Isolated Frost

AFAIK, the netweather forecasts are based on the latest GFS run, whilst the MO, whilst computer generated, take in a gauge of all the NWP. I wouldn't worry about precip values yet, especially when Saturday is just the start. edit: JH beat me to it

112 hours (66 to 178) of constant sub -5c uppers for the east of England and Scotland, -10c incursions common at d5, -5c covers the nation quite a bit. Not the biggest downgrade ever. A downgrade yes, but did you expect anything else after yesterdays output!!

12zs will be interesting to gauge whether cross-model agreement can come back. EC absolute monster again. Heavy snow shrs for much of the British Isles in an unstable E, then NW, then E, then NE flow. Yum. GFS not as good, and UKMO the halfway house. Still superb synoptics in the RELIABLE on them all.

+120, ops and ens. That's all there is to look at. There are a lot of signals and many solutions to come forward, so don't worry about the fluctuations. The fact the ops support it more is definitely encouraging. We are approaching a rapid cool down and there is plenty more to be signed and sealed off. Calm and patience, cold is now within +96 for many.

Interestingly, the hi-res (from 84 to 192) is very cold, at times extremely so, and is as close to perfection for much of the nation, under a east, then north, then north-east, then east flow. If that is perfection, then what is this? The GFS 18z challenges the ECM 12z, and the upper air flow is completely reversed. Absolutely staggering.

Upper low moves NE for Friday/Saturday on latest GFS- snow for East Anglia/East Midlands up to SE Scotland, instead of SE England up to N Yorkshire as on 12z solution. A boost for the NE, but hopefully no further north-ward upgrades!

Just a lovely run up to +96 at least, shifts the upper low slightly NEwards allowing us northerners to get right into the act 2300+!

EC solution is fun but it is v extreme- I'd love the GFS solution as well though, plenty of cold and snow from the N and E.. Plenty to come yet though, at least we know its definitely turning colder, perhaps quite a seismic change from recent anomaly.

Nick! It is completely different to that horrible Feb 2012 spell.. that was sourced from polar continental air, with the bulk of the cold in mainland Europe, the progression from the NWP look much more Nov 2010 style (not to say it will be!!)... cold NE/ENE sourced winds after the original booting on the weekend... bulk of the cold in southern Scandi- the sweet spot as many would say The GFS would be pretty snowy here, maybe some light snow on the wknd, at times heavier, with Monday onwards being really cold and with a high likelyhood of snow shrs UKMO would develop into something similar if not better ECM is a dream... no comment!

I think we have a new 'That ECM' folks

Ha! No chance senor

Bloody hell! EC definitely joins the consensus with a peach... this chart would provide us with a very cold NE flow with snow shrs across eastern and southern parts, some in the far north as well- note the atlantic profile, very.... disrupted!

Just a note that EC 96 is a lot further west and slightly more south orientated than yesterdays EC 120 for the same time- it's a trend that will introduce a E flow into further southern parts and will bring much of England, as well as parts of south and eastern Scotland into the game this wknd- The EC 96 solution has the ridging upper high in the atlantic, though the low pressure system by Greenland is more organised and cut when it comes to a closed circulation- the EC 120 could well shift focus when it comes to later modelling

If it's about the weather models it's related

EC still favours bringing in them cold 850s in earlier than the GFS suite, a very nippy Friday evening with -6c 850s approaching Edinburgh, Newcastle and Hull..

1823 approximately for the 120, 1829 for the 144 when it comes to the EC.. 96 at near enough quarter past. Here is yesterday's ECM 12z 96 panel (for Friday 12z)... and today's GFS 12z 72 panel (also Friday 12z) Very similar, just for comparison with the onset of notably cooler conditions from the continent this time set in as we approach the wkend

Haven't seen a run like that in a while.. here's an animation of Saturday 00z until Wednesday 00z... bare in mind, the coldest stuff could well come afterwards. Urge caution on taking this run though, probably very optimistic, but GFS modelling is in for a hell of a time in comparison to EC signals... fun fun at Exeter

BOOM BOOM

Saturday snow possibility based on the 12z GFS would be around 80-90% confidence in E Anglia and E Midlands/Lincolnshire, with a high chance across SE England and the W Midlands, with some convective snow across N & E Yorkshire and NE England. A very high chance of some heavy wintry precip moving into the home counties in particular, with a height of marginality to be expressed. Saturday 06z -6c 850s into eastern England and Scotland- encouraging E/SE flow, upper low ridge extension should provide a lot of precip for southern parts- as signified above.. increasing window of opportunity for those east of Cardiff and south of Edinburgh for some wintry weather come this weekend

Just popped in to say this thread is a true testament to this forum! Incredible how it has altered my view on meteorology (meteorology is something I've only known for 2-3 years now!), and the research done by Lorenzo, Recretos, Chionomaniac, Glacier Point and others I'm sure has improved this forum ten-fold. This may have even prompted the Met Office to alter it's views, even BBC forecasts we see on the TV mentioning the stratosphere might well be the result of threads like this, that have really raised awareness. 66 pages for the 2011-12 thread, which was superb. 97 pages for the 2012-13 thread, and it's only January the 7th.

Mesoscale modelling time ! GFS solution brings the upper low into SW England for d5 (12z, 12/01)- Precip generally reflected to the NE of the low, in SW England and a signal for heavy precip in central and eastern parts, some light convective precip across the NE at this timeframe also The golden '10c' is progged just off the north-east coast (in line with the -4c 850 temps), with 12c generally accepted around the upper low as 'snow' conductive as well.. this precip will fall mostly as rain across SE England on Saturday on current modelling The EC solution does not do the upper low to the extent of a separate circulated sub-540dm upper low in the channel- a progressive answer with -7c 850s into the NE by Saturday 12z- to me this signifies the notable difference in short-term modelling in regard to the upcoming easterly incursion. The upper low intact well on the EC solution, though more significant at a lower level, I'd suggest rain turning to snow in south and eastern areas with some notable bands following, with convective snow shrs in the north and east What must be expressed is confidence in such a solution is low with the volatile outlook- though it's likely that parts of eastern Scotland and England, potentially pushing inland, could experience wintry showers, and snow at times in the upcoming weekend, with the prospects afterwards very much up in the air

Urm... maybe the -5c line from 96 to 168 and -8c line from 120 to 168 across eastern parts with a E flow, with colder temperatures from today onwards. And the fact that post d4, model guidance is very unstable and will throw up different solutions daily. I recall someone saying yesterdays 12zs would be 'big'. They are not big, like todays and tomorrows, because Wednesday's will be different again. I say Jan 15 before the models get a grip with current downwelling and stratospheric signals.

By day 6 it's back and by day 7 it's in full force?

Do you have a link for them Nick? Can't find them, lost the bookmark somehow!

That would be very cold at the surface, not as cold as progged earlier, but widespread frost and below average easily