john w

Didcot is firmly south central, so no idea where your 3 threads comes from. Prospects, Id agree with the sites based on the models, I can see some mixing out towards the end, the key is whether the precipitation vis a vis the front has passed by the time the warm air arrives. If it has...should be mostly a snow event, unless that pesky power station causes some ridiculous Warm Air Advection and air mass modification.

That Meto fax keeps it pegged west, see I always assume once its over the mountains the natural progression is to push east, assuming planetary physics will always win out even at micro-scale events. I could be wrong, but im not so sure those in what I call SE should be as worried as some of them are (Surrey, Kent etc (though they love the 18z). Progression I am sure will be more east than I think...not so many mountains in the way, but at the moment for the eastern edge of our patch (take a coridoor Reading, Basingstoke ish ways....you could be in the sweet spot)...East of that (i.e. where I am) may see less.....west of it....will have seen the glory. 18z however would have us all seeing snow...then rain, mass progression and quick mixing out. Andrew...to answer I think reading is pretty well placed, but it really does depend how well the cold puts up a fight and in saying that, chances are we wont know properly until meto do last minute updates and we sit watching lamp posts...but I suspect some snow is likely...even if it is a dusting...for anyone who views this forum and is central south

Just to think this time tomorrow the NAE will be done for the event (i.e. it will be in our timescale) and we will probably sing the 18z's praises. I dont want to go on amounts, not yet, the METo can do that! My only concern, mixing out, but I think it really unlikely. AS for the 3 tuns, went a couple of times in hols from uni (one of my mates from Pompey lived literally 2 mins from the place), 3rd is good though for a uni quiz, I dont ever remember reaching such dizzy heights...mainly as my head was too dizzy! I wonder how potent this front will be, guessing if it was a rain event brushing through this would give 10-15mm. So 10-15cm of snow assuming a perfect metric conversion...but im thinking sticky dendronite snow may be less likely if it falls through much colder air...so will go with 7-10cm. Also, as a far away interest that pesky low over italy whipping up warmer air in to the mother of the cold over greece, hungary bulgaria bust be giving an absolute pasting to those areas...add some mountain effects too and you can see why powderheads will be wanting bulgaria right now...

Much as we love to bin the 18z, it always bothers me. Its like the morning after a night on the jaeger, you wake up and feel fine, akin to expecting snow by two pm, but by 2 pm, the snow doesnt arrive, then your massively hung over (jaeger says hello) and you remember...ah the 18z that joined me on that drunken trip...thats reared its ugly head too. These warm incursions always get me nervous. Win the pub quiz nick. Three Tuns on the corner of the showcase roundabout? How I love that car park...stuff of nightmares.

Aye the NAE goes slightly west too, comments off the cusp do annoy me though. Just read one. NAE...much further west. Yeah...at one time stamp and how do you define much 50 miles...is pittance at 48 hours...people should think before they speak sometimes. I remember an event...im sure it was the Jan 10 one...when everyone thought the most east a channel low would get was sort of southampton..it made it right across hants, the home counties and onwards in to kent and W london. I am confident this will do the same, amounts of course will vary, but if you take an anomoly as something between the 18z and the NAE, the mean is smack where we are anyway...id be surprised (unless pending a major blow) if any of what id consider central south england didnt see snow.

The 18z shows warmer air mixing out the cooler and it being a snow to rain event from my interpretation...so further west you are liklihood is it may and I emphasis may, change to rain towards Sunday. Still models not doing well on exact strength ot atlantic. But, it is the 18z and seems to be slightly off the marker. Ha, and the 10:35 bbc making it even more confusing by suggesting its going to be more an event which doesnt quite make the extreme SE.

On the posts regarding last years events, Generally, they have both been channel lows although the one which occurred in 2010 (Jan was it??) was much more of a channel low compared to last Decembers (2010) trough which to the best of my understanding kind of came from Wales way. agree with position of the front, Just over reading would be perfect for GTLTW and those west of it. For the whole region of us it needs to be over west london. Im quite optimistic from the battleground, but as a review of my posts would read never a huge fan of raw easterly as the snow never tends to make it this far inland..though love the crisp clear blue. Ill be a bit more informative over next few days as situ unfolds, Meto being bullish though and I am always careful with this. I remember the disappointment we saw when we had something like -5 and a front approach, none of us believed the air would mix out...it did, and fell as rain.

I couldnt agree more with that, the evolution of the ECM post about 120 is markedly different from GFS and key will be which way the ECM goes post that point as it rolls out now the 00z ecm has the high being easily weakened over the UK, the GFS keeps it stronger alowing some blocking and eventually the trend for cooler air to flood in. the fact these two models are in disagreement to me either meand the ECM is over-playing the strength of the lows or the GFS is over-egging the presence of the high over the UK. Remember, just my opinion, I have no doubt that cooler conditions are likely, but I wouldnt be too excited about snow fest and days on end of embedded cold just yet.

