Yes, it’s what happens after that which is causing all the headaches. The potential is very much there and the timescale is getting closer. A wobble back to colder conditions (further south) would be encouraging, a wobble away would be a bit of a worry. 

This definitely fits into the encouraging category: https://www.wetterzentrale.de/maps/GFSOPEU06_204_2.png  

Originally Posted by: doctormog 

Yes it’s a very good run as we receive the CAA, clean as a whistle.

Thats despite the heights over Iberia. 

To be honest I’m not sure whether it’s worthy analysing the run any further than approx T+200. 

Originally Posted by: Joe Bloggs 

To be honest I’m not sure whether it’s worthy analysing the run any further than approx T+200. 

Originally Posted by: Joe Bloggs 

To be honest I’m not sure whether it’s worthy analysing the run any further than approx T+200. 

Originally Posted by: Joe Bloggs 

Probably best idea not to.

I normally don't exceed 10 days run. Not sure what that is in scientific terms, i.e, what is T+200 exactly and what is it in days?

Originally Posted by: ozone_aurora 

Probably best idea not to.

I normally don't exceed 10 days run. Not sure what that is in scientific terms, i.e, what is T+200 exactly and what is it in days?

Originally Posted by: ozone_aurora 

Using the crucial Day 7 timestamp.

06z GEFS - almost rock solid support for the op. Encouraging.

https://www.wetterzentrale.de/maps/GFSPANELEU06_168_1.png 

 

Originally Posted by: Joe Bloggs 

Haha sorry I should have said a more specific number like T+192 , day 8. T+216, day 9 or T+240, day 10. 

Basically, what I was trying to stay (badly) was that I’m looking to get the clean cold northerly in place first, I’m not arsed what happens afterwards at this stage as it’s too uncertain. 

But without the initial CAA, we will struggle with potential snow events into FI. 

If we can get this initial northerly push, we could get a lot of snow as the pattern attempts to break down, given current background signals. 

Originally Posted by: Joe Bloggs 

As noted in the media thread, it's good to see the MetO mentioning settling snow down here. As part of the ice warning recently issued,

"A few of the snow showers could turn quite heavy; these probably only affecting a narrow zone but a few places could see 1-3 cm, mainly over the north Downs and on grassy surfaces."

Originally Posted by: Retron 

Grassy surfaces? Really pushing the boat out there aren't they, what's next, settling on pavements?

Originally Posted by: Col 

@Brian Gaze
Brian,
This discussion has prompted me to make a suggestion. Would it be simple to add the T+ values to the X-axis of the ensemble plots? At the moment there's just the dates ahead, and on the 850hPa temps the snow row, and to work out that 7 days ahead means T+168 takes a bit of effort. (I'm thinking of the GFS as that's the one I refer to mostly.) Adding these values to the X-axis would make correlating the forecast charts - when referred to by T+ figures - to the ensemble plots much easier.
Thanks, AJ

Originally Posted by: AJ* 

Good shout!  Amazing to think that the pattern change has only just happened and already we are looking at what may
be a return to 'normal service' within 12 days.  Sometimes I pine for the days when all that we had was 3 day models of the synoptic type!  Well, I so enjoyed the fine weather this Saturday and yes a snowfest for the South does look somewhat less likely from current output, but please let's at least have some more like today before any return to  default!

Originally Posted by: UncleAlbert 

They get little mention on here but I still like to have a look at the Met Office Fax charts.

Originally Posted by: fairweather 

Just gone through the precipitation radar forcast for tomorrow on the Met Office and they are forecasting a fair narrow streamer flowing from 5am to 11am from a line Rochester -Maidstone- Tunbridge Wells -Brighton, a very similar line that was followed in early Dec 2009 event.Some red echos in there too so could be interesting. 

Originally Posted by: CField 

I think that the settings have been changed. I can't find the graph with the GFS ensembles any more. That's one of my first go-to's when I want an overview for the medium term forecast. 

Originally Posted by: Lionel Hutz 

It is around day 8 and can be useful for trends if there is a consistent overall pattern (especially in the ensemble data). 

However in reality it is often discounted as FI if it shows real cold but taken as a worrying sign if it shows a breakdown in cold on any one op run. 😉

Originally Posted by: doctormog 

Looked at the various ops this morning, generally nice although ECM was a bit 'meh' albeit it does tease the cold getting south at T240.

Not a great set of ECM ens IMBY with a lot of scatter suggesting any cold getting here from phase 2 is very uncertain and GFS has more scatter than of late albeit still good confidence for 3-4 days of colder uppers.  

Happily I then had a quick look at UKV for Monday and it looks rather nice IMBY, with showers moving through most parts of Kent - looks like the convection will be a little more widespread than just the odd streamer so hopefully most in the county will see something falling. Shower activity also looks robust enough to affect southern parts of the Midlands and Suffolk and to maintain intensity through Surrey and Hampshire all the way down to Devon and maybe even the Western most parts of Cornwall. I doubt it'll be a memorable event and I'm not really expecting anything beyond some falling snow and maybe small accumulations for MBY (I guess some places under any lines of showers may do a bit better) but it's a pretty decent place to be particularly given the uncertainty creeping in WRT the second cold wave and whether it'll get this far or stall further North. 

Cold and dry for the next few days, milder but not to anything more than average or a touch below then very uncertain but could still get 3-4 days of colder weather again. Definitely glass 3/4 full for me this morning - it's not as good as the strong signal for countrywide cold of a few days back but if the models had only just picked up on phase 2 I reckon most people would be pretty happy/excited with the possibilities shown.

Originally Posted by: Hippydave 

Probably best idea not to.

I normally don't exceed 10 days run. Not sure what that is in scientific terms, i.e, what is T+200 exactly and what is it in days?

Originally Posted by: ozone_aurora 

Grassy surfaces? Really pushing the boat out there aren't they, what's next, settling on pavements?

Originally Posted by: Col