble Analysis Starts Again! 

Thanks. I've been away from the computer since before lunchtime and didn't look through all the posts.

So, any snow for the day counts as one, whether it's just at one six-hour point or all four.  

A poor ECM later on especially, the PV just won't give us a break and those low heights over Europe are under threat.

Whilst its pleasing to note that others on the Forum are experiencing snow my opportunities remain at zero until such time as an easterly of any sort can force its way into the equation!  I'll take the GEM please which at least shows that anything is possible I guess.  Worth me keeping an eye on as the other options on the table are no good IMBY!

Brian ought to know, as he's the one who creates the TWO chart presentation, isn't he? 

Snow at any of the four timepoints on a given day for a given member = 1 snow row.

And talking of ensembles, the "double mild bump" for Jan 24 and 26 has now become a single, smaller mild bump on the 26th. Lots of decent clustering below the mean, too, around the end of the month, but I'd like to see the GFSP on board.

And the ECM, of course. Every time the ECM charts start looking interesting, the USA plops out another low pressure into the Atlantic to break down any blocking link-ups.

Polar vortex split into three chunks; mid-Atlantic ridge; continuing low heights over Europe.

The anomaly chart shows the pattern is some way from normal.

To be gradually eroding away. Could we be on the verge of an unexpected upgrade.

Today I have eaten humble pie

Jesus wept. I programmed the bloody thing. 

See: 

https://www.theweatheroutlook.com/twocommunity/default.aspx?g=posts&m=1076828#post1076828

and this example:

The number is always whole so there is never a need to round up or down. 

I'll try and give a better example. Assume the GEFS only goes out to t+24 hours and consists of only 3 runs. Then it would be calculated like this: 

It is strange that IB always imagines that the NWP always shows a strong PV and positive NAO even when the NWP is showing charts like your example.

See my post above.  The issue is simply that you are counting snow at all four 6-hour points in a day as a count of one.  I'm not sure why but it explains the difference.

It isn't about your programming; the point is how many values the ensemble produces.

I don't want to continue this but the ensemble has four sets of values per day, one for each six hours. Otherwise why are there four points each day on the graphs?

For God's sake we were talking about the TWO snow row. Why the hell do you have to be so argumentative? The GEFS doesn't have something called "snow row" - it is simply a construct I created to show how many ensemble members are predicting snow on a given day. 

AIUI, Brian is producing the number of days with snow. If the GFS showed snow on a given day at 0Z, 6Z, 12Z and 18Z, that wouldn't make it 4 days with snow!

 Thank you. Very succinctly put.

Hi all.  The ECMWF 12z is cold on Saturday evening to Sunday night, there is Low Pressure coming SE from North ok Friday 25th, wet with rain on Saturday but after 3 PM cold air cross Southern UK particularly in evening.  Much of the UK seeing heavy snow showers some not!!, PM Saturday.

Downgrade on Monday to Wednesday if 12z ECMWF is to be believed, Cold NW winds later Tuesday 29th January but it turns less cold on Wednesday 30th, as West Central North Atlantic PV Low meets The SE Tracking PV Low over UK, with a wedge of less cold air with SW winds coming.  UK by 31st January less cold but some windy and showery weather Thursday next week with SW the West NW winds, SE and East UK seeing more SW winds.

ENE Canada Tuesday to Thursday cold PV Low Pressure spinning round and High pressure in Central N Atlantic and Greenland causing vold arctic air to drag south to our West and NW, off UK.

Apparently it is snowing in my area since 18:15 and snow covering the surfaces outside, some melted.  1CM covering.  Large snowflakes fell, this shower started as rain as I was looking at it fall at abot 17:50 p.m. It is now light flurries.

Never mind snow rows, that's what I call a "snow row" 

I am reminded of the person on Twitter who asked Jean-Claude Piris if he had ever read the Lisbon Treaty (he wrote a fair chunk of it) https://twitter.com/piris_jc/status/1074932615768092672?lang=en

Good grief, Brian.  My point last night was about the theoretical number of points in the ensemble.  The Meteociel ensemble charts also have a snow count and you can add up the number.  I wasn't aware that the 'snow row' was only referrring to something you produced. It does explain why you are overreacting to a very simple point.

Can we move on please?

Clearly out of your depth. 

Grow up CP. Yet again you've misunderstood the point and decided to intervene unnecessarily.

Why not stick to annoying people in UIA?