Q bar...surely revs trumps that

Im Back, not that I post much, Sungurl, 12z 18z are times models get released z stands for zulu which is GMT time. i.e. 12z means the outputs from the models which are run at 12:00 mid day each day...they appear (once to computers have done their work) from 16:00 to 18:00....at 18:00 they run the model again which begins to appear at between 21:00-22:00. so 12z, 18z, 00z and 06z are the model run times. Some models are done twice a day, such as the UK Met Office, some are done 4 times, such as the GFS. Such to be in the central south, what do I expect in limboland of the M3/M4 corridor, some wet snow perhaps but IF the low pushes through quicker...may get a slight dusting, Bracknell has its high points. Behind on prospects this winter, way behind, though note some of the usual cold enthusiasts are not as up-beat as last year...though to be fair, last year is hard to beat!

Quite a random short burst of an intense storm here, wasnt expecting it either, always a bonus. Mostly clear and sunny now again but some dark counds out west.

I still live in hope though the track shifting gradually makes me think I may well be on the periphery of something good...again. On planes, most airports in SE on Easterly ops which may make tracks look slightly different.

Hope so too, interesting the strength of the westerly around the top of the area of disturbance, amazing amount of development just need to hope it pushed up northerly rather than NNE or NE. Ill check out any reports from Jersey etc.

GTLTW I too hope it continues the due North trend, I remember the pains of a perfect SSW (ish stream) coming up some time back hitting the likes of pompy, guildford, woking, slough, missing us here completely bar the odd rumble. Due north is good, we shall see how it pans out.

Well heard the first rumble at long last, next 30 mins I think will be the best to date...eeerily black sky now

Couldnt agree more. Stuff over IOW at 13:00 I am hoping will give us some action, its bigger and was slightly further west. So painful it has been spitting on and off here for last hour...but not a single rumble

Screwzone = an area that will probably miss it...Im guessing, I fear I also sit in that zone for the time being especially as stains, odiham and farnborough as Robbie says are experiencing T-Storm.

Bracknell is kind of in the firing line yet they break apart coming over the ND and then seem to reform, distinctly darker here though, just heard a huge rumble...nope...just a plane off on the Southampton DP from Heathrow. Swiss 51 Im reckoning

Some specks of rain here, no Thunder I dont think, too bright and the clouds dont look beefy enough. I think south and east of moi is good but also North and East too. I await any rumble but there does seem to be some instability about and boy is it humid

If you lived in Rennes you would be willing it North. I think its a non starter for my part, despite the cloud aloft. Cant even see anything at all occurng overnight, shame as the humidity is awful. Just cant see the development or trajectory coming off, but I would love to eat my hat lol.

You have to hope for a lot of things to go right for those ones from Biscay to make it I think...especially looking at the trajectory of earlier showers today. Urgh, not sure whether to write tonight off just yet...lots of ingrediants in place just no method to make it all go bang it would seem. Shame...

I hear a loud noise and get excited but nope its just the same ridiculously noisy TAM that goes every night to Sao Paulo. Urgh

Publicus...At a stab there appears to be a deinite line between cloud and no cloud here. Out to the west orientated SSW...NNE Id guess hanging over Reading way. Activity from it...zilch...winds SSW-erlies...accoring to a very very unreliable wind vane.

Surrey, agree these cumulus clouds appear to be coming out of nowhere, in Bracknell myself. Sit and wait. The alto-cirrus in the distance seem to be keeping the same. Light diminishing rapidly now so wont see much more.

MB thankyou for your replies. Interestingly with regard to fluvial aspects most of europe looks predominantly dry in the run up to this forecast. In some respects I hope some moisture finds its way to the french alps in any of the setups predicted. Hard and Icy doesnt ring for a good weeks skiing. Nevertheless as RJS will start analysis of charts tomorrow I thought I would take a peek at the GFS ensembles for Shetland. FI starts around the 30th Jan on the models with a scatter on the 1st Feb as being 1005 and 1025 at surface. By the 3rd Feb the scatter in one of the members shoots right down to creare a spread of 972 - 1035. However, only 3 or 4 members take the pressure below 1000 for the forecast period.. Control and mean actually follow reasonably well throught with the operational losing track by about the 30th. Setting the headline start for this forecast with the pressure of 1040mb being centred over ireland (and I have gone on 12:00 on Friday: GFS 18z output puts a high of 1035 in the mid atlantic almost due west of ireland BUT there is generally high pressure influence over the UK with practically the whole of the UK contained within 1020mb. The referred to low pressure at 70n, 20e is appx 975mb (difficult to scale exactly on the GFS maps due to projection distortion). GFZ12z output had the high centred NW of ireland at a strength of 1032 (weather online) and there is a deeper low of appx 964 at 70/20. However, the llatter GFS run trending away. ECM 00z from yesterday in respect of the high and low feature is broadly in agreement with the 12z GFS. But places the low more to the North of 70/20 and is deeper. But, the pressure at 70/20 is appx 965mb. On that very brief brief analysis I would say the forecast of the low is not bad at all. The high appears to be west of the forecast location, but we are still a few days away and all is to play for. Also, as per RJS's suggested scoring. 5mb would not warrant a large inaccuracy. MB, if nothing else, you have provided a very fascinating forum for enthusiasts here with some deeply embedded philosophical debate. This will probably be one of the closely watched forecasts of all time on NW because of its specifics. If its correct, I hope there are no casualties! Right, its time for bed!