Isolated Frost

Models starting to really shape up on a brief NE/E'ly on Tuesday until Thursday. Posting that here because it'll get swallowed up by the bizarre posting in the MT.

Looks like 1-2mb lower pressure accompanied by 1-2c higher 850s for Sunday- nothing at all wrong with that.

Colder than the mean between 96-120, warmer than the mean 144-240. Look at the intense grouping as well after 168- around the continuous cold solution- that's positive

-4c 850s stick to Norfolk the WHOLE way through the EC ENS- as the cold air sticks in the east main point of the run is the atlantic jet fails to enforce itself enough.. 96 a stunner

Always remember the orange clouds that glow when the heavier convective snow shrs come in from the NE at night (late Nov 2010 had a lot of this). Right, time for mesoscale snow forecasting time... Saturday 00z Comparison- NMM -5c 850s @ Durham, 1295dm, 1016mb, SSE flow GFS -4c 850s @ Durham, 1300dm, 1016mb, SSE flow NAE -5c 850s @ Durham, 1300dm, 1016mb, SSE flow (0c 950s) NMM looking at a cold SSE flow early morning- nothing conductive to snow apart from above 250m.. not much lingering precip around either GFS and NAE looking v similar Saturday 12z Comparison- NMM -7c 850s @ Durham, 1290dm, 1018dm, SE flow GFS -7c 850s @ Durham, 1290dm, 1017dm, SE flow NAE -7c 850s @ Durham, 1290dm, 1017dm, SE flow (-1c 950s) The flow then turns SE'ly at sea level- though is increasing northward facing at higher levels and this will promote some shower movement from the NE/E- The flow at uppers of that sort should promote some fresh convection- sub -34c 500mb air popping around.. Dewpoints eventually pulling toward 0c, some mild sector in there- looks suspect but very possible in the flow... shouldn't interfere however GFS keeps a strong upper humidity profile bubbling in the eastern North Sea minimal wind shear in contact with the flow- less than a 60 degree difference.. aloft some hefty CAA and slack (slackkkk) flow- flurries and light snow very likely in a flow with sub 1290dm air- Sunday 00z Comparison- NMM -8c 850s @ Durham, 1285dm, 1021mb, E flow GFS -8c 850s @ Durham, 1290dm, 1021mb, E flow NAE -9c 850s @ Durham, 1285dm, 1021mb, E flow -this is the important timeframe- inbetween Sat 18z and Sun 06z, this is the peak generally with the perfect wind flow at the surface- dew points are quite superb we also see the GFS at it's best, with sub -30c air above our roofs, this is definitely commendable stuff.. messy flows- but generally the upper air low is nearby and conductive to precipitation throughout the north sea- not all too much bubbling up but some real strong squalls in there- probably a few snow shrs here and there tomorrow evening, but the chance of something larger as we move through the night- the coldest upper air arrives around then, and favourable wind shear and upper air dynamics co-exist this as the signal for stronger precip grows I'd do the Sunday 12z predictions but my arms are knackered- I'll do them later hope this helped

Question. After roughly 60 hours of intermittent snow, how cold would this be in East Anglia?

Nothing better than watching the North Sea get into gear, and the cold north-easterlies/easterlies flow across it. Here's hoping this is the start of something really nice.

Superb synoptics again. Saturday seems very cold, with some light snow shrs possible, especially in the east and south-east under a E flow. The low should provide some snow for high ground in southern areas as well. Sunday then looks very cold, but relatively dry. Monday then looks either prolonged mod snow with the EC/UKMO or snappy, heavy snow with the GFS. After Monday we have the GFS bringing in a showery E regime, the UKMO brings in what would turn into a prolonged cold spell, and the EC eventually topples over- though it has not updated to the 12z yet. Signs are for a very fun next 7 days at the least... the crux may even come later on the month which makes this SO exciting. Anyone else notice the agreement from ALL 3 major models for a unstable, showery E flow with heavy snow shrs on eastern coasts from Tuesday to Wednesday (potentially even longer... a la UKMO)

Saturday into Sunday still looks V ripe for some snow shrs on eastern coasts (mainly Sat 18z to Sun 09z). Plentiful cold around that timerange as well- Monday looks very snowy for here on the GFS 12z.. but it's ALL subject to change- we keep on the right side of the shortwave though, and the introduction of a SW/S wind will be perfect for Monday evening- it looks transient but bloody heavy- UKMO and GFS looks superb for some V heavy snow shrs from the E/NE come Tuesday evening and Wednesday, but it is a long time away in times of such uncertainty. One thing we can be sure of, it's going to be bloody cold!

EC 120 highlights the perfect solution for us in the NE. 144 and 168 would be drier (144 would be still snowy) and then a mild regime pulls in- but this a beaut. A slack NE flow with -8c uppers and an upper low in the southern North Sea. Snow showers galore. Plenty of outcomes likely to be thrown out by the NWP. For now though, the wknd looks very cold and potentially quite wintry- starting today. Met office going for mod-heavy snow for Durham from 18z Saturday to 06z Sunday and plenty of intermittent snow on Monday.

This wknd looks like your typical transient e flow, with south-eastern areas faring best- though some northern parts (SE Scotland/NE England in particular) should be affected by some wintriness. Monday seems very snowy across ALL of Scotland, moving Swards throughout the day. After that, and this is a consistent signal- with an upper ridge over Iceland and Scandinavia, dictating the upper flow over the UK and Western Europe.. signalling one thing, NElies.. and us northerners love the NElies. This spell may well be southern delight, but the overwhelming signal developing next week, into late January (perhaps a interlude against this) is for the NE wind to come back and Eastern Scotland and Eastern England to do best, with much of Central Scotland to be very much prone to some bitter air. What is better than a slack NE flow with sub -8c 850s? Nothing, that's what. I think something is really on the cards now, and we play the waiting game for the jigsaw to come in place- perhaps the GFS output today is reflective of the signal to adapt to the stratospheric conditions. Good luck from across the border!

Latest hi-res EC expectations for Fri and Sat... quite cold.

Hmm Anyway, southern areas look to be initially affected most, with high ground in the midlands, and Lincolnshire/E Anglia the hot spots for Saturday/Sunday.. Monday however looks v interesting after Sunday's convective (potential) fun. After that, the EC and GFS is pretty snowy for us, with the UKMO eventually becoming quite snowy after d6.

132-192 on the EC would be SO snowy here!! Sunday looking sexy, v v sexy...

That's not the updated UKMO Steve-

No, the 48hr stage: UKMO at 96 and 120 good enough to keep hold of the track we're on- EC output and ensembles will be v interesting tonight...

The ECM and UKMO dont.

Re: the second spell, UKMO brings in the cold first at 120, cold on the EC at about 132. GFS doesnt go for it still. How this is any different to yesterday I do not know? Did people actually expect -10c uppers and cold easterly winds to be on EVERY EC run?!?

Eh? Am I reading the same models? UKMO just as good if not better than yesterdays 12z. EC not as good as yesterday 12z, but just as snowy for many areas- and just as good as yesterdays 0z. Whats this cr*p about the EC backtracking?! A very snowy EC with the trough dropping around d4... as in previous output GFS the lone wolf again I don't understand people at times, please, if you are going to be reactionary, use the model moan and ramp thread.

Posted 06 January 2013 - 15:12 Runs aren't huge, Ian. They fluctuate all the time.

Bizarre how the ECM det (generally cold) seems to fit right in the middle of the EC ens, whilst the relatively milder GFS op is at the top end of the GFS ens- will be a good old fashioned nwp battle when it comes to the favoured solution- First of all though is the introduction to a E wind tomorrow and Friday, -5c uppers into England by Friday, -10c by Sunday- fleeting but potentially snowy spell for those in the SE

What I see is a model consensus for that upper low near Iceland to sink SSE, apart from the GFS. After that it could well be a strong northerly a la UKMO, or unstable easterlies a la ECM. The potential that follows the period afterwards is mammoth and the only way is cold- the GFS ops will be brought back into this theme in time Wow.

GEM digs in the upper trough a bit later than 00z run, but end result at 168 will be about similar- another run that takes the UKMO, EC line of thinking instead

To Ian Fergusson was just wondering what the general UKMO view was on convective shrs on Sat, Sun and Mon for NE England and SE Scotland- in the general SE turning E flow, I was wondering whether much convection is expected to be sparked off, plenty cold uppers there- just not quite the best 500mb profile with a upper high nearby? Was wondering what Exeter made of the issue- ta

Latest GFS suite has precip hugging the NE coast from h60 to h120- Saturday 0z to Monday 12z. Probably deliver wintry shrs Saturday, snow shrs Sunday, potentially quite heavy before a cold, dry day on Monday. After that, it's all to play for. Slight accumulations very much possible this wknd- GFS would then give us nothing more, the ECM would give us so much more and the UKMO is the realistic halfway house.